Structured abstracts: Volume 6, 1994

Structured Abstracts: Volume 6, 1994. As a service to our readers, we have reprinted all abstracts of original I contributions in 3” X 5” size format to facilitate clipping and filing.

I I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I I

I

L

I

I

I

I I

I

I I

I I

I

I

I

I

I

I

I

I I

L

I

I I

I

I

I

I

I

I

I

I

I

I

I

I I

I

I I

-------------------------------------

Respiratory Effects of Sevoflurane Used in Combination with Nitrous Oxide and Surgical Stimulation Matsuyuki Doi, MD, Tomomi Takahashi, MD, Kazuyuki Ikeda, MD

Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan.

STUDY OBJECTIVE: To evaluate the respiratory effects of sevoflurane anesthesia with and without nitrous oxide (N,O) during surgical stimulation. DESIGN: Randomized study. SETTING: Operating the&r at a university hospital. PATIENTS: IO oatients scheduled for minor head or neck sureerv. INTERVENTIdNS: Sevoflurane anesthesia was administered al&‘or in combination with N,O. After basal measurements were recorded, the following end-tidal anesthetic concentrations were administered: Gro;p I = 1.3 minimum alveolar concentration (MAC) sevoflurane alone: Grotto 2 =0.9 MAC sevoflurane with 0.4 MAC N,O: Grouo 3= 1.5 MAC sevoflurane alone; Gro’“p 4: I.1 MAC sevofl&ne wi;h 0.4 MAC N,O.

., I MEASUREMENTS AND MAIN RESULTS: PaCO,, minute volume (ii,), respiratory rate, tidal volume (V,), percentage of rib cage contribution to tidal volume (%RC), rate of inspiratory time in a breath cycle (T/T,,,,, where T, = inspiratory time and T,,,, = tidal respiratory time), and mean inspired flow (V,/T,) were measured. The substitution of 0.4 MAC N&l for sevoflurane de&ased &CO, and increased v;, with a consequent increase in V, At 1.3 MAC sevoflurane-NrO anesthesia. spontaneous resoiration maintained P&O, at amxooriate levels (42.7 ? 3.6 mmHel. At I.3 MAC sevoflurane .L . “l alone and 1.5 MAC sevoflurane-N,O anesthesia, spontaneous respiration was moderately depressed. Sevoflurane and . XI0 combined did not change %RC or T,/T,..,. CONCLUSION: Sevoflurane administered at an appropriate anesthetic depth maintained spontaneous respiration at acceptable levels during surgical stimulation, especially when combined with N,O.

j. Clin. An&h. 6:14, 1994

-------------------------------------

Bacterial Endocarditk Prophylaxis: What Is Recommended and What Is Practiced? Roy E. Schwartz, MD, FAAP, David A. Lowe, MD, FAAP, FCCM, Stephen A. Stayer, MD, FAAP, Caroline A. Pasquariello, MD, FAAP, Christine M. Schlichting, MD

Department of Anesthesia and Critical Care, St. Christopher’s Hospital for Children, Philadelphia, PA. STUDY OBJECTIVE: To determine how often pediatric anesthesiologists follow the American Heart Association (AHA) recommendations for the administration of prophylactic antibiotics to prevent bacterial endocarditis (BE). DESIGN: Questionnaires mailed to all members of the Society for Pediatric Anesthesia regarding their use of antibiotic7 to prevent BE. SETTING: Anesthesia department at a university-affiliated children’s hospital. MEASUREMENTSAND MAIN RESULTS: 898 questionnaireswere mailed, and 465questionnaireswere returned,yieIding a response rate of 52%. When anesthesiologists administer BE prophylaxis intravenously (Iv), they perform an inhalation anesthetic 76% of the time prior to establishing N access. Ninety percent of the respondents stated that if administration of antibiotics occurs after a mask induction, they do not delay incision or instrumentation for 30 minutes. Therefore, respondents do not follow AHA recommendations for BE prophylaxis 55% of the time. Of the 465 respondents, only 4 recalled pediatric patients who developed perioperative BE. CONCLUSIONS: The majority of anesthesiologists responding to this survey routinely do not follow the current AHA recommendations for BE prophylaxis when caring for children. Since there are no studies demonstrating that administering antibiotics 30 minutes prior to invasive procedures is more effective than administering antibiotics immediately prior to invasive procedures, it may be appropriate to follow a time sequence that is more comfortable and convenient for pediatric patients. We believe that a reconsideration ofthe current AHArecommendationsfor BE prophylaxisiswarranted.

J. Clin. Anesth. 6:5-9, 1994

Effect of Epidural Morphine on Sedation Requirements during Regional Anesthesia Medhat S. Hannallah, MD, FFARCS, Diane J. Mundt, PhD

Department of Anesthesia, Georgetown University Medical Center, Washington, DC.

STUDY OBJECTIVE: To examine the effect of using analgesic doses of epidural morphine on midazolam requirements for conscious sedation during regional anesthesia. DESIGN: Randomized, double-blind, placebocontrolled trial. SETTING: Operating rooms at a university hospital. PATIENTS: 20 ASA physical status II and III patients aged 50 to 70 years undergoing elective peripheral vascular reconstruction with epidural anesthesia. INTERVENTIONS At the beginning of surgery, 10 patients received 3 mg of epidural morphine, and the other 10 patients received normal saline epidurally. AI1 patients received midazolam intravenouslv in bolus doses and as a continuous infusion to maintain a steady state of sedation throughout surgery MEASUREMENTS AND MAIN RESULTS: There was no difference between the dose of midazolam required to maintain sedation in the two groups during the first 3 hours of the study. Beyond the third hour, the midazolam dose required to maintain the same level of sedation was significantly higher in the placebo group titan in the epidural morphine group (p = 0.05). CONCLUSION: An analgesic dose of epidural morphine. after a latent period of 3 hours, may decrease the dose of midazolam required for sedation using regional anesthesia.

/. Clin. An&h. 6:10-13, 1994

7 I

I

I

I

I

I

I

I

I

I

I I I

I

I

I I

I

J

7

I

I I I

I

I

I I

I

I

I

I

I

I

I

I I

I

A

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

L______--______--__-_______--__---_---J 543

Structured Abstracts: Volume 6, I994

_______----__------ ----______-------- i I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

L

i

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

L

I

I

I

I I I I I I I I I I I I I

I

I

I L

Vecuronium Neuromuscular Blockade at the Cricothyroid and Posterior Cricoarytenoid Muscles of the Larynx and at the Adductor Pollicis Muscle in Humans Hiroshi Iwasaki, MD, Motohiko Igarashi, MD, Keiichi Omote, MD, Akiyoshi Namiki, MD

Department of Anesthesiology, Sapporo Medical College and Hospital, Sapporo, Japan

STUDY OBJECTIVE: To compare the wnsitiv’ity to vecuronium ill rhr c rirothyroid ((:Tl and po~rriol c ricoa vlcnmd (PCA) muscles of thr Ia ~nx and the adductor potticis muscles. DESIGN: Prospcctivt. nonrandomized study. SETTING: Oprrating room a~ Sappol-o Medical College and Ho?pitnl. PATIENTS: 9 ASA staws I and II adult parirnts scheduled for total Ia vngc< tom\- LO ~(lw I Iaryrrgc~l ciuicc8 of essrnt~alh umlaterat mvotvemrnt. INTERVENTIONS: Durmg rurgert, elcctromyographic (EMG) trccordillg wrc clew trndrs welt’ uwrtrd mto the (:I nnd t’(:A muscles wth nitrous oxid?, oxygen. and frntanyl anesthesia. The evoked compound EMG responses of the CT alld PC4 muscles were quantified simultaneously in an Identical rnallncr by supr.unnximally stimulating thr sup&or larvngeat and recurrent nerve> at 0.1 Hz and 0.2 millisecond. The ulnar nerve also was stimula&, and the adduction tot-<r of

Spinal Anesthesia Using a 1: 1 Mixture of Bupivacaine and Tetracaine for Peripheral Vascular Surgery Brain H. Hoff, MD, SimonJ. Fletcher, MD, W. J eremy Rickford, MD, M. Jane Matjasko, MD

Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD.

\TUDY OBJECTIVE: I+rsrnt our preliminary erpcnencc using rhrrc rqwl dose\ <,I .i mxtu~ 01 I’% wuncnulc and 0.75% bupivacainc in 8.25% drxtrox for spinal anesthesia 111 patients uudcrgoing pcl-iphcrat wsmlar mrgrr L. SE’ITING: Opelatiug and ~ccovcrv rooms at a univrrsi~y mrdlral renw~ P,4TIENTS: 60 patients who rr<ri\rd femoral poptiteat or Iemoral chstal bypar, wth \pulrd alcsthtw.t. INTERVENTION% All patirnts had intravenous cannutar inscrtrd alld rrtriwd laruted Ringer’, wtulion. IXr! I‘ wrc no holus infusions of fluid prranesthesia. Fluid admimstrarion occurred at a law of 8 fu I5 mt/kg/hr. with additional fluid and inotropic drugs adminisrered LO treat hypotension Oxygen (0,) was drliwrrd 14 nasal cannula. and peripheral 0, saturation was monitored. Blood prrssue (BP) was monitored cvc!w 1 to .5 rnitluw\ using a1 aulonratic BP drwrc. and ECG was displayed (ontinually. MFASUREMENTSAND MAIS RESULTS: Initially, 8 patients rrceibrd .a dose of Ii mg of each dl ug cornbllled wth 0.2 mg <,I epinephriur injrcrrd in a Z&degree head-up tilt. Subsequent paticllts received I2 mg of each dl-ug nrlxed with 0.2 mg 01 wmephrine for cases in which an extended duration was medictrd and 10 me of each drue ulus eoineohrinr for maximal lfrst-&me bypasses. With mixtures of 15 mg, I2 mg, and Id mg of each drug pK,s epinrphr;;;. a m&an &ration oiapproxl- matcly 300 minutes of surgicatfy acceptable anesthesia was obtamrd. As the do3e was dccl-card, thr SD increased. There wa a 0% failure raw for Ihe spmnl anesthetics at doses of 15 mg and 12 mg ofcarh drug and a 19.5Yo failure raw a a dose ol 10 mg of each drug. In each case, the rapid onset of a sensory btockadc regressed in ;k standard and prrdictablr fashion The decline in BP and thr use of inotrooic and vasoconstrictive drues were comoarabtr to those !n mcvioush oublishrd

1. Clin. Anestll. 6: 18-22, 1994

Intravenous Ketorolac as an Adjunct to Patient-Controlled Analgesia (PCA) for Management of Postgynecologic Surgical Pain Ferne B. Sevarino, MD, Raymond S. Sinatra, MD, PhD, Darcy Paige, RN, MSA, David G. Silverman, MD

Department of Anesthesiology, Yale University School of Medicine, New Haven. CT. STI!DY OBJECTIVE: ‘Iir detrrminr whether ineavenous (IX’) doses of kerorolac womrthnmmr probid? sale and rflccti\r augmentafion of postsurgical analgesia for patients using IV patient-controlled analgesia (PCA) with morphine. DESIGN: Randomized, double-bhnd, placebo-controlled, dose-response evaluation. SETTING: Patient care unit al a university medical center. PATIENTS: 62 ASA physical stams I-III females recovermg from inlra-abdominal gvnecotogic surgerv wth gcnernt anesthesia who requested postoperative PCA. INTERVENTIONS: Following initial pain aeessment in rhe lecorcry !oom, pnucnts were rnndomucd to receive ather IV sahne (placebo) followed by IV saline every 6 hours (Group I); IV ketorotac 30 mg loading dose followed by IV krrorolac 1.5 mg rvcry 6 hours (Group 2); or N ketorolac 60 mg loading dose followed by N ketorolac 30 mg wery 6 hours (Group 3). All patient\ were provided N PC& which was programmed to provid? I.2 mg of morphine with a 6 minute lockout interval. MEASUREMENTS AND MAIN RESULTS: Visual analog scale (VAS) rrstmg pain and satisfaction scows wcrc mcasw ed tvrry 2 to 12 hours. Cumulativr PCA with morphine and thr frequencv and severity of side effecu also war arsessed. I\’ ketorotac showed no clinically significant side effects. Group 2 patients exp&xced wgnificant reductions in VAS lesting pain scores (p c 0.05), and a trend toward decreased morphine self-admirlistriltio,l in both active groups was Iloted. Group 2 and (:roup 3 patwnts reported greater satisfaction wth postsurgical anatgwia than CI-oop 1 patirurs. (/I < 0.05). CONCLUSIONS: I!’ kerorolac used as an analgex adjunct prowdrd salt and Fffcrlivc augmrnrarirur of P(:A Mill, rncxphine in pa&mu recovering from intra-abdominal gynecologic wrgc’ru.

j. Clin. An&h. 6:23-27, 1994 _____---------_----------------------

544 J. Clin. Anesth., vol. 6, November/December 1994

Structured Abstracts: Volume 6, 1994

-

Management of Tracheobronchial and Esophageal Foreign Bodies in Children: A Survey Study Zeev N. Kain, MD, Theresa Z. O’Connor, PhD, Charles B. Berde, MD, PhD

Departments of Anesthesiology and Pediatrics, Yale University School of Medicine, and Yale- New Haven Hospital, New Haven, CT; Department ofAnesthesia, Children’s Hospital, Boston; Department of Anaesthesia, Harvard Medical School, Boston, MA.

STUDY OBJECTIVE: To assess the current anesthetic management for aspiration of a foreign body into the airway and esoohaeus of a YOUW child.

