A Comparison between Volume-Controlled Ventilation and Pressure Controlled Ventilation Volume Guaranteed in Providing Better Oxygenation in Obese Patients Undergoing Upper Abdominal Laparotomies, MAI M. EL-RAWAS, IKRAMY M. ABD EL-GHAFFAR, SAHAR A. TAWFIC, MAIE K. HELALY and TAREK A. RAAFAT
Abstract
Background: The maintenance of adequate oxygenation is an important issue during anesthesia of obese patients. There is no specific guideline on the ventilation modes for this group of patients. Although several studies have been performed to determine the optimal ventilatory settings in these patients, the answer is yet to be found. The ideal venti-lation strategy is expected to optimize gas exchange and pulmonary mechanics and to reduce the risk of respiratory complications. This work was planned to test the hypothesis that a new mode of ventilation Pressure-Controlled Ventilation-volume Guaraaranteed (PCV-VG) is associated with improve-ments in gas exchange and outcome when compared with the conventional Volume-Controlled Ventilation (VCV) in obese patients undergoing upper abdominal laparotomies.
Subjects and Methods: Sixty obese patients with normal preoperative pulmonary functions scheduled for upper abdom-inal laparotomies were randomized into two groups. Those in group A received VCV and those in group B received PCV-VG. Arterial blood gases (ABG) were obtained pre-, intra-and postoperatively. Peak expiratory flow rate (PEFR) and CT chest were done pre and postoperatively.
Results: PEFR values were significantly lower postoper-atively when compared to the preoperative values in each group. However, there was no difference when comparing the values of the two groups postoperatively. There was no difference between the two groups as regards to occurrence of postoperative atelectasis. There was no statistical difference in arterial partial pressure of oxygen (PaO2) and arterial oxygen saturation (SaO2) between the two groups intra-and postoperatively. However, arterial carbon dioxide tension (PaCO2) was lower in the PCV-VG group intraoperatively.
Conclusion: PCV-VG group showed no advantage over VCV as regards to the occurrence of atelectasis or as regards to oxygenation. However, PCV-VG offered better CO2 clear-ance.