P aO 2 / F IO 2 ratio: the mismeasure of oxygenation in COVID-19

摘要

We read with interest A. Tulaimat’s letter concerning our recent editorial in the European Respiratory Journal [1]. A. Tulaimat makes several insightful comments on problems with criteria used for entering patients into randomised controlled trials of noninvasive ventilation. Among these, he notes that arterial-to-inspired oxygen (PaO2 /FIO2 ) ratio varied between 170 and 400 among enrollees [2]. Low arterial oxygenation is the fundamental problem in a severely ill patient with coronavirus disease 2019 (COVID-19). PaO2 is directly related to the likelihood of dying and it also influences choice of therapy. Many hypoxaemic patients have been exposed unnecessarily to life-threatening therapy (intubation) when noninvasive modalities were likely to have been successful [3].