Cardiac Arrest and the Role of Targeted Temperature Management: A Meta-Analysis

First Author(s)

• 

  Abhishek Bhardwaj, MD, FACP

  Cleveland Clinic Foundation
  Cleveland, Ohio

  Disclosure information not submitted.

  Slides and Audio

Co-Author(s)

• AB

  Agam Bansal MD

  Resident
  Cleveland Clinic Foundation, Ohio, United States

  Disclosure information not submitted.
• SG

  Samiksha Gupta, n/a

  Resident
  University of Oklahoma Heath Sciences Center, United States

  Disclosure information not submitted.
• TG

  Tyler Greathouse MD

  Resident
  Cleveland Clinic Foundation
  Cleveland, Ohio, United States

  Disclosure information not submitted.
• DG

  David Gaieski, MD, FCCM

  Professor
  Thomas Jefferson University Hospital, United States

  Disclosure information not submitted.
• AD

  Abhijit Duggal, MD, MPH, MSc, FACP

  Assistant Professor
  Cleveland Clinic Foundation, United States

  Disclosure information not submitted.

Title: Cardiac Arrest and Role of Targeted Temperature Management: A meta analysis

Introduction:
Randomized controlled trials (RCTs) assessing the utility of targeted temperature management (TTM) after cardiac arrest have shown conflicting results.

Methods:
We performed a meta-analysis of RCTs to assess the use of TTM after cardiac arrest in adult patients. The primary outcome was all-cause mortality following cardiac arrest and the secondary outcome measure was favorable neurologic outcome defined as Cerebral Performance Category (CPC) 1-2 or Modified Rankin Scale Score > 4 at 6 months. We used Mantel-Haenszel method with Paule-Mandel estimator for tau2, Hartung-Knapp adjustment for random effects model and Q-profile method for confidence interval of tau2 and tau to calculate risk ratio [RR] with 95% confidence interval [CI].

Results:
A total of 7 RCTs with 3820 patients were eligible for the analysis. All-cause mortality occurred in 53.5% (1023/1911) in hypothermia group and 54.4% (1038/1909) in normothermia group. Favorable neurologic outcome occurred in 41.1% and 38.6% in hypothermia and normothermia groups respectively. There were no significant differences in all-cause mortality [RR: 0.97 (0.89-1.05), I2=35%, p=0.16] and neurologic outcome [RR: 1.17 (0.98-1.40), I2=62%, p=0.02] between the hypothermia and normothermia groups. As evident from the cumulative risk ratios, there has been no significant difference in the all-cause mortality and neurologic outcome between the hypothermia and normothermia groups since the RCTs in 2013.

Conclusion:
In this meta-analysis, we found thatTTM at 33 degrees was not associated with improvement in mortality and neurologic outcomes following cardiac arrest. However, it is important to interpret the results with caution due to limitations in individual studies. For example, there are significant differences in cooling protocols, time to reach targeted temperature, bystander CPR, time to ROSC and initial arrest rhythms. TTM1 had two TTM groups, 33 and 36, and TTM2 required TTM in 50% of the normothermia group. In light of the new evidence, we recommend modifying practice where in if the patients meet the criteria for enrollment in TTM 2 study then close observation and normothermia might suffice but all other patients should still receive TTM at 33 or 36 given nuances of patient/resuscitation characteristics that are difficult to capture in a meta-analysis.