TTM with internal cooling provides tighter temperature control, better survival outcomes
In targeted temperature management (TTM) postcardiac arrest, tighter temperature control is achieved with internal than external cooling, a study has shown. Moreover, internal cooling potentially results in better survival-to-hospital discharge outcomes and reduces cardiac arrhythmia complications in carefully selected patients as compared with normothermia.
The study included 45 postresuscitation cardiac arrest patients and 42 matched controls. Patients were randomly assigned to the internal cooling arm (n=23) or the external cooling arm (n=22). Descriptive statistics and frequencies, as well as univariate logistic regression, were used in the analyses.
Survival, neurological outcomes and complications were not found to be significantly different between the internal and external cooling arms. However, the internal cooling arm had a lower risk of developing overcooling (p=0.01) and rebound hyperthermia (p=0.02).
Additionally, compared with normothermia control, internal cooling was associated with higher survival (odds ratio [OR], 3.36; 95 percent CI, 1.130 to 10.412) and lower risk of developing cardiac arrhythmias (OR, 0.18; 0.04 to 0.63).
Subgroup analysis demonstrated better survival with internal cooling vs normothermia among patients with cardiac cause of arrest (OR, 4.29; 1.26 to 15.80) and sustained return of spontaneous circulation (OR, 5.50; 1.64 to 20.39).
In unconscious patients admitted to the intensive care unit after cardiac arrest, short- and long-term outcomes are characterized by prognostic uncertainty and a high risk of death and neurologic deficit. TTM has been used to improve the chance of survival and neurologic recovery, in addition with urgent coronary angiography and percutaneous coronary intervention when appropriate. Current recommendations based on two largest randomized clinical trials on TTM cite that the patient’s temperature should be kept at a target of 32 to 36°C for at least 24 hours. [Circulation 2015;132:S465-S482; N Engl J Med 2013;369:2197-2206; 2002;346:549-556]