AUSTRAliAN PHYSIOTHERAPY

George NtoumenopoulosKenneth Greenwood

OR I GIN A l ART Ie t E

Effects of cardiothoracicphysiotherapyonintrapulmonary shunt inabdominalsurgicaI patients

This study investigated the provIsion ofadditional eveningphysiotherapyon ·pulmonarycomplications and intrapulmonary shunt (Os/Ot)after abdominal surgery. Thirty--one elderlypatients received eitherdayl i9htonIy ordayl ightplus evening physiotherapy for up to 48 hours.Physiotherapy included combinations ofpositioning,gravity assisteddrainage, breathingexercises, manual techniques, coughing andairway suctioning. Measurements inc.luded0s/Qt and post-operative pu Imonarycomplications. While no significant differencein atelectasis was found, the post-operativeQ/Qt data averaged into six-hour time framesdemonstrated significantly lower mean Us/Otfor the daylight plus eveninglJhysiotherapygroup between 18 and 24 hours post-surgery.Additional evening physiotherapy may reducepost-operative deterioration in gas exchangeafter major abdominal surgery.{Ntoumenopoulos G and Greenwood KM:Effects of cardiathoracic physiotherapy onintrapulmonary shunt in abdominal surgicalpatients. Australian Journal of Physiotherapy42: 297,.303]

Key words: Intensive Care;Physical Therapy; Post-OperativeComplications; SurgeryGNtoumenopoulos BAppSc(Phty}, BSc(Anat),PhD is Senior Clinician, CardiothoracicPhysiotherapy, The Royal Melbourne Hospital.KM Greenwood BBSc(Hons), DipCompSc, PhDisa senior lecturer in the School of BehaviouralHealth Sciences J La Trobe University.Correspondence: Dr Ken Gre.enwDod, School ofBehavioural Health Sciences, Faculty of HealthSciences, La Trobe University, Victoria 3083.

he major pulmonarycomplications after surgery andtrauma include atelectasis and

hypoxaemia. The prevalence .ofpulmonary complications followingmajor surgery ranges from 25 per centto more than 90 per cent withincreased rates following upperabdominal surgery (Castillo and Haas1985). The rates reported depend inpart on the specific criteria used todefine complications and on thesophistication of the diagnostictechniques to document them (Beydonet aI1992).

Treatment to prevent.or modifypulmonary complications is a majorfocus of care by physiotherapists forthe peri-operative patient. There isevidence that regular cardiothoracicphysiotherapy·significantly decreasesthe incidence of pulmonarycomplications.after major abdominalsurgery, although there is no indicationofwhich treatment technique orregimen is superior (Castillo and Haas1985, Stiller and Munday 1992).

Ntoumenopoulosand Greenwood(1991) reported that in Australia, 19 ofthe 42 hospitals surveyed providedsome form of 24-hour cardiothoracicphysiotherapy service delivery, whereasthe other hospitals provided daylightonly services (eg 8 am-5 pm). Theobservation ofvariations in the hoursof provision ofcardiothoracicphysiotherapy services provided anoppornmity to study groups of patientswho received the standard treatment

coverage (daylight hours only) and agroup who received extended coverage(daylight plus evening).

Intensive care units (ICUs) thatundertake invasive peri-operativeevaluation and preparation of"at risk"surgical patients (eg Older and Smith1988) have reported reduced morbidityand mortality (Shoemakeret al 1988).Although this form of peri.,.operativeinvasive management is not widelypractised, it provides an oppornmity toinvestigate the effect of cardiothoracicphysiotherapy intervention onoutcome measures such as intra.,.pulmonary shunt (Qs/Q t Intra­pulmonary shunt was selected as themajor outcome variable, as it is a majordeterminant of arterialhypoxaemia(Giovanniniet a11983) and provides amore accurate index ofcardiopulmonary function than arterialoxygenation alone.

The aim of this study was todetermine whether the provision ofadditional after hours cardiothoracicphysiotherapy to the abdominalsurgical patient in the TeU improvedoutcome as gauged by changes inQs/Ql.andthe incidence of pulmonarycomplications as assessedradiologically.