Ly ,

DESIGN: Questionn&e study. MEASUREMENTS AND MAIN RESULTS: A questionnaire regarding choice of induction technique in a variety of foreign body clinical scenarios was sent to 1,342 anesthesiologists, all members of the Society for Pediavic Anesthesia. The foreign body, either a coin (penny) or a safety pin (open), was positioned on radiography in a variety of anatomic locations. De- pending on the foreign body location, the patient was either asymptomatic or exhibited symptoms. Participants indicated their choice of induction for each situation. Of the 1,342 questionnaires mailed, there were 838 respondents (62.4%). Coins and pins in the gastroesophageal tract were managed mostly by a rapid-sequence induction (p< 0.001). Coins and pins at all levels in the tracheobronchial tree were managed most often by a mask induction with no cricoid pressure (p< 0.001). Although 14.5% of respondents chose awake and sedated technique for a foreign body in the supraglottic area, few chose this technique for a foreign body in other locations. The type of object did not affect the choice of drugs for induction of anesthesia in most anatomic locations. Respondents with limited pediatric anesthesia experience used inhalation induction much less often than did those with more experience. Multiple-logistic regression analysis showed that both number ofyears in practice and type of practice (university, private, hybrid) were predictors for the induction. CONCLUSIONS: Inhalation induction is favored for removal of foreign bodies in the airway, while intravenous induction is preferred for removal of foreign bodies in the gastroesophageal tract. In addition, practice type. time spent in pediatric anesthesia, and greater experience are related to a higher likelihood of inhalation induction.

J Clin. Anesth. 6:28-32, 1994 ------------------------------------- J

Cervical Radiculopathy Treated by Infusion of Epidural Analgesics in Homebound Patients J. Antonio Aldrete, MD, MS, Carol A. Brown, RN, Kristy L. Yarcho, RN

:

Center for Pain Management, Destin, FL. I STUDY OBJECTIVE: To determine the efficacy and safety of administering low-dose analgesic infusions through cervical 1 epidural catheters. DESIGN: Retrospective review of medical records. I SETTING: Community hospital. PATIENTS: 14 ambulatorv adult Datients with chronic cervical radicuhmathv due to mxttraumatic or osteoarthritic

I J , . /

degenerative disk disease persisting after steroid epidural blocks. I INTERVENTIONS: 42 catheters were inserted into the cervical epidural space and infused with low-dose fentanyl- bupivacaine mixtures continuously for 2 to 17 days. To prevent side effects, the optimal dose was reached by upgrade

,

adjustments. After catheter insertion, patienu were observed for 6 to 21 days for dose adjustment, then discharged home I and followed by home-care nurses. After removal of catheters, patients were followed for 8 to 10 days. If pain intensity returned to control levels, other treatment was initiated. MEASUREMENTS AND MAIN RESULTS: After each catheter treatment, pain intensity was reduced in 79% of the cases. 1 Upon completion of the therapy, 5 patients had 50% to 75% of their pain reduced. Eight patients experienced 75% or more reduction of their original pain. The most common complications were nausea (35.7%) and pruritus (27%). One 1 case of cellulitis was treated with antibiotics. There were no instances of respiratory compromise. CONCLUSIONS: Patients with chronic persistent cervical radiculopathy pain were effectively treated with infusion of

I analgesics through epidural catheters for 2 to 17 days while they were at home. I

J. Clin. Anesth. 6:33-36, 1994 I

I

____-___--__-------___--__--__------- J _--_------_____--________________--__- Radiation Exposure of Anesthesiologists Kristine H. Henderson, MD, Jeffrey K. Lu, MD, Keith J. Strauss, MS, S.T. Treves, MD, Mark A. Rockoff, MD

Departments of Anesthesia and Radiology, Children’s Hospital Medical Center, and Department of Anaesthesia, Harvard Medical School, Boston, MA.

STUDY OBJECTIVE: To determine the level of radiation exposure of anesthesiologists in the operating rooms and cardiac catheterization laboratory. DESIGN: Prospective study of all anesthesia fellows. SElTING: Operating rooms (ORs) and radiology department of a tertiary care pediatric hospital. SUBJECTS: Anesthesiologists caring for patients in a pediatric hospital requiring anesthesia or monitored anesthesia care. (Patients were not directly studied.) MEASUREMENTS AND MAIN RESULTS: Anesthesiologists wore standard radiation safety film badges, which were sensitive to cumulative doses of radiation greater than 10 mrem. In the ORs, anesthesiologists were exposed to less than 10 mrem/mon. In the cardiac catheterization laboratory, they had d&metric readings that ranged from 20 to 180 mrem/mon and frequently exceeded the guidelines for nonradiation workers. CONCLUSIONS: There is no need for routine dosimevic monitoring of anesthesiologists working in the OR setting, since this is associated with negligible radiation exposure. Monitoring of radiation iilm badges should be considered for anesthesiologists who frequently work in fluoroscopy areas, such as the cardiac catheterization laboratory. All personnel working near radiation sources should wear appropriate shielding and, whenever patient safety permits, distance them- selves as far as possible from the source of radiation.

J Clin. Anesth. 6137-41, 1994

L____--______----___---____----___---_J

J. Clin. Anesth., vol. 6, November/December 1994 545

Structured Abstracts: Volume 6. 1994

r I

I

I

I

I

I

I

I

I

I

I I

I

I I

I

I I L

i-

I

I

I

I

I I I

I

I

I

I

I I I

I I

I

I

L

i

I

I

I

I

I

I I

I

I

I

I

I I

I

I I

I I

L

_______--___--_-------------- ---_---- The Frequency of Postdural Puncture Headache in Obstetric Patients: A Prospective Study Comparing the 24Gauge versus the 22-Gauge Sprotte Needle Daniel H. Sears, MD, Michael I. Leeman, MD, Loren J. Jassy, MD, Laura A. O’Donnell, MD, Stephanie G. Allen, RN, L,aurence S. Reisner, MD

Department of Anesthesiology, Mercy Hospital and Medical Center, San Diego, CL4, Department of Anesthesiology, Scripps Memorial Hospital, Chula Vista, CA, Department of Anesthesiology, Sharp Memorial Hospital, San Diego, CA, Department of Anesthesiology, University of California, San Diego Medical Center, San Diego, CA.

STUDY OBJECTIVE: To compare thr frequency of postdural pwlcture hcadachc (PDPH) m obstetr~ patients whrrr using the 24+uge or the larger 22-gauge Sprotte needle. DESIGN: Prospective, randomized study. SETTING: Four hospitals. PATIENTS: 375 ASA physical status I aud II cesarean section and postpartum tubal ligdfion patients. INTERVENTIONS: Obstetric patients were randomly assigned to r~c~ivt spinal anesthesia via a midline dural puncture using the 24-gauge or the 22gauge Sprotte needle. MEASUREMENTS AND MAIN RESULTS: The rate of PDPH was deter mined by a pcntoperative visit by the anrstheslologist as well as questioning patients by telephone 1 week or more after discharge. In the 24gduge Sprotte needle group (II = I&), 2 mild and 1 moderate PDPHs were reported, for an overall rate of 1.61% In the 22gauge Sprotte needlr group (n = 189), 2 mild and 1 moderate PDPHs were reported, for an overall raw nf 1..59%. All headaches except I resolved within 72 hours with conservative treatment. One patient from the 22gauge Sprotte needle group required an epidural blood patch. There were no failed blocks in either group. CONCLUSIONS: Our results suggest that the 22gauge Sprotte needle, whrn compdrcd with thr smaller 24gaugc Sprottc Ileedle, ran be used in obstetric patients without increasing the frrquenrv of PDPH.

J. Clin. Anesth. 6:42-46, lYY4 _--__----__----_---------------------

Intercostal Nerve Block for Lumpectomy: Superior Postoperative Pain Relief with Bupivacaine Peter G. Atanassoff, MD, Eli Alon, MD, Branko M. Weiss, MD Department of-Anesthesiology, University Hospital of Ziirich, Ziirich, Switzerland. STUDYOBJECTIVES: Arc equipotrnt doses of lidocainr and bupirarainr equally effcctivc for intrrcortal nerve blockade (ICNB), whether a lower amount of lidocaine would be comparablv effective. and whether plasma levels of lidocainr with and without epinephrine ald of plain bupiracainr woud reach toxic ranges. Finally, d evaluate the duration of postoperative analgesia following general anesthesia and regional anesthesia with two different local anesthetics. DESIGN: Randomized. double-blind study, with control group admmwrrrd general anesthrsia. SElTING: Gynecologic operating room of a university hospital. PATIENTS: 48 adult ASA physical status I and II otherwise health) patients undergomg lumpectom\~. INTERVENTIONS: 36 patients received ICNB of T,-T,, unilaterally using either 4 ml/segment of 1.5W bdocaiur with epinephrine 3.75 ~g/ml (II = 10, Group A). 4 ml/segment of 2% lidocaine with cpinephrine .i pg/ml (n = 13, Group B), or 4 ml/serment of plain 0.5% bupivardinr (n = 13, Group C). 12 patients (Group D) received a general anrsthetic using propofo[ alfen&il, and tlarous oxide in oxygen for induction a’nd mainten& of anesthesia”(control group). ‘MEASUREMENTS AND MAIN RESUI.TS: In all three ICNB B~OUDS. the hiehest olasma concentrations were reached aftrr 5 to 10 mmuws following ICNB--l.e., a lidocaine plasma level of 2.77 _ 0.5 fig/ml c * (mean + SEM) in Group A. a bdocdirrc plasma levrl of 2.78 ? 0.2 pg/ml in Group B, and a bupivacairre plasma levrl of 1.44 ? 0.2 &g/ml in Group t:. There were no significant diflerences in plasma levels betwcnl 1.5% lidocaine and 2% lidocaine. For the first 90 minutes after surgery, higher postoperative pain scores were found ill the control group than in thr ICNB groups. Longer-lasting postoperative pain reliefwas achieved with plain bupivacainc The number requiring postoperative analgesic medication, the time of first rrquest, and the total amount of analgesic drugs during the 24 hours postoperatively were signiticantly lowrr in the regional anesthesia groups than in the general anesthesia group (p c 0.05). CONCLUSIONS: ICNB is an alternative to general anesthesia for female breast surgery. Both lidocdiw wth epincphrinc and plain bupivdcaine did not raise v~rmub plasma concentratiorls to potentiallv toxic Irvcls. Duration of postoperative f,airl relief and analgr,ir drug request werr better with local anesthesia.

J. Clin. Anesth. 6:47-51, 1994 __-I

Metal Anesthesia Circuit Components Stop the Progression of Laser Fiis Mitchel B. Sosis, MD, PhD, Berton Braverman, PhD

I Department of Anesthesiology, Rush-Presbyterian-St. Luke’s Medical Center, Chicago, IL. , STUDY OBJECTWt.: To determine whrthrr metallic Y-pieces and elbow would halt the progression of a laser-induced rndotracheal tube fire.

1

DESIGN: A segment of po!pirryl chlonde cndutrdcheal tube was attached to rithrl an all-plastic anesthesia circle brrathmg I wstem (II = 5) or a circuit consisting of a metal Y-piece and elbow with plastic hoses (n = 5). In each case, an Nd-YAG laser was used to ignitr thr rndotracheal tube segment and attached anesthrsia circuit as 5 L/min of oxygen was flowing

l

through them. I SETTING: Research laboratory of a nnwersity-affiliated metropolitan medical centrr. MEASUREMENTS AND MAIN RESULTS: The flames from the rndotracheal tubes burned through the 22 mm hoses ’ that were part of the all-plastic cilcuit3 in 49.5 ? 8.8 seconds (mean i SD). In none of the trials wth the metal I components did the tire advance beyond the endotracheal tube‘s 15 mm adapta. (CONCLUSIONS: Metal circuit rompotrents halt the progression of laser-induced rudouachcal tube firm t~wnrd the I arrcsthesia machinr.

J. Clin. An&h. 6:52-54, 1994 I

-___-----------_____---___----_--____J



--------------_--__-------------------

Infusion of Large Particles of Tbiopental Sodium during Anesthesia Induction I

Usha L. Mahisekar, MD, Clair M. Callan, MD, Manjul Derasari, MD, Anthony F. Kirkpatrick, ’ MD, PhD I

Department of Anesthesiology, University of South Florida College of Medicine, Tampa, FL; Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL.

I

I STUDY OBJECTIVE: To determine the potential clinical significance of admixtures of thiopental sodium and acidic drugs, which are used during induction of general anesthesia and can cause the formation of particles of thiopental. 1 DESIGN: Using an infusion setup similar to that used for a rapid-sequence induction of general anesthesia, injection of either pancuronium bromide or vecuronium bromide caused formation of particles of thiopental that were measured

1 using a particle analyzer. The effects of delaying the injection of the muscle relaxant on particle formation and the I effects of plasma on particle dissolution were studied. MEASUREMENTSAND MAIN RESULTS: The thiopental particles had adiameterof 17 to 39 microns, with a concentration ’ of 15,000 to 20,000 particles/ml. Particle formation was prevented when a S&second delay preceded administration of I pancuronium or vecuronium following injection of thiopental. No particle formation was detected when succinylcholine was injected. Human plasma was far more effective than a crystalloid solution in dissolving thiopental particles. CONCLUSIONS: It is unlikely that clinically significant particles of thiopental will remain intact upon entering the I bloodstream. However, mixing thiopental with pancuronium or vecuronium has the potential of disrupting intravenous access due to occlusion with particles.

J. Clin. Anesth. 6:55-58, 1994

------------------------- ------------ -I ----------------------------- _--------

Epidural Morphine with Butorphanol in Pediatric Patients I

C. David Lawhorn, MD, Raeford E. Brown, Jr., MD I

I Division of Pediatric Anesthesia, Arkansas Children’s Hospital, Little Rock, AR.

