Therapeutic hypothermia in patients after cardiac arrest: A systematic review and meta-analysis of randomized controlled trials

Po-Yun Chiu; Chen-Chih Chung; Yu-Kang Tu; Chien-Hua Tseng; Yi-Chun Kuan

doi:10.1016/j.ajem.2023.06.040

Therapeutic hypothermia in patients after cardiac arrest: A systematic review and meta-analysis of randomized controlled trials

Am J Emerg Med. 2023 Sep:71:182-189. doi: 10.1016/j.ajem.2023.06.040. Epub 2023 Jun 28.

Authors

Po-Yun Chiu¹, Chen-Chih Chung², Yu-Kang Tu³, Chien-Hua Tseng⁴, Yi-Chun Kuan⁵

Affiliations

¹ School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of General Medicine, Department of Medical Education, Taipei Medical University Hospital, Taipei, Taiwan.
² Taipei Neuroscience Institute, Taipei Medical University, Taipei, Taiwan; Department of Neurology, Taipei Medical University Shuang Ho Hospital, New Taipei City, Taiwan; Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
³ Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan.
⁴ Division of Critical Care Medicine, Department of Emergency and Critical Care Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan; Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
⁵ Taipei Neuroscience Institute, Taipei Medical University, Taipei, Taiwan; Department of Neurology, Taipei Medical University Shuang Ho Hospital, New Taipei City, Taiwan; Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan; Cochrane Taiwan, Taipei Medical University, Taipei, Taiwan; Cochrane Taiwan, Taipei Medical University, Taipei, Taiwan. Electronic address: yckuang2@tmu.edu.tw.

PMID: 37421815
DOI: 10.1016/j.ajem.2023.06.040

Abstract

Objective: Targeted temperature management (TTM) with therapeutic hypothermia (TH) has been used to improve neurological outcomes in patients after cardiac arrest; however, several trials have reported conflicting results regarding its effectiveness. This systematic review and meta-analysis assessed whether TH was associated with better survival and neurological outcomes after cardiac arrest.

Method: We searched online databases for relevant studies published before May 2023. Randomized controlled trials (RCTs) comparing TH and normothermia in post-cardiac-arrest patients were selected. Neurological outcomes and all-cause mortality were assessed as the primary and secondary outcomes, respectively. A subgroup analysis according to initial electrocardiography (ECG) rhythm was performed.

Result: Nine RCTs (4058 patients) were included. The neurological prognosis was significantly better in patients with an initial shockable rhythm after cardiac arrest (RR = 0.87, 95% confidence interval [CI] = 0.76-0.99, P = 0.04), especially in those with earlier TH initiation (<120 min) and prolonged TH duration (≥24 h). However, the mortality rate after TH was not lower than that after normothermia (RR = 0.91, 95% CI = 0.79-1.05). In patients with an initial nonshockable rhythm, TH did not provide significantly more neurological or survival benefits (RR = 0.98, 95% CI = 0.93-1.03 and RR = 1.00, 95% CI = 0.95-1.05, respectively).

Conclusion: Current evidence with a moderate level of certainty suggests that TH has potential neurological benefits for patients with an initial shockable rhythm after cardiac arrest, especially in those with faster TH initiation and longer TH maintenance.

Keywords: Critical care; Heart arrest; Hypothermia; Induced; Meta-analysis; Systematic review.

Publication types

Meta-Analysis
Systematic Review

MeSH terms

Cardiopulmonary Resuscitation* / methods
Heart Arrest*
Humans
Hypothermia, Induced* / methods
Out-of-Hospital Cardiac Arrest*
Randomized Controlled Trials as Topic
Treatment Outcome