Lower oxygen target led to better outcomes in ICU patients with COVID-19
Targeting an arterial pressure of oxygen of 60 mm Hg resulted in more days alive without life support within 90 days but no significant improvement in mortality compared to a target of 90 mm Hg, a trial in critically ill COVID-19 patients found.
For patients critically ill with COVID-19, a lower oxygen target may improve outcomes, a recent trial found.
The large multicenter trial assessed the effects of targeting an arterial pressure of oxygen (PaO2) of 60 mm Hg versus 90 mm Hg by randomizing patients with COVID-19 and severe hypoxemia to one or the other. It included 726 patients receiving at least 10 L of oxygen per minute or mechanical ventilation in 11 ICUs in Europe from August 2020 to March 2023. The trial was prematurely stopped prior to outcome assessment due to slow enrollment. Results were published by JAMA on March 19.
Primary outcome data were available for 697 patients (351 in the lower-target group and 346 in the higher-target group). Their median age was 66 years, and 68% were male. On the primary outcome of days alive without life support (mechanical ventilation, circulatory support, or kidney replacement therapy) at 90 days, the lower-target group had a median of 80.0 days compared to 72.0 days in the higher-target group (P=0.009). Mortality rates at 90 days were 30.2% and 34.7%, respectively (risk ratio, 0.86 [98.6% CI, 0.66 to 1.13]; P=0.18). There were no statistically significant differences in serious adverse events or days alive and out of the hospital.
The study authors concluded that in adult ICU patients with COVID-19 and severe hypoxemia, targeting a PaO2 of 60 mm Hg resulted in more days alive without life support in 90 days than targeting a PaO2 of 90 mm Hg. They noted that similar results were seen in an early analysis of COVID-19 patients in 2020 but that subsequent trials have had more mixed findings. The current study may have found benefit from the lower target in part because of the homogeneity of its population: "All patients had severe hypoxemia caused by COVID-19 and predominantly single-organ failure at baseline, with the lowest baseline PaO2:FiO2 ratio among all randomized clinical trials investigating targeted oxygenation in the ICU," the authors said.
An accompanying editorial called the study "one more piece in a growing collection of evidence suggesting that there is no clinical benefit and possibly harm associated with use of supplemental oxygen to achieve oxygen saturation of the blood beyond 90% to 93%." The editorialist noted several ways that higher oxygen targets could harm patients, including increasing lung injury, causing formation of reactive oxygen species, and washing out nitrogen from alveoli.
