Conservative versus Liberal Oxygenation Targets for Mechanically Ventilated Patients. A Pilot Multicenter Randomized Controlled Trial

TLDR

No randomized controlled trials have compared oxygenation targets in ICU patients. The study aims to determine whether a conservative oxygenation strategy is a feasible alternative to a liberal strategy in ICU patients requiring invasive mechanical ventilation. In a multicenter randomized trial, 103 adults were assigned to either a conservative SpO₂ target of 88‑92% or a liberal target of ≥96% while on invasive mechanical ventilation. The trial found no significant differences in organ dysfunction, ICU or 90‑day mortality, although the conservative arm spent slightly more time below 88 % SpO₂ and less time above 98 % SpO₂, supporting feasibility and indicating that larger trials are warranted. The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN 12613000505707).

Abstract

There are no randomized controlled trials comparing different oxygenation targets for intensive care unit (ICU) patients.To determine whether a conservative oxygenation strategy is a feasible alternative to a liberal oxygenation strategy among ICU patients requiring invasive mechanical ventilation (IMV).At four multidisciplinary ICUs, 103 adult patients deemed likely to require IMV for greater than or equal to 24 hours were randomly allocated to either a conservative oxygenation strategy with target oxygen saturation as measured by pulse oximetry (SpO2) of 88-92% (n = 52) or a liberal oxygenation strategy with target SpO2 of greater than or equal to 96% (n = 51).The mean area under the curve and 95% confidence interval (CI) for SpO2 (93.4% [92.9-93.9%] vs. 97% [96.5-97.5%]), SaO2 (93.5% [93.1-94%] vs. 96.8% [96.3-97.3%]), PaO2 (70 [68-73] mm Hg vs. 92 [89-96] mm Hg), and FiO2 (0.26 [0.25-0.28] vs. 0.36 [0.34-0.39) in the conservative versus liberal oxygenation arm were significantly different (P < 0.0001 for all). There were no significant between-group differences in any measures of new organ dysfunction, or ICU or 90-day mortality. The percentage time spent with SpO2 less than 88% in conservative versus liberal arm was 1% versus 0.3% (P = 0.03), and percentage time spent with SpO2 greater than 98% in conservative versus liberal arm was 4% versus 22% (P < 0.001). The adjusted hazard ratio for 90-day mortality in the conservative arm was 0.77 (95% CI, 0.40-1.50; P = 0.44) overall and 0.49 (95% CI, 0.20-1.17; P = 0.10) in the prespecified subgroup of patients with a baseline PaO2/FiO2 less than 300.Our study supports the feasibility of a conservative oxygenation strategy in patients receiving IMV. Larger randomized controlled trials of this intervention appear justified. Clinical trial registered with Australian New Zealand Clinical Trials Registry (ACTRN 12613000505707).