Key words: Complications: carbon dioxide tanks; fire; laparoscopic surgery.
LAPAROSCOPIC surgery for elective cholecystectomy has undergone rapid acceptance since it initially was described in 1988. [1-3]Complications unique to laparoscopic surgery result mainly from the cardiopulmonary impact of creating a pneumoperitoneum and choice of insufflating gas. [4-6]Overall morbidity rates of 2-5% for laparoscopic cholecystectomy compare favorably to the 4-8% documented with open procedures. [7-9]We report a case of intraabdominal fire secondary to insufflating the incorrect concentration of carbon dioxide gas during a laparoscopic cholecystectomy.
This case involves a 62-yr-old, 114-kg, 150-cm man who presented with resolving acute pancreatitis and gallstones for elective laparoscopic cholecystectomy. Physical examination was significant for obesity and dullness to percussion at both lung bases. After induction of anesthesia and tracheal intubation, anesthesia and neuromuscular blockade were maintained with 0.5-1% isoflurane in 40% Oxygen2in nitrogen and vecuronium as needed to maintain two twitches in response to train-of-four stimulation.
Pneumoperitoneum was achieved with a Storz Electronic Laparoflator (Karl Storz Endoscopy-America, Culver City, CA), which was connected to the carbon dioxide tank by a collar specifically pin-indexed for carbon dioxide. The necessary laparoscopic equipment was maintained on a metal cart (Medi-Mech, The Dalles, OR). The carbon dioxide cylinder was located behind the laparoscopic cart, in a metal jacketed well that concealed the lower 90% of the tank. Approximately 2 h into what had been an uneventful surgery, a 2-cm "flame" arising from the tip of the electrocautery unit was visualized on the video monitor. Seconds later, as the electrocautery was being rapidly withdrawn through the trocar, the entire video screen turned orange-red and the abdominal wall was transilluminated. The presumed fire lasted approximately 2 s. Direct visual inspection of the electrocautery tip and trocar (Figure 1) revealed that both of these instruments had undergone combustion. The abdomen was immediately opened through a right subcostal incision. Visual inspection of the abdomen revealed no evidence of thermal injury with the exception of minor charring of the falciform ligament. Gross examination of liver, stomach, pancreas, and intestines was unremarkable. The gallbladder was removed, the peritoneal cavity lavaged with 3 liters of normal saline irrigation, and the abdomen closed in standard two-layer fashion. The remaining intraoperative and postanesthesia course proceeded without incident. The patient was discharged from the hospital on the 9th postoperative day without further complication.
After the incident, the carbon dioxide cylinder was removed from its protective metal jacket mounted on the back of the insufflator cart. Close inspection revealed a 3 cm-wide green stripe at the top of the tank, indicating the presence of oxygen (Figure 2). The remainder of the cylinder was gray, indicating the tank contained carbon dioxide. Examination of the concealed label on the carbon dioxide tank revealed that the gas was a mixture of 14% CO2and 86% O2. A telephone call to the gas supply company revealed that any cylinder with a carbon dioxide content of greater than 7% is fitted with a standard pin-index for carbon dioxide (Figure 3). Comparison of our tank, which contained 14% CO2, with another containing 100% CO2(Figure 2) confirmed that the pin-indexes were identical. None of the involved operating room staff were aware of the potential for this type of error.
Several reports in the literature document major complications during laparoscopic surgery that were the result of either pneumoperitoneum or the insufflating gas. [10-14]The first documented case of intraabdominal explosion was a nonfatal event that occurred in 1933 when Ferver used 100% Oxygen2as the insufflating gas. The use of carbon dioxide has been associated with both fatal and nonfatal injuries sustained during laparoscopic surgery. [11,14]Nitrous oxide has been implicated in several intraabdominal explosions described in the 1970s. [11-13]Current surgical practice is to use 100% CO2, because it is noncombustible and thus will not create an explosion should the electrocautery generate a spark or ignite bowel gas (methane/hydrogen). Diagnostic endoscopists prefer nitrous oxide, because it is better tolerated (less peritoneal irritation) in their awake patients and because they do not use electrocautery.
Several industry standards have been written and adopted to prevent the use of gases other than 100% CO2for laparoscopic surgery.* In addition, standard operating procedure at our institution only permits the placement of 100% CO2cylinders in our operating theater. Gas cylinders with a mixture of carbon dioxide and oxygen come from the distributor with a small green stripe at the top (Figure 2), indicating the presence of oxygen. The distributor also provides a large centrally placed label on the tank identifying the specific gas mixture within. As a further precaution, the gas insufflator collar uses the Compressed Gas Association (CGA) pin-index system, which is specific for carbon dioxide (CGA 940) concentrations greater than 7% (Figure 3). Operating room support personnel (nurses and technicians) are responsible for transporting the carbon dioxide cylinders from the storage area, mounting them on the laparoscopic carts and connecting them to the insufflating device.
Insufflation of this patient's peritoneal cavity with a gas mixture containing less than 100% CO2illustrates that the current safety features are not foolproof. Human error permitted a tank with a carbon dioxide/oxygen mixture into our operating theater. A member of the operating room support personnel mistakenly placed the incorrect cylinder into a metal jacket, concealing the tank's centrally placed label. This left only the thin green stripe at the top of the tank to warn members of the operating room staff of the presence of oxygen. Finally, use of the current medical gas pin-index system, which does not distinguish tanks containing 100% CO2from those containing carbon dioxide mixtures between 7% and 99% permitted us to connect a tank that contained 86% Oxygen2to the insufflation device.
The presence of a pin-index configuration specific for 100% CO sub 2 would have prevented our case of intraabdominal fire. The absence of documentation in the literature of similar disasters infers that the human error made in our case represents a rare breach in existing preventive measures. However, as the number of laparoscopic procedures approaches 1,000,000 per year, the likelihood of an event such as the one we report here will increase. Until a 100% CO2-specific pin-index fitting or appropriate safety mechanism is designed, avoidance of an intraabdominal fire relies solely on the vigilance of informed personnel. Review of this case by our quality improvement program resulted in inservice training of all operating room personnel (physicians, nurses, technicians) to alert them of this potential hazard. In addition, a more stringent check-in procedure for gas cylinders used in the operating theater was established. We report this case of intraabdominal fire during laparoscopic cholecystectomy to alert the anesthesia community of its potential to occur and to prompt efforts to eliminate this rare but potentially devastating complication.
*Manual of the Compressed Gas Association: Standards for Compressed Gas Cylinder Valve Outlet and Inlet Connections. Washington, D.C., 1994.