Differential effect of mild therapeutic hypothermia depending on the findings of hypoxic encephalopathy on early CT images in patients with post-cardiac arrest syndrome

Association of targeted temperature management on progression to brain death after severe anoxic brain injury following cardiac arrest: an observational study

OBJECTIVE

Targeted temperature management (TTM), through its physiological effects on intracranial pressure, may impede the progression to brain death (BD) in severe anoxic brain injury post-cardiac arrest (CA). We examined the potential association between the use of TTM and the occurrence of BD after CA.

DESIGN

Monocentric, retrospective study.

SETTING

Intensive care unit, Versailles Hospital, France.

PARTICIPANTS

Comatose survivors of CA who died from BD or postanoxic encephalopathy (PAE) after 24 hours.

MAIN OUTCOME MEASURES

PAE deaths corresponded to withdrawal of life-sustaining therapy (WLST) due to irreversible postanoxic coma or vegetative state according to prognostication guidelines. BD corresponded to the cessation of cerebral vascularisation secondary to intracranial hypertension. The diagnosis of BD was definite by clinical diagnosis of deep coma according to the Glasgow Coma Scale 3, loss of all brainstem reflexes and the demonstration of apnoea during a hypercapnia test. A cerebral omputed tomography (CT) scan or two isoelectric and unreactive electroencephalograms were used to confirm BD. To identify the independent association between TTM and BD, we conducted a multivariable logistic regression analysis.

RESULTS

Out of 256 patients included between 2005 and 2021, 54.3% received TTM for at least 24 hours, and 56 patients (21.9%) died from BD. In the multivariable analysis, TTM for 24 hours or more was not associated with a decrease in BD (Odds Ratio 1.08, 95% CI 0.51 to 2.32). Factors associated with BD included a total duration of no-flow plus low-flow exceeding 30 min, CA due to neurological causes or hanging and a high arterial partial pressure of carbon dioxide between days 1 and 2 after admission.

CONCLUSIONS

This exploratory analysis of post-CA patients with severe anoxic brain injury did not find an association between TTM ≥24 hours and a reduction in BD. Further studies are needed to identify specific subgroups of post-CA patients for whom TTM may be especially futile or even harmful.

Differential Effectiveness of Hypothermic Targeted Temperature Management According to the Severity of Post-Cardiac Arrest Syndrome

International guidelines recommend targeted temperature management (TTM) to improve the neurological outcomes in adult patients with post-cardiac arrest syndrome (PCAS). However, it still remains unclear if the lower temperature setting (hypothermic TTM) or higher temperature setting (normothermic TTM) is superior for TTM. According to the most recent large randomized controlled trial (RCT), hypothermic TTM was not found to be associated with superior neurological outcomes than normothermic TTM in PCAS patients. Even though this represents high-quality evidence obtained from a well-designed large RCT, we believe that we still need to continue investigating the potential benefits of hypothermic TTM. In fact, several studies have indicated that the beneficial effect of hypothermic TTM differs according to the severity of PCAS, suggesting that there may be a subgroup of PCAS patients that is especially likely to benefit from hypothermic TTM. Herein, we summarize the results of major RCTs conducted to evaluate the beneficial effects of hypothermic TTM, review the recent literature suggesting the possibility that the therapeutic effect of hypothermic TTM differs according to the severity of PCAS, and discuss the potential of individualized TTM.

Latent transition analysis of cardiac arrest patients treated in the intensive care unit

BACKGROUND AND OBJECTIVE

Post-cardiac arrest (CA) syndrome is heterogenous in their clinical presentations and outcomes. This study aimed to explore the transition and stability of subphenotypes (profiles) of CA treated in the intensive care unit (ICU).

PATIENTS AND METHODS

Clinical features of CA patients on day 1 and 3 after ICU admission were modeled by latent transition analysis (LTA) to explore the transition between subphenotypes over time. The association between different transition patterns and mortality outcome was explored using multivariable logistic regression.

RESULTS

We identified 848 eligible patients from the database. The LPA identified three distinct subphenotypes: Profile 1 accounted for the largest proportion (73%) and was considered as the baseline subphenotype. Profile 2 (13%) was characterized by brain injury and profile 3 (14%) was characterized by multiple organ dysfunctions. The same three subphenotypes were identified on day 3. The LTA showed consistent subphenotypes. A majority of patients in profile 2 (72%) and 3 (82%) on day 1 switched to profile 1 on day 3. In the logistic regression model, patients in profile 1 on day 1 transitioned to profile 3 had worse survival outcome than those continue to remain in profile 1 (OR: 20.64; 95% CI: 6.01 to 70.94; p < 0.001) and transitioned to profile 2 (OR: 8.42; 95% CI: 2.22 to 31.97; p = 0.002) on day 3.

CONCLUSION

The study identified three subphenotypes of CA, which was consistent on day 1 and 3 after ICU admission. Patients who transitioned to profile 3 on day 3 had significantly worse survival outcome than those remained in profile 1 or 2.

Outcome Related to Level of Targeted Temperature Management in Postcardiac Arrest Syndrome of Low, Moderate, and High Severities: A Nationwide Multicenter Prospective Registry

OBJECTIVES

The optimal target temperature during targeted temperature management for patients after cardiac arrest remains under debate. The aim of this study was to evaluate the association between targeted temperature management at lower target temperatures and the neurologic outcomes among patients classified by the severity of postcardiac arrest syndrome.

