Comparison of pressure and volume-controlled ventilation in laparoscopic cholecystectomy operations.

Background And Aims: Laparoscopic cholecystectomy has many advantages such as shorter hospital stay of patients, minimal postoperative pain, rapid recovery after the operation; however, systemic disadvantages because intra-abdominal pressure, position and general anaesthesia may also appear. In this study, pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) modes during laparoscopic cholecystectomy operations were compared in terms of their effects on haemodynamic, respiratory and blood gas parameters.

Methods: Patients were randomly assigned to two groups according to the modes of mechanical ventilation, either to the PCV group, group P (35 patients) or to the VCV group, group V (35 patients). A standard electrocardiogram, pulse oximetry, non-invasive blood pressure, end-tidal CO2 , BIS and TOF monitoring were performed. Anaesthesia was induced with propofol, fentanyl and rocuronium. Anaesthesia was maintained with 50% O2  + 50% N2 O, propofol infusion and fentanyl. Haemodynamic data, respiratory parameters, arterial blood gases of the patients were measured. Dynamic compliance of the respiratory system, oxygenation index, alveolar-arterial oxygen gradient and dead space ventilation to tidal volume ratio were calculated.

Results: No difference was detected between the groups in terms of descriptive data, operation, anaesthesia, pneumoperitoneum and recovery period (P > 0.05). Haemodynamic data and blood gas values were compared between the two groups, and no significant difference was found (P < 0.05). After pneumoperitoneum, lung compliance decreased in both groups, more importantly in the Group P (P > 0.05). Tidal volume increased 10 min and 20 min after insufflation in the Group V (P < 0.05). Alveolar dead space ventilation to tidal volume ratio before pneumoperitoneum and alveolar-arterial oxygen gradient after pneumoperitoneum were significantly higher in the Group P compared to the Group V (P < 0.05). Dynamic compliance of the respiratory system was similar in both groups.

Conclusion: In this study, with volume-controlled ventilation anaesthesia in laparoscopic cholecystectomy, higher tidal volume and lower alveolar-arterial oxygen gradient were achieved after pneumoperitoneum. These findings indicated that VCV mode can provide a better alveolar ventilation than PCV mode in laparoscopic cholecystectomy operations.