ObjectivesTo (1) determine whether short, 30-minute sessions of non-invasive ventilation (NIV) is associated with fewer postoperative pulmonary complications (PPC) following elective high-risk upper abdominal surgery and (2) measure feasibility and safety of this intervention when delivered by physiotherapists. DesignProspective, pre post cohort, observational, single-centre study. SettingPrimary referral hospital in Australia. ParticipantsA total of 182 consecutive high-risk elective upper abdominal surgery patients consisting of 101 pre cohort participants compared to 81 post cohort participants. InterventionsBoth groups received standardised preoperative physiotherapy and early postoperative mobilisation. The post cohort group received five additional 30-minute NIV sessions in the first two postoperative days. Main outcome measurePrimary outcome measure was PPC incidence within the first seven postoperative days. Secondary outcomes included feasibility and safety of physiotherapy-led NIV. ResultsIncidence of PPC (7% vs 18%, adjusted relative risk 0.24; 95% CI 0.10 to 0.59, p=0.002) was less in the NIV group compared to those who received no NIV. Mean time to first NIV session was 18.6 (SD 11.0) hours with 74% of participants receiving NIV within 24-hours of surgery. There were no major adverse events. ConclusionThese findings suggest PPC reduction may be possible with postoperative NIV following high-risk elective upper abdominal surgery. Results should be seen as hypothesis-generating associations only considering the significant limitations to this study. Physiotherapy-led NIV was delivered safely to ICU and ward patients. However, the planned protocol was not feasible and appropriate physiotherapy staffing and/or a multidisciplinary approach may be required to provide this service successfully. Trial registrationLIPPSMAck POP (Lung Infection Prevention Post Surgery – Major Abdominal – with Pre Operative Physiotherapy) ANZCTR-12613000664741 (for pre cohort group only).