Door‐to‐Targeted Temperature Management Initiation Time and Outcomes in Out‐of‐Hospital Cardiac Arrest: Insights From the Continuous Chest Compressions Trial

Abstract

Background Targeted temperature management ( TTM ) is a recommended treatment modality to improve neurological outcomes in patients with out‐of‐hospital cardiac arrest. The impact of the duration from hospital admission to TTM initiation (door‐to‐ TTM ; DTT ) on clinical outcomes has not been well elucidated. We hypothesized that shorter DTT initiation intervals would be associated with improved survival with favorable neurological outcome. Methods and Results We performed a post hoc analysis of nontraumatic paramedic‐treated out‐of‐hospital cardiac arrests. The primary outcome was favorable neurological status at hospital discharge, with a secondary outcome of survival to discharge. We fit a logistic regression analysis to determine the association of early compared with delayed DTT , dichotomized by the median DTT duration, and outcomes. Of 3805 patients enrolled in the CCC (Continuous Chest Compressions) Trial in British Columbia, 570 were included in this analysis. There was substantial variation in DTT among patients receiving TTM . The median DTT duration was 122 minutes (interquartile range 35‐218). Favorable neurological outcomes in the early and delayed DTT groups were 48% and 38%, respectively. Compared with delayed DTT (interquartile range 167‐319 minutes), early DTT (interquartile range 20‐81 minutes) was associated with survival (adjusted odds ratio 1.56, 95% CI 1.02‐2.38) but not with favorable neurological outcomes (adjusted odds ratio 1.45, 95% CI , 0.94‐2.22) at hospital discharge. Conclusions There was wide variability in the initiation of TTM among comatose out‐of‐hospital cardiac arrest survivors. Initiation of TTM within 122 minutes of hospital admission was associated with improved survival. These results support in‐hospital efforts to achieve early DTT among out‐of‐hospital cardiac arrest patients admitted to the hospital.

Therapeutic hypothermia and Type II errors: Do not throw out the baby with the ice water

“…[22,30] Recently, a survey of door-to-target temperature shows increasing variation among the US sites. [24] In contrast to the European and Melbourne trials -which excluded patients with nonshockable rhythm -a recent French study showed a significant survival benefit in patients treated with TH after cardiac arrest due to asystole and PEA. [31] Although These data were compiled to generate the plots shown in Figure 5.…”

“…While the exact mechanism of neuroprotection with TH is not known, most observers suggest that cooling should begin urgently after ischemia. [24] If the onset to cooling is delayed significantly, there may be a benefit, but much longer cooling durations are required. [25] Thus, we suggest there is a real probability that TH in the TTM trial started too late to yield a statistically significant difference between the two study groups.…”

Handling of Ventricular Fibrillation in the Emergency Setting

“…The greatest difference between the early (20-81 min) and the late (167-319 min) groups was in survival. The early group had 1.59 times higher chance for survival compared to the late group, while they had only 1.49 times higher chance for a good neurological outcome, which did not prove clearly significant (Stanger et al, 2019). The 2015 resuscitation guideline recommends earliest possible PCI in the case of sudden cardiac death with acute coronary syndrome as the underlying cause (Nikolaou et al, 2015).…”

Targeted temperature management for postcardiac arrest syndrome

“…Table 1 shows longer time intervals to achieve targeted temperature, especially in Hypothermia after Cardiac Arrest Study Group study [5], possibly because cooling devices with temperature feedback were not used. Stanger et al [28] reported that initiation of TTM (door-to-TTM) within 122 minutes of hospital admission was associated with improved survival. Care must be taken to control the time interval between collapse and ROSC, because this interval might determine the outcome.…”