Lack of pupil reflex and loss of consciousness predict 30-day neurological sequelae in patients with carbon monoxide poisoning

Background: Predicting the neurological sequelae of carbon monoxide poisoning (COP) has not been well studied. We investigated the independent predictors of neurological sequelae in patients with COP and combined these predictors to predict the prognosis. Methods: This study was conducted at four hospitals in Shandong Province, China. Data were retrospectively collected from 258 patients with COP between November 1990 and October 2011. Thirty-day neurological sequelae were the primary endpoints. Results: A lack of pupil reflex and a loss of consciousness appear to be independent predictors for neurological sequelae in patients with COP. The presence of either one had a sensitivity of 77.0% (95% confidence interval [CI]: 69.3-83.2), a specificity of 47.1% (95% CI: 38.3-56.0), positive predictive value (PPV) of 62.9% (95% CI: 55.2-70.1), and a negative predictive value (NPV) of 63.6%(95% CI: 52.6-73.4). With both predictors present, the sensitivity was 11.5%(95% CI: 6.9 to 18.3), the specificity was 99.2 (95% CI: 94.7-100.0), the PPV was 94.1%(95% CI: 69.2-99.7), and the NPV was 49.0%(95% CI: 42.5-55.5). Conclusions: The risk for neurological sequelae apparently increased with the number of independent predictors. In patients with both predictors, the risk for neurological sequelae was 94.1%. Almost all (99.2%) patients with neither predictor had no neurological sequelae. This finding may help physicians make decisions about and dispositions for patients with COP. For patients with a higher risk, earlier treatment and more appropriate utilization of health care services, including hyperbaric oxygen, should be considered.