The following is the summary of “Effect of cooling methods and target temperature on outcomes in comatose patients resuscitated from cardiac arrest: Systematic review and network meta-analysis of randomized trials” published in the February 2023 issue of Heart by Matsumoto, et al.

Although targeted temperature management (TTM) has been advocated for use following cardiac arrest (CA), the recommended temperature objectives and cooling strategies (intravascular cooling (IVC) versus surface cooling (SC)) are not well understood. Therefore, randomized clinical trials (RCTs) looking into the effectiveness of TTM following CA were sought by searching PUBMED and EMBASE through October 8, 2022. There were 6 distinct categories for the randomized treatment arms. Standard care without TTM, 34°C to 36°C IVC, 34°C to 36°C SC, Strict NT or FP, and a temperature range of 31.0°C to 33°C IVC and 31.0°C to 34.0°C SC (No-TTM). Neurological improvement was the main goal. The therapies were ranked based on their performance, with a higher P-score indicating better results.

 There were 5,218 patients with CA across 15 randomized controlled trials. Neurological results were considerably better with the other therapy choices compared to the reference of No-TTM (vs. No-TTM; 31..C to 33..C). Risk ratio (IVC) =0.67, 95% CI =0.54 to 0.83; 31.0°C to 34.0°C 95% CI=0.61 to 0.87; 34..C to 36..C; SC RR=0.73 With regards to the IVC, the numbers are as follows: RR=0.66 (95% CI 0.51 to 0.86) and the temperatures range from 34..C to 36..C. Strict NT or FP: RR=0.75, 95% CI 0.62 to 0.90; SC: RR =0.73, 0.59 to 0.90. As a therapeutic measure, IVC temperatures between 31 and 33 degrees centigrade had the best chance of enhancing outcomes (the ranking P-score of 0.836).

When comparing IVC and SC, the ranking P-score indicated that IVC could be an improved cooling method (IVC vs. SC P-score: 0.960 vs. 0.670). Neurological results improved with hypothermia (31..C to 36..C IVC and SC) and active normothermia (Strict-NT and Strict-FP) compared to No-TTM, with IVC likely being the superior cooling approach.