Low-normal oxygenation targets may not reduce organ dysfunction in critically ill: JAMA

Hyperoxemia may increase organ dysfunction in critically ill patients, but optimal oxygenation targets are unknown.

A study was conducted by a group of researchers from the Netherlands to determine whether a low-normal Pao2 target compared with a high-normal target reduces organ dysfunction in critically ill patients with systemic inflammatory response syndrome (SIRS).

It was a multi-centre randomized clinical trial in 4 intensive care units in the Netherlands. Enrollment was from February 2015 to October 2018, with the end of the follow-up to January 2019, and included adult patients admitted with 2 or more SIRS criteria and expected a stay of longer than 48 hours. A total of 9925 patients were screened for eligibility, of whom 574 fulfilled the enrollment criteria and were randomized.

The primary endpoint was SOFARANK, a ranked outcome of non-respiratory organ failure quantified by the non-respiratory components of the Sequential Organ Failure Assessment (SOFA) score, summed over the first 14 study days. Participants were ranked from fastest organ failure improvement (lowest scores) to worsening organ failure or death (highest scores). Secondary endpoints were duration of mechanical ventilation, in-hospital mortality, and hypoxemic measurements.

The results of the study are as follows:

• Among the 574 patients were randomized, 400 (70%) were enrolled within 24 hours, all of whom completed the trial.
• The median Pao2 difference between the groups was −1.93 kPa.
• The median SOFARANK score was −35 points in the low-normal Pao2 group vs −40 in the high-normal Pao2 group.
• There was no significant difference in the median duration of mechanical ventilation.
• Mild hypoxemic measurements occurred more often in the low-normal group.
• Acute kidney failure developed in 20 patients (10%) in the low-normal Pao2 group and 21 patients (11%) in the high-normal Pao2 group, and acute myocardial infarction in 6 patients (2.9%) in the low-normal Pao2 group and 7 patients (3.6%) in the high-normal Pao2 group.

Thus, the researchers concluded that among critically ill patients with 2 or more SIRS criteria, treatment with a low-normal Pao2 target compared with a high-normal Pao2 target did not result in a statistically significant reduction in organ dysfunction. However, the study may have had limited power to detect a smaller treatment effect than was hypothesized.

Reference:

Effect of Low-Normal vs High-Normal Oxygenation Targets on Organ Dysfunction in Critically Ill Patients: A Randomized Clinical Trial by Gelissen H et. al published in the JAMA

doi:10.1001/jama.2021.13011