ABSTRACT : The potential advantages of pressure controlled ventilation(PCV) over volume controlled ventilation(VCV) in non obese patients undergoing laparoscopic surgeries still remains unproven.This study was undertaken to compare the effects of PCV and VCV in non obese patients undergoing laparoscopic cholecystectomy with respect to cardiovascular stability, gas exchange and pulmonary mechanics.

METHODS : This single blind,randomised control trial was conducted in KMC Hospitals, Mangalore. We allocated 54 ASA I and II patients with BMI < 30 kg/m2 , scheduled for laparoscopic cholecystectomy to one of two groups, Group V and Group P to receive either VCV and PCV respectively. The ventilatory settings were adjusted accordingly to maintain EtCO2 of 35-40 mm Hg. Haemodynamic values, gas exchange and ventilator parameters were noted at two time intervals, T1- 5 minutes after tracheal intubation and T2 - 30 minutes after CO2 insufflation. Arterial blood gas analyses were done at the same time. The data was analysed statistically.

RESULTS : Both Group V and Group P were comparable as far as patient characteristics, operating time, volume of CO2 insufflation is concerned. Group P had statistically significant lower peak airway pressures and greater dynamic compliance at T2 than Group V. Group V was associated with lower pH and higher airway resistance at T2 than Group P (p<0.05).

CONCLUSIONS : Our results demonstrate that PCV may be an effective mode of ventilation in laparoscopic surgeries in providing adequate oxygenation, better alveolar recruitment and minimising peak airway pressures.