Ventilation Timing, Mortality, and Outcomes in Emergency Department Patients With Metabolic Acidosis

Metabolic acidosis in the emergency department (ED) is associated with increased mortality and multi-organ dysfunction in critically ill patients, often requiring mechanical ventilation, vasopressors, or renal replacement therapy. While prior studies have focused on timing of ventilation for other critical illnesses like respiratory failure, the effect of ventilation timing specifically in patients with metabolic acidosis remains poorly understood. We aimed to explore whether early versus delayed intubation affects mortality, the need for supportive interventions and cardiac complications.

A retrospective cohort study was conducted using de-identified data from the TriNetX Research Network (2005 to 2025). Adult patients (≥18 years) admitted to the ED with metabolic acidosis (serum bicarbonate ≤18 mmol/L and pH ≤7.3) were included. Patients who died within 24 hours were excluded. Groups were defined as those placed on mechanical ventilation within 24 hours vs. 3-7 days of ED admission and were balanced based on demographics, comorbidities and blood work using 1:1 propensity score matching. Primary outcome was 30-day mortality. Secondary outcomes included tracheostomy, renal replacement therapy, vasopressor use, bicarbonate administration, arrhythmias, and congestive heart failure within 30 days of ED admission.

After matching, 2,133 patients were included in each group. Thirty-day mortality was lower with early ventilation (26% vs 31.2%; RR 0.83, 95% CI 0.76–0.92). There was no significant difference in tracheostomy rates between groups (4.8% vs 4.3%; RR 1.11, 95% CI 0.84–1.47). Early mechanical ventilation was associated with higher rates of renal replacement therapy (20.2% vs 10.2%; RR 1.98, 95% CI 1.67–2.34), vasopressor use (80.8% vs 70%; RR 1.15, 95% CI 1.12–1.20), bicarbonate administration (60.8% vs 41.5%; RR 1.46, 95% CI 1.38–1.56), new onset CHF (30% vs 5.6%; RR 5.32, 95% CI 4.06–6.97) and new arrhythmias within 30 days (35.4% vs 12.5%; RR 2.83, 95% CI 2.34–3.42).

Among ED patients with metabolic acidosis, early mechanical ventilation was associated with lower mortality but higher need for dialysis, vasopressor use and bicarbonate administration and increased cardiac complications.