ECMO in Cardiac Arrest: A Narrative Review of the Literature

Risk factors for neurological disability outcomes in patients under extracorporeal membrane oxygenation following cardiac arrest: An observational study

OBJECTIVES

This study aimed to identify factors associated with neurological and disability outcomes in patients who underwent ECMO following cardiac arrest.

METHODS

This retrospective, single-center, observational study included adult patients who received ECMO treatment for in-hospital cardiac arrest (IHCA) or out-of-hospital cardiac arrest (OHCA) between February 2016 and March 2020. Factors associated with neurological and disability outcomes in these patients who underwent ECMO were assessed.

SETTING

Hamad General Hospital, Qatar.

MAIN OUTCOME MEASURES

Neurological disability outcomes were assessed using the Modified Rankin Scale (mRS) and the Cerebral Performance Category (CPC) scale.

RESULTS

Among the 48 patients included, 37 (77 %) experienced OHCA, and 11 (23 %) had IHCA. The 28-day survival rate was 14 (29.2 %). Of the survivors, 9 (64.3 %) achieved a good neurological outcome, while 5 (35.7 %) experienced poor neurological outcomes. Regarding disability, 5 (35.7 %) of survivors had no disability, while 9 (64.3 %) had some form of disability. The results showed significantly shorter median time intervals in minutes, including collapse to cardiopulmonary resuscitation (CPR) (3 vs. 6, P = 0.001), CPR duration (12 vs. 35, P = 0.001), CPR to extracorporeal cardiopulmonary resuscitation (ECPR) (20 vs. 40, P = 0.001), and collapse-to-ECPR (23 vs. 45, P = 0.001), in the good outcome group compared to the poor outcome group.

CONCLUSION

This study emphasizes the importance of minimizing the time between collapse and CPR/ECMO initiation to improve neurological outcomes and reduce disability in cardiac arrest patients. However, no significant associations were found between outcomes and other demographic or clinical variables in this study. Further research with a larger sample size is needed to validate these findings.

IMPLICATIONS FOR CLINICAL PRACTICE

The study underscores the significance of reducing the time between collapse and the initiation of CPR and ECMO. Shorter time intervals were associated with improved neurological outcomes and reduced disability in cardiac arrest patients.

The Role of Extracorporeal Cardiopulmonary Resuscitation in Pediatric Intraoperative Cardiac Arrest

Refractory pediatric intraoperative cardiac arrest is a rare but challenging situation for the anesthesiologist. This case describes an intraoperative extracorporeal cardiopulmonary resuscitation (ECPR) in a 16-year-old male who suffered a sudden cardiac arrest during elective thoracolumbar stabilization. The patient recovered to his pre-operative baseline without any neurological sequela secondary to cardiac arrest. Good quality of conventional resuscitation measures, prompt activation of the extracorporeal membrane oxygenation (ECMO) team, and a multidisciplinary coordinated approach were key factors in ECPR success. Despite the lack of robust evidence in pediatrics, case reports like ours outline the life-saving potential of intraoperative ECPR in refractory cardiac arrest scenarios.

Recovery and Survival of Patients After Out-of-Hospital Cardiac Arrest: A Literature Review Showcasing the Big Picture of Intensive Care Unit-Related Factors

As an important public health issue, out-of-hospital cardiac arrest (OHCA) requires several stages of high quality medical care, both on-field and after hospital admission. Post-cardiac arrest shock can lead to severe neurological injury, resulting in poor recovery outcome and increased risk of death. These characteristics make this condition one of the most important issues to deal with in post-OHCA patients hospitalized in intensive care units (ICUs). Also, the majority of initial post-resuscitation survivors have underlying coronary diseases making revascularization procedure another crucial step in early management of these patients. Besides keeping myocardial blood flow at a satisfactory level, other tissues must not be neglected as well, and maintaining mean arterial pressure within optimal range is also preferable. All these procedures can be simplified to a certain level along with using targeted temperature management methods in order to decrease metabolic demands in ICU-hospitalized post-OHCA patients. Additionally, withdrawal of life-sustaining therapy as a controversial ethical topic is under constant re-evaluation due to its possible influence on overall mortality rates in patients initially surviving OHCA. Focusing on all of these important points in process of managing ICU patients is an imperative towards better survival and complete recovery rates.

