Does hypocapnia before and during carbon dioxide insufflation attenuate the hemodynamic changes during laparoscopic cholecystectomy?

Background: Hypocapnia before and during carbon dioxide (CO(2)) insufflation for laparoscopic cholecystectomy may reduce the adverse hemodynamic responses.

Methods: After ethical approval, 100 patients scheduled for laparoscopic cholecystectomy were ventilated using a tidal volume of 8 ml/kg, an inspiration:expiration ratio of 1:2.5, and a positive end-expiratory pressure (PEEP) of 5 cm H(2)O. At 15 min before CO(2) insufflation, the patients were randomly allocated into two groups of 50 patients each. For the normocapnia group, the respiratory rate (RR) was adjusted to maintain arterial CO(2) tension (PaCO(2)) at 35 to 45 mmHg. For the hypocapnia group, the RR was adjusted to maintain PaCO(2) at 30 to 35 mmHg. Anesthesia was maintained with sevoflurane 2% to 2.5% in 40% air oxygen and rocuronium. Hemodynamic variables, PaCO(2), end-tidal CO(2) tension (EtCO(2)), arterial-to-end-tidal CO(2) (Pa-ETCO(2)) gradient, and RR were recorded.

Results: Compared with the control group, the use of hypocapnia before and during pneumoperitoneum was associated with significantly lower arterial blood pressures, lower PaCO(2) and EtCO(2) values, a higher Pa-ETCO(2), a higher RR (p < 0.001), and less need for supplemental doses of fentanyl and labetalol.

Conclusion: The authors conclude that the use of hypocapnia before and during CO(2) insufflation is effective in attenuating increases in blood pressure after CO(2) pneumoperitoneum during anesthesia for laparoscopic cholecystectomy.