Outcome of extracorporeal membrane oxygenation use in severe accidental hypothermia with cardiac arrest and circulatory instability: A multicentre, prospective, observational study in Japan (ICE-CRASH study)

Successful prehospital ECMO in drowning resuscitation after prolonged submersion

An 18-year-old drowning victim was successfully resuscitated using prehospital veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Despite 24 min of submersion in water with a surface temperature of 15 °C, the patient was cannulated on-scene and transported to a trauma center. After ICU admission on VA-ECMO, he was decannulated and extubated by day 5. He was transferred to a peripheral hospital on day 6 and discharged home after 3.5 weeks with favorable neurological outcome of a Cerebral Performance Categories (CPC) score of 1 out of 5. This case underscores the potential of prehospital ECMO in drowning cases within a well-equipped emergency response system.

Extracorporeal cardiopulmonary resuscitation in hypothermic cardiac arrest: A secondary analysis of multicenter extracorporeal cardiopulmonary resuscitation registry data in Japan

Aim

Extracorporeal cardiopulmonary resuscitation (ECPR) is used to resuscitate patients with cardiac arrest; however, its effect in treating hypothermic cardiac arrest has not been well studied. Therefore, in this study, we aimed to examine the characteristics and outcomes of patients with hypothermic cardiac arrest who underwent ECPR, using a multicenter out-of-hospital cardiac arrest (OHCA) registry in Japan.

Methods

Baseline characteristics of patients with hypothermic OHCA and body temperature below 32 °C were assessed. Logistic regression analysis was performed to identify factors associated with in-hospital mortality and neurological outcomes in these patients. Outcomes of hypothermic and cardiogenic OHCA cases were compared using propensity-score matching to investigate differences among subgroups.

Results

We included 2,157 patients, with 102 and 1,646 in the hypothermic and cardiogenic groups, respectively. Higher age and longer low-flow time were independent risk factors for mortality, and higher age was an independent risk factor for unfavorable neurological outcomes in the hypothermic OHCA group.Eighty matched pairs were selected during propensity-score matching, and the mortality rate was lower in the hypothermic group than in the cardiogenic group (46.2% vs. 77.5%; p < 0.01). Unfavorable neurological outcome rate was lower in the hypothermic group than in the cardiogenic group (62.5% vs. 87.5%; p < 0.01).

Conclusions

Increased age and prolonged low-flow time were identified as negative prognostic factors in patients with hypothermic OHCA who underwent ECPR. These patients showed lower mortality and unfavorable neurological outcome rates than patients with cardiogenic OHCA, suggesting that ECPR is a promising strategy for treating hypothermic OHCA.

Low-flow time and outcomes in hypothermic cardiac arrest patients treated with extracorporeal cardiopulmonary resuscitation: a secondary analysis of a multi-center retrospective cohort study

BACKGROUND

In out-of-hospital cardiac arrest (OHCA) patients with extracorporeal cardiopulmonary resuscitation (ECPR), the association between low-flow time and outcomes in accidental hypothermia (AH) patients compared to those of patients without AH has not been fully investigated.

METHODS

This was a secondary analysis of the retrospective multicenter registry in Japan. We enrolled patients aged ≥ 18 years who had been admitted to the emergency department for OHCA and had undergone ECPR between January, 2013 and December, 2018. AH was defined as an arrival body temperature below 32 °C. The primary outcome was survival to discharge. Cubic spline analyses were performed to assess the non-linear associations between low-flow time and outcomes stratified by the presence of AH. We also analyzed the interaction between low-flow time and the presence of AH.

RESULTS

Of 1252 eligible patients, 105 (8.4%) and 1147 (91.6%) were in the AH and non-AH groups, respectively. Median low-flow time was 60 (47-79) min in the AH group and 51 (42-62) min in the non-AH group. The survival discharge rates in the AH and non-AH groups were 44.8% and 25.4%, respectively. The cubic spline analyses showed that survival discharge rate remained constant regardless of low-flow time in the AH group. Conversely, a decreasing trend was identified in the survival discharge rate with longer low-flow time in the non-AH group. The interaction analysis revealed a significant interaction between low-flow time and AH in survival discharge rate (p for interaction = 0.048).

CONCLUSIONS

OHCA patients with arrival body temperature < 32 °C who had received ECPR had relatively good survival outcomes regardless of low-flow time, in contrast to those of patients without AH.

Effects of rewarming therapies on outcomes in accidental hypothermia: A secondary analysis of a multicenter prospective study

BACKGROUND

Rewarming therapies for accidental hypothermia (AH) include extracorporeal membrane oxygenation (ECMO) and non-ECMO related (conventional) therapies. However, there are limited data available to inform the selection of conventional rewarming therapy. The aim of the present study was to explore what patients' factors and which rewarming therapy predicted favorable prognosis.

