P55 Gloucestershire NHS foundation trust experience – COVID-19 associated mortality in mechanical ventilation vs non mechanical ventilation

Abstract

<h3>Background</h3> COVID-19 is associated with significant mortality and morbidity in high risk groups requiring ventilatory support as per the Intensive Care National Audit &amp; Research Centre (ICNARC).¹ Mechanical (IMV) and non-mechanical ventilation modalities [Continuous positive airway pressure (CPAP)/High Flow Nasal Oxygen (HFNO)] support acute respiratory failure in COVID-19 but the mortality data comparing these modalities is limited. Gloucestershire NHS Foundation Trust admitted a total of 860 COVID-19 patients, 130 requiring ventilatory support between February-July 2020; the highest number in the South-West. Respiratory High dependency (HDU) and Intensive care units (ITU) were reconfigured in anticipation of clinical demand with HDU expanded to 31 beds compared to a normal capacity of 10 and ITU expanded to 36 beds, compared to a usual capacity of 12. Patients requiring CPAP only were managed on HDU unless deemed at high risk of deterioration to require IMV. <h3>Method</h3> We conducted a prospective observational study to assess comparative mortality in all COVID-19 patients admitted to HDU/ITU with acute respiratory failure and treated with IMV versus CPAP/HFNO or both. Parameters assessed included age, gender, clinical frailty score (CFS), co-morbidities, smoking and resuscitation status. Comparative mortality was assessed statistically by calculating relative risk ratio and p-value using Welch’s t-test. <h3>Results</h3> 130 patients were treated with CPAP/HFNO, IMV or both. Overall mortality was 33% (n=43). Resuscitation status and treatment escalation plans were reviewed for all patients on admission. 1.5% patients (n=2) had a pre-existing DNAR and CPR was not deemed appropriate for 23% patients (n=30). 62% patients (n=58) required IMV out of 72% patients (n=93) deemed suitable for it. Comparative mortality between all 3 subgroups is summarised in table 1. <h3>Discussion</h3> Overall mortality was higher among COVID-19 patients requiring IMV reflecting disease severity. Male gender, previous smoking history, airways disease, hypertension, diabetes, CKD and immunosuppression were associated with higher mortality in patients requiring IMV. Interestingly CFS of &gt;3 was associated with increased mortality in the CPAP cohort compared to CFS of &lt;3 in the IMV cohort. This is likely to reflect selection bias of patients deemed appropriate for IMV. <h3>Reference</h3> ICNARC Reports.<i>[</i>https://www.icnarc.org/Our-Audit/Audits/Cmp/Reports.August 2020]