Ventilatory effects of laparoscopic cholecystectomy under general anesthesia.

Purpose: To investigate the ventilatory effect of laparoscopic cholecystectomy in patients under general anesthesia with epidural block.

Methods: We measured arterial blood gas, pulmonary carbon dioxide elimination (0000126;CO), the dead space/tidal volume ratio (V/V), and the alveolar-arterial PO difference [(A-a)DO] just before and 5, 10, 20, 40, and 80 min after peritoneal insufflation in eight patients who underwent laparoscopic cholecystectomy under general anesthesia with epidural block. The effect of laparoscopic cholecystectomy on these values was evaluated. The patients were ventilated on the controlled mode by Servo 900C with a constant tidal volume (V 10ml·kg) and frequency (respiratory rate 12 breaths·min) throughout the study.

Results: After starting peritoneal insufflation the PaCO showed a sudden increase during the initial 10 min of about 4 mmHg followed by a gradual increase thereafter. The increase in000123;CO was about 30ml·min (20%) on average during the initial 20 min, and a plateau was reached within 20-40 min after peritoneal insufflation. Neither V/V nor (A-a)DO showed significant changes during the study.

Conclusion: These results suggest that (1) transperitoneal absorption of CO may be the main cause of hypercarbia, and the hypercarbia is not attributed to the increase in V/V; and (2) oxygenation is not impaired during pneumoperitoneum.