Impact of therapeutic hypothermia on bleeding events in adult patients treated with extracorporeal life support peri-cardiac arrest

Bleeding and Thrombosis in Patients With Out-of-Hospital Ventricular Tachycardia/Ventricular Fibrillation Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation

BACKGROUND

Extracorporeal cardiopulmonary resuscitation improves outcomes after out-of-hospital cardiac arrest. However, bleeding and thrombosis are common complications. We aimed to describe the incidence and predictors of bleeding and thrombosis and their association with in-hospital mortality.

METHODS AND RESULTS

Consecutive patients presenting with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest between December 2015 and March 2022 who met the criteria for extracorporeal cardiopulmonary resuscitation initiation at our center were included. Major bleeding was defined by the Extracorporeal Life Support Organization's criteria. Adjusted analyses were done to seek out risk factors for bleeding and thrombosis and evaluate their association with mortality. Major bleeding occurred in 135 of 200 patients (67.5%), with traumatic bleeding from cardiopulmonary resuscitation in 73 (36.5%). Baseline demographics and arrest characteristics were similar between groups. In multivariable analysis, decreasing levels of fibrinogen were independently associated with bleeding (adjusted hazard ratio [aHR], 0.98 per every 10 mg/dL rise [95% CI, 0.96-0.99]). Patients who died had a higher rate of bleeds per day (0.21 versus 0.03, P<0.001) though bleeding was not significantly associated with in-hospital death (aHR, 0.81 [95% CI. 0.55-1.19]). A thrombotic event occurred in 23.5% (47/200) of patients. Venous thromboembolism occurred in 11% (22/200) and arterial thrombi in 15.5% (31/200). Clinical characteristics were comparable between groups. In adjusted analyses, no risk factors for thrombosis were identified. Thrombosis was not associated with in-hospital death (aHR, 0.65 [95% CI, 0.42-1.03]).

CONCLUSIONS

Bleeding is a frequent complication of extracorporeal cardiopulmonary resuscitation that is associated with decreased fibrinogen levels on admission whereas thrombosis is less common. Neither bleeding nor thrombosis was significantly associated with in-hospital mortality.

Hypothermia as an Adjunctive Therapy in Cardiogenic Shock: A Systematic Review and Meta-Analysis

In the setting of out-of-hospital cardiac arrest, therapeutic hypothermia (TH) has been shown to improve clinical outcomes. However, trials showing the advantage of TH did not include patients with cardiogenic shock (CS). We performed a comprehensive literature search for studies that evaluated the efficacy and safety of adjunctive TH compared with the standard of care (SOC) in patients with CS. The primary outcome was the mortality rate (in-hospital, short-, and mid-term). The secondary outcomes were the TH-related complications, duration of Intensive Care Unit (ICU) stay, duration of mechanical ventilation (MV-days), and improvement in cardiac function. Relative risk (RR) or the standardized mean difference (SMD) and corresponding 95% confidence intervals (CIs) were calculated using the random-effects model. A total of 7 clinical studies (3 RCTs included), and 712 patients (341 in the TH group and 371 in the SOC group) were included. As compared with the SOC, TH was not associated with a statistically significant improvement in the in-hospital (RR: 0.73%, 95% CI: 0.51-1.03; p = 0.08), short-term (RR: 0.90%, 95% CI: 0.75-1.06; p = 0.21), or mid-term (RR: 0.93%, 95% CI: 0.78-1.10; p = 0.38) mortality rates. Despite the improvement in the cardiac function in the TH group (SMD: 1.08, 95% CI: 0.02-2.1; p = 0.04), the TH strategy did not significantly shorten the MV days, or the ICU stay (p-values >0.05). Finally, there was a trend toward higher risks for infection, major bleeding, and the need for blood transfusion in the TH group. According to our meta-analysis of published clinical studies, TH is not beneficial in patients with CS and has a marginal safety profile. Larger-scale RCTs are needed to further clarify our results.

Temperature Outcomes without heater cooler units in adult patients supported with extracorporeal membrane oxygenation: A retrospective cohort study

INTRODUCTION

Heater-cooler units (HCUs) are frequently incorporated into extracorporeal membrane oxygenation (ECMO) circuits to help maintain patient normothermia. However, these devices may be associated with increased cost and infection risk. This study describes our institution's experience managing adult ECMO patients without the routine use of in-circuit HCUs.

METHODS

We performed a retrospective analysis of adult patients treated with veno-venous (VV) or veno-arterial (VA) ECMO at our institution. The primary outcomes were rates of HCU use and the relative duration of the ECMO treatment course in which patients maintained normothermia (36-37.5°C), with and without HCUs. Secondary outcomes of mortality and ECMO-related complications were planned across HCU and non-HCU groups; exploratory analyses were performed across a 75% "ECMO time in normothermia" threshold.

