Background: Obesity is a serious problem worldwide. During general anesthesia and post-operative period, obese patients more likely to develop post-operative pulmonary complications as atelectasis and impaired pulmonary function compared to non-obese. Intraoperative protective ventilation consisting of low tidal volume, high PEEP and recruitment maneuvers resulted in alveolar recruitment and optimization of intraoperative respiratory mechanics.
Objective: This study tested two strategies of mechanical ventilation in obese patients to find out which is best regarding gas exchange optimization, airway mechanics and atelectasis score.
Methods: Study was a randomized prospective comparative control study was carried out on 50 obese patients with BMI 30-50 kg/m2. Patients were prepared for laparoscopic cholecystectomy. Patient’s selection according to attendees at time of operation as a single numbers were protective ventilation (group A) and a double numbers were conventional ventilation (group B).
Results: Study showed significance between preoperative and postoperative pulmonary function tests and revealed better POST FVC in group A mean 86.04 (± 10.35) L, while in group B was 74.96 (± 14.73) L, p value (0.021). Better POST FEV1 in group A mean 73.56 (± 16.49) L, while in group B was 56.92 (± 8.340) L, p value (0.046). Better post-operative oxygenation in protective ventilation (group A). Mean Post P (A-a) O2 in group A was 27.93 (±7.76) mmHg, while in group B was 35.82 (±11.98) mmHg, p value (0.022).
Study found peak and plateau airway pressures were higher in protective group with no change in airway resistance. Pulmonary compliance was improved but, in this study revealed more alterations of the hemodynamics in the patients who were subjected to protective ventilation despite adequate preoperative fluid preload.
Hemodynamic instability observed in 24% in group A, but only occurred in 8% in group B. Study found that protective ventilation was superior to standard ventilation in prevention of atelectasis development 64%of the cases in group A revealed normal postoperative CT Chest and 36% showed lamellar atelectasis. In group B, 48% of the cases showed normal postoperative CT Chest, 40% revealed lamellar atelectasis and 12% showed plate atelectasis.
Conclusions: Study found protective ventilation was superior to conventional ventilation in prevention of lung atelectasis and associated with better oxygenation and pulmonary function tests in the post-operative in obese laparoscopic cholecystectomy. In spite of it was very effective in optimizing gas exchange, but associated with more hemodynamic affection.