BACKGROUND: 

In patients receiving extracorporeal membrane oxygenation (ECMO) support, the association between arterial hyperoxia and outcomes is unclear. We performed a systematic review and meta-analysis to determine the association between arterial Po₂ (Pao₂) and mortality in patients with ECMO.

METHODS: 

The meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement and registered in International Prospective Register of Systematic Reviews (PROSPERO; CRD42023467361). We systematically searched PubMed and Embase databases up to September 2023 for randomized trials or observational studies that investigated the association between Pao₂ and mortality in pediatric and adult patients receiving venovenous ECMO (VV-ECMO), venoarterial ECMO (VA-ECMO), and extracorporeal cardiopulmonary resuscitation (ECPR). The predefined outcome was 28-day mortality. We synthesized the data using a random-effects model, calculating odds ratios (OR) and corresponding 95% confidence intervals (CI).

RESULTS: 

Thirteen cohort studies (17,766 participants) were included. All studies used categorical Pao₂ cutoff, with varying thresholds ranging from ≥100 mm Hg to ≥300 mm Hg. When compared with patients with normoxia, elevated Pao₂ levels at all studied thresholds were consistently associated with increased mortality (≥300 mm Hg: OR 1.56, 95% CI, 1.31–1.85, P < .01; ≥200 mm Hg: OR 1.43, 95% CI, 1.10–1.87, P < .01; ≥150 mm Hg: OR 1.51, 95% CI, 1.15–1.98, P < .01; and ≥100 mm Hg: OR 1.44, 95% CI, 1.03–2.02, P = .03). A sensitivity analysis focusing on studies reporting adjusted OR yielded similar results. We observed this association in both adult and pediatric populations.

CONCLUSIONS: 

In critically ill patients on VV- or VA-ECMO, increased Pao₂ values were associated with increased 28-day mortality in ECMO patients. Our results should be interpreted with caution given observational nature of included studies. Further randomized trials are warranted to validate these results.