Laparoscopic surgery: It is no necessary to change ventilator mode to improve ventilation conditions; a controlled trial.

Backgrounds/aims: The main objective of this study is to compare the ventilatory effects of AFVC and PC modes with the VC mode in laparoscopic surgery of the gall bladder.

Methods: Thirty-five patients programmed for laparoscopic cholecystectomy were included. Four times were defined for all patients. The parameters studied were recorded ten minutes after anesthetic induction; and this is the time T1. The time T2 fits to 10 min after induction of pneumoperitoneum. Then, the ventilator mode was changed from VC mode to AFVC mode. Ten minutes later, the variables were scored; it was the time T3. The ventilator mode was then changed to a PC mode. The set pressure was adjusted in order to obtain the same Vt as at the time T2. The time T4 was 10 minutes after switching to PC mode.

Results: The Vte were increased, compared to time T2, during the AFVC and PC modes. The induction of pneumoperitoneum with CO induced a rise of PCO between T1 and T2. These had been accompanied by a significant rise in airway pressures. The change from VC mode to AFVC mode resulted in lower Prpeak and Prtray elevation without impacting dynamic compliance.

Conclusions: AFVC mode appears safe for patients in laparoscopic surgery. Its use, compared with VC, is associated with a decrease in Prpeak without effects on the Cdyn, oxygenation, capnia and hemodynamic parameters. We conclude that is no necessary to change ventlatory modes to improve ventilation conditions in non-obese patients.