Predicting Outcome After Out-of-Hospital Cardiac Arrest: Lactate, Need for Vasopressors, and Cytochrome .

BACKGROUND

Outcome prediction after out-of-hospital cardiac arrest (OHCA) is difficult. We hypothesized that lactate and need for vasopressors would predict outcome, and that addition of a mitochondrial biomarker would enhance performance of the tool.

METHODS

Prospective observational study of OHCA patients presenting to an academic medical center September 2008 to April 2016. We conducted univariate and multivariate logistic regressions.

RESULTS

Patients were divided based on 2 variables: vasopressor status and initial lactate (<5 mmol/L, 5-10, ≥10). Three hundred fifty-two patients were evaluated; 249 had a lactate within 3 hours and were included. Patients on vasopressors had higher mortality (74% vs 40%; < .001). A stepwise increase in mortality is associated with increasing lactate (45% lactate <5, 66% 5-10, and 83% ≥10; < 001). Multivariable models with lactate group and vasopressors as predictors demonstrated excellent discrimination (area under the receiver operating curve [AUC]: 0.73 [95% confidence interval, CI: 0.66-0.79]; adjusted for additional covariates: AUC: 0.81 [95% CI: 0.75-0.86]). Thirty-six patients had cytochrome levels available; among these 36, when comparing models with and without cytochrome , there was no difference (AUC: 0.88 [95% CI: 0.76-1.00] vs AUC: 0.85 [95% CI: 0.73-0.98], respectively; = .30).

CONCLUSION

In this prospective validation, the combination of lactate and vasopressors in the immediate postarrest period is predictive of mortality. Cytochrome offered minimal additional predictive power.