RESULTS

Among a cohort of 71 patients, zero (0%) were managed with in-circuit HCUs. A majority of ECMO patient-hours were spent in the normothermic range. Median and mean percentages of ECMO normothermia time were 75% (IQR 49%-81%) and 62% (SD ± 27%). Twenty-nine patients (40%) met the threshold of 75% ECMO normothermia time, as used to evaluate secondary outcomes. At this threshold, mortality risk was significantly higher among the non-normothermic cohort; other ECMO-related complications did not vary significantly.

CONCLUSIONS

In the absence of HCU use, the majority of ECMO patient-hours were spent in normothermia. However, only a minority of patients achieved normothermia for at least 75% of their ECMO course. In-circuit HCUs may be required to maintain high percentages of normothermic time in adult EMCO patients.

Hypothermia may reduce mortality and improve neurologic outcomes in adult patients treated with VA-ECMO: A systematic review and meta-analysis

BACKGROUND

VA-ECMO can greatly reduce mortality in critically ill patients, and hypothermia attenuates the deleterious effects of ischemia-reperfusion injury. We aimed to study the effects of hypothermia on mortality and neurological outcomes in VA-ECMO patients.

METHODS

A systematic search of the PubMed, Embase, Web of Science, and Cochrane Library databases was performed from the earliest available date to 31 December 2022. The primary outcome was discharge or 28-day mortality and favorable neurological outcomes in VA-ECMO patients, and the secondary outcome was bleeding risk in VA-ECMO patients. The results are presented as odds ratios (ORs) and 95% confidence intervals (CIs). Based on the heterogeneity assessed by the I² statistic, meta-analyses were performed using random or fixed-effects models. GRADE methodology was used to rate the certainty in the findings.

RESULTS

A total of 27 articles (3782 patients) were included. Hypothermia (33-35 °C) lasting at least 24 h can significantly reduce discharge or 28-day mortality (OR, 0.45; 95% CI, 0.33-0.63; I² = 41%) and significantly improve favorable neurological outcomes (OR, 2.08; 95% CI, 1.66-2.61; I² = 3%) in VA-ECMO patients. Additionally, there was no risk associated with bleeding (OR, 1.15; 95% CI, 0.86-1.53; I² = 12%). In our subgroup analysis according to in-hospital or out-of-hospital cardiac arrest, hypothermia reduced short-term mortality in both VA-ECMO-assisted in-hospital (OR, 0.30; 95% CI, 0.11-0.86; I² = 0.0%) and out-of-hospital cardiac arrest (OR, 0.41; 95% CI, 0.25-0.69; I² = 52.3%). Out-of-hospital cardiac arrest patients assisted by VA-ECMO for favorable neurological outcomes were consistent with the conclusions of this paper (OR, 2.10; 95% CI, 1.63-2.72; I² = 0.5%).

CONCLUSIONS

Our results show that mild hypothermia (33-35 °C) lasting at least 24 h can greatly reduce short-term mortality and significantly improve favorable short-term neurologic outcomes in VA-ECMO-assisted patients without bleeding-related risks. As the grade assessment indicated that the certainty of the evidence was relatively low, hypothermia as a strategy for VA-ECMO-assisted patient care may need to be treated with caution.

The use of induced hypothermia in extracorporeal membrane oxygenation: A narrative review

Despite venovenous or venoarterial extracorporeal membrane oxygenation (ECMO) being increasingly used in patients with severe acute respiratory disease syndrome, severe cardiogenic shock, and refractory cardiac arrest, mortality rates still remain high mainly because of the severity of the underlying disease and the numerous complications associated with initiation of ECMO. Induced hypothermia might minimize several pathological pathways present in patients requiring ECMO; even though numerous studies conducted in the experimental setting have reported promising results, there are currently no recommendations suggesting the routine use of this therapy in patients requiring ECMO. In this review, we summarized the existing evidence on the use of induced hypothermia in patients requiring ECMO. Induced hypothermia was a feasible and relatively safe intervention in this setting; however, the effects on clinical outcomes remain uncertain. Whether controlled normothermia has an impact on these patients compared with no temperature control remains unknown. Further randomized controlled trials are required to better understand the role and impact of such therapy in patients requiring ECMO according to the underlying disease.

The impact of different targeted temperatures on out-of-hospital cardiac arrest outcomes in patients receiving extracorporeal membrane oxygenation: a nationwide cohort study

BACKGROUND

Targeted temperature management (TTM) is recommended in the management of out-of-hospital cardiac arrest (OHCA) when coma persists after the return of spontaneous circulation. In the setting of extracorporeal membrane oxygenation (ECMO) for OHCA patients, TTM is associated with good neurological outcomes and is recommended in the Extracorporeal Life Support Organization guidelines. However, the optimal targeted temperature for these patients has not yet been adequately investigated. This study aimed to compare the impact of different targeted temperatures on the outcomes in OHCA patients receiving ECMO.

