Increased protocol adherence and safety during controlled normothermia as compared to hypothermia after cardiac arrest

A Systematic Literature Review to Assess Fever Management and the Quality of Targeted Temperature Management in Critically Ill Patients

Targeted temperature management (TTM) has been proposed to reduce mortality and improve neurological outcomes in postcardiac arrest and other critically ill patients. TTM implementation may vary considerably among hospitals, and "high-quality TTM" definitions are inconsistent. This systematic literature review in relevant critical care conditions evaluated the approaches to and definitions of TTM quality with respect to fever prevention and the maintenance of precise temperature control. Current evidence on the quality of fever management associated with TTM in cardiac arrest, traumatic brain injury, stroke, sepsis, and critical care more generally was examined. Searches were conducted in Embase and PubMed (2016 to 2021) following PRISMA guidelines. In total, 37 studies were identified and included, with 35 focusing on postarrest care. Frequently-reported TTM quality outcomes included the number of patients with rebound hyperthermia, deviation from target temperature, post-TTM body temperatures, and number of patients achieving target temperature. Surface and intravascular cooling were used in 13 studies, while one study used surface and extracorporeal cooling and one study used surface cooling and antipyretics. Surface and intravascular methods had comparable rates of achieving target temperature and maintaining temperature. A single study showed that patients with surface cooling had a lower incidence of rebound hyperthermia. This systematic literature review largely identified cardiac arrest literature demonstrating fever prevention with multiple TTM approaches. There was substantial heterogeneity in the definitions and delivery of quality TTM. Further research is required to define quality TTM across multiple elements, including achieving target temperature, maintaining target temperature, and preventing rebound hyperthermia.

Changes Over 7 Years in Temperature Control Treatment and Outcomes After Out-of-Hospital Cardiac Arrest: A Japanese, Multicenter Cohort Study

Temperature control is the only neuroprotective intervention suggested in current international guidelines for patients with return of spontaneous circulation after cardiac arrest, but the prevalence of temperature control therapy, temperature settings, and outcomes have not been clearly reported. We aimed to investigate changes over 7 years in provision of temperature control treatment among out-of-hospital cardiac arrest (OHCA) patients in Kanto region, Japan. Data of all adult OHCA patients who survived for more than 24 hours in the prospective cohort studies, SOS-KANTO 2012 (conducted from 2012 to 2013) and SOS-KANTO 2017 (conducted from 2019 to 2021), in Japan were included. We compared the prevalence of temperature control and the proportion of mild (≥35°C) and moderate (from 32°C to 34.9°C) hypothermia between the two study groups. We also performed a Cox regression analysis to evaluate 30-day mortality adjusted by temperature control therapy (none, moderate hypothermia, or mild hypothermia), age, sex, past medical history, witnessed status, bystander cardiopulmonary resuscitation, initial rhythm, location of arrest, and dataset (SOS-KANTO 2012 or 2017). We analyzed data from 2936 patients (n = 1710, SOS-KANTO 2012; n = 1226, SOS-KANTO 2017). Use of temperature control was lower (45.3% vs. 41.4%, p = 0.04), moderate hypothermia was lower (p < 0.01), and mild hypothermia was higher (p < 0.01) in SOS-KANTO 2017 compared with SOS-KANTO 2012. The survival rate was significantly higher for patients with mild (p < 0.01) and moderate (p < 0.01) hypothermia compared with those who did not receive temperature control therapy. Overall, the incidence of moderate hypothermia decreased and that of mild hypothermia increased and the use of temperature control decreased between the two studies conducted 7 years apart in the Kanto area, Japan. Temperature control management might improve survival of patients with OHCA.

Target temperature management versus normothermia without temperature feedback systems for out-of-hospital cardiac arrest survivors

Objective

The clinical benefit of automatic temperature control devices remains unclear. We investigated the outcomes of out-of-hospital cardiac arrest (OHCA) survivors who had undergone either target temperature management (TTM) with a temperature feedback system (TFS) or maintenance of normothermia without a TFS during post-resuscitation care.

Methods

This study was a retrospective analysis of a multicenter prospective cohort of OHCA survivors who had received postcardiac arrest care from August 2014 to December 2018. The overlap propensity score weighting method was applied for adjustment between groups.

Results

A total of 405 OHCA survivors were included. TTM with a TFS and normothermia without a TFS were applied to 318 and 87 patients, respectively. Fever events were more common in patients with normothermia without a TFS. After propensity score matching, no statistically significant differences were observed in the 1-month good neurologic outcome (odds ratio 0.99, 95% confidence interval [CI] 0.56–1.25) or survival rate (odds ratio 1.25, 95% CI 0.88–1.78).

Conclusion

No significant differences in the 1-month neurologic outcome were observed between patients receiving TTM with a TFS and those undergoing normothermia without a TFS.

Which Target Temperature for Post-Anoxic Brain Injury? A Systematic Review from "Real Life" Studies

There is a persistent debate on the optimal target temperature to use during cooling procedures in cardiac arrest survivors. A large randomized clinical trial (RCT) including more than 900 patients showed that targeted temperature management (TTM) at 33 °C had similar mortality and unfavorable neurological outcome (UO) rates as TTM at 36 °C in out-of-hospital cardiac arrest patients with any initial rhythm. Since then, several observational studies have been published on the effects of changes in target temperature (i.e., from 33 to 36 °C) on patients’ outcome. We performed a systematic literature search from 1 January 2014 to 4 December 2020 and identified ten retrospective studies (very low levels of certainty; high risk of bias), including 5509 patients, that evaluated TTM at 33 °C vs. TTM at 36 °C on the occurrence of UO (n = eight studies) and mortality (n = ten studies). TTM at 33 °C was associated with a lower risk of UO when studies assessing neurological outcome with the Cerebral Performance Categories were analyzed (OR 0.80 [95% CIs 0.72–0.98]; p = 0.03). No differences in mortality were observed within the two TTM strategies. These results suggest that an inappropriate translation of TTM protocols from large well-conducted randomized trials into clinical management may result in unexpected effects on patients’ outcome. As for all newly commercialized drugs, epidemiological studies and surveillance programs with an adequate follow-up on large databases are necessary to understand how RCTs are implemented into medical practice.