Conservative oxygen therapy does not confer survival gains in ARDS

A conservative oxygenation strategy, with target partial pressure of arterial oxygen (Pao₂) 55–80 mm Hg, during the first 7 days of mechanical ventilation falls short of improving survival at 28 days in patients with acute respiratory distress syndrome (ARDS), a study has shown.

A total of 205 ARDS patients randomized to receive either conservative oxygen therapy (target Pao₂, 55–70 mm Hg; oxygen saturation as measured by pulse oximetry [Spo₂], 88–92 percent) or liberal oxygen therapy (target Pao₂, 90–105 mm Hg; Spo₂, ≥96 percent) for 7 days. Both groups used the same mechanical ventilation strategies.

The trial was discontinued prematurely due to safety concerns and a low likelihood of achieving a between-group difference in the primary outcome of death from any cause at 28 days. Four patients who did not meet the eligibility criteria were excluded.

The primary outcome was reported in 34 of 99 patients (34.3 percent) in the conservative-oxygen group and 27 of 102 patients (26.5 percent) in the liberal-oxygen group (difference, 7.8 percentage points, 95 percent confidence interval [CI], −4.8 to 20.6).

By day 90, the number of patients who died increased to 44 (44.4 percent) in the conservative-oxygen group and to 31 (30.4 percent) in the liberal-oxygen group (difference, 14.0 percentage points, 95 percent CI, 0.7–27.2).

There were five mesenteric ischaemic events documented in the conservative-oxygen group.