Ventilatory load reduction by combined mild hypothermia and ultra-protective mechanical ventilation strategy in very severe COVID-19-related ARDS: a feasibility study.

Background: Low tidal volume (Vt) strategy is currently the standard of care for ARDS. However, this approach may result in harmful airway pressures in severe ARDS. We report the feasibility of a combined approach of very low-VT and mild therapeutic hypothermia (MTH) to decrease the ventilatory load in a very severe COVID-19-related ARDS cohort. Methods: Seven patients were reported. Inclusion criteria were patients ≥ 18years-old, very severe COVID-19-related ARDS, driving pressure (DP) > 15 cmH 2 O despite low-VT strategy, and extracorporeal therapies were not available. Patients with uncontrolled superinfection, active bleeding, severe brain injury, or end-of-life care were excluded. MTH was induced with a surface cooling device aiming at 34ºC. MTH was maintained for 72h, followed by rewarming of 1ºC per day. VT was adjusted as tolerated, aiming at 4 ml/kg PBW. Data are shown in mean±SEM. Mixed effects analysis and Dunnett's test were used for comparisons. Significance was set at p<0.05Results: Target temperature was achieved during the first hour. Ventilatory load decreased during the first 24h, minute ventilation 180±4.7 to 154±7.5 ml/kg/min (p=0.007) and mechanical power 36±1.9 to 29±2.1 J/min (p= 0.03). At 48h VT decreased from 5.4±0.2 to 4.2±0.3 ml/kg. Surviving patients did not worsen after rewarming. Five patients survived ICU and were discharged home. Conclusions: A combined strategy of MTH and ultra-protective mechanical ventilation decreased minute ventilation and mechanical power in very severe COVID-19-related ARDS. The decreasing of ventilatory load may allow maintaining MV within safety thresholds.