Survival to hospital discharge and neurological outcomes with targeted temperature management after in-hospital cardiac arrest: a systematic review and meta-analysis.

BACKGROUND

Multiple randomized controlled trials have shown that targeted temperature management (TTM) has favorable effects in out-of-hospital cardiac arrest. However, the benefit of TTM in patients with in-hospital cardiac arrest (IHCA) remains to be verified.

METHODS

The PubMed, Cochrane Library, and EMBASE databases were searched for clinical studies with the primary outcomes of survival to hospital discharge and neurological outcomes. Neurological outcomes were evaluated by the categorical scale of cerebral function (CPC); a score of 1-2 points was considered neurologically good, and a score of 3-5 points was considered a poor outcome. Revman 5.3 and Stata 14 software with the random effects model were used for analysis. P<0.05 was considered statistically significant.

RESULTS

Six retrospective controlled studies with a total of 14,607 patients (TTM group: 1,845, control group: 12,762) were included and analyzed. There were no statistically significant differences between the two groups in survival to hospital discharge [odds ratio (OR) =1.02, 95% CI: 0.77-1.35, P=0.89, I2=47%] or favorable neurological outcomes (OR =1.06, 95% CI: 0.56-2.02, P=0.85, I2=79%). After excluding patients with non-shockable initial rhythms, TTM did not show any significant improvement in survival to hospital discharge. Subgroup analysis was performed according to the sample size. No significant improvement was observed between the two groups in terms of survival to hospital discharge or neurological outcome.

DISCUSSION: In this meta-analysis, the effects of TTM on discharge survival and neurological prognosis were evaluated by studying the results of IHCA in 14,607 patients. We found that the TTM did not improve survival and neurological function in discharged patients. Our results showed that the sample size discrepancy had a large effect on the heterogeneity; to address this, subgroup analyses were performed according to the different sample sizes. However, TTM treatment in different sample size subgroups showed no significant effect on survival to hospital discharge. Moreover, in the large sample size subgroup, therapeutic hypothermia was associated with increased unfavorable neurological outcome compared with no hypothermia.