P8 Ventilation in COVID-19: lessons to be learnt?

Abstract

<h3></h3> COVID-19 posed unprecedented challenges on healthcare systems globally especially on inpatient beds, oxygen and ventilatory support: continuous positive airway pressure (CPAP), high flow nasal oxygen and invasive mechanical ventilation (IMV). West Herts NHS Trust, a secondary care provider for a population of 650,000 had 1200 admissions during the first wave (March to June) with a 30% mortality. Ventilatory outcomes in 116 consecutive admissions were analysed to assess the utility of CPAP in a respiratory specialist ward versus ITU, and prompt versus delayed invasive mechanical ventilation (IMV). Respiratory support was provided in four pathways: CPAP in intensive care unit (ITU) (n=18), CPAP in respiratory ward setting (usually as ceiling of care, n=50), IMV after initial trial of CPAP (n=21) and IMV with no delay or interim CPAP (n=27). The demographics, comorbidities, functional status, severity of presentation and outcomes differed greatly between the ward group and all the ITU arms. Within the ITU arms, patients were younger, had worse chest x-rays, higher CRP as well as had lower lymphocyte counts, PF (PaO2/FiO2) ratios and comorbidities. Delayed intubation with a trial of CPAP was associated with significant mortality compared to prompt IMV. All ventilatory outcomes were poor in patients over 80 years. Mortality rate was significantly lower in prompt IMV, 37%, compared to 95% in those with a delayed intubation by a median of 6 days with a prior CPAP trial. Median PF ratio on admission for patients with prompt IMV was 73 mmHg vs 115 mmHg in those with CPAP prior to IMV. In summary, ward CPAP as ceiling of care for older patients and with comorbidities is safe and associated with a relatively similar mortality rate compared to ITU CPAP but must be reviewed regularly to ensure improvement on treatment. Mortality is significant in those with lower PF ratios especially if IMV is delayed. Whilst acknowledging the heavy burden on clinicians to rationalise treatment during times of limited resources, we believe that careful assessment of age, comorbidities (cardiac and frailty), PF ratios, CRP and a 24 hourly review should be undertaken to prevent delayed IMV in appropriate patients.