Urinary Output Predicts Survival in Patients Undergoing Extracorporeal Membrane Oxygenation Following Cardiovascular Surgery.

OBJECTIVES: Extracorporeal membrane oxygenation represents a valuable and rapidly evolving therapeutic option in patients with severe heart or lung failure following cardiovascular surgery. However, survival remains poor and accurate risk stratification challenging. Therefore, we evaluated the predictive value of urinary output within 24 hours after extracorporeal membrane oxygenation initiation on mortality in patients undergoing venoarterial extracorporeal membrane oxygenation support following cardiovascular surgery and aimed to improve established risk prediction models.

DESIGN: Single-center, observational registry.

SETTING: University-affiliated tertiary care center.

PATIENTS: We included 205 patients undergoing veno-arterial extracorporeal membrane oxygenation therapy following cardiovascular surgery at a university-affiliated tertiary-care center into our single-centre registry.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: During a median follow-up time of 35 months (interquartile range, 19-69), 64% of patients died. Twenty-four-hour urinary output was the strongest predictor of outcome among renal function variables with an adjusted hazard ratio per 1 SD of 0.55 (95% CI, 0.40-0.76; p < 0.001) for 30-day mortality and of 0.65 (95% CI, 0.53-0.86; p = 0.002) for 2-year long-term mortality. Most remarkably, 24-hour urinary output showed additional prognostic value beyond that achievable with the simplified acute physiology score-3 and sequential organ failure assessment score indicated by improvements in the category-free net reclassification index for 30-day mortality (simplified acute physiology score-3: 36%, p = 0.015; sequential organ failure assessment score: 36%, p = 0.02), as well as for 2-year mortality (simplified acute physiology score-3: 33%, p = 0.02; sequential organ failure assessment score: 43%, p = 0.005).

CONCLUSIONS: We identified 24-hour urinary output as a strong and easily available predictor of mortality in patients undergoing extracorporeal membrane oxygenation therapy following cardiovascular surgery. Implementation of 24-hour urinary output leads to a substantial improvement of established risk prediction models in this vulnerable patient population. These results are particularly compelling because measurement of urinary output is inexpensive and routinely performed in all critical care units.