METHODS

This study is a secondary analysis of the Intensive Care with Extra Corporeal membrane oxygenation Rewarming in Accidentally Severe Hypothermia (ICE-CRASH) study, a multicenter prospective, observational study conducted in Japan. Enrolled in the ICE-CRASH study were patients aged ≥18 years with a core temperature of ≤32 °C who were transported to the emergency departments of 36 tertiary care hospitals in Japan between 1 December 2019 and 31 March 2022, among whom those who were rewarmed with conventional rewarming therapy were included in the present study. Logistic regression analysis was performed with 28-day survival as the objective variable; and seven factors including age, activities of daily living (ADL) independence, sequential organ failure assessment (SOFA) score, and each rewarming technique as explanatory variables. We performed linear regression analysis to identify whether each rewarming technique was associated with rewarming rate.

RESULTS

Of the 499 patients enrolled in the ICE-CRASH study, 371 were eligible for this secondary analysis. The median age was 81 years, 50.9% were male, and the median initial body temperature was 28.8 °C. Age (odds ratio [OR]: 0.97, 95% confidence interval [CI]: 0.94-1.00) and SOFA score (OR: 0.73, 95% CI: 0.67-0.81) were associated with lower survival, whereas ADL independence (OR: 2.31, 95% CI: 1.15-4.63) was associated with higher survival. No conventional rewarming therapy was associated with 28-day survival. Hot bath was associated with a high rewarming rate (regression coefficient: 1.14, 95% CI: 0.75-1.53).

CONCLUSION

No conventional rewarming therapy was associated with improved 28-day survival, which suggests that background factors such as age, ADL, and severity of condition contribute more to prognosis than does the selection of rewarming technique.

Etiology-Based Prognosis of Extracorporeal CPR Recipients After Out-of-Hospital Cardiac Arrest: A Retrospective Multicenter Cohort Study

BACKGROUND

A better understanding of the relative contributions of various factors to patient outcomes is essential for optimal patient selection for extracorporeal CPR (ECPR) therapy for patients with out-of-hospital cardiac arrest (OHCA). However, evidence on the prognostic comparison based on the etiologies of cardiac arrest is limited.

RESEARCH QUESTION

What is the etiology-based prognosis of patients undergoing ECPR for OHCA?

STUDY DESIGN AND METHODS

This retrospective multicenter registry study involved 36 institutions in Japan and included all adult patients with OHCA who underwent ECPR between January 2013 and December 2018. The primary etiology for OHCA was determined retrospectively from all hospital-based data at each institution. We performed a multivariable logistic regression model to determine the association between etiology of cardiac arrest and two outcomes: favorable neurologic outcome and survival at hospital discharge.

RESULTS

We identified 1,781 eligible patients, of whom 1,405 (78.9%) had cardiac arrest because of cardiac causes. Multivariable logistic regression analysis for favorable neurologic outcome showed that accidental hypothermia (adjusted OR, 5.12; 95% CI, 2.98-8.80; P < .001) was associated with a significantly higher rate of favorable neurologic outcome than cardiac causes. Multivariable logistic regression analysis for survival showed that accidental hypothermia (adjusted OR, 5.19; 95% CI, 3.15-8.56; P < .001) had significantly higher rates of survival than cardiac causes. Acute aortic dissection/aneurysm (adjusted OR, 0.07; 95% CI, 0.02-0.28; P < .001) and primary cerebral disorders (adjusted OR, 0.12; 95% CI, 0.03-0.50; P = .004) had significantly lower rates of survival than cardiac causes.

INTERPRETATION

In this retrospective multicenter cohort study, although most patients with OHCA underwent ECPR for cardiac causes, accidental hypothermia was associated with favorable neurologic outcome and survival; in contrast, acute aortic dissection/aneurysm and primary cerebral disorders were associated with nonsurvival compared with cardiac causes.

Predictors of cardiac arrest in severe accidental hypothermia

STUDY OBJECTIVE

To indicate predictors of witnessed hypothermic cardiac arrest.

METHODS

We conducted a retrospective analysis of 182 patients with severe accidental hypothermia (i.e., with core body temperature of ≤28 °C) who presented with preserved spontaneous circulation at first contact with medical services. We divided the study population into two groups: patients who suffered hypothermic cardiac arrest (HCA) at any time between encounter with medical service and restoration of normothermia, and those who did not sustain HCA. The analyzed outcome was the occurrence of cardiac arrest prior to achieving normothermia. Hemodynamic and biochemical parameters were analyzed with regard to their association with the outcome.