Improved Extracorporeal Cardiopulmonary Resuscitation (ECPR) Outcomes Is Associated with a Restrictive Patient Selection Algorithm

INTRODUCTION

Out-of-hospital cardiac arrest (OHCA) is a leading cause of mortality. Despite decades of intensive research and several technological advancements, survival rates remain low. The integration of extracorporeal cardiopulmonary resuscitation (ECPR) has been recognized as a promising approach in refractory OHCA. However, evidence from recent randomized controlled trials yielded contradictory results, and the criteria for selecting eligible patients are still a subject of debate.

METHODS

This study is a retrospective analysis of refractory OHCA patients treated with ECPR. All adult patients who received ECPR, according to the hospital algorithm, from 2013 to 2021 were included. Two different algorithms were used during this period. A "permissive" algorithm was used from 2013 to mid-2016. Subsequently, a revised algorithm, more "restrictive", based on international guidelines, was implemented from mid-2016 to 2021. Key differences between the two algorithms included reducing the no-flow time from less than three minutes to zero minutes (implying that the cardiac arrests must occur in the presence of a witness with immediate CPR initiation), reducing low-flow duration from 100 to 60 min, and lowering the age limit from 65 to 55 years. The aim of this study is to compare these two algorithms (permissive (1) and restrictive (2)) to determine if the use of a restrictive algorithm was associated with higher survival rates.

RESULTS

A total of 48 patients were included in this study, with 23 treated under Algorithm 1 and 25 under Algorithm 2. A significant difference in survival rate was observed in favor of the restrictive algorithm (9% vs. 68%, p < 0.05). Moreover, significant differences emerged between algorithms regarding the no-flow time (0 (0-5) vs. 0 (0-0) minutes, p < 0.05). Survivors had a significantly shorter no-flow and low-flow time (0 (0-0) vs. 0 (0-3) minutes, p < 0.01 and 40 (31-53) vs. 60 (45-80) minutes, p < 0.05), respectively.

CONCLUSION

The present study emphasizes that a stricter selection of OHCA patients improves survival rates in ECPR.

Development and assessment of novel assist device for cardiac cannulation

PURPOSE

Congenital heart defects are the most common birth defects in the USA and in 25% of cases need to be treated with cardiovascular interventions. One of such interventions is the postoperative use of an extracorporeal membrane oxygenation (ECMO) machine for the treatment of cardiorespiratory failure. The process of placing the patient on the ECMO is extremely time-critical and requires the use of cardiac cannulation. For the first time, our team developed and evaluated a new quick-connect cannulation system that allows for rapid, easy, and safe ECMO cannulation in the pediatric population. The design should eliminate the need for purse-string sutures that are currently used to secure cannulas, as the cannulas will be inserted through a port that is glued to the cardiovascular tissue.

METHODS

The rapid cannulation assistance device was designed on the SolidWorks computer-aided design software using the dimensions of the commercially available arterial and venous catheters. These designs were then 3D printed, and tensile testing was performed. Then, a flow loop was developed, and cannulation was performed and analyzed on both 3D-printed hearts and porcine hearts.

RESULTS

The rapid cannulation assistance device was designed and 3D printed. Tensile testing found that the parts were strong enough to withstand forces that may be introduced in studies. 3D-printed and porcine heart tests with a flow loop found no leakage with the 3D-printed hearts but minimal leaking with the porcine hearts. However, this leakage was observed at the junction between the device and the heart, leading us to believe that a glue better suited to attach the device to the heart would prevent leakage in the future.

CONCLUSIONS

This project successfully demonstrated how a rapid cannulation assistance device could be developed and tested. Future studies will be conducted that address device adhesion to the cardiovascular tissue so that accurate pressure and flow rates can be measured. Future studies will also include testing the device in a fluid environment to more effectively analyze the device success and comparing the time required to cannulate using our device compared to the standard of care.

