High fresh gas flow during non-inhalational anaesthesia during the COVID-19 pandemic. Comment on Br J Anaesth 2020; 125: 773-778.

Editor—We read with interest the recent article of Zhong and colleagues that provided a useful estimation of the cost and environmental benefits of using a ‘high-flow’ anaesthetic technique without inhalational anaesthetics. However, given the current pandemic status of coronavirus disease 2019 (COVID-19) and surges in case numbers around the world, we wonder if oxygen may be of greater value than just its monetary cost, as attributed by the authors. We agree that medical oxygen and air are relatively inexpensive (estimated costs of AU$0.40 [~ £0.22; US$0.28] and AU$0.028 [~ £0.015; US$0.02] 1000 L−1, respectively), and that clinicians must take responsibility to reduce the economic burden and environmental impact of medical care. Of note, this study was conducted in Australia before the COVID-19 pandemic; Australia has until recently been relatively spared from the huge numbers of COVID-19-positive patients seen in other countries and from the impact on healthcare systems related to those numbers.

At the time of writing (15 October 2020), Australia had reported 27 364 cases with 904 deaths. Other countries have been inundated with cases and their healthcare systems have strained to find enough resources to cope: for example, 676 455 cases with 43 383 deaths in the UK, 7 972 886 cases with 217 721 deaths in the USA, and 7 307 097 cases with 111 266 deaths in India. Many hospitals in these countries have reported nearly, or completely, running out of oxygen as a result of the burden of both ventilated and non-ventilated patients (e.g. in the UK, South Africa, and India).

For a given 6 h case with a circle system, running an inhalational agent-free anaesthetic with fresh gas flows (FGF) of 1 L min−1, 36 L and 126 L of oxygen would be consumed with a fraction of inspired oxygen (FiO2) of 0.3 and 0.5 respectively. The recommendation of Zhong and colleagues of an FGF of 6 L min−1 would increase the oxygen consumption, for the same length of case, to 252 L and 792 L with FiO2 of 0.3 and 0.5 respectively. Higher flows may be used for induction and emergence with both modes of anaesthesia, thus allowing a fair comparison. Within the confines of safety, improving cost efficiency and reducing environmental burdens must be a priority. Given the current shortage of the most precious of medical resources in many countries across the world, we feel that the high-flow anaesthesia suggested here would be best left until after this pandemic has abated.

Declarations of interest

The authors declare that they have no conflicts of interest.