Outcome of Patients with Carbon Monoxide Poisoning at a Far-East Poison Center

Introduction

Many cases of carbon monoxide poisoning in Taiwan are due to burning charcoal. Nevertheless, few reports have analyzed the mortality rate of these patients who survive to reach a hospital and die despite intensive treatment. Therefore, this study examined the clinical features, physiological markers, and outcomes after carbon monoxide poisoning and the associations between these findings.

Methods

We analyzed the records of 261 patients who were referred for management of carbon monoxide intoxication between 2000 and 2010. Patients were grouped according to status at discharge as alive (survivor, n = 242) or dead (non-survivor, n = 19). Demographic, clinical, laboratory, and mortality data were obtained for analysis.

Results

Approximately half of the cases (49.4%) attempted suicide by burning charcoal. Most of the patients were middle-aged adults (33±19 years), and were referred to our hospital in a relatively short period of time (6±10 hours). Carbon monoxide produced many serious complications after exposure: fever (26.1%), hypothermia (9.6%), respiratory failure (34.1%), shock (8.4%), myocardial infarction (8.0%), gastrointestinal upset (34.9%), hepatitis (18.4%), renal failure (25.3%), coma (18.0%) and rhabdomyolysis (21.8%). Furthermore, the non-survivors suffered greater incidences of hypothermia (P<0.001), respiratory failure (P<0.001), shock (P<0.001), hepatitis ((P=0.016), renal failure (P=0.003), coma (P<0.001) than survivors. All patients were treated with high concentration of oxygen therapy using non-rebreather mask. However, hyperbaric oxygen therapy was only used in 18.8% of the patients. In a multivariate-Cox-regression model, it was revealed that shock status was a significant predictor for mortality after carbon monoxide poisoning (OR 8.696, 95% CI 2.053-37.370, P=0.003). Finally, Kaplan-Meier analysis confirmed that patients with shock suffered greater cumulative mortality than without shock (Log-rank test, Chi-square 147.404, P<0.001).

Conclusion

The mortality rate for medically treated carbon monoxide-poisoned patients at our center was 7.3%. Furthermore, the analysis indicates that shock was most strongly associated with higher risk of mortality.