I

STUDY OBJECTIVE: To determine whether the addition of butorphanol to epidural morphine is effective in reducing I the frequency of side effects caused by neuraxial opioids. DESIGN: Randomized, double-blind study. I SETTING: Large tertiary care pediatric hospital. PATIENTS: 20 children between the ages of 2 and 17 years undergoing spinal, abdominal, or thoracic procedures.

I INTERVENTIONSz Patients were divided randomly into one of two groups to receive either 80 pg/kg of preservative- 1 free epidural morphine (Group 1) or 80 pg/kg of preservative-free epidural morphine with 40 pg/kg of butorphanol (Group 2).

, MEASUREMENTS AND MAIN RESULTS: Blood pressure, heart rate, respiratory rate, and the first need for additional I opioids were monitored in the two groups. In addition, pruritus, nausea and vomiting, and supplemental oxygen (0,) required to maintain oxygen saturation (SpO,) above 90% were monitored. Children who received butorphanol in

,

addition to epidural morphine were much less likely to develop pruritus or nausea and vomiting or to require supplemental I 0, to maintain SpO, above 90%. CONCLUSION: Butorphanol 40 pg/kg added to epidural morphine 80 (rg/kg is effective in decreasing the occurrence 1 of side effects caused by neuraxial opioids in pediatric patients. I

J Clin. Anesth. 6:91-94, 1994 I

I

----__-_______ ----___-_________ ------ J ----------- ----___________ _-----____--

Dissociation of Mixed Venous Oxygen Saturation and Cardiac Index during Opioid Induction Pietro Colonna-Romano, MD, Jan C. Horrow, MD

I

I Department of Anesthesiology, Hahnemann University, Philadelphia, PA. I

STUDY OBJECTIVEz_To evaluate the independent effects of opioid induction and paralysis on changes in mixed venous I oxygen saturation (SvO,). DESIGN: Prospective, with each patient serving as his or her own control. I

SETTING: Cardiac operating rooms of a major U.S. teaching hospital. PATIENTS: 15 elective patients for aortocoronary bypass graft surgery.

I

INTERVENTION% Prior to induction with sufentanil 2 to 3 kg/kg (t)), after recovery from succinylcholine 1 to 1.5 1 mg/kg ( tP) , and after subsequent paralysis with vecuronium .( ts), we recorded cardiac index (CI), arterial oxygen saturation (SaO,) , and SirO%, then calculated oxygen consumption (VO,) and arterial oxygen content (C.0,).

,

MEASUREMENTS AND MAIN RESULTS: SK& increased from 75% at t, to 82% at ty (p = 0.03) and to 83% at 4 I (p = 0.006). CI decreased from 3.1 L/min/m’.at t, to 2.5 L/min/mz at tz (p = 0.023) and to 2.1 L/mitt/m2 at t? (t, vs. t,, p = 0.019; ts vs. tr, p = NS). Calculated VO, decreased from 2.88 ml O,/min/kg at t, to 2.09 ml O,/min/kg at ’

(p = 0.03) and to 1.87 ml O,/min/kg at t? (t, vs. ts, p = 2002; ty us. ts, p = 0.027). C O2 remained unchanged. I

CONCLUSIONS: Opioid anesthesia, not paralysis, increases SK),. Most of the decreasesin VO, occurs from anesthesia, 1 not paralysis. The direct relationship between CI and SQO, no longer holds upon induction of anesthesia. Parallel changes 1 in CI cannot be inferred based on SqOy alone.

I

J C&z. Anesth. 6:95-98, 1994 I

L___________-____---__----------------A



r I

I

I

I

I

I

I

I

I

I

I

I

I

I

I I

I

I

L

I

I

I

I

I

I

I I

I

I I

I

I

I I

I

I

I

I

L

i-

I

I

I I I I

I

I I I

I

I I

I I I

I

I

L

_--- Effect of Nicardipine and Diltiazem on Internal Carotid Artery Blood Flow Velocity and

I

Local Cerebral Blood Flow during Cerebral Aneurysm Surgery for Subarachnoid Hemorrhage ’ Kazuo Abe, MD, Hideaki Iwanaga, MD, Eiichi Inada, MD I

Department of Anesthesia and Department of Surgery, Osaka Police Hospital, Osaka, Japan; Department of Anesthesia, Teikyo University Hospital, Tokyo, Japan.

I

I STUDY OBJE(:TIVE: To determine thr hemodynamic effertc of a bolus m~ect~on of nicardipmc 1 mg 01 diltiarem 5 mg on local cerebral blood flow (LCBF) and internal carotid blood flow velocity (ICBFV) with isofluranc anesthesia. DESIGN: Randomized study. SETTING: Inpatient neurosurgery and anesthesia clinic at a cl5 hospltal.

I PATIENTS: 26 patients with suharachnoid hemorrhage who were scheduled for cerebral aneurysm clipplng. I INTERVENTIONS A holus iniection of either nicardiDine or diltiazem was administered to patieno whose systolic blood I pressure increased to over 156 mmHg after opening hf the dura. MEASUREMENTS AND MAIN RESULTS: After the holus injection, both drugs rapldl) drcrrascd arterial blood pressure Nicardipine increasrd LCBF [before iniection, 42.1 + 12.3 m1/100 a/min; after in&don, 47 + 10.7 m!/lOOn/min (p < 0.65 us. control); after recorrry, k.4 -t 11.1 cm/set], but dil~azem did not”change LCBF. Nlcardipine 1 mg moderatelv increased ICBFV [before iniection. 14.2 + 9.3 cm/xx: after iniection. 40.6 -C 8.7 cm/xc (6 c 0.01 UI

I ;1 (ontrol); after recovery. 34.1 i 8.9 cm/xc], hut diltiazem did not change I?BFV. In addition. venous parual oxyger pressure and saturation of the intrrnal jugular did not changr throughout the study. There was a rlosr correlatior hrtwcen presurglcal neurologic status and LCBF (rs = -0.743; p < 0.01) and ICBFV (rs = -0.721: p < 0.01). CONCLUSIONS: Nicardipine increased LCBF and ICBFV, but dihiazem did not changr either. These result suggest that both drugs are usrful and safe for the treatment of intraoperativr hypertension during cerebral aneurysm wrgerv.

1. Clin. An&h. 6:99-105, 1994

-----_------_------------------------ The Effect of d-tubocurarin e Priming on an ED,, Dose of Vecuronium Bromide Rafael V. Miguel, MD, Ivan K. Barlow, MD, Diane L. Dombrowski, BS

Department of Anesthesiology, University of South Florida College of Medicine, Tampa, FL.

STUDY OBJECTIVE: To cxamme how priming with ED,,, d-tuhocurarine prior to the administration of ED.,; vecurouiwx hromide affects onset and duration of nruromuscular blockade. DESIGN: Prospective, randomized, observer-blinded study. SETTING: Operating room at a university cancer center. PATIENTS: 40 ASA physical status 1 and 11 patients undergoing ambulatory wrgical procedures. INTERVENTIONS Patients were randomized to one of two groups. Group I patients received d-tuhocurarinr 50 pg/ kg intravenously (IV), followed by vecuronium 60 Fg/kg N. Group 2 patients received vecuronium 60 wg/kg N without priming. All patxnts rrrei\ed a total N anesthetic consisting of alfcntanil and propofol for induction of anrsthesia and propofol alone for maintenance of anesthesia. MFASUREMENTS .4ND MAIN RESULTS: Onset of muscle relaxation wa dcterminrd with an electromyograph (Data Relaxograph), docunwnting time to 80% depression of the first twitch in a train-of-four (T,80%), percent depression of T, at 60 and 90 seconds (T,60 and T,90, respectively), T,:T, ratio at 90 seconds, and time to achieve maximal hlockadr (B.,,.). Recovery was evaluated by measuring the time required for return of T, to 25% of the baseline value. lntubating conditions were assessed at 90 seconds after vecuronium administration and graded on a 1 (jaw tight, impossible to intuhate) to 4 (jaw relaxed, vocal cords immobile) scale. All criteria measuring onset of neuromuscular blockade (IX. T,SO%, T,60, T,90, T,:T,, and B,,.,,) were sirniiicantlv shorter (0~ 0.05) in patients who rrceived d-tuhocurarine. Recovery was similar in both groups. h~tuhation &es were’signiticanily better 9d seconds after priming (p < 0.05). CONCLUSIONS: These results indicate that crossover dosinr of nondeoolariaine muxle ~relaxants mav have svnereistic - ‘1 , I /7 effects. Priming with ED,,, d-tubocurarine prior to an ED,, dose of vrcuronium shortens the time to 80% T, depression and produces satisfactory intuhating conditions at 90 seconds, without prolonging thr duration of the block. Thrrcforr. d-tubocurarinr is an attractive drug for primingvecuronium in short operative procedurrr that require muscle rrlaxation.

,/. Clin. An&h. Ii:106109, 1994 ----__-------------------------------

Intravenous Ketorolac as an Adjuvant to Pediatric Patient-Controlled Analgesia with Morphine Thomas R. Vetter, MD, Elizabeth J. Heiner, MSN

Department of Anesthesiology, Children’s Hospital Medical Center of Akron, Akron, OH. STUDY OBJECTIVE: li, assess the effects of a single intraoperativr do-r of intrd\amus (N) kctorolac on postoperatwe rrpioid dose requirements, quality of analgesia as assessed by the patient, and frequency of opioid-related side effects during pediatric patient-controlled analgesia (PCA) with morphine. DESIGN: Prospective, randomized, double-blind study. SETTING: Operating rooms, postanesthesia care unit (PACU). and inpaurnt care units of n freestanding childrrn‘s hospital. PATIENTS: 50 ASA physical status I-II orthopedic surgical patients ages 8 to 16 years. INTERVENTIONS: Either 0.8 mg/kg of N ketorolac or no additional analgesic was administered at the time of wound closure. After surgery, all patients were placed on PC4 with morphine. MEASUREMENTS AND MAIN RESULTS: Individual morphine use during the first 12 hours of PCA therapy was rrcorded. A visual analog scale (VAS) pain score was obtained from the patient at the time of discharge from the PACU and at 4, 8, and 12 hours postoperatively. Any vomiting, pruritis, or urinary retention occurring during the first 12 postoperative hours was noted. The morphine plus ketorolac group administered significantly less PCA with morphine during the first 12 postoperative hours than did the morphine only group (p = 0.002). The morphme plus ketorolac group also reported signdicantly lower overall VAS pain scores (p < 0.01). Although similar frequencies of vomiting and pruritis were observed, the morphine plus kctorolx group experienced significantly less urinary retention than did th? morphine group (p = 0.02). CONCLUSIONS: A single intraoperative dose of N ketorolac appears to he opioid dose sparing, to provide superior analgesia, and to decrease the frequency of urinary retention during the first 12 hours of postoperative pediatric PC4 with morphine.

/. Clin. An&h. 6:110-l 13, 1994

--___----------------------_---------


Calcium Channel Blockers Do Not Enhance Increases in Plasma Potassium after Succinylcholine in Humans G. Alec Rooke, MD, PhD, Peter R. Freud, MD, Jeff Tomlin, MD

Department of Anesthesiology, University of Washington School of Medicine, and Anesthesiology Service, Veterans Affairs Medical Center, Seattle, WA.

STUDY OBJECTIVE: To determine whether chronic calcium channel blocker therapy exaggerates the rise in plasma potassium concentration ([K’]) after succinylcholine administration. DESIGN: Prospective clinical study. SETTING: University and Veterans Affairs hospitals. PATIENTS: 36 ASA physical status III and IV male patients: 21 patients taking chronic calcium channel blockers and 15 patients not receiving calcium channel blockers, all of whom were scheduled for inpatient surgical procedures with general anesthesia. INTERVENTIONS: In all patients, anesthesia was induced with high-dose opioids plus a sedative-hypnotic, and intubation was facilitated with 1 to 1.5 mrr/kn succinvlcholine without nondeoolarizine neuromuscular blocker oretreatment. MEASUREMENTSAND MAI<RE?XJLTS: plasma [K+] was mea&d prior to induction and 1, 3,5,8, il, and 15 minutes after succinylcholine was administered. A modest average peak rise of 0.5 mEq/L in plasma [K’] was observed, but there were no differences between patients who were or were not receiving calcium channel blockers. CONCLUSIONS: Patients receiving chronic calcium channel blocker therapy are at no greater risk of hyperkalemia after succinylcholine than those not taking such medications.

,J Clin. An&h. 6:114-118, 1994

---_---_----------------------------- Acute Effects of Sucralfate Aspiration: Clinical and Laboratory Observations Kenneth E. Shepherd, MD, Charles S. Faulkner, MD, James C. Leiter, MD

Department of Anesthesia, Massachusetts General Hospital, Boston, MA, Department of Clinical Pathology, Department of Physiology, and Department of Medicine, Dartmouth Medical School, Lebanon, NH.