The Beginning of an ECLS Center: First Successful ECPR in an Emergency Department in Romania-Case-Based Review

According to the latest international resuscitation guidelines, extracorporeal cardiopulmonary resuscitation (ECPR) involves the utilization of extracorporeal membrane oxygenation (ECMO) in specific patients experiencing cardiac arrest, and it can be considered in situations where standard cardiopulmonary resuscitation efforts fail if they have a potentially reversible underlying cause, among which we can also find hypothermia. In cases of cardiac arrest, both witnessed and unwitnessed, hypothermic patients have higher chances of survival and favorable neurological outcomes compared to normothermic patients. ECPR is a multifaceted procedure that requires a proficient team, specialized equipment, and comprehensive multidisciplinary support within a healthcare system. However, it also carries the risk of severe, life-threatening complications. With the increasing use of ECPR in recent years and the growing number of centers implementing this technique outside the intensive care units, significant uncertainties persist in both prehospital and emergency department (ED) settings. Proper organization is crucial for an ECPR program in emergency settings, especially given the challenges and complexities of these treatments, which were previously not commonly used in ED. Therefore, within a narrative review, we have incorporated the initial case of ECPR in an ED in Romania, featuring a successful resuscitation in the context of severe hypothermia (20 °C) and a favorable neurological outcome (CPC score of 1).

Cardiac arrest centres: what do they add?

There are wide regional variations in outcome following resuscitated out of hospital cardiac arrest. These geographical differences appear to be due to hospital infrastructure and provider experience rather than baseline characteristics. It is proposed that post-arrest care be delivered in a systematic fashion by concentrating services in Cardiac Arrest Centres, with greater provider experience, 24-hour access to diagnostics, and specialist treatment to minimise the impact of ischaemia-reperfusion injury and treat the causative pathology. These cardiac arrest centres would provide access to targeted critical care, acute cardiac care, radiology services and appropriate neuro-prognostication. However implementation of cardiac arrest networks with specialist receiving hospitals is complex and requires alignment of pre-hospital care services with those delivered in hospital. Furthermore there are no randomised trial data currently supporting pre-hospital delivery to a Cardiac Arrest Centre and definitions are heterogeneous. In this review article, we propose a universal definition of a Cardiac Arrest Centre and review the current observational data evidence and the potential impact of the ARREST trial.

Emergency Medical Services Handoff of Patients in Cardiac Arrest in the Emergency Department: A Retrospective Video Review Study of Duration and Details of Handoff

STUDY OBJECTIVES

We aimed to evaluate the duration and frequency of communication between EMS (Emergency Medical Services) and ED (Emergency Department) staff during handoff and the subsequent time to critical cardiac care (rhythm determination, defibrillation) using CA (cardiac arrest) video review.

METHODS

A single-center retrospective study of video-recorded adult CAs between August 2020 and December 2022 was performed. Two investigators assessed the communication of 17 data points, time intervals, EMS initiation of handoff, and type of EMS agency. Median times from initiation of handoff to first ED rhythm determination and defibrillation were compared between the groups above versus below the median number of data points communicated.

RESULTS

Overall, 95 handoffs were reviewed. The handoff was initiated in a median of 2 seconds (interquartile range (IQR) 0-10) after arrival. EMS initiated handoff in 65 (69.2%) patients. The median number of data points communicated was 9 and median duration was 66 seconds (IQR 50-100). Age, location of arrest, estimated down time, and medications administered were communicated >80% of the time, initial rhythm 79%, and bystander cardiopulmonary resuscitation and witnessed arrest <50%. The median times from initiation of handoff to first ED rhythm determination and defibrillation were 188 (IQR 106-256) and 392 (IQR 247-725) seconds, though not statistically different between handoffs with <9 vs. ≥9 data points communicated (p>0.40).

CONCLUSION

There is no standardization for handoff reports from EMS to ED staff for CA patients. Using video review, we demonstrated the variable communication during handoff. Improvements to this process could reduce the time to critical interventions.

ECMELLA as a bridge to heart transplantation in refractory ventricular fibrillation: A case report

Background

Extracorporeal membrane oxygenation (ECMO) is an effective cardiorespiratory support technique in refractory cardiac arrest (CA). In patients under veno-arterial ECMO, the use of an Impella device, a microaxial pump inserted percutaneously, is a valuable strategy through a left ventricular unloading approach. ECMELLA, a combination of ECMO with Impella, seems to be a promising method to support end-organ perfusion while unloading the left ventricle.

