Factors associated with non-invasive positive pressure ventilation failure in a COVID-19 Intermediate Care Unit

Background: The use of non-invasive positive pressure ventilation (NIPPV) in COVID-19 patients with hypoxaemia is still under debate. The aim was to evaluate the efficacy of NIPPV (CPAP, HELMET-CPAP or NIV) in COVID-19 patients treated in the dedicated COVID-19 Intermediate Care Unit of Coimbra Hospital and University Centre, Portugal, and to assess factors associated with NIPPV failure. Patients admitted from December 1st 2020 to February 28th 2021, treated with NIPPV due to COVID-19 were included. Failure was defined as orotracheal intubation (OTI) or death during hospital stay. Factors associated with NIPPV failure were included in a univariate binary logistic regression analysis; those with a significance level of p < 0.001 entered a multivariate logistic regression model. Results: A total of 163 patients were included, 64.4% were males (n = 105). The median age was 66 years (IQR 56–75). NIPPV failure was observed in 66 (40.5%) patients, 26 (39.4%) were intubated and 40 (60.6%) died during hospital stay. Highest CRP (OR 1.164; 95%CI 1.036–1.308) and morphine use (OR 24.771; 95%CI 1.809-339.241) were identified as predictors of failure after applying multivariate logistic regression. Adherence to prone positioning (OR 0.109; 95%CI 0.017-0.700) and a higher value of the lowest platelet count during hospital stay (OR 0.977; 95%CI 0.960–0.994) were associated with a favourable outcome. Conclusions: NIPPV was successful in 59.5% of patients. Highest CRP during hospital stay and morphine use were predictors of failure. Adherence to prone positioning and a higher value of the lowest platelet count during hospital stay were associated with a favourable outcome.