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Christopher Watson, MD, MPH Medical Director, Pediatric Sedation Unit Walter Reed NMMC – Bethesda September 2011
Christopher Watson, MD, MPHMedical Director, Pediatric Sedation UnitWalter Reed NMMC – BethesdaSeptember 2011
The purpose of this course is to provide you with the tools and information you need to effectively sedate pediatric patients and manage pain while minimizing risk and maximizing safety.
After completing this course you will be able to:Better understand Moderate Sedation policies at WR-BethesdaProperly screen patients and perform pre-sedation history and examinationsUnderstand the importance of documentation before, during, and after a procedureList pre-procedure fasting guidelinesMinimize risk by utilizing aspiration prophylaxis protocolsKnow when to monitor and which monitoring aids to useIdentify the causes and treatments of airway compromiseSelect appropriate drugs and routes of administration for the provision of moderate sedationManage procedural and post-procedure pain
In patients of any age, moderate sedation / analgesia can rapidly and unpredictably become deep sedation / analgesia or general anesthesia with catastrophic consequences.
None Minimal Moderate Deep GeneralAnesthesia
In the majority of sedation mishaps, the first problem is respiratory:
Respiratory depression
Airway obstruction
Cardiac events (hypotension, arrhythmias, and cardiac arrest) are less common and are usually secondary to respiratory depression.
Monitoring allows early detection of a problem and early intervention.
The individual performing a procedure cannot safely sedate a patient.Electronic monitoring and vigilance aids are not a substitute for observation, auscultation, and palpation!!Monitoring by a second individual with no responsibilities is mandatory.
Almost all of the drugs used for sedation, whether for painful or non-painful procedures:
Depress minute ventilation (respiratory rate and / or tidal volume)
Blunt ventilatory response to CO2 and O2
Allow the tongue to obstruct the airway when the head is in a flexed position.
The slide demonstrates the ability of a patient to alter respiratory drive in response to a number of conditions. The normal response to increasing CO2 is an increase in minute ventilation (line 2).
Hypoxia will increase respiratory drive (line 1).
This response is blunted by opioids(line 3). Benzos may blunt even further (line 4).Finally, if you use combinations, you may have a supra-additive effect such as in line 5.
1 = Hypoxia, 2 = Normal, 3 = Opioids, 4 = Sedatives, 5 = Opioids + sedatives
Appropriate monitors, equipment and
personnel for the level of sedation until
patient returns to baselineTwo sedation trained personnel (a
practitioner and patient monitor), with
current PALS certification, throughout
sedation including during transport
Continuous HR, RR, SpO2 and ETCO2
monitoring
Go through your checklist:MonitorsSuctionOxygenAirway equipmentIV fluids and administration setsResuscitation drugsPharmacologic antagonistsCrash cart nearby with defibrillator/ECG
Transport bag
S = Suction: working suction tubing, catheters
O = Oxygen: O2 source with sufficient supply to last several hours, tubing, and bag-valve-mask
A = Airway: size appropriate and oral and nasal airways/masks
P = Pharmacy: all medications needed including those for resuscitation and antagonists
S = Special considerations: equipment and drugs for specific patient needs
Record vital signs every 5 minutes during
sedationTime, LOC, BP, HR and rhythm, RR, adequacy of
ventilation, SpO2, ETCO2, O2 delivery /
concentration / method, pain score
Record IV catheter placement and fluid status /
administration throughout procedure
Document times and dose of all medications
given
Observation and palpation:Chest wall movement
Skin color
Capillary refill
Auscultation:Heart tones
Breath sounds
Adequacy of ventilation must be continuously monitored!!
Use at least one of the following:Direct observation
Chest wall movement
Skin color
AuscultationBreath sounds
Capnography is very useful, particularly when your patient cannot be observed directly!!
NEW – Required for all moderate sedations!
Capnography is a graphic record with display on a screen of CO2concentration during each respiratory cycle.Carbon dioxide monitoring allows for continuous, non-invasive measurement of CO2elimination, respiratory rate, depth of respiration, and pulmonary blood flow.
Shivering
Malignant Hyperthermia
Increased CO, during resuscitation
Bicarb infusion
Effective drug therapy for bronchospasm
Decreased minute ventilation
Decreased muscular activity or muscle relaxant
Hypothermia
Decreased CO, cardiac arrest
PE
Bronchospasm
Increased minute ventilation
Common method of assessing ventilation.
Most ECG monitoring devices used in sedation detect chest wall motion (impedance pneumography) and interpret this motion as a respiratory rate.
