CHANGES IN PULMONARY MECHANICS DURING LAPAROSCOPIC GASTROPLASTY IN MORBIDLY OBESE PATIENTS

Background: Obesity is an important respiratory risk factor after abdo minal surgery. Laparoscopic surgical techniques seem beneficial in obe se patients in terms of respiratory morbidity, with a faster return to normal respiratory function. However, there is little information abo ut intraoperative respiratory mechanics and about patient tolerance to abdominal insufflation in the morbidly obese. Methods: We studied res piratory mechanics and arterial blood gases in 15 morbidly obese patie nts (mean BMI = 45) undergoing laparoscopic gastroplasty under general anaesthesia and controlled ventilation. Respiratory mechanics were an alysed using side-stream spirometry. Results: When compared to preinsu fflation values, servocontrolled abdominal insufflation to 2.26 kPa ca used a significant decrease in respiratory system compliance (31%), a significant increase in peak (17%) and plateau (32%) airway pressures at constant tidal volume with a significant hypercapnia but no change in arterial O-2 saturation. Respiratory system compliance and pulmonar y insufflation pressures returned to baseline values after abdominal d eflation. Conclusion: These alterations in pulmonary mechanics are les s than those observed with comparable degrees of abdominal inflation i n non-obese patients, and were well tolerated. From the point of view of intraoperative respiratory mechanics, laparoscopic surgery is safe in morbidly obese patients.