Significance of the carboxyhemoglobin level for out-of-hospital cardiopulmonary arrest

BACKGROUND: At low concentrations, carbon monoxide (CO) can confer cyto and tissue-protective effects, such as endogenous Heme oxygenase 1 expression, which has antioxidative, anti-inflammatory, antiproliferative, and antiapoptotic effects. The level of carboxyhemoglobin in the blood is an indicator of the endogenous production of CO and inhaled CO. AIM OF STUDY: To investigate the significance of the value of carboxyhemoglobin for out-of-hospital (OH) cardiopulmonary arrest (CPA). MATERIALS AND METHODS: This study involved a medical chart review of cases treated from January to December 2005. The inclusion criteria included a patient who was transported to this department due to an OH CPA. The exclusion criteria included a patient who did not undergo blood gas analysis on arrival and who experienced CPA due to acute carbon monoxide intoxication. The subjects were divided into two groups based on their final outcome of either survival or non-survival. RESULTS: There was no significant difference associated with the sex, age, frequency of witness collapse, bystander cardiopulmonary arrest, electrocardiogram at scene, cause of CPA, value of PCO(2), HCO(3)(-), and methemoglobin. The frequency of OH return of spontaneous circulation and the value of pH, PO(2), base excess, and carboxyhemoglobin in the survival group were greater than those values in the non-survival group. There were no subjects whose carboxyhemoglobin level was 0% on arrival in the survival groups. CONCLUSION: There appeared to be an association between higher carboxyhemoglobin levels and survival in comparison with non-survival patients.