In a patient with an obstructed airway, these devices will continue to record a respiratory rate (may even be exaggerated) as the patient will attempt to breathe, but not exchange gas.
Impedance pneumography detects chest wall motion. It will not detect airway obstruction nor the adequacy of ventilation.
Capnography is the best method of detecting airway obstruction and should be the first line of defense in monitoring.
Pulse oximetry (SpO2) is a continuous noninvasive method of measuring oxygen saturation (SaO2).It measures neither PaO2
nor oxygen content.It can detect a change in oxygen saturation much more quickly than the human eye.
Once the SaO2 falls below 85 to 90%, the rate of fall will be PRECIPITOUS.
It does not measure the adequacy of ventilation.
Respiratory depression and airway obstruction are detected indirectly and late.
Variable auditory tones are helpful in monitoring.
There may be a time lag between intervention and correction of hypoxemia.
Limitations:
Low blood pressure
Light
Movement
Electrocautery
PaO2 < 50 mm Hg
Nail polish
False alarms:
False alarms occur 90% of the time.
10% OF ALARMS ARE REAL
Sites:
Finger, toes
Nose, ear
Tongue
ECG provides much less information.
Bradycardia and tachycardia occur very late and are indirect signs of hypoxemia and hypercarbia.
Arrhythmias are rare in children.
ECG is an exquisitely sensitive detector of cardiac ischemia.
Myocardial ischemia is rare in children.
Pick the right sized cuff!!Width 20 to 50% greater than diameter of arm
A cuff which is too small will give artificially elevated blood pressure.
Obtain blood pressure at regular intervals:Every 5 minutes even in moderate sedation
Every 15 minutes in recovery
All sedatives and general anesthetic agents are negative inotropes (cause hypotension).
Exception: ketamine
Respiratory depression
Airway obstruction
Laryngospasm
Chest wall rigidity
We need to be familiar with these common causes of compromise and how to manage them.
Paradoxical chest wall movement
Accessory muscle use
StridorInspiratory only suggests a problem above the vocal cords (upper airway).
Inspiratory and expiratory suggests a problem below the larynx (lower airway).
Loss of CO2 trace on capnograph
Lack of airflow at mouth or nose
Noisy breathing
Snoring
Wheezing
Crowing, stridor
Gurgling
Loss of consciousness + flexion of the head = Airway obstruction
A shoulder roll will fix this!
Physical signs and symptoms
Capnography…best, earliest
Oximetry…very late
Tachycardia progressing to bradycardia…very late
Impedence pneumography will NOT detect!!
Supplemental oxygen may or may not prevent hypoxia if the airway is obstructed.
Perform triple jaw maneuver:
Head-tilt
Lift the jaw forward and up
Open the mouth
Stimulate patient (pain)
Insert oral / nasal airway
Use bag-valve-mask device
Antagonize opioids(nalaxone) and / or benzodiazepines (flumazenil)
Inadequate oxygenation and/or ventilation?
Open Airway:Use head tilt & jaw thrust
Consider shoulder roll for < 2yo
Provide supplemental oxygenCall for help
Signs of airway obstruction?
Insert NP or OP airway
Attempt PPV
Prepare for intubation
Apneic? Begin PPV
Consider drug-inducedrespiratory depression
Opioid-induced:Give nalaxone (Narcan)
0.01 mg/kg/dose IV, may double and repeat (max 2 mg)
Benzodiazepine-induced:Give flumazenil 0.01 mg/kg/dose IV, may double and repeat (max 1 mg)
Safe and effectivePainless route of administrationPredictable, rapid onset (< 15 minutes)Predictable duration (not much longer than the procedure)Antagonizable (“reversible”)No side effectsNo residual mental depression
Four questions should be asked when choosing a sedative drug for procedural sedation:
What are the desired clinical effects?
How quickly are the effects desired?
What is the desired duration of effects?
Are there any adverse “other” clinical effects?
• Titrate to effect• Give small incremental doses:
You can always give more, but its hard to take it back. “You have to give 10 before you give 20 and sometimes 10 is enough and 20 is too much.”
• Allow time for the dose to take effect before giving more.
• Different classes of drugs are often mixed to achieve a balanced effect; however, when different classes of drugs are mixed, the risk of respiratory depression is increased dramatically.
Hypnotics: Produce a state of sleep
Chloral hydrateBarbiturates:
Pentobarbital
IV General Anesthetics:PropofolKetamineDexmedetomidine
Anxiolytics: Reduce anxiety
Benzodiazepines
Amnestics: Inhibit formation of memory
BenzodiazepinesKetamine
Analgesics: Provide pain relief
Opiates
All of the above drugs have sedative properties. It is their additional properties which make them unique that we must also understand. These are what influence
our sedation planning and performance.