MethodSubiectsArotal of31 consecutive elderlyabdominal surgical patients considered-

ORIGINAl ARTIClE AUSTRAliAN PHYSIOTHERAPY

Page 291to be at risk on the basis of increasedAmerican Association ofAnesthesiologists (ASA) scale and age(Hall and Hall 1996) were studied,with patients alternately allocated tothe daylight physiotherapy group(n = 15) and to the daylight plusevening physiotherapy group (n = 16).The patients studied were similar tothe "at risk" group described andinvestigated by Older and Smith(1988). Baseline data demonstratedthat the two physiotherapy groups didnot differ significantly on a number ofvariables relevant to cardiopulmonaryfunction (Table 1). The surgicalprocedures included repair ofabdominal aortic aneurysms, colorectalsurgery and other major vascularabdominal surgery, with no significantdifferences between the physiotherapygroups (Table 2).

MeasuresIn this study, Qs/Qt was the mainoutcome measure. The incidence ofpulmonary complications, assessed by-chest radiograph, and the requirementfor continuing mechanical ventilatorysupport, were also assessed. Shuntwas measured immediately before andafter cardiothoracic physiotherapytreatment (short-term effects) and alsoat regular intervals throughout thepatient's post-operative stay in theleu to determine whether the long-

term effects were related to the short­term effects.

A pulmonary arterial and intra­arterial catheter were inserted bymedical staff 24h prior to the plannedabdominal surgery, together withcontinuous electrocardiograph (ECG)monitoring. Baseline arterial andmixed venous blood were direcdysampled by nursing staff and analysedby a blood gas analyser(Instrumentation Laboratories 1312) toenable the calculation of arterial(PaOz) and mixed venous (PvOz)partial pressure of oxygen, arterial

(5aOz) and mixed venous (Sv02)

saturation, and Qs/Qt using a modifiedversion of the Bergrrens equation(Older and Smith 1988).

Qs/Qt was calculated according to thefollowing equation:

Q /Q = (CcOz - CaOz)s t

(Cc02 - CvOz)where Cc02 equals the oxygen

content in end capillary blood; Ca02equals the oxygen content of systemicarterial blood; and evo equals theoxygen content of mixeSvenous blood.The direct measurement of CcO isimpossible, therefore the Ideal AIveolarEquation is used as it is assumed thatthe end capillary P02 is equal to theIdeal Alveolar Oxygen. The CaOzandCv02 are calculated from themeasurement of arterial and mixedvenous saturation respectively (Olderand Smith 1988). Shunt values arenormally below 5 per cent (Older andSmith 1988).

The samples of arterial and mixedvenous blood required for thecalculation of Qs/Q

twere always taken

after the patient had been sittingupright for at least 20 minutes. Pre­operative cardiac output, using thethermodilution method, was alsodetermined by nursing staff (Older andSmith 1988). A portable erectanteroposterior chest radiograph wasobtained 1-2h following the insertionof the pulmonary artery catheter. Prior

AUSTRAliAN PHYSIOTHERAPY

to surgery, the physiotherapistclinically evaluated the patient'srespiratory system including thepattern of breathing, lung auscultationand cough adequacy and instructed thepatient in the peri-operativephysiotherapy regimens includinghourly deep breathing, coughing andlower limb circulation exercises.

Cardiopulmonaryfunctionmeasurements, including Q/Q} andoxygenation (arterial and mixedvenous) were determined and obtainedby nursing staff as previouslydescribed, at least Ih before andimmediately prior to physiotherapyand then at 20min and approximately2h following each physiotherapytreatment (short-term outcome). Inaddition to the measurement of Qs/Qtimmediately before and after eachsession of physiotherapy,measurements were obtained at leastevery 4-6h whilst in the leu (normally48h) to evaluate long-term outcome.

A further portable anteroposteriorchest radiograph (upright) was takenwithin 2 hours of the patient's returnto the ICU from surgery to determinethe post-operative pulmonarycomplications that may have developedimmediately after surgery prior to thecommencement of physiotherapy. Thechest radiographs were also repeated atapproximately 0600h each morning.One of three radiologists blind to thephysiotherapy group allocationevaluated the radiographs regardingthe film quality and the presence andseverity ofcardiopulmonary pathology.If the patients returned to the leuintubated and mechanically ventilated,then the time on mechanicalventilatory support was recorded. It isacknowledged ·that radiographic andauscultatory findings may have limitedreliability (Allingameet al 1995,Beydon et aI1992). However, thesevariables were included as they remaina routine part of clinical decisionmaking by the physiotherapist in themajority of settings.

All tabular nominal data wereanalysed using Chi-square or Fisher'sexact text (when appropriate). All twogroup comparisons with interval orratio data were made with independent

ORIGINAL ARTie l E

t tests. Intrapulmonary shunt data wereanalysed with two factor split plotfactorial ANOVA comparing the twogroups over time with post hoc testingvia simple main effects. For allanalyses, p < 0.05 was consideredsignificant.