STUDY OBJECTIVE: To assess the complications associated with the aspiration of sucralfate. DESIGN: Clinical (case report) and bench observations. SETTING: Inpatient intensive care unit and experimental animal laboratory. SUBJECTS: The case of a critically ill patient who aspirated sucralfate is presented. Fifteen SpragucDawley rats served as experimental animals to investigate the acute histologic effects of large-volume aspiration of sucralfate. INTERVENTIONS: The patient underwent emergent intubation to relieve acute upper airway obstruction. All the animals were anesthetized and had tncheostomies performed. The experimental groups had acidic intratracheal injections of 2 ml/kg of a nonparticulate liquid (pH, 2.3; II = 6) or a sucralfate aspirate (1 ml/kg of a 5% sucralfate suspension of pH 3.6, followed by 1 ml/kg 0.1 of normal hydrochloric acid of pH 1.0; n = 4). Four hours after simulated aspiration, the rats were sacrificed and their lungs removed for histologic examination by light microscopy. MEASUREMENTS AND MAIN RESULTS: Differences were noted in histopathologic injury in the experimental groups compared to the control group using a numeric scoring scale. Nonparticulate acidic liquid aspiration caused a significant increase (p< 0.05) in inflammation. Sucralfate caused a significant increase (p< 0.05) in lung hemorrhage. A nonsignificant trend was seen with simulated sucralfate aspiration for edema and inflammatmn. No long-term sequelae were attributed to the clinical aspiration episode. CONCLUSIONS: Acute complications associated with aspiration of sucralfate have been identified. In the laboratory setting, simulated aspiration of sucralfate led to acute lung injury.

1. Clin. Anesth. 6119-123, 1994

__-__--__--_--------___-___--__--__-- _--_----------------__--__---_---_--- Anesthetic-Postoperative Morphine Regimens for Cesarean Section and Postoperative Oxygen Saturation Monitored by a Telemetric Pulse Oximetry Network for 24 Continuous Hours Peter H. Pan, MSEE, MD, Christopher F. James, MD

Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL.

STUDY OBJECTIVE: To document the effects of compromised respiratory function on oxygen saturation (SpO,) after cesarean section via the telemetric pulse oximetry network (TPON) for 24 continuous hours. DESIGN: Prospective study. SETTING: Postpartum ward of a university hospital. PATIENTS: ASA physical status I or II parturients undergoing cesarean section. INTERVENTION% Healthv !xrturients were assigned to 1 of 3 anesthetic-postoperative morphine regimens as follows: general anesthesia-parent~rH1 morphine as nee&ed (GA/PM; n = 11); &pidu;al anesthesia-parent&al morphine as needed (m/PM; n = 15); epidural anesthesia-epidural morphine 4 to 5 mg @A/EM; n = 10). MEASUREMENTS AND MAIN RESULTS: For 24 continuous hours after cesarean section, SpO,, heart rate, and plethysmo gram every 10 seconds were recorded by the TPON computer. In addition, pain, somnolence, respiratory rate(RRj, and side effects were recorded evew 30 minutes to 2 hours. SDO, less than 94% and less than 92% occurred least with GA/PM. The highest mean cumulative time of SpOp between 95%‘anh 901 o occurred with F.A/EM. The longest episode of SpO, less than 92% and the lowest SpOp for more than 1 minute also occurred with EA/EM. With all 3 regimens, SpOy decreased to less than 80% for 20 to 30 seconds at a time. Average RRwas within normal limits, but mean RR was significantly lower with EA/EM than with GA/PM or EA/PM from the 8th to the 14th postoperative hours. Somnolence did not differ significantly amone the 3 reeimens. Pain score was sienificantlv lower with EA/EM than with GA/PM or F.A/PM for the first 20 hours. CONdIJSIO& All 3 regimens risked&w SpO,:with the EA/EM regimen having the highest risk but the best analgesia. Neither general nor epidural anesthesia combined with postoperative parenteral morphine influenced SpO, postoperatively. In this study, the TPON provided a feasible method of detecting hypoxemia early on in the general ward setting.

J Clin. An&h. 6:124-128, 1994 _--_---------------------- --_--------


7 I

I

I

I

I

I

I

I

I I

I I I I I I

I

I _I

7 I

I

I

I

I

I

I

I

I

I I

I I

I

I I

I

I J

-i I

I

I

I

I I I

I

I

I

I

I

I

I

I I

I I

J



____-____-__-_--_----------------- --_- I

I

I

I

I

I

I

I

I

I

I

I

I

I I

I I

I

I

L

r

I

I

I

I

I

I

I I

I I

I I

I I

I I

I

I L

I I

I I

I

I I

I

I I

I I I I I I

I I I

L

Market Costs of Short-Term Physician and N- Anesthesia Services Robert E. Johnstone, MD

Department of Anesthesiology, West Virginia University, Morgantown, WV.

STUDY OBJECTIVE. To estimate the market cosls of short-term physician and ccrtlfird registered nurse-anlesthesia (CRNA) services. DESIGN: Survey of large loam tenens agencies. SETTING: University hospital. MEASUREMENTS AND MAIN RESULTS: Negotiations were carried out wth agernes for best prices for four weeks 01 Iroutine anesthesia work. The average cost for an anesthesiologist was $133 per hour and a CRNA, $86 per how. The agencies recewed approximately 18480 of these cosb. CONCLUSIONS: Despite competitive pressures, the locum tenens market charges 55% more for phvsiaarr than CRNA wwices. The implications for thP diffrrrnt charges arr discussed.

/. Clin. Anesth. 6:129-132, 1994

_------------------------------------

Postanesthesia Monitoring Revisited: Frequency of True and False Alarms from Different Monitoring Devices Lars Wiklund, MD, PhD, Bertil Hok, PhD, Kristina Stahl, CRNA, Agneta Jordeby-Jiinsson, CRNA

Department of Anesthesiology and Intensive Care, Uppsala University Hospital, Uppsala, Sweden. STUDY OBJECTIVES: To determine the frequency of true and false alarms alld the fwquency of alarm failures using a postanesthesia monitoring system. DESIGN: Open prospective study. SETTING: Ijos&est/lesla care unit at a university hospital. PATIENTS: 123 ASA Dhvsical status I-N oatienw who underwent eenrral or soinal-eoidural anesthesia for erneral. urologic, orthopedic, bphthalmologic, otoiaryngologic, or plastic surgery. ’ ’ . . MEASUREMENTS AND MAIN RESULTS: Monitoring mcluded ECG, oxygen saturation, aud respiratory rate (RR) hy either transthoracic impedance or nasal-oral air-flow detection. We observed patients and monitors, recording true and false alarms; the latter were defined as those comciding with a clearly observed, unrelated cause. During a mean observation period of 101 minutes per patient, the average frequency of pulse oximetry alarms was once every 8 minutes, with 77% of the alarms being false, caused bv sensor displacement, motion artifacts, poor perfusion, or a combination of these factors. Apnea alar& occurred on average once every 37 minutes, with the *‘f&e” fraction b&g 28% and 27% for impedance and flow detection, reswctivelv. The imtxdance sensor failed to detect aonea on at least 6 occasions: the flow sensor failed on 1 occasion. The &incideAce of p&e oximetry and apnea alarms &as small, and ECG exhibited a low alarm rate but a high fraction of false alarms. Patients receiving opioids and neuromuscular relaxants had a higher frequency of “true” apnea than patients not receiving these drugs. No clear correlation was found in regard to age distribution, type of surgery, duration of anesthesia, oxygen administration, or ASA physical status between the patient groups that exhibited many apnea or many pulse oximeter alarms and the whole study population. CONCLUSIONS: The high frequency of apnea strongly motivates the USC of continuous RR monitoring, preferably hy flow-sensing techniques, since both central and obstructive apnea are then detected.

J. (Xn. Anesth. 6:182-188, 1994 -------------_-__-_-----------------_ ------------------------------------- Transarterial Bra&al Plexus Anesthesia for Hand Surgery: A Retrospective Analysis of 346 Cases Riku Aantaa, MD, PhD, Olli Kirvela, MD, PhD, Arttu Lahdenperl, BSc, Seppo Nieminen, MD, PhD

Department ofAnesthesiology and Department of Surgery, Turku University Hospital, Turku, Finland.

STUDY OBJECTIVES: To study the safety and efficacy of the transarterial approach to brachial plexus block wth 60 tu 70 ml of local anesthetic solution, and to compare the success and comdication rates of this block oerformed bv experienced or mexperienced anesthesiologists. . DESIGN: Retrospective analysis of 346 records of ASA physical status I-IV patienti who underwent electivr unilateral orthopedic upper limb surgery with transarterial plexus anesthesia. SETTING: University teaching hospital. MEASUREMENTS AND MAIN RESULTS: Blood pressure (BP) and heat rate were measured at 5-mmutc intervals. Analgesia was registered as successful, incomplete, or failed. Any patient complaints or adverse reactions were recorded. The first 60 ml of local anesthetic provided surgical analgesia to 64% of patients. With a supplemental 10 ml of anesthetic, the overall success rate was 94%, with only 19 of 346 patients requiring general anesthesia. Experience in performing the block increased the success rate from 90% to 98% (p < 0.001). Six patienu experienced either nausea or a transient BP decrease that did not require medication. There was no record of toxic or other serious adverse reaction. CONCLUSIONS: Transarterial brachial plexus block administered with a 60 to 70 ml dose of local anesthetic provides surgical analgesia for hand surgery with an excellent success rate and without serious adverse effects.

J. Clin. Anesth. 6:189-192, 1994

-_-__---_---------_----_-_-_---------A



----------------_------________ Clinical Pharmacokinetics of Propofol Given as a Constant-Rate Infusion and in Combination with Epidural Blockade Arne We&n, MD, Peter M. Persson, PharmD, PhD, Anders Nilsson, MD, PhD, Per Hartvig, PharmD, PhD

Department of Anesthesiology, University Hospital, Uppsala, Sweden

STUDY OBJECTIVES: Investigate the pharmacokinetics of propofol in combination with epidural anesthesia or intravenous (Iv) alfentanil infusion, and the clinical feasibility of this anesthetic in lower abdominal surgery. DESIGN: Randomized, open clinical study. SETTING: Operating theaters and postanesthesia recovery unit at the department of gynecology of a university medical center. PATIENTS: 20 healthy, consenting ASA physical status I and II adult female patients undergoing lower abdominal surgery. INTERVENTIONS: A total N anesthetic technique was used in all patients. In Group 1, a continuous infusion of propofol was combined with eoidural buoivacaine. Grour, 2 ~atienu received vrooofol and alfentanil infusions. MEASUREMENTS tiD MAIN &iULTS: The ~ha;macokinetics of p&ofol are best fitted to a two-compartment open model and were similar in both patient groups. Propofol blood clearance was 29.8 i 6.51 ml/min/kg, and volume of distribution was 3.60 f 1.34 L/kc. resultine in a blood elimination half-life of 144 i 46 minutes. The entire txriod of anesthesia was stable in the alfe~tanil groip. In the epidural group, the initial period of anesthesia was to6 light as judged by the autonomic response to tracheal intubation, which also correlated in time to a lower propofol blood concentration than was seen in the alfentanil group. No evidence was found that an epidural block induced a change in propofol kinetics, apart from the lower blood concentration during the initial period of anesthesia. CONCLUSIONS: We could not show any statistically significant influence of an epidural blockade on the pharmacokinetic parameters of propofol. Nevertheless, the concentration-time profile changed during infusion, rendering the described infusion regimen, in combination with epidural anesthesia, unsatisfactory for adequate hypnosis. The propofol infusion regimen combined with alfentanil provided immediate and stable blood concentrations that were adequate for surgery.

J Clin. Anesth. 6:193-198, 1994 -___----__------_-------------------- J

Changes in End-Tidal Carbon Dioxide during Gynecologic Laparoscopy: Spontaneous versus Controlled Ventilation Magnus Vegfors, MD, PhD, Lars Engborg, MD, EDA, Anil Gupta, MBBS, DA, FFABCS, Claes Lennmarken, MD, PhD

Department of Anesthesiology, University Hospital, Linkoping, Sweden.

STUDYOBJECTNF.: To study the changes in P&O, during spontaneousand controlled ventilation in patients undergoing gynecologic laparoscopy. DESIGN: Randomized, unblinded study. SETTING: Department of Gynecology, University Hospital, Link6ping, Sweden; Central Hospital, Norrkcping, Sweden. PATIENTS: Forty healthy patients undergoing gynecologic laparoscopy. INTERVENTIONSz Patients were divided into 4 groups: Group 1 breathed spontaneously via an endotracheal tube, while the other three groups underwent controlled ventilation to an initial PLTCOI of 3 kPa (22 mmHg) (Group 2), 4 kPa (30 mmHg) (Group 3), or 5 kPa (37 mmHg) (Group 4). MEASUREMENTS AND MAIN RESULTS: P&O, levels were measured at fixed time intervals. Arterial blood gas analyses were done to compare the difference between PLTCOy and PaCO,. In Group 1, P&O, increased soon after insufflation and remained above 6 kPa (44 mmHg) throughout the procedure. In Groups 2, 3, and 4, P&O, also rose after insufflation, and an initial P&O, of 4 kPa (30 mmHg) was ideal, as all P&O, values were less than 5.5 kPa (41 mmHg). Occasional episodes of arrhythmia were seen in Group 1. However, no major adverse effects were observed in any of the groups. CONCLUSIONS: In view of the high PETCOI levels, spontaneous breathing should be avoided during gynecologic laparoscopy, and ventilation to an initial PETCOi of 4 !+‘a (30 mmHg) is recommended during controlled ventilation.

J Clin. Anesth. 6:199-203, 1994

-__------- __________---_---------- --- ----------- -----_-___--_____________- Dexmedetomidine Premeditation before Intravenous Regional Anesthesia in Minor Outpatient Hand Surgery Marja-Leena Jaakola, MD

Department of Anesthesiology, Turku University Hospital, Turku, Finland.