DESIGN

A multicenter observational study from the out-of-hospital cardiac arrest registry of the Japanese Association for Acute Medicine, which is a nationwide prospective registry of out-of-hospital cardiac arrest patients.

SETTING

A total of 125 critical care medical centers or hospitals with an emergency care department across Japan.

PATIENTS

A total of 1,111 out-of-hospital cardiac arrest patients who had received targeted temperature management.

MEASUREMENTS AND MAIN RESULTS

We divided all 1,111 postcardiac arrest syndrome patients treated with targeted temperature management into two groups: those who received targeted temperature management at a lower target temperature (33-34°C) and those who received targeted temperature management at a higher target temperature (35-36°C). In regard to classification of the patients, we divided the patients into three categories of severity (low, moderate, and high severities) using the risk classification tool, post-Cardiac Arrest Syndrome for Therapeutic hypothermia, which was previously validated. The primary outcome was the percentage of patients with a good neurologic outcome at 30 days, and the secondary outcome was the survival rate at 30 days. Multivariate analysis showed that targeted temperature management at 33-34°C was significantly associated with a good neurologic outcome and survival at 30 days in the moderate severity (odds ratio, 1.70 [95% CI, 1.03-2.83] and 1.90 [95% CI, 1.15-3.16], respectively), but not in the patients of low or high severity (pinteraction = 0.033). Propensity score analysis also showed that targeted temperature management at 33-34°C was associated with a good neurologic outcome in the moderate-severity group (p = 0.022).

CONCLUSIONS

Targeted temperature management at 33-34°C was associated with a significantly higher rate of a good neurologic outcome in the moderate-severity postcardiac arrest syndrome group, but not in the low- or high-severity group.

Targeted temperature management guided by the severity of hyperlactatemia for out-of-hospital cardiac arrest patients: a post hoc analysis of a nationwide, multicenter prospective registry

Background

The International Liaison Committee on Resuscitation guidelines recommend target temperature management (TTM) between 32 and 36 °C for patients after out-of-hospital cardiac arrest, but did not indicate patient-specific temperatures. The association of serum lactate concentration and neurological outcome in out-of-hospital cardiac arrest patient has been reported. The study aim was to investigate the benefit of 32–34 °C in patients with various degrees of hyperlactatemia compared to 35–36 °C.

Methods

This study was a post hoc analysis of the Japanese Association for Acute Medicine out-of-hospital cardiac arrest registry between June 2014 and December 2015. Patients with complete targeted temperature management and lactate data were eligible. Patients were stratified to mild (< 7 mmol/l), moderate (< 12 mmol/l), or severe (≥ 12 mmol/l) hyperlactatemia group based on lactate concentration after return of spontaneous circulation. They were subdivided into 32–34 °C or 35–36 °C groups. The primary endpoint was an adjusted predicted probability of 30-day favorable neurological outcome, defined as a cerebral performance category score of 1 or 2.

Result

Of 435 patients, 139 had mild, 182 had moderate, and 114 had severe hyperlactatemia. One hundred and eight (78%) with mild, 128 with moderate (70%), and 83 with severe hyperlactatemia (73%) received TTM at 32–34 °C. The adjusted predicted probability of a 30-day favorable neurological outcome following severe hyperlactatemia was significantly greater with 32–34 °C (27.4%, 95% confidence interval: 22.0–32.8%) than 35–36 °C (12.4%, 95% CI 3.5–21.2%; p = 0.005). The differences in outcomes in those with mild and moderate hyperlactatemia were not significant.

Conclusions

In OHCA patients with severe hyperlactatemia, the adjusted predicted probability of 30-day favorable neurological outcome was greater with TTM at 32–34 °C than with TTM at 35–36 °C. Further evaluation is needed to determine whether TTM at 32–34 °C can improve neurological outcomes in patients with severe hyperlactatemia after out-of-hospital cardiac arrest.

Differential effect of lactate in predicting mortality in septic patients with or without disseminated intravascular coagulation: a multicenter, retrospective, observational study

Background

We examined whether high lactate level in septic patients was associated with 90-day mortality based on the patients’ disseminated intravascular coagulation (DIC) status.

Methods

We conducted a multicenter, retrospective, observational study of patients admitted to the intensive care unit (ICU) with a suspicion of severe infection and diagnosed with sepsis. Regression analyses were performed to estimate the interaction effect between DIC status and the lactate level. Then, the association between the lactate level and 90-day mortality was assessed in the DIC and non-DIC subgroups.

Results

The data of 415 patients were analyzed. We found a significant interaction between DIC status and the lactate level for predicting 90-day mortality (p_interaction = 0.04). Therefore, we performed a subgroup analysis and found that high lactate concentration was significantly associated with 90-day mortality in the DIC group (odds ratio = 2.31, p = 0.039) but not in the non-DIC group.

Conclusions

In patients with DIC, a high lactate level significantly predicted 90-day mortality; no such association was found in the non-DIC group. Thus, DIC status may serve as a possible effect modifier of lactate level in predicting mortality in patients with sepsis.