METHODS

This was a retrospective analysis of data from the Japanese Association for Acute Medicine (JAAM)-OHCA Registry, a multicentre nationwide prospective database in Japan in which 103 institutions providing emergency care participated. OHCA patients aged ≥ 18 years who required ECMO with TTM between June 2014 and December 2019 were included in our analysis. The primary outcome was 30-day survival with favourable neurological outcomes, defined as a Glasgow-Pittsburgh cerebral performance category score of 1 or 2. Patients were divided into two groups according to their targeted temperature: normothermic TTM (n-TTM) (35-36 °C) and hypothermic TTM (h-TTM) (32-34 °C). We compared the outcomes between the two targeted temperature groups using multivariable logistic regression and inverse probability weighting (IPW).

RESULTS

A total of 890 adult OHCA patients who received ECMO and TTM were eligible for our analysis. Of these patients, 249 (28%) and 641 (72%) were treated with n-TTM and h-TTM, respectively. The proportions of patients with 30-day favourable neurological outcomes were 16.5% (41/249) and 15.9% (102/641), in the n-TTM and h-TTM groups, respectively. No difference in neurological outcomes was observed in the multiple regression analysis [adjusted odds ratio 0.91, 95% confidence interval (CI) 0.58-1.43], and the result was constant in the IPW (odds ratio 1.01, 95% CI 0.67-1.54).

CONCLUSION

No difference was observed between n-TTM and h-TTM in OHCA patients receiving TTM with ECMO. The current understanding that changes to the targeted temperature have little impact on the outcome of patients may remain true regardless of ECMO use.

HEROES V-A-HEmoRrhagic cOmplications in veno-arterial Extracorporeal life Support-Development and internal validation of a multivariable prediction model in adult patients

BACKGROUND

Risk factors for bleeding complications during extracorporeal life support (ECLS) indicated for cardiac support remain poorly investigated. The aim is to develop and internally validate a prediction model to calculate the risk for bleeding complications in adult patients receiving veno-arterial (V-A) ECLS.

METHODS

Data of the Extracorporeal Life Support Organization registry of adult patients undergoing V-A ECLS between 2010 and 2020 were analyzed. The primary outcome was bleeding complications recorded during V-A ECLS. Multivariable logistic regression with backward stepwise elimination was used to develop the prediction model. Performance of the model was tested by discriminative ability and calibration with receiver operator characteristic, area under the curve, and visual inspection of the calibration plot. Internal validation was performed to detect overfitting of the model.

RESULTS

In total 28 767 adult patients were included, of which 29.0% developed bleeding complications. Sex, body mass index, surgical cannulation, pre-ECLS respiratory and hemodynamic variables, pre-ECLS support and interventions, and different type of diagnosis were included in the prediction model. This prediction model showed a predictive capability with an AUC of 0.66.

CONCLUSION

The model is based on the largest cohort of V-A ECLS patients and is the best available predictive model for bleeding events given the predictors that are available in V-A ECLS compared to current literature. The model can help in identifying patients at high risk for bleeding complications and will help in developing further research and decision-making in terms of anticoagulation management. External validation is warranted to extrapolate this model in the clinical setting.

Optimal Time of Collapse to Return of Spontaneous Circulation to Apply Targeted Temperature Management for Cardiac Arrest: A Bayesian Network Meta-Analysis

Background: Both the American Heart Association (AHA) and European Resuscitation Council (ERC) have strongly recommended targeted temperature management (TTM) for patients who remain in coma after return of spontaneous circulation (ROSC). However, the role of TTM, especially hypothermia, in cardiac arrest patients after TTM2 trials has become much uncertain.

Methods: We searched four online databases (PubMed, Embase, CENTRAL, and Web of Science) and conducted a Bayesian network meta-analysis. Based on the time of collapse to ROSC and whether the patient received TTM or not, we divided this analysis into eight groups (<20 min + TTM, <20 min, 20–39 min + TTM, 20–39 min, 40–59 min + TTM, 40–59 min, ≥60 min + TTM and ≥60 min) to compare their 30-day and at-discharge survival and neurologic outcomes.

