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

Rationale: Supplemental oxygen is widely administered to intensive care unit (ICU) patients, but appropriate oxygenation targets remain unclear. Objective: This study aims to determine whether a low-oxygenation strategy would lower 28-day mortality compared to a high-oxygenation strategy. Methods: This randomized multicentre 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 (PaO2 55-80 mmHg or SpO2 91-94%) or high-oxygenation (PaO2 110-150 mmHg or SpO2 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 due to the COVID-19 pandemic when 664 of the planned 1512 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 PaO2 was 75 mmHg [IQR, 70-83] and 115 mmHg [IQR 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 group, 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 group, respectively. Conclusion: 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 to a high-oxygenation strategy. Clinical trial registration available at www.who.int/clinical-trials-registry-platform, ID: NTR7376.