Send to

Choose Destination
J Crit Care. 2010 Mar;25(1):3-9. doi: 10.1016/j.jcrc.2009.04.007. Epub 2009 Jul 9.

Risk factors for the deterioration of oxygenation ratio in ventilated intensive care unit patients: a retrospective cohort study.

Author information

Radboud University Nijmegen Medical Center, PO-Box 9101, 6500HB Nijmegen, The Netherlands.



The aim of the study is to determine which factors are associated with the deterioration of Pao(2)/fraction of inspired oxygen (Fio(2)) ratio in patients with normal oxygenation at admission and ventilated according to a lung protective ventilation strategy.


Retrospective cohort study of ventilated (>/=3 days) intensive care unit patients with an admission Pao(2)/Fio(2) ratio of 300 mm Hg or higher (n = 105). Patients who developed lung injury (Pao(2)/Fio(2) ratio, <300 mm Hg) on day 7 (n = 37) were compared to those who did not (n = 68), with regard to ventilator settings, gas exchange variables, and lung injury risk factors.


Mean +/- SD of administered tidal volume was 7.9 +/- 1.3 mL/kg. Patients who developed lung injury were older (P = .019), had lower Pao(2) (P = .009), higher Paco(2) (P = .045), and lower Pao(2)/Fio(2) ratio (P = .002) at admission. Postoperative state (Hazard risk [HR], 5.1) and controlled ventilation mode (HR, 4.3) were identified as independent risk factors. Lung injury-free time was shorter in patients with low initial Pao(2)/Fio(2) ratio (odds ratio, 1.7; P = .039). This effect was not only caused by the baseline difference, as the decrease in Pao(2)/Fio(2) ratio was more pronounced in patients who developed lung injury compared to those who did not (P = .008).


Lung injury exacerbates during mechanical ventilation. In patients treated with a mean tidal volume of 7.9 mL/kg, controlled ventilation is a major risk factor.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center