VENTILATORY AND BLOOD-GAS CHANGES DURING LAPAROSCOPIC AND OPEN CHOLECYSTECTOMY

As part of a randomized trial, ventilatory and arterial blood gas changes were assessed during open (n = 30) and laparoscopic (n = 30) cholecystectomy. Measurements were made during anaesthesia before the start of surgery and at the time of removal of the gallbladder. Despite an increase in minute ventilation from a mean(s.d.) of 5.7(1.4) to 6.1(1.2) litres, mean(s.d.) arterial carbon dioxide tension (P(aCO2)) rose from 5.3(0.9) to 6.0(0.9) kPa during laparoscopic cholecystectomy. End-tidal carbon dioxide tension (P(E'CO2)) had poor precision in predicting P(aCO2) (95 per cent interval of agreement - 0-61 to 1.93 kPa). Mean(s.d.)peak airway pressure increased from 17(4) to 23(4) cmH2O. The mean P(aCO2) - P(E'CO2) value did not change significantly, although there was significant within-patient variation. Arterial oxygen levels did not change significantly. By comparison, no clinically significant changes in ventilation or blood gas values occurred during open cholecystectomy. In conclusion, laparoscopic cholecystectomy requires a substantial but variable increase in minute ventilation to compensate for carbon dioxide absorption from the peritoneum.