77 Rchard W.M. Wahba Ma ach MSc r:rcpc, Mchael J. Tessler MD FRCPC, Smcha J. Kleman MD FRCPC Contnung Medcal Educaton Acute ventlatory complcatons durng laparoscopc upper abdomnal surgery Purpose: Ths artcle examnes and summarzes the publshed reports dealng wth subcutaneous emphysema, pneumothorax and carbon doxde (C02) embolsm durng laparoscopc upper abdomnal surged,. The purpose s to descrbe the expected clncal pcture, the d(fferental dagnoss and the management of these complcatons. Source: The nformaton was obtaned from a Medlne lterature search and the annual meetng supplements of Anesthesology, Anesth Analg, Br J Anaesth and Can J Anaesth. Prncpal fndngs: An abrupt ncrease n PztCO e s the frst sgn of subcutaneous emphysema and of pneumothorax. Desaturaton and ncreased arway pressure occur wth pneumothorax, but not wth subcutaneous emphysema alone. Desaturaton and ncreased arway pressure also occur wth bronchal ntubaton. The prelmbzary dagnoss s made by verj),ng the poston of the tube, examnaton of the patent./?)r swellng and creptus and auscultaton Jbr ar entry. Chest radography and paracentess confrm the dagnoss of pneumothorax, whch frequently occurs wth subcutaneous emphysema but s rarely of the tenson type. Pulmonary embolsm due to CO~ durng LUAS has not been reported, but the avalable data suggest that small, haemodynamcally nconsequental COe embolsm occurs wthout change n PLT"C02. Massve Key words COMPLICATIONS: respratory, subcutaneous emphysema, pneumothorax, pulmonary embolsm; LUNG: subcutaneous emphysema, pneumothorax, pulmonary embolsm; SURGERY: laparoscopy. From the department of anaesthesa, SMBD-Jewsh General Hosptal and McGll Unversty, Montreal, Canada. Address correspondence to: Dr. R.W.M. Wahba, SMBD- JGH, 3755 C6te Ste-Catherne, Montr6al, Qu6bec H3T I E2. Accepted for publcaton 31 August, 1995. embolsm s possble and wll markedly decrease PErC02, arteral 02 saturaton (Sp02) and blood pressure. Concluson: The mmedate recognton of the three complcatons requres contnuous montorng of PE't'COz, arteral saturaton, arway pressure, and an ndex of pulmonary complance. Objectf: Ce traval ~Stude et r~sume les publcatons portant sur l'emphys~me sous-cutand, le pneumothorax et I'embolsaton au gaz carbonque (C02) survenant pendant la chrurge laparoscopque de l '6tage sup~reur de l 'abdomen. L'objectf est de ddcrre le tableau clnque, le dagnostc d(ffdrentel et le tratement de ces complcatons. Source: Recherche nformatsde sur Medlne et les suppldments annuels d'anesthesology, Anesth Analg, Br J Anaesth et Can J Anaesth. Rdsultats: Une augmentaton subte de la PE'rC02 pr~yc~de l'emphysbme cutan~ et le pneumothorax. La ddsaturaton et l'augmentalon de presson aux voles adrennes survennent avec le pneumothorax mas non avec l'emphys~me cutand seul. Le dagnostc pr~;lmnare se fat en v~rfant la poston de la camde trach~ale, en recherchant le gonflement et les cr~ptatons, et en auscultant le thorax. La radographc pulmonare et la paracentbse confrment la dagnostc de pneumothorax qu survent fr~quemment avec l'emphysbme souscutan~ mas est rarement sous tenson. On n 'a pas rapportd d'emboles pulmonares au C02 pendant la chrurge laparoscopque de l'abdomen sup~reur, mas les donndes actuelle suggbrent que de pettes emboles de C02.vans consdquences h~;modynamques se produsent sans modfer la PL'rC02. L'embolsaton massve demeure possble et dmnue fortement la PL-t'C02, la saturaton artdrelle en 02 (SP02) et la presson art~relle. Concluson: La d~tecton mmddate des tros complcatons mentonn~es ndcesste un montorage contnu de la P.ErC02, de la saturaton en oxygbne, de la presson des voes adrennes et d' un ndce de la complance pulmonare. CAN J ANAESTH 1996 /43:1 /pp77-83
