Highly Accessed Letter

Clinical relevance of the PaO2/FiO2 ratio

Mohamad F El-Khatib1* and Gassan W Jamaleddine2

Author Affiliations

1 American University of Beirut, PO Box 11-0236, Beirut 1107-2020 Lebanon

2 SUNY, Downstate Medical Center, 450 Clarkson Ave, Brooklyn, New York 11203, USA

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Critical Care 2008, 12:407 doi:10.1186/cc6777


See related research by Karbing et al., http://ccforum.com/content/11/6/R118

Published: 14 February 2008

First paragraph (this article has no abstract)

We read with interest the report by Karbing and coworkers [1] in which they assess the clinical relevance of variation in the arterial oxygen tension (PaO2)/fractional inspired oxygen (FiO2) ratio, a widely used oxygenation index, alongside changes in FiO2. In mechanically ventilated and spontaneously breathing patients, they showed that the clinical utility of PaO2/FiO2 ratio is doubtful unless the FiO2 level at which the PaO2/FiO2 ratio is measured is specified. They included data from 28 mechanically ventilated patients and from an additional eight mechanically ventilated patients at one or two different positive end-expiratory pressure (PEEP) settings.