Cardiothoracic physiotherapytreatment protocolsPhysiotherapy treatment after surgeryincorpor~teda combination oftechniques dependent on theevaluation findings, including deepbreathing exercises (diaphragmatic),positioning, gravity assisted drainagewith or without manual techniques(chest wall percussion and/or chestwall vibrations), coughing, airwaysuctioning and/or mobilisation of thepatient out of bed.

With the presence ofacute lungatelectasis/consolidation on the chestradiographandlor added lung soundson auscultation such as bronchialbreathing/crackles, physiotherapytreatment included gravity assisteddrainage, deep breathing exercises,manual techniques, coughing and/orairway suctioning. With the absence ofmajor clinical signs as previouslydescribed, treatment included deepbreathing exercises and coughingcombined with positioning.such assitting upright, sitting out of bed orside-lying.~ Once the patient was stabilised aftersurgery (body temperature> 36degreesC, ·heart rate >60 ·bpm and< 130 bpm without any compromisingarrhythmia, mean arterial bloodpressure> 70 mmHg < 120 mmHg,mean pulmonary arterial pressure< 30mmHg, pulmonary capillarywedge pressure < 17 mmHg, calculatedSaOz > 90 per cent and calculatedSvOz > 60 per cent (from sampledarterial and mixed venous bloods,respectively), cardiothoracicphysiotherapy was commenced.Cardiothoracic physiotherapytreatments were applied by the samephysiotherapist (GN) to reduce thevariability in the method of assessmentand treatment application. Thephysiotherapist was blind to themeasures of oxygenation and Qs/Qt

throughout the study, so these resultswere not considered in the treatmentdecision making process.

Daylightcardiothoracicphysiotherapy involved the provisionof two sessions of physiotherapybetween 0830h and 1700h, once in themorning.andonce in the afternoon.Such procedures are consideredstandard practice in many Australianhospitals (Ntoumenopoulos andGreenwood 1991). Daylight plusevening physiotherapy alsoincorporated two sessions oftherapybetween 0830h and 1700h and at leastone further session oftherapy between1700h and 21 OOh. These routines werecontinued for up to 48h after surgery.In between these physiotherapytreatments, nursing staff wouldencourage deep breathing andcoughing hourly, perform airwaysuctioningand position patients fromside to side two-hourly as required.

All patients in this study were thosewho would normally have beenadmitted to the leu pre-operatively asa matter of policy of the Division ofAnaesthesia and Intensive Care ofWestern Hospital in Melbourn. Theperi-operative ICU procedures wereexplained to the patients by themedical staff and· patient consent forthe procedures was obtained. Thedirector of the ICUdeemed that asthis study involved standardcardiothoracic physiotherapytreatment as already provided in thislCU, patient consent for the additionalevening physiotherapy was notrequired. Ethical approval for theconduct of the .study was obtainedfrom the Western Hospital EthicsBoard.

ResultsClinical management andassessment finaingsAll patients were transferred directlyfrom theatre to the ICU. Somepatients were· left intubated and otherswere extubated in theatre.Approximately 50 per cent of thepatients returned to the leu

Figure 1.Mean (Sf) six-hourly QJ~ peri ..operative data for daylight and daylight plus eveningphysiotherapy groups from the pre..operative baseline (pre) to up to 5411 after surgery.

From Page 299intubated, with no significantdifferences between the physiotherapygroups. During the majority ofphysiotherapy treatments (83 per cent),patients were non-intubated. Patientswere receiving some form of inotropicsupport, including dopamine,dobutamine and/or glyceryl trinitrate(GTN) during 79 per cent ofphysiotherapy treatments. The methodof analgaesic management included theadministration of narcotics via theintravenous route (22 per cent),epidural route (52 per cent), orcombination of both (26 per cent),with no significant differences betweenthe two physiotherapy groups.Decreased and adventitious lungsounds were often auscultated by thephysiotherapist before treatment.Diminished breath sounds, cracklesand bronchial breathing were notedprior to 97 per cent, 59 per cent and 21percent of treatment sessionsrespectively. There were no majordifferences between the twophysiotherapy groups on any of thesefindings.

