THE RISK OF CARBON-MONOXIDE POISONING AFTER PROLONGED LAPAROSCOPIC SURGERY

Objective: To evaluate whether thermal energy produced by laser and bi polar electrosurgery during laparoscopic procedures significantly elev ates blood carboxyhemoglobin levels. Methods: We prospectively studied 27 healthy nonsmoking patients, mean +/- standard deviation (SD) age 39.1 +/- 8.0 years (range 22-56), scheduled for laparoscopic procedure s in which smoke was generated. Prolonged operative laparoscopy involv ed high-flow carbon dioxide insufflation, intensive evacuation of intr a-abdominal smoke, and controlled hyperventilation with 50-100% oxygen . Laser and bipolar electrosurgery were used in all cases. Blood sampl es were drawn before and after surgery. Carboxyhemoglobin concentratio ns were measured using a highly accurate gas chromatography method. Re sults: The mean +/- SD duration of surgery was 141 +/- 72 minutes (ran ge 45-300). The mean +/- SD carboxyhemoglobin levels were 0.70 +/- 0.1 5% (range 0.44-1.20%) before surgery and 0.58 +/- 0.20% (range 0.30-1. 33%) after surgery. A significant decrease (P < .001) in carboxyhemogl obin concentrations occurred during surgery (mean +/- SD, 20 +/- 11%; range 3-46%). The carboxyhemoglobin level was increased at the end of surgery in only one woman. In only one patient did the levels exceed 1 % (1.33%), still well below the human threshold tolerance level of 2%. The Spearman correlation coefficient between carboxyhemoglobin concen trations and duration of surgery was r = 0.308 (P = .12). Conclusion: Carbon monoxide (CO) poisoning is not associated with even prolonged l aparoscopic surgical procedures. This may be attributed to aggressive smoke evacuation that minimizes exposure to CO, and to active eliminat ion of CO by ventilation with high oxygen concentrations.