STUDY OBJECTIVE: To assess the efficacy and safety of intravenous (N) dexmedetomidine, an alpha-2 agonist, as a premeditation before N regional anesthesia. DESIGN: Randomized, double-blind, placebocontrolled study with two parallel groups. SETTING: Dayiase surgery unit, Department of Surgery, Turku University Hospital, Turku, Finland. PATIENTS: 30 healthy ASA physical status I outpatients scheduled for minor hand surgery with N regional anesthesia. INTERVENTIONS Patients were assigned to one of two groups to receive either denmedetomidine 1 wg/kg N (n = 15) or saline placebo N (n = 15) 10 minutes before exsanguination and inflation of a tourniquet. Regional blockade was induced with 0.5% lidocaine 3 mg/kg (maximum 200 mg). Additional fentanyl 1 pg/kg intraoperatively and oqcodone 0.05 mg/kg postoperatively were administered for analgesia if needed. MEASUREMENTS AND MAIN RESULTS: Dexmedetomidine preoperatively induced 16% to 20% decreases in systolic blood pressure (p < O.OOl), diastolic blood pressure (p< O.OOl), and heart rate (p < O.OOl), which were mainly abolished within the 4hour postoperative follow-up period. A clinically significant decrease in arterial oxygen saturation was not observed, The subjective intensity of pain during tourniquet inflation was similar in both groups, but fewer intraoperative (p = 0.009) opioid analgesicswere needed in the dexmedetomidine group. Dexmedetomidine decreased sympathoadrenal responses: plasma norepinephrine concentration decreased to one-fourth of the baseline level (p < O.OOl), and one of its main metabolites, 3,4dihydroxyphenylglycol, decreased by 27% (p < 0.001). Dexmedetomidine also prevented an increase in plasma epinephrine concentration following tourniquet inflation (p = 0.003). Dexmedetomidine induced subjective sedation (p = 0.002), but the Maddox Wing test did not show any statistically significant differences between the groups. General effectiveness was graded superior in the dexmedetomidine group (p < 0.001). CONCLUSIONS: Denmedetomidine is an effective premeditation before IVregional anesthesia because it reduces patient anxiety, sympathoadrenal responses, and opioid analgesic requirements.

J C&n. Anesth. 6204-211, 1994 ___------ ----------- ---_----------- --

l

I

I

I

I

I

I

I

I

I I

I

I

I

I

I

I I

I A

7 I

I

I

I

I I

I

I I

I I

I

I

I

I I I

I

-J

.J. Clin. Anesth., vol. 6, November/December 1994 551


r I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I I

L

7 I I

I

I I I

I

I I

I I

I

I I

I I I

I L

i-

I

I

I

I I

I

I I

I

I I I I I I I

I

I L

____--__-------- _______-___--_---- --- Effect of General Anesthesia and Major versus Minor Surgery on Late Postoperative Episodic and Constant Hypoxemia Jacob Rosenberg, MD, Peter Oturai, MD, Carl Johan Erichsen, MD, Mikael H.jorth Pedersen, MD, Henrik Kehlet, MD, PhD

Department of Surgical Gastroenterology and Department of Anesthesiology, Hvidovre University Hospital, Hvidovre, Denmark; Department of Anesthesiology, Bispebjerg Hospital, Copenhagen, Denmark. STUDY OBJECTIVE To rvaluat~ the relativr contribution of grucrrl anesthrria alone and ill <ombinatiou with the surgical procedurr to rhr pathogen& of late postoperative hypoxemia. DESIGN: Open, controlled study. SETTING: University hospital. PATIENTS: 60 patients rmderaomn maior abdominal rurc-rry and Iti wtirllts underyoin~ middle ear wrgcrv, both with

night and the second postoperatiw night. Signiticant episodic or constant hypox;mia did not ‘occur on’ thr’second postoperative uight following middlr ear surgery and general anesthesia, but xvcrc episodic and constant hypoxemia did occur on the second postoprratiw after major abdominal surgery and general anrsthrsia. (X)NCLUSIONS: Grnrral anesthesia in Itself is not an important factor in the development of late postoperative < onstant .uld rpisodic hypoxrmia. which instead may be related to the magnitod? of trauma and/or opioid administraricru

,/. Clin. Anesth. 6:212-216, 1994

Pharmacokinetics of Glycopyrrolate in Children Pirkka Rautakorpi, MD, Timo Ah-Melkkill, MD, PhD, Timo Kaila, MD, PhD, Klaus T. Olkkola, MD, PhD, Eila Iisalo, MD, PhD, Esko Iisalo, MD, PhD, Jussi Kanto, .MD, PhD

Department of Anesthesiology, Turku University Hospital, Turku, Finland. STUDY OBJWTIVE: Tb irwrrtigatc thr pharmacokinedc~ 01 ghc<,pvrrolarc !n rhildlvl, DESIGN: Open study with threr parallel groups. SETTING: Pediatric surgery drp&tmen~ it a Lmiverslty hu\pir,ll. PATIENTS: 26 healthy ASA physical statu I children undergomg muwr rulger!. INTERVENTIONS: Patients wcrr assigned to 1 of 3 groups: under I yrar of age (Group I, LI = 8). betwrru I and 3 wars of age (Croup 2, II = 7). and over 3 yrara of age (Group 3, LI = II). Glycopyrrolatc .5 &g/kg was given as a single lntrawnous (IV) illJeChm before induction of genrral anesthrsia. Blood samples (for determination OS drug concentrations in plasma) were collecled \ia venous cannula inserted into the contralateral antecubital win. ,MWSUREMENTS AND MAIN RESULTS: ECGwas observed continuouslr. blood D~CSSWS was measured with an automatic !~oninvasive d&cc, and blood samples wrrc taken iust before and at 2,‘4, 6, 10: 15, 30, 60, 120, 180, 240, 360, and 480 minutes after ilrjection of glycopyr~olatr. Glycopy&latr concentrations m plasma were determined with a radloreceptor assav. The only siznificant difference in the oharmacokinrtic oaramrrers was the shortened elimination half-life in Datirnts bet&en 1 arid 3-years of age. Glvcopyrrol& 5 &kg IV d/d not cause any significant alterations in heart rate.’ CONCLUSIONS: Thrrc were no &ificant changes in the distribution volume or clearance ofglycopyrrolate it) chddrclr r,f different ages. Thr shortened zhminatiorl half’life ill childrrll hrtwcrn I and 3 ymr? of age IS of minor clinical I,npWtZWe.

1, Cain. Anesfh. 6:217-220, 1994

_-___-__-___--__-___------_--__---_--

Frequency of Anesthetic Cardiac Arrest and Death in the Operating Room at a Single General Hospital over a SO-Year Period Yukio Kubota, MD, Yoshiro Toyodd, MD, Hiroshi Kubota, MD, Yutdka Ueda, MD, PhD, Akira Asada, MD, PhD, Takeshi Okamoto, MD, PhD, Hideo Matsuura, DDS, PhD, Hidemaro Mori, MD, PhD, Saburo Sasai, MD, Isao Hirose, DDS, PhD, Masaharu Koide, MD, Kimei Shirai, MD, PhD, Nobukata Urabe, MD, PhD, ShigeharuJoh, DDS, PhD, Masahiro Murakawa, MD

Department of Anesthesia, Osaka Kohseinenkin Hospital, Osaka, Japan STUDY OBJECTIVES: To determmr the anesthetic cardiac arrest (CA) and death rates in the operating room (OR) and to determine whether aneahetic CA and death are preventable. DESIGN: Prospective study. SETTING: OR suite of a general teaching hospital. PATIENTS: 85,708 pauents undergoing surgery over a J@year period. MEASUREMENTS AND MAIN RESULTS: Anesthetic CA and deaths wrrr identified, thei causes and prcventalxlity were determined on the day of occurrcncc, and they were recorded over the years 1962 to 1992. Four anesthetic C.&s (0.5 arrest per 10,000 anesthetics) and 1 death (0.1 death per 10,000 anesthetics) occurred during thr 30.year study period. CONCLUSIONS: The resrdts of 30 years’ experience do not support the hvpothesia that all anertheuc <;As and deaths are preventable. However, careful clinical management can reduce their frequency to a level lower than those reported in the referenced literature.

J. Clin. Anesth. 6:227-238, 1994



-____--------------------------------- Sevoflurane Degradation Product Concentrations with Soda Lime during Prolonged I Anesthesia I

Edward J. Frink, Jr, MD, R. Joseph Isner, MD, T. Philip Malan, Jr, MD, PhD, Scott E. Morgan, 1 BS, Elizabeth A. Brown, RN, Burnell R. Brown, Jr, MD, PhD, FRCA I

Department of Anesthesiology, University of Arizona Health Sciences Center, Tucson, AZ. ’ STUDY OBJECTIVES: To evaluate the decomposition of sevoflurane in soda lime during prolonged sevoflurane anesthesia in humans. To evaluate for evidence of renal or hepatotoxicity as a result of exposure to these sevoflurane degradation compounds. DESIGN: Prospective evaluation in healthy volunteers. SETTING: Clinical research unit and postanesthesia care unit of a university hospital. PATIENTS: Six healthy male volunteers. INTERVENTIONS Subjects were anesthetized with sevoflurane 1 to 1.2 minimum alveolar concentration for greater than 9 hours with a semiclosed circuit anesthetic technique (sliter total flow) with fresh soda lime as the absorbent. MEASUREMENTS AND MAIN RESULTS: Laboratory tests of renal and hepatic function were performed before anesthesia and 1 and 5 days after anesthesia. During sevoflurane anesthesia, inhalation and exhalation circuit limb gas samples were obtained for degradation compound analysis. Only one degradation product, fluoromethyl-2,2-difluorwl-(trifluore methyl) vinyl ether (compound A), was detected. Inhalation concentration was maximal (7.6 f 1.0 ppm) at 2 hours and did not increase further after this time point. There were no differences in preanesthesia and postanesthesia tests of hepatic and renal function. CONCLUSIONS: Levels of the degradation compound (compound A) produced in semiclosed circuit sevoflurane anesthesia with soda lime are well below potential toxic levels and thus appear safe. Wheu sevoflurane is administered under these conditions for prolonged anesthesia, concentrations of compound A do not continue to increase throughout anesthesia.

J. Clin. Anesth. 6239-242, 1994 I _---_-----_----_--------------------- -l -------------------------------------- A Simple Method for Calculating Component Dilution during Fluid Resuscitation: The Leuven ’ Approach Yves J. Mortelmans, MD, Gery A. Vermaut, MD, Hugo Van Aken, MD, PhD I

Department of Anesthesiology, University Hospitals, Katholieke Universiteit Leuven, Leuven, Belgium.

I

STUDY OBJECTIVES: To test the reliability of the Leuven approach, a balance between oversimplified empiric rules and more complex calculations requiring the use of nomograms or computers, to determine blood component dilution during large transfusions. To present schemes for blood component dilution and stabilization, as well as four examples showing the practicability of the method. DESIGN: Prospective study. SETTING: Orthopedic operating rooms at a university hospital. PATIENTS: 108 patients undergoing total hip replacement with expected large blood loss. INTERVENTIONS: Cornportent concentrations were measured after patient arrival in the recovery room. Blood loss was followed clinically. MEASUREMENTS AND MAIN RESULTS: Preset target component concentrations [hematocrit (Hct) 31%; total serum protein (TSP) 5.0 g/dl; prothrombin time (PT) 50%; blood platelets (BLPL) 5O,OOO/pl)l were compared with concentrations measured on arrival in recovery after dilution and stabilization. according to the transfusion scheme. Average blood loss was 3,226 + 1.600 ml (mean 2 SD). End comoonrnt concentrations were Hct. 33.4% ? 3.3%: TSP. 5.2 ? 0.5 g/d]; PT. 52% 2 12%; BLPL; 97,OOO/pl. I&t and TSP’showed significant (p c 0.05) but clinically unimportant differences from target concentrations. Possible reasons for variability in end concentrations are discussed. CONCLUSIONS: The Leuven approach produces reliable blood componeut concentrations after extensive transfusions. It allows the clinician to decide i& hi&If or herself, in accordance with genera1 consensus and the patient’s individual needs, when to stabilize blood components.

J. Clin. An&h. 6:279-287, 1994

------------------------------------- _I _________-----------------------------

I Clinical Pharmacology of Rocuronium (ORG 9426): Study of the Time Course of Action, Dose Requirement, Reversibility, and Pharmacokinetics Lambertus van den Broek, MD, J. Mark K.H. Wierda, MD, PhD, Nicky J. Smeulers, MD, Gert- Jan van Santen, Monique G.L. Leclercq, Pim J. Hennis, MD, PhD

Research Group for Experimental Anesthesiology and Clinical Pharmacology, Department of Anesthesiology, University of Groningen, Groningen, Netherlands.

I

I

I

I

I I

I

I

I

I

I

I

I I

I

I

I

I

A

STUDYOBJECTIVE: Evaluate time course of action, dose requirement, reversibility, and pharmacokinetics ofrocuronium (Org 9426) under nitrous oxide-fentanyl supplemented with propofol, halothane, or isoflurane. DESIGN: Prospective, randomized study. SETTING: Operating suite at a university hospital. PATIENTS: 36 ASA physical status I-III patients aged 18 to 65 years who were scheduled for elective surgery. INTERVENTIONS The time course of action of an intubatiou dose of rocuronium 600 pg/kg was investigated in 36 patients. In 18 the maintenance dose requirement of rocuronium and reversibili~ by neostigmine were evaluated. In the remaining 18 patients, the pharmacokinetics of rocuronium after the intubating dose were studied. Neuromuscular transmission was monitored by mechanomyography. MEASUREMENTS AND MAIN RESULTS: With the exception of a longer clinical duration of rocuronium-induced neuromuscular block in the isoflurane group compared with the propofol group (p = 0.03), time course of action variables were similar in the 3 groups. In patients receiving maintenance doses of rocuronium, the dose requirement until reversal was 636 ? 191 pg/kg/hr, 496 + 107 pg/kg/hr, and 384 + 127 pg/kg/hr for the propofol, halothane, and isoflurane groups, respectively (p = 0.02 for the isoflurane group vs. the propofol group). Reversal of a rocuronium- induced neuromuscular block showed there were no differences in the percentage or rate of recovery among the 3 groups. Pharmacokinetic analysis showed no significant differences for rocuronium during the 3 anesthetic techniques. CONCLUSION: Isoflurane potentiates the rocuronium-induced neuromuscular block, resulting in a longer clinical duration and lower maintenance dose requirement. This difference is not explained by differences in pharmacokinetics but is probably due to increased sensitivity of the neuromuscular junction to rocuronium during isoflurane anesthesia.