Specific physiotherapytreatment procedures usedPhysiotherapy techniquespredominantly included positioning(gravity assisted drainage, side-lyingand sitting out of bed), deep breathingexercises (Stiller and Munday 1992),coughing and airway suctioning(endotracheal or nasopharyngeal).Details of the techniques used areprovided in Table 3. No significantdifferences were found between thephysiotherapy groups on any of thesetreatment variables. Mean (SD)duration of physiotherapy assessmentand treatment was 41 (10) minuteswith no differences between thephysiotherapy groups.

The daylight plus eveningphysiotherapy group did, of course,receive significantly morephysiotherapy treatments than thedaylight physiotherapy group (5.3 [0.7]vs 3.1 [0.9] treatments respectively).Treatment also commencedsignificantly sooner after surgery in thedaylight plus evening physiotherapy

ORIGINAl ARTICLE

group (3.4 [1.4] hours) compared withthe daylight physiotherapy group (8.418.6] hours). This resulted becausephysiotherapy treatment co~encedfor all, the patients in the daylight plusevening physiotherapy group on theevening ofsurgery, whereas somepatients (n =5) in the daylightphysiotherapy group, due to the timingof their return from surgery (lateafternoon or evening), did not receivephysiotherapy treatment until the firstpost-operative day

Post-oJ?er~tive pulmonarycomplicationsAcute atelectasis, verifiedradiologically, developed in 16/31patients (51 per cent) with nosignificant differences between the twophysiotherapy groups. Patients fromthe daylight physiotherapy group whoreturned to the leu intubated andmechanically ventilated, remainedintubated for (mean [SD])18.10 [12.90] hours, compared withonly 9.40 [17.90] hours for the daylightplus evening physiotherapy group, butthe difference was not significant(t(13) = 1.10, P=0.29).

AUSTRAliAN PHYSIOTHERAPY

Investigation of short-termeffects of cardiothoracicphysiotherapyA total of 132 treatments were appliedto the 31 patients after surgery, with 85treatments applied to the daylight plusevening physiotherapy group and 47treatments applied to the daylightphysiotherapy group. There were nosignificant changes in Q IQimmediately after physi~thetrapy.Themean (SD) pre-treatment Q /Qr was17.3 (7.4) per cent which did not differsignificantly from the post-treatmentvalue of 16.9 (6.8) per cent.

long-term changes in Qs/QtMean (SE) Q/Qr values during the 6htime periods tollowing surgery arepresented in Figure 1 for both groups.The groups had similar pre-operativeQs/Qt values of approximately 10 percent. In the first six hours aftersurgery, Qs/Qt was increased to around15 per cent for both groups, againwithout major differences between thetwo groups. After this time, the valuesfor the daylight group exceeded thoseseen in the daylight plus evening

AUSTRAliAN PHYSIOTHERAPY

group. The values beyond 42h shouldbe viewed with some caution, as a largenumber of patients had left the ICU bythis stage and these values wereobtained from more seriously illpatients.To analyse the averaged Qs/Qt data

by two factor ANOVA, comparing thetwo treatment groups (daylight versusdaylight plus evening) over the nine 6h

ORIGINAL ARTICLE

time periods, complete data sets foreach subject over the repeated measureare required. The most complete datasets for this analysis were available onlyup to 36h after surgery, with 16/16patients from the daylight plus eveningphysiotherapy group and 13/15patients from the daylightphysiotherapy group included. At 42h,only 12 daylight and 15 daylight plus

evening patients remained. At 48h thenumbers remaining in the ICU werenine and 15 respectively and at 54honly five remained in each group.

The two factor ANOVA comparingthe average Qs/Qt data in six hour timeframes across the 36h post-operativeperiod resulted in a significant maineffect for time (F(6 162) = 19 ~ 15,P < 0.001) and a si'gmficant group bytime interaction (F(6 162) = 2.33,P< 0.05). Post hoc tests, using simplemain effects, found no differences inQs/Qt before surgery and for each 6htime period up to 18 hours aftersurgery in both physiotherapy groups(Table 4). However, between 18 and24 hours after surgery, significantlylower Qs/Qt was displayed in thedaylight plus evening physiotherapygroup compared with the daylightphysiotherapy group (Table 4). Beyondthis time frame, differences ofimportant clinical magnitude werefound but they failed to reachstatistical significance.

