Use of anaesthesia machines for mechanical ventilation and sedation in patients with COVID-19 ARDS.

Editor – Gouel-Cheron and colleagues reported on the use of anaesthesia ventilators in patients with acute respiratory distress syndome (ARDS; N=50), the majority having COVID-19. Since the authors did not reference our previous study on the use of anaesthesia machines to ventilate and sedate patients with COVID-19 ARDS, we take this opportunity to compare and synthesize the findings.

Our cohort included 35 patients with COVID-19 ARDS; these patients received invasive mechanical ventilation with Draeger Apollo anaesthesia machines (Draeger Medical, Telford, PA) in a single ICU. Sedation with isoflurane was also delivered to some patients (N=18) with no observed complications, and isoflurane administration was associated with reduced propofol and hydromorphone infusion. Anaesthesia resident physicians and nurse anaesthetists assumed responsibilities for machine and breathing circuit maintenance. This included performance of machine check every 72 h, heat and moisture exchanger/high-efficiency particulate air filter and breathing circuit exchange at least every 24 h, and changes of water traps and CO2 absorbers as needed. Challenges with management of patient-ventilator asynchrony, auto-PEEP, increases in airway pressures, and associated episodes of haemodynamic instability were reported in this same cohort and required continuous vigilance of anaesthesia-trained providers. However, the frequency of these ventilator events was not quantified. In-hospital mortality was 22.9%.

Gouel-Cheron and colleagues reported similar challenges with maintaining anaesthesia machines and breathing circuits, finding that median frequency of filter changes was once daily. A switch from anaesthesia ventilator to ICU ventilator appeared clinically necessary in at least two patients. Mortality in their cohort was 24%.

While neither of the studies evaluated the impact of anaesthesia machine on lung mechanics and patient outcomes, both studies concluded that prolonged ventilation with anaesthesia machines in patients with ARDS was feasible. Although this approach may expand hospital ventilator capacity during a surge of critically ill patients with COVID-19, the demands on the anaesthesia-trained personnel to perform ventilator disconnections and immediately respond to anaesthesia machine alarms may preclude broader use in overwhelmed healthcare systems.

Declaration of interest

The author declares that they have no conflict of interest.