P52 Impact of prone positioning on oxygenation of conscious self-ventilating patients during the COVID-19 pandemic

Abstract

<h3>Introduction and Objectives</h3> During the COVID-19 pandemic unparalleled numbers of patients presented with clinical features similar to those found in acute respiratory distress syndrome. Awake prone positioning (aPP) was posited to improve oxygenation in COVID-19. We aimed to assess the efficacy of aPP in improving oxygenation in self-ventilating patients with COVID-19. <h3>Methods</h3> In this observational retrospective study we recorded pulse oximeter oxygen saturation (SaO₂) before and after aPP for adults with COVID-19 on medical wards. SaO₂ was recorded immediately after aPP, then at 1 and 4 hours. Patients were included whenever aPP was attempted by the treating physician. We recorded outcomes for improvement to discharge, requirement for escalation to ICU, or death. <h3>Results</h3> 24 patients were assessed, of median age 65 years (IQR 58–69). aPP was attempted on day 3 of admission (IQR 2–5) and the median duration was 4 hours (IQR 3–12). All were on maximal ward-based oxygen therapy (15 litres per minute via a reservoir facemask) when aPP was attempted. aPP produced an increase from a median of 86% SaO₂ (IQR 84.5 – 89) prior to intervention, to a median of 92% SaO₂ (IQR 90.5 – 94%) immediately post-prone. The median SaO2 after one hour was 90% (IQR 88 – 95%) and after four hours 90% (IQR 87 – 94%). Among patients who improved without assisted ventilation the median pre-proning SaO₂ was 91% (IQR 90.5 – 91.5%). Lower SaO₂ prior to aPP was associated with a need for assisted ventilation (median pre-proning SaO₂86% [IQR 85 – 87]), or re-orientation towards end-of-life care (median pre-proning SaO₂83% [IQR 77 – 86]). All four patients who were not for CPR or ITU-level care died subsequent to prone-positioning. <h3>Conclusion</h3> Our study suggests that aPP of the non-intubated self-ventilating patient produces short-term improvements in SaO₂ and may delay the need for critical care or assisted ventilation. None of those who were not for CPR survived to discharge after aPP, suggesting that the treating clinician should carefully consider whether aPP will be in the patient’s best interest. Further work is needed to see whether earlier or prolonged prone positioning can reduce need for intubation and critical care.