Assessment of changes in lung aeration and diaphragmatic function using ultrasonography in laparoscopic abdominal surgery: a prospective observational study

Background: A few studies investigating the perioperative use of lung ultrasound (LUS) have shown loss of lung aeration with decline in diaphragmatic function after general anesthesia. We aimed to measure changes in lung aeration and diaphragmatic functions using LUS in patients undergoing elective laparoscopic cholecystectomy. Methods: Forty patients of American Society of Anesthesiologists I/II undergoing elective laparoscopic cholecystectomy under general anesthesia were enrolled. For all patients, LUS examination was performed at 5 time points: preoperative room, after intubation, after deflation of pneumoperitoneum, 30 min after extubation, and 24 h post-extubation. The aeration loss was assessed using the modified LUS score. The diaphragmatic excursion was also evaluated preoperatively, and at 30 min and 24 h post-extubation. Results: A progressive increase in modified LUS score was seen after intubation, after deflation of pneumoperitoneum, 30 min postoperative, after extubation and 24 h post-extubation at postoperative anesthesia care unit (PACU) as compared to preoperative room (P < 0.0001). The maximum modified LUS score was observed postoperatively after 30 min: 8 (5, 10) and 24 h post-extubation in PACU: 8 (4.25, 11.0). No significant change in the diaphragmatic excursion or respiratory complications was observed. Conclusions: Our study found a progressive loss of lung aeration after the induction of general anesthesia in laparoscopic cholecystectomy, extending up to the 24-h perioperative period. However, diaphragmatic excursion remained unchanged. The study also suggests that LUS is a valuable tool for detecting perioperative atelectasis and quantifying the aeration loss.