Transperitoneal absorption of thermocautery-induced carbon monoxide formation during laparoscopic cholecystectomy

Carbon dioxide pneumoperitoneum (PP) during laparoscopic cholecystectomy (LC) causes hypercapnia and acidemia. Thermocautery carbon monoxide formation during LC was studied in 15 patients. CO samples were read by electrochemical sensor as parts per million (ppm) and obtained intraperitoneally at PP, gallbladder takedown (GBTD), and exhalation. In blood, CO was measured by spectrophotometry as percentage of carboxyhemoglobin (HbCO) during anesthesia induction, at end of PP, at GBTD, and in the recovery room. Heart rate, mean arterial pressure, oxygen saturation, and end-tidal CO2 were followed prospectively. Data were analyzed by analysis of variance and Student's t test. In 35 min, thermocautery increased intraperitoneal CO from 4.7 +/- 3.8 ppm at baseline to 326 +/- 360 ppm at GBTD (p < 0.004). HbCO increased from PP to GBTD (0.7 +/- 0.6 vs. 1.2 +/- 0.7%; p < 0.01). Thermocautery produces high levels of CO intraperitoneally, which are absorbed into the circulation. Exposure time is short, which may explain the lack of hemodynamic and oxygenation changes.