78 The laparoscopc approach to upper abdomnal surgery (LUAS) now ncludes a large varety of major procedures (Table 1) performed on larger portons of the surgcal populaton, many of whom can be Amercan Socety of Anesthesology (ASA) physcal class 11I and IV. The sheer ncrease n the number of patents and the varety of operatons performed should lead us to expect serous complcatons, whch must be recognzed mmedately and managed approprately. Two complcatons n partcular, pneumothorax (? carbothorax), whch s often preceded by subcutaneous emphysema, and pulmonary gas embolsm, are potentally lethal. A number of case reports, artcles and letters to the Edtors dealng wth these complcatons have been publshed. The purpose of ths presentaton s to collate and summarze the pertnent features of these case reports to provde a clear pcture of the clncal presentaton and of the dfferental dagnoss. An algorthm to ad n the latter s provded. The mechansms of these complcatons and ther management wll then be dscussed. As wll be seen, the frst sgn s an abrupt change n end-tdal CO 2 tenson (PETCO2). The latter can, n general, be used as an estmate of arteral PCO2 (PaCO2). There are tmes when ths does not hold true. The arteral to end-tdal PCO2 dfference may be ncreased n healthy and n ASA 3--4 patents durng LUAS, ~ such that PETCO2 may underestmate PaCO2. End-tdal PCO2 sometmes exceeds PaCO 2 (reversed gradent), ~ thus overestmatng PaCO2 Fgure 1 s a graphc representaton of publshed data showng these three possbltes. 2 We beleve that an early, modest ncrease n mnute volume to mantan PETCO2 at a constant, albet ncreased, level s helpful n mmedately detectng abrupt alteratons n PETCO2. Subcutaneous emphysema and pneumothorax Subcutaneous emphysema (SCE) s not a serous complcaton but t may be the harbnger of pneumothorax. Subcutaneous emphysema The clncal presentaton, accompanyng problems and the dagnoss that wll be presented are based on the nformaton avalable n eght case reports 3-1~ of SCE n 12 patents (Table II) and the prelmnary results of a prospectve study.~t CLINICAL PRESENTATION In most nstances, subcutaneous emphysema wll be evdent at about 45 mn after the start, although t may appear later or only at the end of surgery. There s no apparent age or sex predlecton. That complcaton frequently occurs durng surgcal manpulaton around the oesophagus. I1 The most consstent fndng s a sudden and brsk n- TABLE I CANADIAN JOURNAL OF ANAESTHESIA Laparoscopc upper abdomnal surgery I Cholecystectomy and blary surgery 2 Vagotomy and pyloroplasty 3 Nssen fundoplcaton 40esophagogastrectomy 5 Splenectomy 6 Colon resecton 7 Nephrectomy 8 Abdomnal trauma FIGURE I Arteral: end-tdal PCO2 gradents durng laparoscopc choleeystectomy. In most nstances the Pa-PETCO 2 gradent s mantaned at a level that the data ponts wll be wthn the parallelogram shown n the fgure. Ths les between the zero and 8 mmhg dfference lnes. At tmes, the gradent may be ncreased or reversed (the two rectangles). Under these two condtons, PE'rCO2 wll not provde a relable ndex of PaCO 2. Data from reference 2. crease n PETCO 2 and a very marked ncrease n PaCO2 (as hgh as 100 mmhg), 3'S concdent wth the appearance of subcutaneous emphysema n the upper body (face, neck and thorax). An ncrease n arway pressure (Paw) or decreased lung complance ndcate the presence of pneumothorax. 4,6,8 Ths was found n most nstances, but was of the tenson type n only two. Blateral pneumothoraces and pneumomedastnum also occurred (Table I1). A brsk ncrease n PETCO2 should be followed by an examnaton of the patent for SCE and auscultaton of the chest for ar-entry Chest radography s essental to verfy the presence of pneumothorax, unless one s dealng wth a tenson pneumothorax, wth ts attendant haemodynamc effects, whch requres mmedate thoracentess. MECHANISM The source of the subcutaneous emphysema durng LUAS s ether supradaphragmatc (from drect njury)
