The impacts of super obesity versus morbid obesity on respiratory mechanics and simple hemodynamic parameters during bariatric surgery

Background: This study was designed to determine the impact of the degree of obesity on respiratory mechanics and simple hemodynamic parameters at laparoscopic bariatric surgery. Methods: The patients were divided into two groups, each of which included 24 patients (a morbidly obese group and a super obese group) undergoing laparoscopic bariatric surgery. Dynamic respiratory compliance, respiratory resistance, and peak inspiratory pressures were measured at four time points: 10 min after anesthesia induction (T1: induction), 10 min after pneumoperitoneum (T2: pneumoperitoneum), 10 min after terminating pneumoperitoneum (T3: end-pneumoperitoneum), and before extubation (T4: extubation). The systolic, diastolic, and mean arterial pressures and the heart rate values were measured noninvasively in T0 (10 min before operation). Results: Obesity was found to cause a statistically significant increase in respiratory resistance and a peak inspiratory pressure and a decrease in dynamic respiratory compliance. In the morbidly obese group, the lowest dynamic respiratory compliance was 37 ± 12 mL/cm H₂O, but it was 33 ± 13 mL/cm H₂O in the super obese group. The systolic pressure, diastolic pressure, and mean arterial pressure were found to decrease significantly in both groups. Conclusions: Morbid obesity and super obesity have negative effects on hemodynamics and respiratory mechanics.