One therapeutic intervention that, over the last decade, has generated many discrepancies and controversies regarding the management of post-cardiac arrest patients is targeted temperature management (TTM).
Currently, there is no specific recommendation on the level of temperature.1,2 To give skeptics more reasons to remain skeptical, and feed the undecided, the long-awaited TTM2 clinical trial has recently been published to add fuel to the file.3 Prematurely and not very much pondered unfavorable opinions have appeared regarding the results of this study to the point that TTM has been declared dead for the management of post-cardiac arrest syndrome. In the study results no significant differences were found regarding mortality or improved neurological prognosis at 6 months in patients managed with TTM at 91.4°F vs 96.8°F.3
We’ll now try to expose some of the reasons why we should not overlook the TTM2 results just like that.
Regarding other results reported, there is a huge number of patients who were resuscitated by witnesses (80%), which is well above the rates reported in previous trials and observational studies. On the other hand, a high percentage of patients had defibrilable rhythm (74%), and a relatively low percentage of patients were in shock (29%),3 which means that the characteristics of patients from the trial population have been less serious compared to those assessed in other studies, which may have impacted findings significantly.
Scientific evidence indicates that most severe patients (PCAC 3-4), categorized as such based on the Pittsburg Cardiac Arrest Category (PCAC) scale benefited from TTM to 91.4°F vs 96.8°F in terms of survival and neurological prognosis at hospital discharge.4 Also, the same study said that less serious patients (PCAC 2) benefited from TTM at 96.8°F. This supports an approach oriented to the personalized management of the therapy, which to this date has not been assessed in any trial, which by the way, is something that should be considered in future studies.
The controversial results from the studies published to this date have made many centers have to change their routine clinical practice regarding the temperature targets of post-cardiac arrest patients from 91.4°F to 96.8°F, which has resulted in a tendency towards clinical worsening and poor prognosis.5
Scientific evidence is often poorly translated into the routine clinical practice or else its results are poorly interpreted, which leads to possible risks for the patient and worse clinical outcomes. In the future, we should set our sights on individualized medicine and identify subgroups of patients who may benefit from specific target temperature management. We should not abandon therapies when biological plausibility, great cumulative evidence in animal models, and clinical trials with positive harmless results have been reported.
FundingThis work received no public or private funding whatsoever.
Please cite this article as: Blandino Ortiz A, Higuera Lucas J, Márquez Alonso JA, de Pablo R. ¿Debemos abandonar el control estricto de la temperatura a 33 °C, en el manejo del paciente posparada cardiaca? Med Intensiva. 2022;46:481–482.