Wahba el al.: VENTILATORY COMPLICATIONS 79 TABLE II Subcutaneous emphysema: data table lap Onset Ste of Pneumo- Ref # Age Sex Op mmhg (ran) APETCO z emphysema Other sgns Remarks thorctr 3 I 61 F LC 20 30-45 To69 mmhg Face, chest No. Paw No evdent daphragmatc wrent. No followed unchanged PaCO2 104 mmhg. Increased by legs ventlaton to control PaCO 2 4 I 21 M LC 5-10 45 +13 mmhg Head, neck, Complance Blateral chest decreased 5 I 69 F LC 13 15 32 to 85 Neck, face No A Paw Mnute volume 16 L but PaCO2 No 100 mmhg 6 3 28 F LC 28 50 Intally Neck and chest Inc Paw Reduced QRS voltage No 32 M LC End Modest Scrotum, trunk Pneumomedastnum No 46 F LC End Not mentoned Chest, neck, Not mentoned face Pneumomedastnum 7 I 55 F LC 16 45 Increased Neck, chest 8 1 M LC? 45 Increased Face, neck, chest Inc Paw Blateral 9 2 33 LF? Late? Neck, chest Nl 32 LF? Late? Neck, chest Nl 10 2 M V 15? Increased Left neck M V I I? Increased Left neck Pneumomedastnum Surgcal njury recognzed Pneumomedastnum Thoracentess: CO2 < 10% I I 16 LF 13 Marked ncrease PE'rCO 2 stablzed by ncreasng mnute ventlaton by 33.3 (6)% vs 8.9 (5)% n the other 9 patents *Prospectve study of 25 patents. Abbrevatons: M = male; F = female; LC = laparoscope cholecystectomy; LF = laparoscopc fundoplcaton; V = vagotomy; lap = ntraabdondnal pressure; A = change; Paw = arway pressure. or nfradaphragmatc. Carbon doxde can pass through the daphragmatc foramna nto the medastnum and from there to the subcutaneous tssue planes of the head and neck -3,1~ Alternatvely, the nsufflated gas can track along a low resstance condut from the trocar nto the subcutaneous tssue planes drven by the nsufflatng pressure, 3,5 partcularly wth defectve or mproperly placed 3,t2 Verres needles. The gas may also be ntroduced drectly n the thorax tollowng nadvertent perforaton of the daphragm. PARTICULAR FEATURES There s no clear-cut level of nsufflatg pressure above whch subcutaneous emphysema s more lkely and no report has mentoned the volume of CO2 nsufflated. In uncomplcated laparoscopc cholecystectomy (LC), 27 _+ 2.5 L CO2 may be nsufllated durng the frst 30 mn. 2 Thus, any nsufflated volume greater than expected should arouse suspcon. The volume of CO2 that the lungs receve durng LC wth SCE s twce as large as that durng uncomplcated LC, wth a markedly ncreased PETCO 2.13 Durng the repar of ngunal hernae by the extrapertoneal approach (ntentonal SCE), the volume of CO2 delvered to the lungs and the PETCO 2 are much larger than that durng uncomplcated LC. t4 Subcutaneous emphysema durng LC has been reported n 9/40 patents n one study 13 and 2/10 n another report, t5 and s more lkely durng lengthy procedures, n partcular, fundoplcaton durng whch SCE occurred n 16/25 patents. ~t Subcutaneous emphysema can cause upper arway obstructon by compresson. ~6 Thus, close observaton of the patent for four to sx hours s necessary. In general, the emphysema wll resolve wthn a day or two, whereas the pneumopertoneum may persst for a week after surgery. ~7 MANAGEMENT The presence of SCE requres the followng: I Rulng out the presence of pneumothorax. 2 Increased ventlaton to mantan an acceptable PETCO2 and/or PaCO2. Ths has been acheved by ncreasng mnute volume by 33.3 _ 6%. ~ 3 Evaluaton of the upper arway at the end of the procedure. 4 Reassurance of the patent. Pneumothorax The followng presentaton of the clncal pcture, pertnent features and dagnoss s based on the nformaton avalable n 20 reported cases 7-~~ (Table III).