Painful vs. non-painful procedureNeed for immobility, amnesia, loss of consciousness?
** The procedure and drug plan should match. However, there’s no “magic bullet” or universal recipe for pediatric sedation.
A 6 year-old female needs a bone scan as part of an evaluation for persistent fevers. She otherwise has no significant past medical history and has never been sedated before. You classify her as an ASA I. Her airway and cardiopulmonary exams are normal.
Appropriate initial sedation strategies include all of the following:
A. Pentobarbital onlyB. Midazolam (Versed) onlyC. Midazolam (Versed) and pentobarbitalD. Chloral hydrateE. PropofolF. Ketamine IMG. A, B and CH. All of the above
Low
pai
nH
igh
pai
nLow immobility High immobility
Goal: Cooperation Sedative
Ex.: Echo, U/S, CT
Meds:Chloral hydrateMidazolam only
Goal: Sleep Hypnotic
Ex.: MRI, Nuc Med
Meds:Chloral hydrate ± MidazolamPentobarbital ± Midazolam
Goal: Cooperative/Comfortable Analgesia + Sedation/Anxiolysis
Ex.: Lac repair, CT or CVC insertion
Meds:Fentanyl ± MidazolamKetamine ± Midazolam
± Propofol
Goal: Cooperative/Analgesia Sedation + Analgesia
Ex.: BMA/biopsy, endoscopy, LP
Meds:Ketamine ± MidazolamFentanyl ± Midazolam
± Propofol
Chloral hydrate: The Gold Standard of the 1950sSedative, hypnotic, NOT analgesic, NOT amnesticUseful for immobility for non-painful procedures
Diagnostic imaging such as CT or MRI
“Antanalgesia” may intensify sensation of pain for patients in pain.Slow onset (15 to 45 minutes) and very long duration (4 to 6 hours)
Often leads to administration of additional doses, however then the patient remains over-sedated requiring prolonged observation.
Unreliable efficacy (fails more than 30% of the time) particularly in patients > 2 years of ageParadoxical excitement very commonCNS depressant – when it works it does one thing; it produces SLEEP and unconsciousnessDon’t use repeatedly or in hepatic/renal disease or in patients with dysrhythmias
Dosing:50 mg/kg PO for infants < 6 months75 to 100 mg/kg PO for older infantsMaximum: 1 g/dose, 2 g/dayAfter 20 minute and not sufficiently sedate then add 25mg/kgIf 2nd dose ineffective, consider augmenting with midazolam0.05 mg/kg up to 0.2 mg/kg IV.
Onset: 10 to 20 minutesPeak effect: 30 to 60 minutesDuration: 4 to 8 hours, rarely up to 40 hours
Works best in infants < 18 months of ageRectal route unreliableOral route best but nausea and vomiting are commonConsider co-administration of an anti-emetic:
Hydroxyzine (Vistaril®, Atarax®)Diphenhydramine (Benadryl®)
Poorly metabolized in the neonate and associated with hyperbilirubinemia(contraindicated in neonates)
Hypnotic, no analgesic or amnestic propertiesDose-dependent depression of all excitable tissues (CNS, autonomic NS, respiration, cardiovascular, GI tract, and liver)Anti-convulsant (particularly phenobarbital)Increased total sleep time and altered stages of sleepDepressed transmission in autonomic ganglia
May account in part for hypotension
Useful for sedation for non-painful procedures
Barbiturates depress respiratory drive, both response to hypercarbia and hypoxiaWith loss of consciousness, airway reflexes are lost and laryngospasm and airway obstruction may occur.Cardiovascular depression: direct vasodilator and blunts reflex response to hypotension.Barbiturates may produce paradoxical excitement (10%).Residual sedation may last 24 hours.
Oral (PO) Dosing:2 to 4 mg/kg, maximum 100 mgOnset time: 20 to 30 minutesDuration: 2 to 3 hours
Parenteral (IV) Dosing:3mg/kg IV, max dose 100 mg at one timeMay repeat in 1mg/kg aliquots every 3-5 minutes up to a total dose of 8 mg/kgOnset time: 3 to 10 minutesDuration: 1 to 3 hours, prolonged when combined with other sedatives
Not compatible with other drugs and IV fluidsWhen giving IV, give slowly by titration in small aliquots over 5 minutes
No faster than a rate of 50 mg/minCan produce general anesthesiaSlow onset, long durationMonitor, monitor, monitor
Generic Name:Midazolam
Diazepam
Lorazepam
Oxazepam
Triazolam
Brand Name:Versed®
Valium ®
Ativan ®
Serax ®
Halcion ®
**The physiologic effects are qualitatively similar for all of the benzodiazepines: All provide hypnosis, anxiolysis, sedation, amnesia, and are anti-convulsants.
