A tidal volume of 7 mL/kg PBW or higher may be safe for COVID-19 patients

Abstract

Purpose: The novel coronavirus disease (COVID-19) has revived the debate on the optimal tidal volume during acute respiratory distress syndrome (ARDS). Some experts recommend 6 mL/kg of predicted body weight (PBW) for all patients, while others suggest 7-9 mL/kg PBW for those with compliance >50 mL/cmH₂O. We investigated whether a tidal volume ≥ 7 ml/kg PBW may be safe in COVID-19 patients, particularly those with compliance >50 mL/cmH₂O.

Materials and methods: This secondary analysis of a multicenter study compares the Intensive Care Unit (ICU) mortality among 600 patients ventilated with <7 or ≥ 7 mL/kg PBW. Compliance was categorized as <40, 40-50, or > 50 mL/cmH₂O.

Results: 346 patients were ventilated with <7 (6.2 ± 0.5) mL/kg PBW and 254 with ≥7 (7.9 ± 0.9) mL/kg PBW. ICU mortality was 33 % and 29 % in the two groups (p = 0.272). At multivariable regression analysis, tidal volume ≥ 7 mL/kg PBW was associated with lower ICU mortality in the overall population (odds ratio: 0.62 [95 %-confidence interval: 0.40-0.95]) and in each compliance category.

Conclusions: A tidal volume ≥ 7 (up to 9) mL/kg PBW was associated with lower ICU mortality in these COVID-19 patients, including those with compliance <40 mL/cmH₂O. This finding should be interpreted cautiously due to the retrospective study design.

Trial registration: ClinicalTrails.govNCT04388670.

Keywords: Acute respiratory distress syndrome (ARDS); Coronavirus disease 2019 (COVID-19); Driving pressure; Lung protective ventilation; Mechanical ventilation; Tidal volume.