80 CANADIAN JOURNAL OF ANAESTHESIA TABLE III Pneumothorax: datatable Onset IA P Ref # Age M/F Op. Sde (mn) (mmhp) Clncal montors SCE Paw BP SpO 2 PL'tC02 x-ray Features and remarks 4 6 8 18 19 20 21 21 M I,C Blat 45'? 55 F LC Blat 45' 16? M LC Rt 45'? 60 F LC Lt Early? 50 F LC Rt Early? 61 F LC Rt 50'? 53 F LC Rt Alter?? No No lnc Inc Dec Dec Inc Inc? Dec Inc 9 Inc Dec Dec?? Inc? Dec Inc? No No Dec No 9 Dec Decreased complance Gas bubbles from thoracentess tube. Thoracenless CO 2 > 10% Thoracentess 800 ml 100% CO2 10 I 33 M LV Lt? 15 I 32 M LV Lt? 11 9 I 33 M LF Lt After ') 1 75 F LF After 22 I? M LF Lt Early? 23 I 29 M LF Lt 30' 12 I 41 F LF Lt 20' 12 No No Dec Inc? No Dec lnc 9 Inc? Dec? No Inc No Inc Thoracentess CO, > 10%. No bubbles durng oesophagoscopy Pneumomedastnum Complance decreased by 30 to 40% n the two patents 24 6 LF Lt:5 Durng 14 Blat: I Inc? No Inc Dec C dyn. PEEP 5 cm H20 curatve. Tear Dec In 2 Durng dssecton over Lt daphragmatc PaO2 crux Abbrevatons: M = male; F = female; LC = laparoscopc cholecystectomy; LF = laparoscopc fundoplcaton; V = vagotomy; lap = ntraabdomnal pressure; A = change; Paw = arway pressure. CI.INICAL PRESENTATION Ths complcaton can occur at any tme durng the procedurc 3'7"8'10'18-24 but may be noted only at the end. 9"21 As wth SCE, there s no predlecton for age or sex, and t may occur durng any LUAS. Pneumothorax s more lkely to occur on the rght sde durng LC (wth two reported blateral pneumothoraces) whle performng surgery around the oesophagus, t occurred mostly on the left sde. In the vast majorty, SCE was noted. The three most consstent sgns are an abrupt and marked ncrease n (I) PETCO2, (2) arway pressure (Paw) and a decrease n dynamc complance accompaned by (3) decreased arteral desaturaton (reduced SpO2). In some cases 7.~s mean blood pressure (MBP) was reduced, rasng the strong possblty that n those two cases a tenson pneumothorax probably occurred. There s lttle documentaton of the nsufflaton pressure used. The clncal dagnoss must be confrmed by auscultaton of the chest, and f possble, by an mmedate radologcal examnaton. Thoracentess wll provde mmedate relef and further confrmaton. The clncal presentaton of pneumothorax may be confused wth that of bronchal ntubaton. In both, an ncrease n Paw and a decrease n SpO2 occur. However, wth bronchal ntubaton, PETCO 2 should not ncrease ntally. Further, bronchal ntubaton usually occurs durng changes n patent poston and durng nsufflaton, whch causes a cephalad shft of the daphragm. The dfferentaton between pneumothorax and bronchal ntubaton s by consderng: (a) tmng: earler n the procedure n the case of bronchal ntubaton (b) PETCO2: no ntal ncrease wth bronchal ntubaton (c) repostonng the endotracheal tube wll rapdly mprove SpO2 and Paw wth bronchal ntubaton. Fgure 2 s an algorthm to ad n the dfferental dagnoss, and also summarzes the dfferences between SCE, bronchal ntubaton and pneumothorax. MECHANISM There are several suspected mechansms of LUASnduced pneumothorax. (a) Daphragmatc defects are often nvoked. 3'4,7'18,19 hnproper closure of the communcatons between the pleural and pertoneal cavtes durng gestaton result n daphragmatc defects. 4 A pleuro-pertoneal communcaton has been demonstrated n patents wth asctes. 25 It s qute probable that hgh abdomnal pressures open these potental canals. Daphragmatc blebs, whch may rupture causng pneumothorax, have been seen. 4 The nsufflated gas can reach the pleural space through the vena caval orfce n the daphragm. 7't~176 The falcform lgament dvdes superorly nto two layers and leaves a "bare area" from whch, f the lgament s perforated, gas can enter the medastnum, a~ Two other routes are the result of sur-