RESULTS

Fifty-two (29%) patients suffered HCA. In a univariable analysis, four variables were significantly associated with the outcome, namely heart rate (p < 0.001), systolic blood pressure (p = 0.03), ventricular arrhythmia (p = 0.001), and arterial oxygen partial pressure (p = 0.002). In the multivariable logistic regression the best model predicting HCA included heart rate, PaO2, and Base Excess (AUROC = 0.78). In prehospital settings, when blood gas analysis is not available, other multivariable model including heart rate and occurrence of ventricular arrhythmia (AUROC = 0.74) can be used. In this study population, threshold values of heart rate of 43/min, temperature-corrected PaO2 of 72 mmHg, and uncorrected PaO2 of 109 mmHg, presented satisfactory sensitivity and specificity for HCA prediction.

CONCLUSIONS

In patients with severe accidental hypothermia, the occurrence of HCA is associated with a lower heart rate, hypoxemia, ventricular arrhythmia, lower BE, and lower blood pressure. These parameters can be helpful in the early selection of high-risk patients and their allocation to extracorporeal rewarming facilities.

The Role of Extracorporeal Membrane Oxygenation ECMO in Accidental Hypothermia and Rewarming in Out-of-Hospital Cardiac Arrest Patients-A Literature Review

Accidental hypothermia, defined as an unintentional drop of the body core temperature below 35 °C, is one of the causes of cardiocirculatory instability and reversible cardiac arrest. Currently, extracorporeal life support (ECLS) rewarming is recommended as a first-line treatment for hypothermic cardiac arrest patients. The aim of the ECLS rewarming is not only rapid normalization of core temperature but also maintenance of adequate organ perfusion. Veno-arterial extracorporeal membrane oxygenation (ECMO) is a preferred technique due to its lower anticoagulation requirements and potential to prolong circulatory support. Although highly efficient, ECMO is acknowledged as an invasive treatment option, requiring experienced medical personnel and is associated with the risk of serious complications. In this review, we aimed to discuss the clinical aspects of ECMO management in severely hypothermic cardiac arrest patients.

Hyperoxia for accidental hypothermia and increased mortality: a post-hoc analysis of a multicenter prospective observational study

BACKGROUND

Supraphysiologic oxygen administration causes unfavorable clinical outcomes in various diseases, including traumatic brain injury, post-cardiac arrest syndrome, and acute lung injury. Accidental hypothermia is a critical illness that reduces oxygen demands, and excessive oxygen is likely to emerge. This study aimed to determine whether hyperoxia would be associated with increased mortality in patients with accidental hypothermia.

METHODS

A post-hoc analysis of a nationwide multicenter prospective observational study (ICE-CRASH study) on patients with accidental hypothermia admitted in 2019-2022 was conducted. Adult patients without cardiac arrest whose core body temperature was < 32 °C and whose arterial partial pressure of oxygen (PaO₂) was measured at the emergency department were included. Hyperoxia was defined as a PaO₂ level of 300 mmHg or higher, and 28-day mortality was compared between patients with and without hyperoxia before rewarming. Inverse probability weighting (IPW) analyses with propensity scores were performed to adjust patient demographics, comorbidities, etiology and severity of hypothermia, hemodynamic status and laboratories on arrival, and institution characteristics. Subgroup analyses were conducted according to age, chronic cardiopulmonary diseases, hemodynamic instability, and severity of hypothermia.

RESULTS

Of the 338 patients who were eligible for the study, 65 had hyperoxia before rewarming. Patients with hyperoxia had a higher 28-day mortality rate than those without (25 (39.1%) vs. 51 (19.5%); odds ratio (OR) 2.65 (95% confidence interval 1.47-4.78); p < 0.001). IPW analyses with propensity scores revealed similar results (adjusted OR 1.65 (1.14-2.38); p = 0.008). Subgroup analyses showed that hyperoxia was harmful in the elderly and those with cardiopulmonary diseases and severe hypothermia below 28 °C, whereas hyperoxia exposure had no effect on mortality in patients with hemodynamic instability on hospital arrival.

CONCLUSIONS

Hyperoxia with PaO₂ levels of 300 mmHg or higher before initiating rewarming was associated with increased 28-day mortality in patients with accidental hypothermia. The amount of oxygen to administer to patients with accidental hypothermia should be carefully determined.

TRIAL REGISTRATION

The ICE-CRASH study was registered at the University Hospital Medical Information Network Clinical Trial Registry on April 1, 2019 (UMIN-CTR ID, UMIN000036132).