Limitations of care and comorbidities are associated with increased mortality in patients treated with non-invasive ventilation: A retrospective observational study in a single-center ICU. [version 1; peer review: 2 approved with reservations]

Background: Non-invasive ventilation (NIV) is a common treatment for acute respiratory failure in intensive care units (ICU). While there is increasing data on outcomes after NIV treatment, there are large variations in staffing and monitoring where NIV is provided, making results hard to generalize. The aim of this study was to characterize patients treated with NIV, describe outcomes, and identify factors associated with outcome in an ICU at a Swedish county hospital. Methods: A single-centre retrospective observational study during 2018 of patients treated with NIV in a six-bed ICU at a Swedish county hospital. Patient characteristics, including comorbidities, details of ICU stay, simplified acute physiology score (SAPS-3), details of NIV treatment and 30-day mortality were collected, and the Charlson co-morbidity index (CCI) was calculated. Primary outcomes were 30-day mortality and associated factors. Results: 92 patients with mean age (71,3, SD 12,1) were treated with NIV during the study period. 42 (46%) were women. Median CCI was 3 (25 th-75 th percentiles 1.4)) and median SAPS-3 score was 66 (25 th-75 th percentiles 58). The 30-day mortality was 37% and in the univariate analysis, SAPS-3 score >66, Charlson comorbidity index, CCI>=3, pCO2