Results: From an initial search of 3,023 articles, a total of 9,005 patients from 42 trials were eligible and were included in this network meta-analysis. Compared with other groups, patients in the <20 min + TTM group were more likely to have better survival and good neurologic outcomes (probability = 46.1 and 52.5%, respectively). In comparing the same time groups with and without TTM, only the survival and neurologic outcome of the 20–39 min + TTM group was significantly better than that of the 20–39 min group [odds ratio = 1.41, 95% confidence interval (1.04–1.91); OR = 1.46, 95% CI (1.07–2.00) respectively]. Applying TTM with <20 min or more than 40 min of collapse to ROSC did not improve survival or neurologic outcome [ <20 min vs. <20 min + TTM: OR = 1.02, 95% CI (0.61–1.71)/OR = 1.03, 95% CI (0.61–1.75); 40–59 min vs. 40–59 min + TTM: OR = 1.50, 95% CI (0.97–2.32)/OR = 1.40, 95% CI (0.81–2.44); ≧60 min vs. ≧60 min + TTM: OR = 2.09, 95% CI (0.70–6.24)/OR = 4.14, 95% CI (0.91–18.74), respectively]. Both survival and good neurologic outcome were closely related to the time from collapse to ROSC.

Conclusion: Survival and good neurologic outcome are closely associated with the time of collapse to ROSC. These findings supported that 20–40 min of collapse to ROSC should be a more suitable indication for TTM for cardiac arrest patients. Moreover, the future trials should pay more attention to these patients who suffer from moderate injury.

Systematic Review Registration: [https://inplasy.com/?s=202180027], identifier [INPLASY202180027]

eCPR Combined With Therapeutic Hypothermia Could Improve Survival and Neurologic Outcomes for Patients With Cardiac Arrest: A Meta-Analysis

Background: Extracorporeal membrane oxygenation with CPR (eCPR) or therapeutic hypothermia (TH) seems to be a very effective CPR strategy to save patients with cardiac arrest (CA). Furthermore, the subsequent post-CA neurologic outcomes have become the focus. Therefore, there is an urgent need to find a way to improve survival and neurologic outcomes for CA. Objective: We conducted this meta-analysis to find a more suitable CPR strategy for patients with CA. Method: We searched four online databases (PubMed, Embase, CENTRAL, and Web of Science). From an initial 1,436 articles, 23 studies were eligible into this meta-analysis, including a total of 2,035 patients. Results: eCPR combined with TH significantly improved the short-term (at discharge or 28 days) survival [OR = 2.27, 95% CIs (1.60-3.23), p < 0.00001] and neurologic outcomes [OR = 2.60, 95% CIs (1.92-3.52), p < 0.00001). At 3 months of follow-up, the results of survival [OR = 3.36, 95% CIs (1.65-6.85), p < 0.0008] and favorable neurologic outcomes [OR = 3.02, 95% CIs (1.38-6.63), p < 0.006] were the same as above. Furthermore, there was no difference in any bleeding needed intervention [OR = 1.33, 95% CIs (0.09-1.96), p = 0.16] between two groups. Conclusions: From this meta-analysis, we found that eCPR combined with TH might be a more suitable CPR strategy for patients with CA in improving survival and neurologic outcomes, and eCPR with TH did not increase the risk of bleeding. Furthermore, single-arm meta-analyses showed a plausible way of temperature and occasion of TH.

Does Targeted Temperature Management Improve Neurological Outcome in Extracorporeal Cardiopulmonary Resuscitation (ECPR)?

PURPOSE

Targeted temperature management (TTM) is a standard of care in patients after cardiac arrest for neuroprotection. Currently, the effectiveness and efficacy of TTM after extracorporeal cardiopulmonary resuscitation (ECPR) is unknown. We aimed to compare neurological and survival outcomes between TTM vs non-TTM in patients undergoing ECPR for refractory cardiac arrest.

METHODS

We searched PubMed and 5 other databases for randomized controlled trials and observational studies reporting neurological outcomes or survival in adult patients undergoing ECPR with or without TTM. Good neurological outcome was defined as cerebral performance category <3. Two independent reviewers extracted the data. Random-effects meta-analyses were used to pool data.

RESULTS

We included 35 studies (n = 2,643) with the median age of 56 years (interquartile range [IQR]: 52-59). The median time from collapse to ECMO cannulation was 58 minutes (IQR: 49-82) and the median ECMO duration was 3 days (IQR: 2.0-4.1). Of 2,643, 1,329 (50.3%) patients received TTM and 1,314 (49.7%) did not. There was no difference in the frequency of good neurological outcome at any time between TTM (29%, 95% confidence interval [CI]: 23%-36%) vs. without TTM (19%, 95% CI: 9%-31%) in patients with ECPR (P = 0.09). Similarly, there was no difference in overall survival between patients with TTM (30%, 95% CI: 22%-39%) vs. without TTM (24%, 95% CI: 14%-34%) (P = 0.31). A cumulative meta-analysis by publication year showed improved neurological and survival outcomes over time.

CONCLUSIONS

Among ECPR patients, survival and neurological outcome were not different between those with TTM vs. without TTM. Our study suggests that neurological and survival outcome are improving over time as ECPR therapy is more widely used. Our results were limited by the heterogeneity of included studies and further research with granular temperature data is necessary to assess the benefit and risk of TTM in ECPR population.