Assessment of myocardial injury in the emergency department independently predicts the short-term poor outcome in patients with severe carbon monoxide poisoning receiving mechanical ventilation and hyperbaric oxygen therapy.

OBJECTIVES

Patients with severe carbon monoxide (CO) poisoning are often prone to unconsciousness and respiratory distress and as a result will receive mechanical ventilation and hyperbaric oxygen (MV-HBO) therapy. Factors associated with poor outcome at discharge are less defined in this patient population. This study was conducted to identify the prognostic predictors of short-term poor outcome in severely CO-poisoned patients receiving MV-HBO therapy.

METHODS

The departmental database and the medical records of 81 patients treated with MV-HBO therapy were reviewed. Demographic and clinical data were extracted for analysis. HBO therapy with 2.5 or 2.8 atmosphere absolute (ATA) was administered to these patients. Short-term poor outcome was defined as an in-hospital death or neurologic sequelae at discharge. All patients were divided into two groups: those with a poor outcome and those without a poor outcome.

RESULTS

Nine patients died while in the hospital, 32 patients had neurologic sequelae at discharge, and the incidence of poor outcome was 50.6%. Parameters that were assessed in the emergency department (ED) and highly associated with patients with a poor outcome included myocardial injury, typical findings on brain computed tomography related to CO poisoning, and higher serum levels of alanine transaminase, aspartate aminotransferase, blood urea nitrogen, creatinine, creatine kinase, creatine kinase-myocardial band, troponin-I, and C-reactive protein. These poor outcomes were also correlated with prolonged lag times from the end of CO exposure to ED arrival and from ED arrival to HBO therapy. In a multivariate analysis, myocardial injury was the only independent predictor of poor outcome (odds ratio, 8.2; 95% confidence interval, 1.012-67.610; p=0.049).

CONCLUSIONS

The results of this study indicate that myocardial injury assessed at ED arrival independently predicts the short-term poor outcome in severely CO-poisoned patients who receive MV-HBO therapy. Emergency physicians could use this objective marker to identify patients with an increased risk of poor outcome at discharge and refine the treatment protocol by shortening the time of patient transport and administering HBO therapy as soon as possible.