Outcome and prognostic factors of patients treated in the intensive care unit for carbon monoxide poisoning

Abstract

Carbon monoxide (CO), a colorless and odorless gas, is one of the common causes of poisoning-related deaths worldwide. CO poisoning can result in hypoxic brain damage and death, but intensive care can improve the likely outcome for critically ill patients. However, there is a paucity of clinical data regarding the prognostic factors and association between organ dysfunction and clinical outcome of patients treated for CO poisoning in the intensive care unit (ICU). We performed a retrospective study of patients admitted to a university affiliated hospital ICU between July 2001 and December 2010 following CO poisoning. Outcomes were survival to ICU discharge and to hospital discharge. Seven hundred and eighty-seven patients were admitted to the university hospital following CO poisoning, of which 140 (17.8%) were admitted to the hospital ICU. The overall mortality rate of the patients admitted to the ICU was 14.3% (20/140). Univariate analysis indicated that non-surviving patients with CO poisoning were more likely to have initial blood carboxyhemoglobin (COHb) level>30%, shock, acute respiratory failure, Acute Physiology and Chronic Health Evaluation II (APACHE II) score≥25, Glasgow coma scale (GCS) score of 3, acute renal failure, dysfunction or failure of more than 3 organs, low blood pH, low HCO3- level, high potassium level, and high glucose level. They were also more likely to have not received hyperbaric oxygen (HBO) intervention. Multivariate logistical regression analysis indicated that the mortality rate of patients treated in the ICU for CO poisoning was higher if their initial APACHE II score was ≥25, GCS was 3, and more than 3 organs were dysfunctional. Moreover, HBO intervention in ICU significantly decreased patients' risk of mortality due to CO poisoning. In conclusion, we observed that APACHE II score >25, GCS 3, and dysfunction of more than 3 organ systems on admission to emergency department was associated with a significant mortality risk in patients treated in the ICU for CO poisoning. Moreover, HBO therapy could reduce the risk of mortality in patients with CO poisoning in ICU.