Quality of targeted temperature management and outcome of out-of-hospital cardiac arrest patients: A post hoc analysis of the TTH48 study

Temperature Control in the Era of Personalized Medicine: Knowledge Gaps, Research Priorities, and Future Directions

Hypoxic-ischemic brain injury (HIBI) is the leading cause of death and disability after cardiac arrest. To date, temperature control is the only intervention shown to improve neurologic outcomes in patients with HIBI. Despite robust preclinical evidence supporting hypothermia as neuroprotective therapy after cardiac arrest, there remains clinical equipoise regarding optimal core temperature, therapeutic window, and duration of therapy. Current guidelines recommend continuous temperature monitoring and active fever prevention for at least 72 h and additionally note insufficient evidence regarding temperature control targeting 32 °C-36 °C. However, population-based thresholds may be inadequate to support the metabolic demands of ischemic, reperfused, and dysregulated tissue. Promoting a more personalized approach with individualized targets has the potential to further improve outcomes. This review will analyze current knowledge and evidence, address research priorities, explore the components of high-quality temperature control, and define critical future steps that are needed to advance patient-centered care for cardiac arrest survivors.

Relationship between cooling time and neurological outcomes in targeted temperature management

OBJECTIVES

The relationship between cooling time (CT) variables and neurological outcomes is controversial. We evaluated the relationship between CT and neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients treated with targeted temperature management (TTM).

METHODS

We conducted a multicenter, prospective, and registry-based study of OHCA survivors treated with TTM. CT was defined as the time from restoration of spontaneous circulation to achievement of the target temperature. The primary outcome was a favorable neurological outcome at 6 months. Multilevel logistic regression analysis was performed to test the relationship between CT and the primary outcome.

RESULTS

Overall, the favorable neurological outcome rates at 6 months were 29.8% in 937 patients. When CT was stratified into categories of 0-3, 3.1-6, 6.1-9, 9.1-12, and >12 h, according to 3-h intervals, the primary outcome rates were 8.2%, 22.7%, 35.5%, 44.7%, and 44.5%, respectively (p < 0.001). Significant differences were not found in multilevel logistic regression analysis; the adjusted odds ratios (95% confidence interval) of each category for the primary outcome compared to the 0-3-h group were 0.81 (0.32 to 2.04), 0.77 (0.30 to 2.01), 1.26 (0.43 to 3.68), and 1.06 (0.37 to 3.06).

CONCLUSIONS

We did not find a relationship between CT and neurological outcomes at 6 months.

Comparison of hydrogel pad and water-circulating blanket cooling methods for targeted temperature management: A propensity score-matched analysis from a prospective multicentre registry

BACKGROUND

Various methods have been used to control body temperature in targeted temperature management (TTM), but few studies have compared specific subtypes of surface cooling systems. The aim of this study was to compare the efficiencies and neurological outcomes between hydrogels pad and water-circulating blanket cooling methods.

METHODS

We conducted a multicentre, prospective, registry-based study of out-of-hospital cardiac arrest patients treated with TTM between 2015 and 2018. We compared the neurological outcomes, efficacies for cooling, and adverse events between patients who received TTM using a hydrogel pad and water-circulating blanket cooling. Patients were one-to-one matched using propensity scores to adjust for differences in the baseline characteristics of each cooling method. The primary outcome was a favourable neurological outcome at 6 months.

RESULTS

We included 1,132 patients in the analysis, 870 of whom underwent hydrogel pad cooling, and the remaining 262 underwent water-circulating blanket cooling. In the unmatched cohort, a greater number of adverse events occurred in the water-circulating blanket group. The favourable neurologic outcome rates at 6 months were similar between the hydrogel pad group and the water circulating blanket group (30.2% vs. 29.8%, p = 0.939). In the propensity-matched cohort, which included 184 pairs, the rates of adverse events between the two groups were similar. The similarity of favourable neurologic outcome rates at 6 months between the two groups persisted (28.8% vs. 29.9%, p = 0.819).

CONCLUSION

Neurological outcomes and adverse events between the hydrogel pad cooling and water-circulating blanket cooling groups were similar.