J. Clin. Anesth. 6:288-296, 1994 L_---_____________-________-_________-

.J. Clin. Anesth., vol. 6, November/December 1994 553


I I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

L

I

I

I

I

I

I

I

I I I

I

I

I I

I

I

I

I I

L

i-

I

I I I I I

I

I I

I

I I I I

I

I

I

I

Predictive Accuracy of Midazolam in Adult Patients Scheduled for Coronary Surgery Luc Barvais, MD, Alain A. D’Hollander, MD, PhD, Francis Cantraine, MD, PhD, Edouard Coussaert, MS, Gangji Diamon, MD, PhD

Department of Anesthesiology and Department of Clinical Oncology, Erasmus Hospital, Brussels, and Department of Anesthesiology and Department of Computer Science, Free University of Brussels, Brussels, Belgium.

STUDY OBJECTIVE: To evaluate the predictive accuracy of mida_lolam during cardiac aoesthcsia so as to onent the xlection of the most appropriate pharmacokinetic model for USC in a computer-assisted continuoucinfusion syswm. DESIGN: Retrospective analysis. SETTING: Operating room at a uniwrcity hospital. PATIENTS: 66 consecutive middle-aged and elderly coronary patients rrhrdulcd for coruuary artvr~ bvpnss graft (CAB(;) surgery. ISTERVENTIONS: Patients were anesthetirrd usiug a variable-rate mlusion of alfentanil combinrd with midazolam in an attempt to achieve and maiutain target concentrations of 100 ng/ml or 500 ng/ml. MEASUREMENTS Ah’D MAIN RESULTS:B A total of 323 arterial blood samples wcrc taken, and SCI um midazolam ( oucentrations were measured by high-perfwmance liquid chromatography. PFedicted uudazolam concentrations were calculated using 3 selected data sets. Theu bias, inaccuracy, aud dispersion w.cre assessed by determimng the media prrformance error, the median absolutr performance error (MDAPE). and the 10th aud 90th percentdes. Two of the selected data sets of midalolam. with a clearance lower than 5 ml/ke/min. were vrrv accurate IMDAPE Icss than 20%) in predicting low or high prebypass concentrations of midazolam in adult patients with good left ventricular function CONCLUSIONS: Two of the 3 pharmacokinetic data sets of midazolam studied may be srlrctrd when using a computcr- assisted infusion system in adult coronary patients.

I. Clin. Anesth. 6:297-302, 1994

-----____---------------------------- ______-----_------------------------- Bair Hugger Forced-Air Warming Maintains Normothermia More Effectively Than Thermo-Lite Insulation Steven F. Borms, MD, Stefan LE. Engelen, MD, Dirk GA. Himpe. MD, Maria R.R. Suy, MD, Wilfried J.H. Theunissen, MD

Department of Anesthesiology, Middelheim General Hospital, Antwerp, Belgium

STIJDY OBJECTIVE: To compare the ability of forced-au warming nnd rrflrrtir~r inrularion to mantan mtraopcratwc normothermia. DESIGN: Prospectivr, Irandomized clinral trial. SETTING: Op&atiug rooms of a general hospital. PATIENTS: 20 ASA Dhvsical satus I and II DatieuLc uudcreome CICCIIW total hio arrhxonlactv INTERVENTIONS l%ents were randomly &signed to he w&&d intraoperativelv using forced-air or reflcc we insulation. Inspired gases were conditioned using a heat-and-moisture exchanger in both’groups, and iufused intravenous fluids wre warmed to 37°C. MEASUREMENTS AND MAIN RESULTS: Distal esophageal (corr) temperatures decreased approximatcl~ 0.5”C m both groups during the first 45 minutes of anesthesia. Subsequently, corr trmperatures iucreasrd slightly in the patients given forced-air warming. In contrast. core temperatures continued to decrease in patients covered with reflective insulatmn. .After 135 minutes of anesthesia, core temperatures were 36.4 i 0.672 (mean t SD) in the forced-air group but only 35.4 2 0.6”C in the insulated group (p < 0.01, unpaired t-test). These data indicate that forced-air warming is sup&o, to reflective insulation. (CONCLUSION: Reflertivc insulation was unable to maintain intraoperative normothrl-mla during tot.d hip arrhroplasv. .Artwr warming, Fuch as that provided bv forced air, was required to prevent hypothermia.

I. Clin. Anesth. 6:303-307, 1994

------------------------------------- ----_-------------------------------- Continuous Administration of Fentanyl for Postoperative Pain: A Comparison of the Epidural, Intravenous, and Tranadermal Routes Caroline van Lersberghe, MD, Frederic Camu, MD, Eric de Keersmaecker, MD, Serge Sacre, MD Department of Anesthesiology, Flemish Free University of Brussels, School of Medicine, Brussels, Belgium. STUDY OBJECTNES: Evaluate the influence of route of administration [epidural, iutrawnous (IV). or transdermal] ou onsrt and quality of analgesm and to evaluate the pharmacokinetics of continuous administration of fentanyl. DESIGN: Randomized, open, singledosr. prospective study. SETTING: Postanesthesia care unit of a university hospital. PATIENTS: 54 ASA physical status I-III patients scheduled for lower major abdomulal, gvurc olog~, or urologic wrgtry. INTERVENTIONS: Patients recewed, for 72 hours postoperatively. an IV (Group IV) or epidural (Group EP) coustant- rate infusion of fentarryl or a transdermal patch (Group TX), applied preoperativelu. MEASUREMENTS mD MAIN RESUI,T.Ts: Pain intensity, vital signs, blood gas status, and plama f?nranyl concentration (Cp) were measured for up to 96 hours postoperatively. Onset of analgesia was delayed in Group ‘ITS. Analgesic eff~xv was similar for all 3 routes of administration except duriug the first 4 hours in Group TTS. Initially, the patients in Groups ‘ITS aud N needed significantly more rescue morphine than those in Group EP. The time course for fentanyl Cp in Croups TTS and N evolved to similar plateau levels. However, fentanyl Cp continued to rise throughout the study period m Group EP, reaching concentrations that elicited hypoxemiaafter48 hours. Asignificantnegative relationshipexisted bctwrrn fentanyl Cp and oxygen saturatiau in this group. CONCLUSIONS: The epidural, transdermal, and N administrauon of idenrlcal doses of fentanyl gwcll at a xmslilnt rate provided almost equivalent degrees of analgesia. But continuing epidural administration produced a steady r&se in svstemic fentanyl concentratious into the ventilatorydepressant rangr, affecting the hvpoxemic regulation of breathing.

J Clin. Anesth. 6:308-314, 1994 L____________________-____-___--------


Epidural Administration of Liposome-kssociated Bupivacaiue for the Management of Postsurgical Pain: A Fit Study Jean G. Boogaerts, MD, PhD, Noelle D. Lafont, MD, Anne G. Declercq, RN, Hongwen C. Luo, PhD, Etienne T. Gravet, Pharm, Joseph A. Bianchi, MD, Franz J. Legros, PhD

Department of Anesthesiology and Intensive Care, Reine Fabiola Hospital, Montignies-sur- Sambre; Laboratory of Physiopathology, Free University of Brussels, Brussels; and Institut Medical de Traumatologie et Revalidation, Loverval, Belgium. STUDY OBJECTIVES: Explore the influence of liposomes on the pharmacodynamic action of bupivacaine; determine whether postsurgical analgesia can be obtained from epidural delivery of liposomal bupivacaine. DESIGN: Open, nonrandomized study. SETTING: Physiopathology laboratory, general operating theaters, and intensive care units of the hospital. PATIENTS: 26 ASA physical stat”s II and III patients who had undergone major surgery (abdominal, vascular, urologic, thoracic, orthopedic). INTERVENTIONS After completion of the operation, the patientswere divided into 2 groups to receive 1 of 2 bupivacaine preparations epidurally for postsurgical pain: Group I (n = 12) received plain 0.5% bupivacaine with 1:200,000 epinephrine; Group 2 (n = 14) received liposomal 0.5% bupivacaine. MEASUREMENTS AND MAIN RESULTS: The followine observations were made: onset and “ualitv of an&&i. “ualitv of motor block according to the Bromage scale, and &pathetic block, Onset time of sensory bloci average; 15 minuted in both groups. Pain relief durations were 3.2 ? 0.4 hours with plain bupivacaine and 6.25 f 1.13 hours with the liposomal preparation (p < 0.05). In the liposomal bupivacaine group, no motor block was recorded. Low sympathetic block occurred in all patients. Analgesia in a subset of patients following abdominal aortic surgery increased from 2.4 + 0.35 hours to 10.6 2 1.4 hours bv encaosulatio” of buoivacaine (4~ 0.011. There was no neurotoxicitv or cardiotoxicitv. CONCLUSIONS: The liposomal ~rm&io” of bupi&ai”e i”c&ased duration of analgesia with& motor block dr adverse side effects.

J Clin. An&h. 6315-320, 1994 ------------------------------------- ------------------------------------- Costs Incurred by Outpatient Surgical Centers in Managing Postoperative Nausea and vomiting Norman V. Carroll, PhD, Patrick A. Miederhoff, PharmD, PhD, Fred M. Cox, PhD, Jan D. Hirsch, PhD

School of Pharmacy, Virginia Commonwealth University, Richmond, VA, Glaxo Research Institute, Research Triangle Park, NC.

STUDY OBJECTIVE: To estimate the financial costs incurred by outpatient surgical centers in managing postoperative nausea and vomiting (PONV). DESIGN: Prospective, observational study. SETTING: 6 hospital-based outpatient surgery centers. PATIENTS: 211 adult patients undergoing outpatient surgery for laparoscopy, dilatation and curettage, knee arthroscopy, or hernia repair. MEASUREMENTS AND MAIN RESULTS: Of the 21 I patients studied, 34 experienced PONV in the recovery room. For those patients experiencing POW, personnel, supply, and drug costs for management of this condition averaged $14.94 per patient. In addition, PONV increased the centers’ operating costs by delaying patient discharge by a” average of 24 minutes. A minimum estimate of this cost, based on nurses’ wage rates, was $7.12. This estimate is appropriate only for short-run considerations in outpatient surgery centers that operate at low capacity. A” appropriate valuation for long- run considerations and for centers operating “ear capacity is based on the revenue that centers lose as a result of extended stays. Lost revenue was estimated to be $415 per patient experiencing POW. CONCLUSIONS: PONV substantially increases the costs incurred by outpatient surgical centers.

J. Clin. An&h. 6:364-369, 1994

__------__-------- ------__----------- __------------------------- ------~--- Costeffectiveness Analysis of Antiemetic Therapy for Ambulatory Surgery Mehernoor F. Watcha, MD, Ian Smith, BSc, MB BS, FRCA

Department of Anesthesiology and Pain Management, University of Texas, Southwestern Medical Center at Dallas, Dallas, TX. STUDYOBJECTNE: Compare the cost-effectiveness ratios of (1) therapy with ondansetron, droperidol, and metoclopramide in the prevention of postoperative nausea and vomiting (PONV), and (2) prophylactic versus rescue therapy of POW. DESIGN: Costeffectiveness analysis based on estimated costs of 12 mutually exclusive outcomes by decision analysis. SETTING: Computer model of outcome established using data extracted from published studies and a survey of current practice in two ;“iversity-affiliated hospitals. PATIENTS: Patients “ndereoine operations associated with a hieh risk of PONV. MEASUREMENTS AND hiAINuR&SULTS: Direct costs in&d& drug acquisition, drug delivery, equipment used in managing vomiting, and additional nursing time costs. Indirect costs included drugs and materials used to treat persistent nausea and/or vomiting and the side effects of prophylactic drugs, increased time spent in the postanesthesia care ““it, unanticipated hospitalization, and lost earnings due to hospitalization. Separate models were created for patients with both nausea and vomiting and with isolated nausea. The total incremental costs associated with the prophylactic use of ondansetron, metoclopramide, and droperidol were $37.74, $28.43, and $18.17 per patient, respectively. The costs per emesisfree patient with the prophylactic use of ondansetron, metoclopramide, and droperidol, were $55.91, $71.08, and $30.15, respectively, and per nausea-free patient $68.93, $82.74, and $33.52, respectively. Prophylactic antiemetic therapy was cost-effective for operations with a high frequency of emesis, whereas treatment of established symptoms was more cost-effective when the frequency was lower. For ondansetron, prophylactic use was cost-effective only when the frequency of emesis exceeded 33%. whereas prophylactic droperidol was cost-effective eve” if the frequency was 10%. CONCLUSIONS: When drug co&, e&&y, and adverse events were all considered, proph$actic droperidol was more cost-effective than ondansetro”, and both drugs were more costeffective than metoclopramide. However, the expected frequency of PONV, as well as local drug acquisition costs, can significantly influence whether a particular antiemetic is cost-effective when given prophylactically or only as therapy for established PONV.

