Clinical paperLong-term neurological outcome after cardiac arrest and therapeutic hypothermia☆
Introduction
Neurological sequelae in survivors after cardiac arrest (CA) constitute a major cause of handicap and illness.1, 2, 3 The high energy utilization and limited energy stores render the brain particularly vulnerable to interrupted circulation, with a narrow margin of minutes until definite damage to brain tissue occurs.4 A large number of therapeutic interventions have been tried, but all have failed to prolong the time until definitive damage occurs or to minimize the effects.5 Based on two controlled randomized trials6, 7 therapeutic hypothermia (TH) has been recommended and implemented as a means of brain protection. In the larger of these two studies, 55% of patients treated with TH survived with good neurological outcome vs. 39% in the group that received conventional treatment.6 In a sub-group of patients from this study, 67% of survivors were found to be cognitively intact 3 months following cardiac arrest.8 Our study was initiated to make a detailed analysis of the types and the extent of neurological defects in survivors after CA after the implementation of TH as standard treatment in our hospitals. As it was considered unethical not to initiate TH based on the favourable results from the two randomized controlled studies and current treatment recommendations,9 no untreated group was enlisted for direct outcome comparison.
Section snippets
Inclusion criteria for cooling
Patients with a witnessed or unwitnessed CA, irrespective of initial rhythm, cause or location, who were successfully resuscitated with a return of spontaneous circulation (ROSC). Patients eligible for TH were unconscious (Glasgow Coma Scale, GCS < 7) until the time for initiation of the cooling procedure (within 240 min from the CA).
Exclusion criteria for TH
Primary coagulation defect and terminal illness, CA secondary to aortic dissection, intracranial haemorrhage or other massive bleeding.
Patients
Patients were consecutively
Results
The proportion of survivors at the time of follow-up was 55.3%, n = 52/94. All surviving patients were CPC scored, see Table 3. The majority of survivors (50/52) had a good outcome, defined as CPC 1–2, only two patients scored CPC 3 and no patient was in a vegetative state (CPC 4). Good outcome was more common in patients with ventricular tachycardia/ventricular fibrillation (VT/VF) as initial rhythm and in patients from hospitals 2 and 3. Length of ICU-stay did not differ significantly between
Discussion
This study shows that mild cognitive impairment is common in hypothermia-treated CA survivors. Despite mild impairment, survivors have a high level of functioning as reflected in the CPC categories, and their quality of life is good. Overt neurological findings are uncommon in a clinical examination. Clearly the outcome following TH-treated CA is dichotomized into survival with good neurological outcome or death.
We found CPC1 in 79% of survivors at 7.2 months which is comparable with Graves et
Conclusions
Mild cognitive impairment is common following hypothermia-treated cardiac arrest but has only minor effect on functional activity and quality of life. It is characterized by memory and executive, frontal lobe disturbance which could easily be detected by simple tests in an outpatient setting.
Conflicts of interest
None.
Acknowledgements
Dr. Niklas Nielsen, Dept. of Anaesthesia, Helsingborg Hospital, Helsingborg, Sweden and Dr. Torbjörn Karlsson, Dept. of Anaesthesia, University Hospital Malmö (UMAS), Sweden referred patients for assessment.
Financial support: ALF (Academic Learning and Research grants), Lund University Medical Faculty to Håkan Widner. Regional Research Support, Region Skåne, Lund University Hospital, to Håkan Widner, Hans Friberg, and Tobias Cronberg.
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A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2009.06.021.