France: Study on Hypothermia and Cardiogenic Shock

A recent study reveals that the early application of moderate hypothermia for 24 hours versus normothermia does not significantly increase survival in patients with cardiogenic shock receiving venoarterial ECMO. The study was published in the Journal of the American Medical Association (JAMA) on February 1, 2022.

"30-day mortality was not significantly lower in those treated with moderate hypothermia during venoarterial extracorporeal membrane oxygenation (ECMO) (42%) compared to those held at normothermia during ECMO (51%)," Bruno Levy, Université de Lorraine, Nancy, France, and the team wrote in their study. "Adverse events, such as nosocomial infections and bleeding, occurred at a similar rate in the hypothermia and normothermia groups, however, the hypothermia group required more RBC transfusions."

Dr. Levy and the team conducted the study with an objective to determine whether early use of moderate hypothermia (33-34 °C) compared with strict normothermia (36-37 °C) improves mortality in patients with cardiogenic shock receiving venoarterial ECMO.

For this purpose, they conducted a randomized clinical trial of patients who had been endotracheally intubated and were receiving venoarterial ECMO for cardiogenic shock for <6 hours. The study was set in the intensive care units at 20 French cardiac shock care centers between October 2016 and July 20. 374 were randomized out of 786 eligible patients to receive early moderate hypothermia (33-34 °C; n = 168) for 24 hours or strict normothermia (36-37 °C; n = 166). The primary outcome was mortality at 30 days.

Among the 374 randomized patients, 334 completed the trial (mean age, 58 years; 24% women) and were included in the primary analysis.

Key Findings of the Study:

• At 30 days, 71 patients (42%) in the moderate hypothermia group had died vs 84 patients (51%) in the normothermia group (adjusted odds ratio, 0.71).
• For the composite outcome of death, heart transplant, escalation to left ventricular assist device implantation, or stroke at day 30, the adjusted odds ratio was 0.61 for the moderate hypothermia group compared with the normothermia group and the risk difference was −11.5%.
• Of the 31 secondary outcomes, 30 were inconclusive.
• The incidence of moderate or severe bleeding was 41% in the moderate hypothermia group vs 42% in the normothermia group.
• The incidence of infections was 52% in both groups.
• The incidence of bacteremia was 20% in the moderate hypothermia group vs 30% in the normothermia group.

"Our results showed that early application of moderate hypothermia for 24 hours did not significantly increase survival compared with normothermia in patients with refractory cardiogenic shock treated with venoarterial ECMO," wrote the authors. "However, because the 95% CI was wide and included a potentially important effect size, these findings should be considered inconclusive."

Reference:

Levy B, Girerd N, Amour J, et al. Effect of Moderate Hypothermia vs Normothermia on 30-Day Mortality in Patients With Cardiogenic Shock Receiving Venoarterial Extracorporeal Membrane Oxygenation: A Randomized Clinical Trial. JAMA. 2022;327(5):442–453. doi:10.1001/jama.2021.24776