J Clin. Anesth. 6~3’70-377, 1994 __-------- ---------------- -----------

7 I

I

I

I

I

I

I

I

I

I

I

I

I I I

I

I

I

-I

I

I

I

I

I

I

I

I

I

I I

I I

I

I

I I I I

_J

7 I

I

I

I I

I

I

I

I

I

I

I

I

I

I

I I

I

J




i- I

I

I

I

I

I

I

I

I I I I

I

I

I I I

I L

i I I

I I I

I

I

I I I

I

I I

I

I

I I I

L

I

I I

I

I I

I

I I

I I I I

I I

I

I

I

I

L

Impact of a Cost Containment Program on the Use of Volatile Anesthetics and Neuromuscular Blocking Drugs James F. Szocik, MD, David W. Learned, MD

Department of Anesthesiology, University of Michigan, Ann Arbor, MI.

STUDY OBJECTIVE: To determine the impact of a cost containment program on thz use of volatile anesthetics and neuromuscular blocking drugs. DESIGN: Historical, controlled, retrospective analysis. SETTING: Main operating rooms of an adult general hospital at a university medical ~cntcr. PATIENTS: All patients undergoing anesthesia between July 1991 and November 1993. MEASUREMENTS AND MAIN RESULTS: Cost per case was determined by dividmg the monthly rxpalditurc for each class of drug by the caseload for that month. Cost per case of volatile anesthetic drugs decreased from $19.20 ? 1.16 to $15.16 -C 0.39 (p = 0.0034 by unpaired &test). For neuromuscular blocking drugs, cost per case decreased from 519.67 2 1.35 to $12.23 -+ 0.66 (p = 0.003). CONCLUSIONS: Concerted educational efforts can decrease the per case expenditures for both volatile anesthetic drugs and neuromuscular blocking drugs.

1. Clin. Anesth. 6~37%382, 1994

-----_--------___-------------------- Operating Room Start Ties and Turnover Times in a University Hospital William J. Mazzei, MD

Department of Anesthesiology, University of California, San Diego, Medical Center, San Diego, CA.

STUDY OBJECTIVE: To mrdsuw the start tune for the first case of thr day ald the turnover timrs for subsequent cases in the operating rooms (OR\) at an academic hospital. DESIGN: Prospectwe study. SE’ITING: ORs at a umversity medical center. PATIENTS: All patients undergoing an operative procedure that started between 7 ,z M nud 5 p>t tieekdays tot- the period lanuary 1, 1989, through June 30, 1989. INTERVENTIONS For each patient, the followng tunes were recorded: OR ready, patient rnters OR, anesthesia inductloo complete, surgery start, surgery end, patient leaves OR. MEXSUREMENTS AND MAIN RESULTS: Patients were brought mto the OR~ust before the schedulrd curt txne. Surgical incision was made 21 to 49 minutes after the patient was brought into the OR. Room turnover time (time from patient in to patient out) was almost uniformly 36 minutes. Patient turnover time (time from end of surgery in one patient to rod of induction of next patient) was generally 1 hour. Turnover times were shorter for those ORs m which primanly monitored anesthesia care was provided and longer in ORs in which patients routinely required invasive monitoring. (CONCLUSIONS: The scheduled start time for the first case of the day was generally the time the patient was brought lnto the OR. Because of the variable amount of time required for anesthesia induction and surgical preparation and draping, incision occurred 21 to 49 minutes later. The time between cases when no surgery was occurring was significantly longer than room turnover time because of the need to wake up one patient and induce the followmg patient. Because of a lack of standardized definitions, there is probably a strong percepttral difference among anesthesiologists, OR nurses, and surgeons when vlewing start and turnover times. At our own teaching institution, shortening turnover times would mcrease the amount of elective OR time available, but the impact would not be significant because the number of procedures done per OR each day is low.

/. Clin. Anesth. 6:405-408, 1994 .-__---------------------------------- _____-------------------------------- Does the Design of the Sprotte Spinal Needle Reduce the Force Needed to Deform the Tip? Eugene G. Lipov, MD, Mitchel B. Sosis, MD, PhD, Robert J. McCarthy, PharmD, Anthony D. Ivankovich, MD

Department of Anesthesiology, Rush-Presbyterian-St. Luke’s Medical Center, Chicago, IL..

STUDYOBJECTIVE: To determine whether the window design of pencil-point spinal needles leads to deformation under lateral or axial loading conditions. DESIGN: Independent-measure, multigroup study of the force required to deform nwdles. SETTING: Independent testing laboratory. MEASUREMENTS AND MAIN RESULTS: The force necessary to bend 22. and 24-gauge Sprottc, 22. and 25.gauge Whitacre, and 22. and 2.5gauge Quincke needles was measured using an Instron gauge (Instron Corp., Canton, MA) after microscopic verification of needle uniformity. Effects of lateral and axial forces were evaluated in separate experiments. Tbe force needed to bend the Sprotte needles was less than that needed for the Whitacre and Quincke needles of similar size when lateral or axial pressure was applied. Microscopic inspection of the needles showed a marked variability in the window area placement in a single lot of Sprotte needles. Examination of the needle tips demonstrated that the Sprotte needles were most likely to bend at the needle window, while the Quincke and Whitacre needles deformed at the point OS clamping. CONCLUSIONS: The Sprotte needles have an inherent design weakness to lateral and axial pressure, which may result in a greater number of needle tip deformations upon needle insertion. The nature of this deformation may result in difficulty in needle withdrawal and possibly fracture of the needle tip.

1. Clin. Anesth. 6:411-413, 1994



-----------------------______________ Effects of Subcutaneous Verapamil on the Duration of Local Anesthetic Blockade Charles E. Laurito, MD, Stephan J. Cohn, MD, Gerald L. Becker, MD

Department of Anesthesiology, University of Illinois-Chicago, and Department of Anesthesiology, Humana Hospital-Michael Reese, Chicago, IL.

STUDY OBJECTIVES: To determine whether a subcutaneous injection of verapamil will provide local anesthesia and whether a mixture of lidocaine and verapamil will prolong the anesthetic effect of lidocaine alone. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Preanesthetic area of a large metropolitan teaching hospital. PATIENTS: 20 volunteers. INTERVENTION% All volunteers received 4 injections of normal saline, verapamil, lidocaine, and lidocaineverapamil at the volar aspect of the forearm. The sites were tested with a 26gauge needle to be sure the sensation of sharp could be appreciated. The injections were performed in a randomized, double-blind fashion using a sterile technique. The 4 areas were tested at l-minute intervals using a 26-gauge needle until the sensation of sharp was again perceived. MEASUREMENTS AND MAIN RESULTS: Injection sites were examined for the presence and degree of erythema. Volunteers were asked to rate the degree of pain felt during and immediately after injection. The time elapsed until the person was again able to perceive sharp from a 26gauge needle prick was measured at all 4 sites. When compared with the effects of normal saline, subcutaneous verapamil provided local anesthesia to pinprick. The mixture of verapamil and lidocaine also provided anesthesia to pinprick, but the duration of effect was less than that provided by lidocaine alone. The use of verapamil alone and in combination with lidocaine was associated with a marked degree of erythema and edema. CONCLUSIONS: Verapamil injected subcutaneously provides a degree of local anesthesia. However, this effect is hampered by a local reaction at the injection site and a short duration of action. The mixture of lidocaine and verapamil provides a shorter duration of action than does lidocaine alone.

J Clin. Anesth. 61414-418, 1994

------------------------------------- _------------------------------------ Serum and Urine Inorganic Fluoride Levels following Prolonged Low-Dose Sevofl-e Anesthesia Combined with Epidural Block Chihoko Matsumura, MD, Osamu Kemmotsu, MD, PhD, FCCM, Yoshiteru Kawano, MD, Koichi Takita, MD, Hisashi Sugimoto, MD, Takahisa Mayumi, MD, PhD

Department of Anesthesiology and Intensive Care, Hokkaido University School of Medicine, Sapporo, Japan. STUDY OBJECTIVES: To determine whether serum and urine inorganic fluoride levels with prolonged (more than 7 hours\ low-dose (0.8 to 2.0 vol %) sevoflurane anesthesia nlus enidural anesthesia were increased as cornoared with isoflu&e anesthksia plus epidural gnesthesia. To measure tie urin’e tubular enzymes N-acetyl-eglucosaminidase (NAG), u,-microglobulin (a,-M), and &-microglobulin (P,M) for renal tubular injury in both groups. DESIGN: Randomized. nrosnective studv. SETTING: University h&pi&l. PATIENTS: 15 ASA physical status I and II adults (7 males, 8 females) who were scheduled for prolonged laparotomy (lasting 9.5 to 10.2 hours) with general anesthesia. MEASUREMENTS AND MAIN RESULTS: Epidural anesthesia was administered before induction of general anesthesia which was maintained with either sevoflurane or isoflurane in nitrous oxide and oxygen. Standard monitoring was used in all patients. Serum and urine inorganic fluoride and urine tubular enzymes were measured periodically. Serum inorganic fluoride was 54 bmol/L at 4.3 minimum alveolar concentration (MAC) hours of sevoflurane; the peak level for isoflurane was 8 pmol/L at the same MAC hours. Sevoflurane also increased urine inorganic fluoride excretion to 96 pmol/hr 8 hours. NAG excretion started to increase after inhalation of either sevoflurane or isoflurane. a,-M and PrM excretion increased markedly postoperatively. Even though fluoride levels and tubular enzymes were high, there was no evidence of postoperative renal dysfunction. CONCLUSIONS: There was no increase in urinary enzymes, indicators of tubular injury, specific to sevoflurane. There was no postoperative renal dysfunction, as indicated by unchanged serum creatinine and blood urea nitrogen levels.

J. Clin. Anesth. 6419-424, 1994

__------------------------ ----------- ____---------- ----------------------- Evaluation of the Efficacy of a Forced-Air Warmer (Bair Hugger) during Spinal Surgery in Children Isabelle Murat, MD, PhD, Josee Bern&e, MD, Isabelle Constant, MD

Department of Pediatric Anesthesia, Hopital Armand Trousseau, Paris, France.

STUDY OBJECTIVE: To evaluate the efficacy of a forced-air warmer during spinal surgery for correction of scoliosis in children. DESIGN: Prospective randomized study (group allocation based on the availability of the warming device). SETTING: Children’s teaching hospital. PATIENTS: 51 ASA physical status I and II children (mean age, 15 years; mean weight, 45 kg) scheduled for posterior spinal fusion with general anesthesia. INTERVENTIONS: Study group (warmed; n = 26)-legs covered with the forced-air warmer (Bair Hugger, Augustine Medical, Inc., Eden Prairie, MN) after installation of the patient in prone position--versuscontrol group (n = 25)4OOW heat lamp placed over the head during surgery as is usually done in our institution MEASUREMENTS AND MAIN RESULTS: Rectal temperature was taken every 15 minutes during surgery and during the first 2 hours in the recovery room. Time required for the wake-up test, time to extubation, and blood loss also were noted. Temperature profiles were very different in the 2 groups. In the control group, rectal temperature decreased during the first 180 minutes to a minimum of 34.8”C + 0.6’C, followed by a slow rewarming phase. In the warmed group, the lowest temperature (35.6”C ? 0.5”C) was recorded 45 minutes after placement of the forced-air warmer, followed by an effective warming phase. At the end of surgery, temperature was significantly higher in the warmed group than in the control group (36.5”C + 0.8”C vs. 35.4”C i 0.9”C). However, time required for the wake-up test, time to extubation, and blood loss did not differ between groups. CONCLUSION: The forced-air warmer (Bair Hugger) is effective during spinal surgery, although only about 20% of body surface area can be covered.

J. Clin. Anesth. 6425-429, 1994

----------- ------------- -------------

7 I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I I I

J

7

I

I

I

I I

I

I

I

I

I I

I

I

I

I

I

I

I J

7

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

J



i I

I

I

I

I

I

I

I

I I I

I

I

I

I

I

I

I

L

i I

I

I

I

I

I

I

I

I

I

I

I

I

I I I I I L

I

I I

I

I

I

I

I

I

I

I

I

I

I I I I I

I

L

_-----------------_--------------- --- Comparative Pharmacokinetics of Oral versus Sublingual Clonidine Francesca E. Cunningham, PharmD, Verna L. Baughman, MD, Joseph Peters, MD, PhD, Charles E. Laurito, MD

Department of Anesthesiology, University of Illinois College of Medicine, and Department of Anesthesiology, Michael Reese Hospital and Medical Center, Chicago, IL.

STUDYOBJECTIVE: To compare the pharmacokinetic and pharmacodynamic profile of orally nnsussubli~~gually admims- tered clonidine. DESIGN: Randomized, c rossowr, nonblinded, open-label study. SETTING: University tertiary-care center. PATIENTS: 10 healthy male’and female volunteers aged 20 to 42 years. INTERVENTIONS A hroarinized catheter was olaced ir~traver~ouslv for blood-samoline DUTDOXS. An automatic mhvamtr- . ,Y manometer was placed on the volunteers’ left upper arm to obtain systolic and d&olic blood pressure, and a pulse oximeter was placed on the right index finger to measure heart rate (HR). .MEASUREMENTS AND MAIN RESULTS: Serial blood samples were collected throughout the ‘24-how study period to determine clonidine concentrations. The effect of clonidine on blood pressure (BP) and HR also was measured. The half-life, area under the curve, maximum concentration, and timr to reach maximum concentration were similar for both the sublingual and oral routes. BP and HR changes were similar for both sublingual and oral clonidine. CONCLUSION: Both routes of administration resulted in similar pharmacokinetic and pharmacodynamic profiles. Attempts to shorten clonidine’s latency with sublingual administration were unsuccessful. Our study shows that a single dose of clonidine 0.3 mg has the sane pharmacokinetic and dynamic profile whrn administered orally or sublingually. Therefore, the sublingual route can be predictably used in fasting patients, those having difftculty swallowing, or those *ho are unable to absorb drugs through the gastrointestinal tract; the sublingual dose is the same as the oral dose.

