Settings: International multicenter trials; 1:1 randomization, blinded assessment of outcomes.

Patients: adults with witnessed OHCA, regardless of initial rhythm.  Patients had more than 20 minutes of CPR.  Eligible patients were unconscious, not able to follow command, no verbal responses to painful stimuli.

Intervention: hypothermia to target of 33C for 28 hours, then rewarming at rate of 1/3C every hour until  37C.

Comparison: maintaining temperature at 37.5C or less.  Cooling if body temperature reached 37.8C to 37.5C

Outcome: primary outcome was Any cause mortality at 6 months; secondary outcome was poor functional outcome at 6 months (modified Rankin Scale 4-6).

Study Results:

1. 930 hypothermia, mortality 465/925 (50%, RR 1.04, 95%CI 0.94-1.14); 488/881 (55%) had mRS 4-6 (RR 1.0, 95%CI 0.92-1.09).

2. 931 normothermia, mortality 446/925 (48%); 479/866 (55%) had mRS 4-6.

Discussion Points:

• Hypothermia would lead to higher rates of arrhythmia-related hemodynamic instability.
• More studies reinforced that preventing fever is beneficial.
• ED clinicians will not have to rush to cool patients while awaiting for ICU beds (Yay).

Conclusion:

Normothermia in coma patients after OHCA did not lead to higher morality or worse neurologic outcomes.

References

Dankiewicz J, Cronberg T, Lilja G, Jakobsen JC, Levin H, Ullén S, Rylander C, Wise MP, Oddo M, Cariou A, B?lohlávek J, Hovdenes J, Saxena M, Kirkegaard H, Young PJ, Pelosi P, Storm C, Taccone FS, Joannidis M, Callaway C, Eastwood GM, Morgan MPG, Nordberg P, Erlinge D, Nichol AD, Chew MS, Hollenberg J, Thomas M, Bewley J, Sweet K, Grejs AM, Christensen S, Haenggi M, Levis A, Lundin A, Düring J, Schmidbauer S, Keeble TR, Karamasis GV, Schrag C, Faessler E, Smid O, Otáhal M, Maggiorini M, Wendel Garcia PD, Jaubert P, Cole JM, Solar M, Borgquist O, Leithner C, Abed-Maillard S, Navarra L, Annborn M, Undén J, Brunetti I, Awad A, McGuigan P, Bjørkholt Olsen R, Cassina T, Vignon P, Langeland H, Lange T, Friberg H, Nielsen N; TTM2 Trial Investigators. Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest. N Engl J Med. 2021 Jun 17;384(24):2283-2294. doi: 10.1056/NEJMoa2100591. PMID: 34133859.