Ethnicity and Observed Oxygen Saturations, Fraction of Inspired Oxygen, and Clinical Outcomes: A Post Hoc Analysis of the Oxy-PICU Trial of Conservative Oxygenation

Abstract

Objectives: A conservative oxygenation strategy, targeting peripheral oxygen saturations (Spo 2) between 88% and 92% in mechanically ventilated children in PICU, was associated with a shorter duration of organ support and greater survival compared with Spo 2 greater than 94% in our recent Oxy-PICU trial. Spo 2 monitors may overestimate arterial oxygen saturation (Sao 2) in patients with higher levels of skin pigmentation compared with those with less skin pigmentation. We investigated if ethnicity was associated with changes in distributions of Spo 2 and Fio 2 and outcome. Design: Post hoc analysis of a pragmatic, open-label, multicenter randomized controlled trial. Setting: Fifteen PICUs across the United Kingdom and Scotland. Patients: Children aged 38 weeks corrected gestational age to 15 years accepted to a participating PICU as an unplanned admission and receiving invasive mechanical ventilation with supplemental oxygen for abnormal gas exchange. Methods: Hierarchical regression models for Spo 2 and Fio 2, and ordinal models for the primary trial outcome of a composite of the duration of organ support at 30 days and death, were used to examine the effects of ethnicity, accounting for baseline Spo 2, Fio 2, and mean airway pressure and trial allocation. Measurements and Main Results: Ethnicity data were available for 1577 of 1986 eligible children, 1408 (89.3%) of which were White, Asian, or Black. Spo 2 and Fio 2 distributions did not vary according to Black or Asian ethnicity compared with White children. The trial primary outcome measure also did not vary significantly with ethnicity. The point estimate for the treatment effect of conservative oxygenation in Black children was 0.64 (95% CI, 0.33–1.25) compared with 0.84 (0.68–1.04) in the overall trial population. Conclusions: These data do not suggest that the association between improved outcomes and conservative oxygenation strategy in mechanically ventilated children in PICU is modified by ethnicity.