I. Clin. An&h. 6:430-433, 1994

-----------_____--------------------- Investigation of the Pharmacokinetics and Analgesic Effects of an Intramuscular Injection of Sustained-Release Sufentanil for Postoperative Pain: An Open Study Gerard Bergmans, MD, Bernard Vanacker, MD, Hugo Van Aken, MD, PhD, Henk Noorduin, Achiel Van Peer, PhD, Joris Gryseels, MD, Bruno Verhamme, MD

Department of Anesthesiology, University Hospitals, Katholieke Universiteit Leuven, Leuven, and Janssen Research Foundation, Janssen Pharmaceutics, Beerse, Belgium. STUDY OBJECTIVES: To investigate the pharmacokinetics afta dn intramuscular (IM) inJection ot sufrutarlil ill thill vegetable oil in postsurgical patients and to determine whether sustained-releasr IM sufentanil call provide cafe and sufficient analgesia of long duration in these patients. DESIGN: Open study. SETTING: University bosp~tal. PATIENTS: 10 ASA phys&l status I and II patients aged 18 to 65 years who were scheduled for rlrctne auger). (NTERVENTIONB All vatients were oremedicated with lorazeoam and anesthetized with a aeneral anesthetic techmaw D tontaining nitrous oxide, fentanyl, and isoflurane. As soon as’significant pain [visual analog scale score of 5 or greater (range, 0 = no pain to IO = worst pain imaginable)] occurred during the early postoperative period, the patient received an IM injection of sustained-release sufentanil. MEASUREMENTS AND .MAIN RESULT.Ts: During the first 48 hours following surgery, blood samplrr wcrc takrn for determination of plasma sufentanil concentrations. Blood pressure, heart rate, respiratory rate, pain scores, and sedation scores were documented. The IM administration of sufentanil in vegetable oil provided sufficient pain relief, although the onset of analgesia was rather slow ( % I). The analgesic effect was still apparent 48 hours later. Plasma concentration of sufentanil at the different time points varied from 0.021 to 0.142 ng/ml, with a mean maimal peak concentration of 0.103 ng/ml. The plasma concentration 48 hours after injection varied from 0.026 to 0.074 ng/ml. (CONCLUSIONS: Although an IM injection of sufentanil in thiu vegetable oil is effective for postoperative pain relief, ar is associated with widr interindividual variability in plasma concentration of sufentanil and long duration of action.

J. Clin. Anesth. 6:462-468, 1994

- Central Venous Catheter Placement Using the ECGGuided Cavafii-Certodyn SD Catheter Stijn A. Corsten, MD, Boudewijn van Dijk, MD, Niels C. Bakker, MD, Jaap J. de Lange, MD, PhD, Gert J. Scheffer, MD, PhD

Department of Anesthesiology, Free University Hospital, Amsterdam, and Department of Anesthesiology, Diaconessen Hospital, Voorburg, Netherlands.

STUDY OBJECTIVE: To evaluate the clinical use of a new ECGguided central venous catheter with regard to positioning in the superior vena cava (SVC). DESIGN: Prospective study. SETTING: Operating rooms of university hospital and a general hospital. PATIENTS: 89 elective and emergency adult surgical patienu requiring central venous cathctcriration penoperatively. INTERVENTION% We performed ECGguided placement of the central venous catheter from several insertion sites. After we observed an intra-atria1 pwave (patriale), the catheter was withdrawn 3 cm back into the SVC. Postoperative anterior-posterior chest radiographs were performed for verification of tip localization. MEASUREMENTS AND MAIN RESULTS: In all 81 patients who exhibited a patriale that reverted to a normal-sire p wave (pSVC) after withdrawal of the catheter 3 cm, the tip was located in the SVC or the SVC-right atrial junction on the chest radiograph. In 7 of the 8 cases without a patriale, the catheter tip was shown to be located at all incorrect position on the chest radiograph. The size of the patriale was always at least twice that of the p.SVC. CONCLUSIONS: Use of this wire-conducted intravascular ECG signal is a reliable tool for positioning the central venous catheter via various insertion sites. The technique proved to be an inexpensive, easy, and clrar method. When a p-atriale IS seen, uncomplicated insertions do not require radiologic guidance to control catheter tip position

J. Clin. An&h. 6:469-472, 1994

----____---___-__________-----_____-_i



-----------------------__----_________ Pretreatment with Sedative-Hypnotics, but Not with Nondepolarizing Muscle Relaxants, Attenuates Alfentanil-Induced Muscle Rigidity

:

Theodore J. Sanford, Jr., MD, Matthew B. Weinger, MD, N. Ty Smith, MD, James L. Benthuysen, I MD, Norman Head, BS, Holly Silver, RN, CRTT, Thomas A. Blasco, MD I

Department of Anesthesiology, University of California, San Diego, School of Medicine, and ’ Department of Anesthesiology, San Diego Veterans Affairs Medical Center, San Diego, CA; 1 Department of Anesthesiology, University of Michigan School of Medicine, Ann Arbor, MI. I STUDY OBJECTIVE: To evaluate and compare the efficacy of various pretreatment agents to attenuate or prevent opioid- 1 induced muscle rigidity using a well-established, previously described clinical protocol. DESIGN: Prospective, controlled, single-blind, partially randomized study: I

SETTING: Large medical center. I PATIENTS: ASA physical status I-III patients undergoing elective surgical procedures of at least 3 hours’ duration. INTERVENTIONS: The effect of pretreatmentwith nondepolarizing muscle relaxants (atracurium 4Opg/kg or metocurine ’ 5O+g/kg), benzodiazepine agonists (diazepam 5 mg or midazolam 2.5 mg), or thiopental sodium 1 mg/kg on the I increased muscle tone produced by alfentanil 175 pg/kg was compared with a control group (given no pretreatment). MEASUREMENTS AND MAIN RESULTS: Rigidity was assessed quantitatively by measuring the electromyographic activity ’ of five muscle groups (biceps, intercostals, abdominals, quadriceps, and gastrocnemius). Rigidity also was rated qualitatively by attempts to initiate and maintain mask ventilation, attempts to flex an extremity, and the occurrence of myoclonic

I movements. Pretreatment with the two nondepolarizing muscle relaxants had no effect on the severe muscle rigidity 1 produced by high-dose alfentanil. Whereas thiopental was only mildly effective, the benzodiazepines midazolam and diazepam significantly attenuated alfentanil rigidity (p < 0.05).

I CONCLUSION: This study suggests that benzodiazepine pretreatment is frequently, but not always, effective in preventing I opioid-induced muscle rigidity.

I

J. Clin. Anesth. 6:473+30, 1994 I

----__--------------_________________ J -------------------------------------- Midazolam Does Not Antagonize Fe&my&Mediated Analgesia in Surgical Patients I

Michael Behne, MD, Volker Lischke, MD, Fatima As&ah, PhD, Steffen Probst, MD, Robert ’ Hermann, MD, Jiirg Vettermann, MD I

Department OfAnesthesiology and Resuscitation, Johann Wolfgang Goethe University Clinics, ’ Frankfurt a. Main, Germany.

STUDY OBJECTIVE: To determine whether midazolam possesses a clinically significant antianalgesic action in surgical I

patients. I DESIGN: Randomized, controlled study. SETTING: Inpatient anesthesia at a university department of neurosurgery.

I

PATIENTS: 2 groups of 10 patients each who were scheduled for supratentorial brain surgery, did not have elevated I intracranial pressure, and were free from systemic disease. INTERVENTIONS Patients underwent anesthesia induction with hexobarbital, succinylcholine, and pancuronium; anes- ’ thesis was maintained with injections of droperidol-fentanyl (Group 1) or with midazolam-fentanyl (Group 2) following I a predetermined repetitive dosing schedule, such that fentanyl 0.1 mg was injected upon predominant increases in heart rate, whereas droperidol 2.5 mg or midazolam 2.5 mg was injected upon increases in blood pressure. MEASUREMENTS AND MAIN RESULTS: Duration of anesthesia and invasiveness of surgery were similar in both groups. The amount of fentanyl required was 0.55 + 0.18 mg/hr (mean ? SD) in Croup 1 and 0.53 2 0.17 mg/hr in Group

1

2. Injections of draperidol 7.5 + 3.4 mg/hr (Group I) and midazolam 5.9 f 2.3 mg/hr (Group 2) were administered 1 intraoperatively. This redosing regimen was associated with uninterrupted hemodynamic stability, indicating comparable and adequate anesthetic depth. Plasma concentrations of metabolites and hormones indicative of humoral stress activation

,

did not differ between groups. I CONCLUSION: Under these clinical conditions, the administration of midazolam, when compared with droperidol, was not associated with signs of any antagonistic or antianalgesic action toward fentanyl-mediated analgesia.

,

I J Clin. Anesth. 6:481-486, 1994

_------------------------------------ J _______------------------------------ Subarachnoid Bupivacaiue Blockade Decreases Midazolam and Thiopental Hypnotic Requirements Mark Tverskoy, MD, PhD, Mikhael Shagal, MD, Jacob Finger, MD, Igor I&sin, MD, PhD

Department of Anesthesiology, Rebecca Sieff Hospital, Safed, Israel; Department of Anesthesia, Brigham and Women’s Hospital, Boston, MA.

STUDY OBJECTIVE: To test the hypothesis that subarachnoid bupivacaine blockade decreases hypnotic requirements for thiopental sodium and midazolam. DESIGN: Randomized, double-blind, placebocontrolled study. SETTING: Teaching hospital. PATIENTS: 53 nonpremedicated ASA physical status I and II adult male patients scheduled for elective lower abdominal, pelvic, or lower limb surgery. INTERVENTIONS: Intravenous injections of midazolam or thiopental were administered with or without subarachnoid bupivacaine blockade (12.5 mg) at the L,L, level. Thiopental or midazolam hypnotic requirements were determined using loss of ability to open eyes in response to verbal command as an endpoint. The thiopental requirements were determined from dose-response curves obtained with bolus injections of predetermined doses of the drug. MEASUREMENTSAND MAIN RESULTS: Subarachnoid bupivacaine blockade decreased the hypnotic dose of thiopental from 3.40 + 0.68 mg/kg (mean ? SD) with a dose range of 2.3 to 4.5 mg/kg (intramuscular saline) to 2.17 t- 0.48 mg/kg with a dose range of 1.3 to 2.8 mg/kg (p < 0.005 for the difference). The EDSo value of midazolam decreased with the bupivacaine blockade, from 0.23 mg/kg (95% confidence limits: 0.08 to 0.38 mg/kg) to 0.06 mg/kg (0.01 to 0.14 mg/kg), with p < 0.0001 for the difference. CONCLUSION: Subarachoid bupivacaine blockade decreases hypnotic requirements for both thiopental and midazolam. The results suggest that the reduction in hypnotic requirements is due to the decrease in afferent input induced by spinal anesthesia.

j C&n. Anesth. 6z487-490, 1994

_____------------ --------------------

7 I

I

I

I

I

I I

I

I

I

I

I

I

I I

I

I

I J


Structured Abstracts: Volume 6. I994

___--------- -----____---------------- I I

I

I

I

I

I

I

I

I

I

I

I

I

I I I I

I

Intraoperative Pulse Oximetry: Frequency and Distribution of Discrepant Data Peter H. Pan, MSEE, MD, Nikolaus Gravenstein, MD

Departments of Anesthesiology and Neurosurgery, University of Florida College of Medicine, Gainesville, FL; Department of Anesthesiology, Medical College of Virginia, Richmond, VA.

STUDYOBJECTIVE To determine thr tvpes of dibrrepant data dunng inuaoprl-atlvr pulse oximrtry and thcll- II-equenc\ and duration. DESIGN: Prospectwr \tudy SETTING: University medlcal ccntcr. PATIENTS: 46 consecutive ASA physical status I-III patients undcrgomg general anesthesia for electw wrglcal opemuons. MEASUP.EMENTS A!!D MAIN RESULTS: With an integrated computer algorithm on the pulse oximeter and armthrr computer linked to it, data were srrrcned and the frequency and distribution of the following oximrter signals recorded: absent; low quality or interrupted, as detected by the pulse oximrtrr algorithm; nonphysiologic, identified by the personal computer as a heart rate change greater than 10 beats per minute within 2 consecutive Z-second samples, with no similar abrupt change reported simultaneously on ECG. The number of episodrs per hour of disrrepant oximcter data and the duration of the episodes wcrr recorded by phase of arwsthrsia: induction, maintenanrr. and cmrrgenrc. Dircrepallt data occurred most frequently and lasted longest during rmrrgrncc (p < 0.05); the majority of episodes 01 discrepant data during emergence lasted less than I2 seconds. Excluding disrrrpant data that lasted less than 12 wconds decreased the frequency of discrepant data bv 63% and excluding those that lastrd less than 30 seconds drcrrasrd thr frrquenc\ of discrepant data by 93% CONCLUSIONS: Pulse oximeters frrqucrltly report discrepant daw intraopcrauwly, most frrqurutly dunng amergencc lrom anesthesia. An alarm delay triggered by discrepant data and lasting I2 to 30 seconds would kerp most discrepant data from becoming falsr alarms and, thus, may reduce distracting sound pollution in the nprrating room.

,/. Cl&. An&h. 6:491-495, 1994

L_____-________-----------------_-----J


Date post:	30-Dec-2016
Category:	Documents
Upload:	dangthu
View:	219 times
Download:	1 times

Structured abstracts: Volume 6, 1994

Documents