Manual Intermittent Positive Airway Pressure (IPAP) for the Management of Secretion-Related Hypoxemia During One-Lung Ventilation: A Case Report

Hypoxemia during one-lung ventilation (OLV) is a well-established complication in thoracic surgery, typically resulting from an increased intrapulmonary shunt due to continued perfusion of the non-ventilated lung. However, some episodes cannot be attributed solely to shunt-related mechanisms, as airway obstruction from excessive secretions in the ventilated lung may also cause impaired ventilation, severe hypercapnia, and reduced lung compliance. We report the case of a 64-year-old male patient undergoing left-sided video-assisted thoracoscopic surgery in whom severe hypoxemia and hypercapnia developed shortly after the initiation of OLV. Fiberoptic bronchoscopy revealed dense purulent secretions in the ventilated lung, and standard rescue strategies failed to restore adequate oxygenation. Manual intermittent positive airway pressure (IPAP) was therefore applied to the non-ventilated lung while bronchoscopic aspiration and lavage were performed. Following the application of manual IPAP, oxygen saturation improved, PaCO₂ decreased markedly, and lung compliance increased, allowing the surgery to be completed without further complications. This case suggests that hypoxemia during OLV may result from mechanisms other than an increased intrapulmonary shunt and that manual IPAP applied to the non-ventilated lung may represent an effective rescue strategy in cases associated with ventilation impairment due to secretion accumulation.