Conservative versus Liberal Oxygenation Targets in Intensive Care Unit Patients (ICONIC): A Randomized Clinical Trial

L. Imeen van der Wal,  Chloe C. A. Grim,  Michael R. del Prado, et al

Am J Respir Crit Care Med 2023; 208: 770-779

Abstract

Rationale: Supplemental oxygen is widely administered to ICU patients, but appropriate oxygenation targets remain unclear.

Objectives: This study aimed to determine whether a low-oxygenation strategy would lower 28-day mortality compared with a high-oxygenation strategy.

Methods: This randomized multicenter trial included mechanically ventilated ICU patients with an expected ventilation duration of at least 24 hours. Patients were randomized 1:1 to a low-oxygenation (Pa_O2, 55–80 mm Hg; or oxygen saturation as measured by pulse oximetry, 91–94%) or high-oxygenation (Pa_O2, 110–150 mm Hg; or oxygen saturation as measured by pulse oximetry, 96–100%) target until ICU discharge or 28 days after randomization, whichever came first. The primary outcome was 28-day mortality. The study was stopped prematurely because of the COVID-19 pandemic when 664 of the planned 1,512 patients were included.

Measurements and Main Results: Between November 2018 and November 2021, a total of 664 patients were included in the trial: 335 in the low-oxygenation group and 329 in the high-oxygenation group. The median achieved Pa_O2 was 75 mm Hg (interquartile range, 70–84) and 115 mm Hg (interquartile range, 100–129) in the low- and high-oxygenation groups, respectively. At Day 28, 129 (38.5%) and 114 (34.7%) patients had died in the low- and high-oxygenation groups, respectively (risk ratio, 1.11; 95% confidence interval, 0.9–1.4; P = 0.30). At least one serious adverse event was reported in 12 (3.6%) and 17 (5.2%) patients in the low- and high-oxygenation groups, respectively.

Conclusions: Among mechanically ventilated ICU patients with an expected mechanical ventilation duration of at least 24 hours, using a low-oxygenation strategy did not result in a reduction of 28-day mortality compared with a high-oxygenation strategy.

Clinical trial registered with the National Trial Register and the International Clinical Trials Registry Platform (NTR7376).