Effects of Adjunctive Therapeutic Hypothermia Combined With Hyperbaric Oxygen Therapy in Acute Severe Carbon Monoxide Poisoning

Objective: To determine the effects of adjunctive therapeutic hypothermia, by comparing hyperbaric oxygen therapy versus hyperbaric oxygen therapy combined with therapeutic hypothermia in acute severe carbon monoxide poisoning. Design: Retrospective analysis of data from our prospectively collected carbon monoxide poisoning registry. Setting: A single academic medical center in Wonju, Republic of Korea. Patients: Patients with acute severe carbon monoxide poisoning older than 18 years. Acute severe carbon monoxide poisoning was defined as mental status showing response to painful stimulus or unresponsive at the emergency department, and a continuation of this depressed mental status even after the first hyperbaric oxygen therapy. Patients were classified into the no-therapeutic hypothermia and therapeutic hypothermia groups. Hyperbaric oxygen therapy was performed up to twice within 24 hours after emergency department arrival, whereas therapeutic hypothermia was performed at a body temperature goal of 33 degrees C for 24 hours using an endovascular cooling device after the first hyperbaric oxygen therapy. Interventions: Hyperbaric oxygen therapy versus hyperbaric oxygen therapy combined with therapeutic hypothermia. Measurements and Main Results: We investigated the difference in the Global Deterioration Scale score at 1 and 6 months after carbon monoxide exposure, between the no-therapeutic hypothermia and therapeutic hypothermia groups. Global Deterioration Scale scores were classified as follows: 1-3 points (favorable neurocognitive outcome) and 4-7 points (poor neurocognitive outcome). During the study period, 37 patients were treated for acute severe carbon monoxide poisoning, with 16 and 21 patients in the no-therapeutic hypothermia and therapeutic hypothermia groups, respectively. The therapeutic hypothermia group demonstrated significantly higher number of patients with favorable outcomes (p= 0.008) at 6 months after carbon monoxide exposure and better improvement of the 6-month Global Deterioration Scale score than the 1-month score (p= 0.006). Conclusions: Our data suggest that in acute severe carbon monoxide poisoning, patients who were treated using therapeutic hypothermia combined with hyperbaric oxygen therapy had significantly more favorable neurocognitive outcomes at 6 months after carbon monoxide exposure than those treated with hyperbaric oxygen therapy alone.