Air-Test for prediction of postoperative pulmonary complications after general anaesthesia: promise, performance and limitations

Background and clinical relevancePostoperative pulmonary complications (PPCs) are a major clinical and financial burden, and are associated with prolonged hospital stay, increased healthcare costs, and worse postoperative outcomes (1-3).Even minor PPCs lead to increased perioperative morbidity and mortality (4).Early identification of patients who are at risk can lead to interventions that would reduce this burden or may lead to better allocation of postoperative resources (5).ARISCAT remains the best-established PPC risk score (2,6).External validation in the PERISCOPE study showed generally good discriminative performance, although calibration varied across geographic regions and specialised populations (2,6).A 2025 systematic review reported that ARISCAT remains among the most consistently validated and best-performing tools (2).The LAS VEGAS score demonstrated moderate predictive accuracy in derivation and validation cohorts, although wider external validation was recommended before routine clinical implementation (7).Although established PPC prediction models are available, they require multiple variables and may be less practical in fast-paced clinical settings (6,7).A simple bedside screening tool capable of rapidly identifying at risk patients would therefore be valuable.The Air-Test concept has been developed through a series of prior studies.Its diagnostic accuracy was examined against computed tomography (CT)-confirmed atelectasis in healthy patients after surgery, demonstrating an area under the receiver operating characteristic curve (ROC-AUC) of 0.90 with a sensitivity and specificity over 80% (8).A feasibility study in laparoscopic surgery showed that room-air oxygen saturation (SpO 2 ) could help individualize lung recruitment and identify opening and closing pressures (9).In thoracic surgery patients undergoing one-lung ventilation, the broader iPROVE-OLV programme extended this line of research into perioperative management (10).Recently, a prospective laparoscopic surgery study of 250 patients found that a positive postoperative Air-Test was independently associated with PPCs, but discrimination was modest (AUC 0.66) (11).