Lung ultrasound and diaphragmatic excursion assessment for evaluating perioperative atelectasis and aeration loss during video-assisted thoracic surgery: a feasibility study.

BACKGROUND Although lung-protective strategies are widely used in thoracic surgery, postoperative atelectasis can still occur. Both lung ultrasound (LUS) and diaphragmatic excursion assessments are accurate and noninvasive for bedside imaging and examination. This study aimed to test the feasibility of using LUS during the perioperative period of video-assisted thoracic surgery (VATS) and to continuously evaluate aeration changes through LUS examination and diaphragmatic excursion assessment. METHODS Between January 2019 and May 2019, data were prospectively collected from patients that were scheduled to undergo a VATS with one-lung ventilation (OLV). LUS was performed at four specific timepoints: before the induction of general anesthesia (timepoint A), 5 minutes after intubation (timepoint B), at the end of surgery (timepoint C), and 15 minutes after extubation (timepoint D). Diaphragmatic excursion assessment was performed only at the first (timepoint A) and last timepoints (timepoint D) for the use of paralytics during surgery. RESULTS This study included 80 consecutive patients (37 men, 43 women). Among them were patients undergoing lobectomy (14 patients; 17.5%), segmentectomy (35 patients, 43.8%), wedge resection (19 patients; 23.8%), or mediastinal tumor resection (12 patients, 15.0%). LUS was possible for all patients. As a result, LUS helped detect postoperative atelectasis in 12 patients (15.0%). Among them were 4 (33.3%) lung resection patients and 8 (66.7%) mediastinal tumor resection patients. Pneumothorax and small effusions were also diagnosed through LUS examination. There was significant aeration loss throughout the surgery from the start of induction (P<0.001). We discovered that changes in LUS scores were found to be associated with an increase of diaphragmatic excursions after assessment (Spearman's r=-0.54, P<0.001). CONCLUSIONS LUS is feasible during all phases of the perioperative period in VATS and can facilitate the early investigation of perioperative atelectasis. Perioperative LUS and diaphragmatic excursion assessment are also feasible for the continuous assessment of aeration loss in patients undergoing VATS.