Effect of high-frequency oscillation on reduction of atelectasis in perioperative patients: a prospective randomized controlled study

Background Atelectasis affects approximately 90% of anaesthetized patients, with laparoscopic surgery and pneumoperitoneum reported to exacerbate this condition. High-frequency oscillation therapy applies continuous positive pressure pulses to oscillate the airway, creating a pressure difference in small airways obstructed by secretions. This process helps reduce peak airway pressure, open small airways, and decrease atelectasis incidence, while also facilitating respiratory tract clearance. This study examines the efficacy of high-frequency oscillation on reduction of atelectasis in laparoscopic cholecystectomy (LC) patients under general anaesthesia, evaluated using lung ultrasound.Methods Sixty-four patients undergoing laparoscopic cholecystectomy were randomly divided into a control group and a high-frequency oscillation (HFO) group. Both groups underwent total intravenous anaesthesia under invasive arterial monitoring. The HFO group received a 10-minute continuous high-frequency oscillation therapy during surgery, while the control group received no intervention. Lung ultrasound evaluations were performed three times: five minutes post-intubation (T1), at the end of the surgery (T2), and before leaving the Post-Anaesthesia Care Unit (PACU; T3). Blood gas analysis was performed twice: prior to induction with no oxygen supply and before PACU discharge (oxygen supply off).Results The HFO group displayed a significantly lower incidence of atelectasis at T3 (57.5% vs. 90.3%, OR 6.88, 95%CI (1.74 to 27.24)) compared to the control group. Moreover, the HFO group's PaO2 levels remained consistent with baseline levels before PACU discharge, unlike the control group. Although there was no significant difference in LUS scores between the groups at T1 (8.56 +/- 0.15 vs. 8.19 +/- 0.18, p = 0.1090), the HFO group had considerably lower scores at T2 (13.41 +/- 0.17 vs.7.59 +/- 0.17, p < 0.01) and T3 (13.72 +/- 0.14 vs.7.25 +/- 0.21, p < 0.01).Conclusion Our study indicates that high-frequency oscillation effectively reduces atelectasis in patients undergoing laparoscopic cholecystectomy. Additionally, it can mitigate the decline in oxygen partial pressure associated with atelectasis.