Evaluation of the effects of different ventilation modes used during awakening from anesthesia on the frequency of postoperative atelectasis in adult patients undergoing surgical intervention

BACKGROUND: In our study, we aimed to detect atelectasis developing in patients undergoing surgery under general anesthesia using transthoracic lung ultrasonography and to investigate the effect of ventilation methods used during recovery from anesthesia on the formation of postoperative atelectasis. METHODS: After obtaining the approval of the ethics committee, 278 patients who were 18 years of age and older, who underwent endotracheal intubation for 1-3 hours and who would undergo surgery under general anesthesia with physical status I and III of the American Society of Anesthesiologists (ASA) were included in the study. Patients were divided into groups according to their mode of awakening at the end of surgery.In the postoperative recovery unit, a total of 12 regions were examined by transthoracic lung ultrasonography, 4 of the anterior wall of the thorax, 4 of the right and left lateral regions, and 4 of the posterior region. According to the modified lung USG system, each region was scored between 0 and 3 according to the rate of development of atelectasis, and the total score was obtained for each patient. Oxygen saturations, measured by pulse oximetry at the 30th minute of admission to the recovery unit and recovery, were recorded for all patients. The results were evaluated as significant at the p<0.05 level. RESULTS: There was no statistically significant difference between the groups in terms of demographic data, operation time and recovery time from anesthesia. A statistically significant difference was found in the postoperative lung USG score in the group that underwent manual ventilation during extubation compared to the group that underwent pressure support ventilation (p<0.05). Atelectasis was observed in 106 (76%) patients in the ventilation group and 84 (60%) in 139 patients in the pressure support ventilation group (p=0.005). Atelectasis was most common in the posterior and basal dependent regions of the lungs. Oxygen saturation measured in the postoperative recovery unit at the entrance and at the 30th minute was not statistically different between the groups (p=0.740, p=0.388). CONCLUSİON: The incidence of postoperative atelectasis was lower in patients who received pressure support ventilation during recovery from general anesthesia compared to those who received intermittent manual assistance. It is important for anesthesiologists to gain experience in detecting this developing atelectasis with lung USG, which is a rapid and reproducible method in the early period.