Wahba etal.: VENTILATORY COMPLICATIONS 81 I : DoutumUon J Incensed Paw! a) Reduced ar entry b) Hypen'uonnruco NO r ~/m~llng & r No ~u~ffve ] dagnoss FIGURE 2 LUAS.? IncmNd P~-r CO: I T "COS I yet Posldbty I Endobronchlal, Pnoun~4florax, IntuNtlon YeS No chango NO r No NO [? decr~sod PETCO2 ] OesaluraUon I NO change Um h~pot@nson Y~ EGG changes emphysema. I_.j Jo~ Algorthm: acute ventlatory complcatons durng gcal manpulaton. The tssue space surroundng the oesophagus s contnuous superorly wth the medastnum. As ths tssue plane s opened, as for example durng laparoscopc vagotomy, the nsufflated gas can track up nto the medastnum and create a pneumomedastnum. Further, the medastnal pleura mght be ruptured drectly durng dssecton resultng n a pneumothorax. 9.]7 A remotely possble route s retropertoneal nsufflaton. Fnally, durng laparoscopc herna repar, gas can track along the ngunal blood vessels va the retropertoneal space and nto the medastnum. ]6 The ncreased ntraabdomnal pressure and the head up poston have both been mplcated as contrbutory factors. MANAGEMENT I The dscontnuaton of nsufflaton and release of the pneumopertoneum. 2 Thoracentess 3 Hyperventlaton to lmt the ncrease n PCO 2, wth the knowledge that excessve hyperventlaton can be deleterous. An alternatve method of treatment recently advocated s the use of 5 cm H20 postve end-expratory pressure (PEEP). 24 The reasonng s that PEEP should reexpand the lung suffcently to permt reasonable gas exchange. In the fve patents n whom ths was attempted, arteral blood gases mproved and Paw decreased. 24 However, ths approach may not be ndcated n all cases. SUMMARY An abrupt and marked ncrease n PETCO 2 s lhe frst sgn of SCE and/or pneumothorax. But an ncrease n PETCO2 may also reflect an ncreased CO2 load or an ncreased cardac output, t A tenson pneumothorax wll cause smultaneous desaturaton and hypotenson. The approprate measures for ether complcaton are (I) dscontnue the nsufflaton temporarly (2) releve the pneumothorax by chest tube dranage (3) ncrease mnute ventlaton. The use of 5 cm H20 PEEP may be consdered. Carbon doxde embolsm Massve ar embolsm 26 has occurred durng laser laparoscopc cholecystectomy wth the classcal sgns: (a) precptous reducton n PETCO2, (b) auscultaton of a "mll-wheel" murmur (c) hypotenson and (d) desaturaton. We are unaware of documented cases of haemodynamcally mportant C02 embolsm durng LUAS. The nformaton regardng CO2 embolsm that wll be presented s from llustratve cases of CO2 embolsm durng gynaecologcal laparoscopes, from anmal work and from prelmnary reports utlsng transoesophageal echocardography (TEE) n patents undergong LUAS. Clncal presentaton Two case reports noted an ncrease rather than a decrease n PETCO2.27"28 In the frst, the authors noted a sudden 10% ncrease n FETCO2 shortly after the detecton of a "mll-wheel" murmur. 27 An ncrease n PETCO2, pror to the severe hypotenson, was also noted n the second case report. 28 Ths presentaton contrasts wth the abrupt reducton of PETCO2 followed by hypotenson 29 and the detecton of the murmur. However, the sequence of events followng the reported ncrease n PETCO2 n the frst two case reports explans the reason for ths dfference. In the frst case, 27 nsufflaton was mmedately stopped and the pneumopertoneum released. In the second, 28 very severe hypotenson followed and further nformaton on PETCO2 was not provded. The patent had to undergo complete cardopulmonary by-pass to vent the trapped CO2, wth full recovery. It s possble that the reported ncrease n PETCO 2 merely reflects the usual pertoneal uptake of CO2 pror to the embolzaton. Ths explanaton s supported by the ncreased "nose" detected by TEE durng LUAS, as wll be dscussed later. Mechansm In consderng the condtons necessary for CO2 embolsm durng LUAS, two ponts should be kept n mnd. The frst s that CO2 s very soluble n blood, whch also has a huge bufferng capacty. The medan lethal dose of CO2 gas embolsm n dogs s 25 ml- kg -I but only 5 ml. kg -I n the case of ar. 3~ That dfference s due to the hgh solublty of CO 2 n blood compared wth that n ar. The other s that central venous and pul-
