A Descriptive Analysis of Therapeutic Hypothermia Application Across Adult Age Groups

Therapeutic hypothermia (TH) has been recommended for comatose adults recovering from out-of-hospital cardiac arrest (OHCA) for a decade. However, TH has never been evaluated in a randomized control trial in patients aged 75 or older. How the administration of TH varies across age groups experiencing an OHCA is unknown. The objective was to describe the use of TH across predefined age groups with an emphasis on geriatric OHCA survivors using data compiled through Cardiac Arrest Registry to Enhance Survival (CARES). We hypothesized that TH provision would decline in patients aged 75 or older. This was a secondary analysis of prospectively collected and verified registry data. The study was Institutional Review Board exempt. Through December 2013, CARES had 130,852 completed records for consideration. All nontraumatic adult index arrests of presumed cardiac etiology with attempted resuscitation were study eligible. Sustained return of spontaneous circulation with survival to hospital admission was a prerequisite for inclusion. Exclusion criteria were as follows: records before November 2010 when TH became a mandatory reporting field; pre-existing Do Not Resuscitate directive; missing TH status or outcome classification; and OHCA location and timing variables potentially affecting treatment decisions or eligibility. All records in our final sample were categorized (TH or no TH) for descriptive analysis. Our final sample size was 11,533. The percentage of patients <75 who received TH was 58.5% (95% CI: 57.5-59.6) and 46.4% (95% CI: 44.5-48.3) for those 75 or older. There was no difference in the rate of TH across the age groups from <25 to 65-74 (p = 0.205). Treatment rates significantly decreased from age 75-84 to 95+ (p < 0.001). There is a significant decline in the provision of TH at age 75 years within CARES. Further research is needed to determine if age is an independent predictor of TH underutilization in the elderly.