Author: Goh G et al.
Anaesthesia Critical Care & Pain Medicine, 2025. doi:10.1016/j.accpm.2025.101591
This multicenter retrospective cohort from 12 Queensland ICUs (2015–2021) evaluated ICU-acquired metabolic alkalosis. Among 24,676 eligible adult admissions (ICU LOS >48 h; no alkalosis in first 24 h), 36% (n=8,889) developed alkalosis, typically on day 4 (IQR 3–6). Diuretics (28%) and steroids (24%) were the most frequent contributory factors, though no cause was identified in 43%. Alkalosis was associated with longer ventilation-free days, ICU and hospital stays. After adjusting for immortal time bias, survival curves showed higher mortality in the alkalosis group; however, in multivariable models adjusting for APACHE III, diagnostic category, and comorbidities, alkalosis was not an independent predictor of mortality. Respiratory-failure–associated alkalosis carried the highest unadjusted mortality. Severity analyses suggested only minimal survival differences across higher base-excess levels.
What You Should Know
• ICU-acquired metabolic alkalosis was common (36%), usually appearing around day 4.
• Diuretics and steroids were frequent contributors, but 43% had no identifiable cause.
• Alkalosis correlated with worse crude outcomes, but was not an independent mortality driver after case-mix adjustment.
• Respiratory failure–related alkalosis had the worst unadjusted survival.
• Findings support careful cause-finding (meds, GI losses, bicarbonate) and bias-aware outcome analyses; whether correcting alkalosis improves outcomes remains unclear.
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Thank you to Anaesthesia Critical Care & Pain Medicine for making this work available.