Comparison of survival outcomes between patients ventilated on anaesthetic machines and conventional ventilators during the Coronavirus pandemic: A retrospective case series

Introduction: The coronavirus disease 2019 (COVID-19) pandemic has led to rapid exhaustion of intensive care facilities across the UK and the world The use of anaesthetic machines for long term ventilation as an off label use received regulatory clearance in this setting We compare the survival outcomes of COVID-19 patients between 2 groups - those ventilated on anaesthetic machines and on those on standard ventilators This was a retrospective observational case series conducted at Epsom and St Helier university hospitals in London Methods: 63 patients admitted to our intensive care unit with confirmed SARS-CoV2 (severe acute respiratory syndrome coronavirus-2) infection between 07 March and 27 April were included in this case series These patients were either ventilated on anaesthetic machines or conventional ventilators depending on the availability of these machines All the patients were treated with similar management protocols The mortality rates, APACHE 2 scores and the length of ventilator days of the deceased patients were compared between the two groups Results: The mean±standard deviation (SD) APACHE2 score in the anaesthetic machine group was 14 21 ± 4 05 and in the ventilator group was 19 72 ± 5 66;p-value 0 0002 The mean±SD number of ventilator days was 6 87 ± 4 3 and 8 36 ± 6 68 in the anaesthetic machine and ventilator groups respectively (p-value 0 41) The mortality rate in the anaesthetic machine group was 80% and in the ventilator group was 66 66%;p value 0 82 Conclusion: There was no difference in outcomes between the patients ventilated on conventional ventilators versus those with anaesthetic machines However, the results could be different if the APACHE scores were similar Anaesthetic machines were not intended for long term ventilation and their use in the times of such pandemics seem justified and essential when the availability of the conventional ventilators is limited This is important because having a back up stock / inventory of conventional ventilators anticipating the occasional pandemic may not be viable financially for most healthcare organisations