Abstract 159: The Impact of Hypothermia Treatment on Survival to Hospital Discharge for Patients with Out-of-Hospital Cardiac Arrest in the Circulation Improving Resuscitation Care (CIRC) Trial
Background: Therapeutic hypothermia (TH) has been associated with increased survival after out-of-hospital cardiac arrest (OHCA). There is ongoing debate over when TH should be applied to a patient after OHCA. For patients enrolled in the Circulation Improving Resuscitation Care (CIRC) trial, application of TH was captured for three distinct treatment periods: prehospital (PH), in the emergency department (ED), and in-hospital (IH). In a post hoc analysis of the CIRC database we evaluated the effect of TH during these three periods on survival to hospital discharge.
Methods: All study patients admitted to hospital were included in the analysis, regardless of treatment of arm. Because patients could have TH initiated in the PH, ED, or IH phase of their care and not all patients had hypothermia maintained between one phase of care and the next a TH score was created. The score awarded points for each location where TH was provided: 3 for PH, 2 for ED, and 1 for IH. Patients could receive a maximum score of 6 if they had TH in all three settings or a minimum score of 0 if no TH was provided. Logistic regression was used to determine the interaction between the TH score and survival to hospital discharge, adjusting for the same covariates used in the CIRC study survival analysis: shockable initial rhythm, witnessed arrest, age group, and study site.
Results: Of the 4231 subjects enrolled in CIRC, 1068 were admitted to hospital. Survival information could not be obtained for two subjects. Of the remaining 1066, 36% had a score of 0 (no TH), 8% score of 1 (IH - TH only), 3% score of 2 (ED - TH only), 26% score of 3, 6% score of 4, 3% score of 5, and 17% score of 6 (PH-, ED-, and IH-TH). The adjusted OR for survival to discharge was 1.105 (95% confidence interval 1.030 - 1.186, p < 0.01) for each one point increase in the TH score. For example, a subject that received PH-, ED-, and IH-TH (score of 6) had an OR of 1.8 for survival to hospital discharge.
Conclusion: Our analysis indicates that TH treatment in OHCA patients shows the most benefit when started in the field and continued into the hospital without interruptions in the emergency department.
- © 2012 by American Heart Association, Inc.