Dose-dependent respiratory depressionRarely, an IV bolus can produce apnea
More vulnerable at extremes of age
Potentiated by concomitant opioid use
Blocks CO2 and O2 ventilatory drive
Hypnotic doses have minimal effects on ventilation in normal patients
The most commonly used benzodiazepine for procedural sedationSedative, anxiolytic, amnesticPeaks in 5 to 7 minutes, thus dose stacking is a concernMay precipitate hypotension which is additive with other drugsOccasional produces paradoxical disinhibition
Dose Stacking
DosingIV: 0.05 – 0.1 mg/kg/dose IV q3-5 min, Max 0.2 mg/kg or 6 mg/total dosePO: 0.25 – 0.5 mg/kg/dose x 1, Max 20 mg/doseIntranasal: 0.2 – 0.4 mg/kg/dose q10 min
Pharmacodynamics:Onset (min): 1 to 3 IV, 10 to 30 PO, 5 INDuration: 1 to 2 hoursReversible with flumazenil
Flumazenil is a specific benzodiazepine antagonist.Dose :
0.01 mg/kg IV, give in 0.2 mg increments to a max of 1 mg
A lack of response to flumazenil within 2 to 10 minutes strongly suggests that a benzodiazepine is not the cause of sedation or respiratory depression.The effects last for 30 to 60 minutes; resedation is possible.Flumazenil is ineffective for opioid, barbiturate, or tricyclic antidepressive overdose; it may induce seizures in the latter.
Produces general anesthesia (deep sedation) in one circulation time (approximately 30 to 40 seconds)
Rapid on, rapid off, titratable
Minimal analgesiaSignificant respiratory and hemodynamic side-effectsContraindicated for long-term sedation in pediatric ICU patients (>12 hours) due to fatal metabolic acidosisRequire Deep Sedation credentialing and Critical Care / Anesthesia training.
Selective 2 adrenoreceptor agonistT1/2 2 hours; undergoes hepatic metabolization
Spontaneous respiratory drive maintained
Sedative and analgesic properties
ICU and procedural Sedation as drip
Significant reduction in BP and HRRequire Deep Sedation credentialing and Critical
Care / Anesthesia training.
A 7 year-old male needs a bone marrow biopsy and aspirate as well as lumbar puncture for his 2 year acute lymphoblastic leukemia (ALL) protocol follow-up. You classify him as an ASA II. His airway and cardiorespiratoryexams are normal.
Appropriate choices to provide sedation and analgesia include:
A. PentobarbitalB. Midazolam (Versed)C. Midazolam (Versed) and fentanylD. Midazolam (Versed) and ketamineE. Chloral hydrateF. C and DG. B, C, and DH. All of the above
Low
pai
nH
igh
pai
nLow immobility High immobility
Goal: Cooperation Sedative
Ex.: Echo, U/S, CT
Meds:Chloral hydrateMidazolam only
Goal: Sleep Hypnotic
Ex.: MRI, Nuc Med
Meds:Chloral hydrate ± MidazolamPentobarbital ± Midazolam
Goal: Cooperative/Comfortable Analgesia + Sedation/Anxiolysis
Ex.: Lac repair, CT or CVC insertion
Meds:Fentanyl ± MidazolamKetamine ± Midazolam
± Propofol
Goal: Cooperative/Analgesia Sedation + Analgesia
Ex.: BMA/biopsy, endoscopy, LP
Meds:Ketamine ± MidazolamFentanyl ± Midazolam
± Propofol
Procedure pain is the pain inflicted on patients during medical procedures and includes:
Endoscopy
Bone marrow aspirations and biopsies
Interventional radiology (angiography, central line insertion)
Chest tube insertion
The drugs most commonly used to treat procedure pain are local anesthetics and opioids.
