Effects of out-of-bed armchair positioning on oxygenation in spontaneously breathing ICU patients receiving respiratory support: a randomized controlled trial

Comparing the effects of an out-of-bed armchair position versus an in-bed semi-recumbent position on oxygenation in spontaneously breathing intensive care unit (ICU) patients, receiving respiratory support is a common practice with limited supported evidence. A single-center randomized controlled trial in spontaneously breathing adult ICU patients receiving invasive pressure support ventilation, high-flow nasal oxygen, or non-invasive ventilation. Patients were assigned to armchair or semi-recumbent in-bed positioning for 3 h. Arterial blood gasses were obtained immediately before and after positioning. PaO2/FiO2 (P/F) changes were analyzed with a linear mixed-effects model including group, time, and their interaction, adjusted for stratification variables. 284 patients were randomized (146 and 138 in the armchair and bed groups, respectively). Baseline P/F ratios did not differ between groups. A significant interaction between group and time was observed (p = 0.002). In the armchair group, the P/F ratio increased by 13 mm Hg (95% CI 1–24), whereas it decreased by 13 mm Hg (95% CI − 25 to − 1) in the bed group. The post-positioning marginal mean P/F ratio was higher in the armchair group (241 mm Hg, 95% CI 214–268) than in the bed group (206 mm Hg, 95% CI 179–233; p = 0.004). No serious adverse events occurred. Minor adverse events were more frequent in the armchair group but had minimal impact on positioning duration. In spontaneously breathing ICU patients receiving respiratory support, out-of-bed armchair positioning was associated with higher oxygenation after 3 h than remaining in a semi-recumbent position, with no serious adverse events observed. NCT04446559.