Cognitive Function in Survivors of Out-of-Hospital Cardiac Arrest After Target Temperature Management at 33ºC Versus 36ºC
Background—Target temperature management is recommended as a neuro-protective strategy after out-of-hospital cardiac arrest. Potential effects of different target temperatures on cognitive impairment commonly described in survivors are not sufficiently investigated. The primary aim of this study was to evaluate whether a target temperature of 33ºC compared to 36ºC was favourable for cognitive function, and secondary to describe cognitive impairment in cardiac arrest survivors in general.
Methods and Results—Study-sites included 652 cardiac arrest survivors originally randomized and stratified for site to temperature control at 33ºC or 36ºC within the Target Temperature Management trial. Survival until 180 days after the arrest was 52% (33ºC n=178/328 36ºC n=164/324). Survivors were invited to a face-to-face follow-up and 287 cardiac arrest survivors (33ºC n=148/36ºC n=139) were assessed with tests for memory (Rivermead Behavioural Memory Test), executive functions (Frontal Assessment Battery) and attention/mental speed (Symbol Digit Modalities Test). A control-group of 119 matched patients hospitalized for acute ST-elevation myocardial infarction (STEMI) without cardiac arrest performed the same assessments. Half of the cardiac arrest survivors had cognitive impairment, which was mostly mild. Cognitive outcome did not differ (p >0.30) between the two temperature groups (33ºC/36ºC). Compared to STEMI-controls attention/mental speed was more affected among cardiac arrest patients, but results for memory and executive functioning were similar.
Conclusions—Cognitive function was comparable in survivors of out-of-hospital cardiac arrest when targeting a temperature of 33ºC and 36ºC. Cognitive impairment detected in cardiac arrest survivors was also common in matched STEMI-controls not having had a cardiac arrest.
Clinical Trial Registration Information—ClinicalTrials.gov. Identifier: NCT01946932.
- out-of-hospital cardiac arrest
- hypothermia, induced
- cardiovascular diseases
- brain injuries
- heart arrest
- myocardial infarction
- follow-up study
- Received November 21, 2014.
- Revision received January 30, 2015.
- Accepted February 6, 2015.