Using CPAP in COVID-19 patients outside of the intensive care setting: a comparison of survival and outcomes between dialysis and non-dialysis dependent patients

Abstract

Background: SARS-CoV-2 (COVID-19) is a novel coronavirus associated with high mortality rates. The use of Continuous Positive Airway Pressure (CPAP) has been recognised as a management option for severe COVID-19 (NHS, Specialty guides for patient management during the coronavirus pandemic Guidance for the role and use of non-invasive respiratory support in adult patients with coronavirus (confirmed or suspected), https://www.nice.org.uk/guidance/ng159). We offered ward-based CPAP to COVID-19, dialysis patients not suitable for escalation to ICU. The aim of the study was to evaluate the use of CPAP for COVID-19 dialysis patients compared to non-dialysis COVID-19 patients outside of the intensive care setting. We further aimed to investigate factors associated with improved outcomes. Methods: Data was collected from a single centre (Royal Preston Hospital, UK), from March to June 2020. Treatment outcomes were compared for dialysis and non-dialysis dependent patients who received CPAP with limitations on their escalation and resuscitation status. Kaplan-Meier survival curves and Cox regression models were used to compare outcomes. The primary study outcome was 30 day mortality. Confounders including length of admission, systemic anticoagulation and ultrafiltration volumes on dialysis were also analysed. Results: Over the study period, 40 dialysis patients tested positive for COVID-19, with 30 requiring hospital admission. 93% (n = 28) required supplementary oxygen and 12% (n = 9) required CPAP on the ward. These patients were compared to a serial selection of 14 non-dialysis patients treated with CPAP during the same period. Results showed a significant difference in 30 day survival rates between the two groups: 88.9% in the dialysis group vs. 21.4% in the non-dialysis group. Statistical modelling showed that anticoagulation was also an important factor and correlated with better outcomes. Conclusion: This is to the best of our knowledge, the largest series of COVID-19 dialysis patients treated with CPAP in a ward-based setting. In general, dialysis dependent patients have multiple co-morbidities including cardiovascular disease and diabetes mellitus making them vulnerable to COVID-19 and not always suitable for treatment in ICU. We showed a significantly lower 30 day mortality rate with the use of CPAP in the dialysis group (11.1%) compared to the non-dialysis group (78.6%). Despite a small sample size, we believe this study provides impetus for further work clarifying the role of CPAP in treating COVID-19 dialysis dependent patients.