DiscussionThis study provides some evidence thatthe provision of additional eveningcardiothoracic physiotherapy asdescribed in this study may assist inlowering Qs/Qt in the elderlyabdominal surgical patient. Thephysiotherapy groups did not differsignificantly on relevant measures ofcardiopulmonary function prior to orimmediately after surgery, whichprovides some support for theinference that the additionalcardiothoracic physiotherapy wasresponsible for the differences inQs/Qt observed~ However, the studyhas several limitations, including thesmall numbers of patients investigated(which may have reduced power) andthe use of multiple physiotherapytechniques. In addition, the daylightplus evening physiotherapy groupcontained a slightly greater proportion(not statistically significant) oflowerabdominal surgery patients in whichhas been previously reported to beassociated with a lower incidence ofpost-operative pulmonary

from Page 301complications (Castillo and Haas1985).The statistically significant

differences in Qs/Qt

observed emergedbetween 18 and 24 hours post-surgery,and, while significant only during thattime period, appeared to persist for theremainder of the 48hobservationperiod. Whether the magnitude of thedifferences in Qs/Q

tbetween the two

physiotherapy groups affectedmortality and morbidity (eg length ofstay), should be further investigatedwith greater patient numbers(Shoemaker et aI1988).

The additional physiotherapy failedto lower the incidence of acuteatelectasis. However, considering thepoor sensitivity of the portable chestradiograph in detecting atelectasis(Beydon etal 1992), a limited emphasisshould be placed on these findings. Atrend in the data indicated a reducedrequirement for mechanical ventilatorysupportin the daylight plus eveningphysiotherapy group. This may havebeen due to the earlier start ofcardiothoracic .physiotherapytreatment after surgery and theincreased frequency ofcardiothoracicphysiotherapy treatment over the earlypost-operative period.

It is not clear from this study exactlywhat aspect of the additionalcardiothoracicphysiotherapy receivedby the daylight plus evening group mayhave been responsible for the improvedQs/Qt. It could be associated with theincreased number of physiotherapysessions received by this group.Alternatively, it could be a function ofthe extension of treatment into theevening hours rather than beingassociated solely with increasedtreatment sessions. A final potentialexplanation is that the improvedoutcome in the group was due to lesstime elapsing between surgery and thefirst treatment session. A differentstudy would be required to separatethese alternative explanations.

Improvement in Qs/Qt after similarcardiothoracic physiotherapy regimensas used in the present study has been

o RIG INA L ARTie lE

demonstrated by Mackenzie and Shin(1985) in young multi-trauma patients.In addition, increased clearance ofairway secretions (Hammon 1983),improved totallung/thorax .complianceGones et a11992, Mackenzie and Shin1985) and arterial oxygenation (Stilleret al 1990) after physiotherapy has alsobeen demonstrated in a variety oftrauma, surgical and medical patients.

However, some studies have alsoreported adverse short-term effectsassociated with cardiothoracicphysiotherapy, including increased ordecreased cardiac output (Laws andMcIntyre 1969),· reductions in arterialoxygenation (Conners et al 1980, Tyleretal 1980) and mixed venousoxygenation (Barrell and Abbas 1978).Possible causes of these adverseresponses include ventilation andperfusion mismatching with change ofposition, in addition to arterial andmixed venous desaturation with theincreased metabolic demands of thephysiotherapy procedures (Aitkenheadeta11984, Glauseret a11988, Klein etal 1988, Weissmannet aI1984).Pharmacologic therapy may be used toalleviate some of the increasedmetabolic and haemodynamic demandsofcardiothoracic physiotherapytreatment (Kleinet al 1988). Thepresent study overall did not find anyadverse short-term changes incardiopulmonary function as assessedby.Qs/Qt• Even if these occurred, itseems that over the long term, thecardiothoracic physiotherapytechniques applied in this study had nodetrimental effects on the patientsstudied.

ConclusionThis study provides some evidencesuggesting that additional eveningcardiothoracic physiotherapy aftermajor abdominal surgery may lowerthe post-operative deterioration ingaseous exchange as.indicated byQs/Q

tin elderly at risk patients.

However, it is unclear whichteclmiques of physiotherapy, if any,were beneficial. Further investigationwith larger patient numbers iswarranted.

AUSTRAliAN PHYSIOTHERAPY

AcknowledgmentsThe authors.gratefully acknowledgethe support and assistance of Dr PaulOlder, Director of Critical Care, andthe nursing staff at the WesternHospital Critical Care Unit, withoutwhom this study could not have beenundertaken4In addition, we would liketo thank Dr Jim French and theRadiology Department for theevaluations of the chest radiographsand the Physiotherapy Department fortheir valued support and dedication tothis study.

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