Age
Culture
Socioeconomic status
Previous pain experience
Anxiety-fear
Sleep deprivation
Respiratory↓ Tidal volume, functional residual capacity (FRC)
Cardiovascular↑ HR, BP, myocardial oxygen demand
Increased release of stress hormones↑ Catabolism, Na+ and H2O retention
Immunomodulation and immunocompromise
Altered coagulation
Dissociative anesthetic (hallucinations)
Potent analgesic
Amnesia
Minimal respiratory depression
Minimal hemodynamic side-effects
Bronchodilator
Nystagmus
Sialogogue
Emergence delirium and night terrors
“Herky-jerky” movements
Laryngospasm although rarely occurs
“ A real battlefield type of drug.”
Indications:
“High risk,” hypotensivepatients
Congenital heart disease
Asthma
Painful proceduresBurn debridement
Thoracostomy tube placement
Fracture reduction
Liver, kidney biopsy
Oral surgery
Contraindications:
Head trauma
Increased intracranial pressure
Increased intraocular pressure
Open globe ocular injury
Dosing0.5 to 1 mg/kg IV q 3 to 5 min, max 2 mg/kg
AdjunctsGlycopyrrolate (antisecretory) 0.005 – 0.01 mg/kg IV x 1, max 0.1 mg to minimize secretions
Consider supplementing with midazolam (may also reduce emergence delirium), particularly for older patients
Pharmacodynamics:Onset: Within 30 seconds
Duration: 1 to 2 hours
Nystagmus provides the best sign that the patient is unconscious
Eyes will remain open even after consciousness is lost
Patients may continue to talk (“dissociated”)
Spontaneous movement is common (myoclonus)
Opioids are strong analgesics that can be administered by virtually any route.
Most are agonists at the µ (mu) receptor (G protein coupled receptors).
At equipotent doses, all commonly used mu agonists (e.g. morphine, meperidine, fentanyl, etc.) produce similar degrees of respiratory depression, sedation, nausea, vomiting, constipation, and biliary spasm.
0.1 mg/kg Morphine = XX mg/kg
IV:0.001 fentanyl
0.015 hydromorphone
0.1 methadone
1 meperidine
PO:0.1 oxycodone
0.1 hydrocodone
0.3-0.5 morphine
1.2 codeine
Adverse effects:Sedation
Nausea / vomiting
Decreased bowel motility
Urinary retention
Histamine release
Seizures
Meperidine is no longer recommended for procedure pain.
It is associated with multiple problems:
Seizures
Catastrophic interactions with other drugs [monoamine oxidase(MAO) inhibitors]
1 mcg fentanyl = 50 to 100 mcg morphine
Parenteral (IV) Dosing: 0.5 - 1 mcg/kg/dose IV over 3-5 minutes
May repeat q 3 – 5 minutes
Max 50 mcg/dose, 3 mcg/kg/total dose
Pharmacodynamics:Onset: Almost immediately
Duration: 30 to 60 minutes
Sedation and analgesia, minimal amnesia
Risk of chest wall rigidity is associated with the rate
of infusion, thus slower infusion is better tolerated.
All of the bad (respiratory depression) and good (analgesia) effects of opioids can be antagonized (reversed) with nalaxone.Dose:
Respiratory depression: Start with 1 mcg/kg and keep doubling the dose until effectiveRespiratory arrest: 0.1mg/kg , 2 mg/dose max
Nalaxone can be given by any route and will work within seconds.The duration of action is approximately 30 to 45 minutes, which may be shorter than the drug (morphine or fentanyl) being reversed.
Maintain observation and consider giving by infusion.
Skin can be anesthetized with forethought!
Eutectic mixture of lidocaine and prilocaine (EMLA) cream, a combination of two local anesthetics, will anesthetize the skin in 90 minutes.
Lidocaine 4% cream anesthetizes skin within 30 to 60 minutes.
Placed on a needle site during patient preparation will significantly reduce pain during the procedure.
Interventional radiology
Lumbar puncture
IV insertion
Don’t forget – amnesia is often beneficial
Opiates, barbiturates, and chloral hydrate do not have amnestic properties.
Drugs without analgesic properties may exacerbate pain and cause delirium and excitement in sedated patients undergoing painful procedures.
The individual performing a procedure cannot also safely sedate a patient. A second provider is required.
All sedatives may cause respiratory depression. Drug combinations increase the risk of side effects.
The ability to RESCUE is key to safe sedation.
Evaluate for hypoventilation if there are changes in respiratory rate or pulse oximetry.
Sedation related hypotension occurs commonly. Consider giving a NS bolus.
Hepatic or renal insufficiency may prolong sedative metabolism and excretion.
Avoid using 2 non-reversible drugs.
Only narcotics and benzodiazepines have antagonists.
The same standard applies in all places, day or night!
Monitor, examine and remember to think!