82 CANADIAN JOURNAL OF ANAESTHESIA monary artery pressures are markedly ncreased durng laparoscopc surgery n the reverse Trendelenburg postonj The "drvng" pressure tbr embolzaton s the dfference between ntraabdomnal pressure and ntracardac pressure. That pressure dfference wll determne the volume of gas ntroduced nto the crculaton. The CO2 must come ether from massve transpertoneal uptake or by ntravenous njecton under pressure to tbrm a CO2 "lock." The effects of ntravenously njected CO2 on PE'rCO2, mean pulmonary artery pressure (MPAP) and systemc pressures n the pg depend on the volume njected. 31 Volumes greater than 0.1 ml kg -I- mn -I, e,ther by bolus njecton or by nfuson, caused a reducton n PETCO2, an ncrease n MPAP and hypotenson. Smaller volumes resulted n nsgnfcant changes n PETCO2. The volume of CO2 requred for detecton by transoesophageal echocardography was 0.26 _ 0.24 ml. kg -~ whle that requred to change PErCO2was 0.66 _ 0.51 ml. kg -~. The response s thus determned by the volume of CO 2 njected. Another study examned the effects of varous ntraabdomnal pressures durng CO2 nsufflaton on the occurrence of embolsm wth the vascular uptake of the gas occurrng through a 5 mm cut n an lac ven, thus more closely mmckng the clncal crcumstance. 32 At ntraabdomnal pressures <10 cm H20, only bleedng was seen through the laparoscope. In the pressure range of 10 to 25 cm H20, the transoesophageal Doppler consstently detected gas bubblng. Pressures >25 cm H20 caused collapse of the vens and cessaton of bleedng and gas bubblng. Thus, the dfference between ntraabdomnal and ntravascular pressure determnes whether CO2 embolsm and/or haemorrhage wll occur. Transoesophageal echocardographc montorng Transoesophageal echocardography s consdered the "gold standard" for the detecton of embol) ~ Pulmonary gas embol were detected by TEE n 10 of 15 patents undergong laparoscopc cholecystectomy. 33 In fve, the embol occurred durng nsufflaton and n the others durng dssecton, suggestng that small CO2 embol can occur ether by transpertoneal absorpton or by uptake va cut vessels. However, PE'rCO2, blood pressure, heart rate and saturaton were not altered durng the epsodes of CO2 embolsm. Haemodynamcally nconsequental, small echogenc dots travellng at hgh speed, suggestve of pulmonary embolsm, were noted n all patents n a smlar prospectve study of patents undergong laparoscopc cholecystectomy. 34 No changes n PETCO 2 occurred. Management 1 The patent must be placed mmedately n the left at- 2 3 4 5 eral poston. Ths wll releve the mechancal obstructon of the gas "lock" to blood flow through the rght ventrcular outflow tract. The change n the poston places the outflow tract below the rght atrum. lnsufflaton must be dscontnued and the pneumopertoneum released. Full cardo-pulmonary support must be nsttuted. Aspraton of gas by large bore catheters n the rght heart and pulmonary artery may be of some value. Complete cardopulmonary by-pass may be requred to evacuate the gas "lock" Summary Small CO2 embol occur durng LUAS and can be detected by TEE. Such mcroembol may ncrease PE'rCO2. Macroembol, suffcent to cause a gas "lock" and to decrease PEICO2 and hypotenson are also possble. Anmal studes suggest that the volume of gas njected and pressure of njecton are mportant. We should be aware that fatal CO2 embolsm can occur followng the laparoscopy) 5 Acknowledgment We thank Mrs. Sarah Scholl for her patent secretaral work. References 1 Wahba RWM, B~'que F, Kleman SJ. Cardopulmonary functon and laparoscopc cholecystectomy. Can J Anacsth 1995; 42" 51-63. 2 Wahba RWM, Mamazza J. Ventlatory requrements durng laparoscopc cholecystectomy. Can J Anaesth 1993; 40: 206-10. 3 Kent Il RB. Subcutaneous emphysema and hypercarba followng laparoscopc cholecystectomy. Arch Surg 1991 ; 126: 1154-6. 4 Prystowsky JB, Jercho BG, Epsten HM. Spontaneous blaleral pneumothorax - complcaton of laparoscopc cholecystcctomy. Surgery 1993; 114: 988-92. 5 Pearce D.I. Respratory acdoss and subcutaneous emphysema durng laparoscopc cholecystectomy. Can J Anaesth 1994; 41 : 314-6. 6 Hasel R, Arora SK, Hckey DR. Intraoperatve complcatons of laparoscopc cholecystectomy. Can J Anaesth 1993; 40: 459-64. 7 Woo/her DF, Johnson DM. Blateral pneumothorax and surgcal emphysema assocated wth laparoscopc cholecystectomy. Anaesth Intensve Care 1993; 21: 108-10. 8 Massey SR, Balaj B. Surgcal emphysema and laparoscopc surgery (Letter). Anaesthesa 1994; 49-356--7. 9 Bswas TK, Smth JA. Laparoscopc total fundoplcaton"
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