Case summary

The present case report describes the clinical course of a patient with ischemic and dilated cardiomyopathy who presented with refractory ventricular fibrillation (VF) leading to CA in the late postmyocardial infarction (MI) period, and who was successfully treated with ECMO and IMPELLA as a bridge to heart transplantation.

Discussion

In the case of CA on VF refractory to conventional resuscitation maneuvers, early extracorporeal cardiopulmonary resuscitation (ECPR) associated with an Impella seems to be the best strategy. It provides organ perfusion, left ventricular unloading, and ability for neurological evaluation and VF catheter ablation before allowing heart transplantation. It is the treatment of choice in cases of end-stage ischaemic cardiomyopathy and recurrent malignant arrhythmias.

The Effects of Extracorporeal Cardiopulmonary Resuscitation According to Covariate Adjustment

This study compared the effects of extracorporeal cardiopulmonary resuscitation (ECPR) using propensity-score matching (PSM) analyses. A nationwide registry of out-of-hospital cardiac arrest (OHCA) patients in Korea between 2013 and 2016 was used. Patients with OHCA aged ≥15 years with cardiac etiology and resuscitation time >30 minutes were enrolled. Resuscitation-related variables before the initiation of ECPR were included. Two PSM analyses were performed separately, with and without post-ECPR variables. The primary outcome (PO) was a favorable neurologic outcome at hospital discharge. The rate of PO was 8.1% (13/161) in the ECPR group and 1.5% (247/16,489) in the conventional CPR (CCPR) group. In the matched cohort with post-ECPR variables, there was no significant difference in the rate of PO between the ECPR and CCPR groups (7.9% vs. 7.9%; p = 0.982). In the matched cohort without post-ECPR variables, the rate of PO was higher in the ECPR group than that in the CCPR group (8.3% vs. 3.6%; p = 0.012). PSM analysis without post-ECPR variables compared outcomes of all patients experiencing OHCA and treated with ECPR versus CCPR, which showed better neurologic outcomes for ECPR. PSM analysis with post-ECPR variables compared outcomes between ECPR survivors and CCPR survivors, which exhibited similar neurologic outcomes.

Extracorporeal cardiopulmonary resuscitation location, coronary angiography and survival in out-of-hospital cardiac arrest

INTRODUCTION

The best location for safe and timely implementation of extracorporeal cardiopulmonary resuscitation (ECPR) is currently uncertain. We aimed to evaluate the association between the location of ECPR and survival outcomes in out-of-hospital cardiac arrest (OHCA) patients. We also evaluated whether the effects of ECPR location on survival differed between patients who underwent coronary angiography (CAG) and those who did not.

METHODS

We used data collected between 2013 and 2020 from a nationwide OHCA database. Adult OHCA patients with presumed cardiac etiology who underwent ECPR were included in the study. The primary outcome was survival to discharge. The main exposure was the ECPR location (emergency department [ED] or cardiac catheterization laboratory [Cath lab]). We compared primary outcomes of ECPR between the ED and Cath lab using multivariable logistic regression. The interaction between ECPR location and CAG was also evaluated.

RESULTS

Of 564 ECPR patients, 448 (79.4%) and 116 (20.6%) underwent ECPR in the ED and Cath lab, respectively. CAG was observed in 52.5% and 72.4% of the patients in the ED and Cath lab groups, respectively. There were no significant differences in survival to discharge between the ED and Cath lab groups (14.1% vs. 12.9%, p = 0.75, adjusted odds ratio [AOR] [95% confidence interval] 1.87 [0.85-4.11]). AOR of interaction analysis (95% CI) for survival to discharge of the ED group was 2.34 (1.02-5.40) in patients with CAG and 0.28 (0.04-1.84) in patients without CAG (p for interaction was 0.04).

CONCLUSION

In adult OHCA patients who underwent ECPR and CAG, ECPR in the ED shortened time to ECMO pump-on time and increased survival to discharge compared to ECPR in the Cath lab.

Cellular recovery after prolonged warm ischaemia of the whole body

After cessation of blood flow or similar ischaemic exposures, deleterious molecular cascades commence in mammalian cells, eventually leading to their death^1,2. Yet with targeted interventions, these processes can be mitigated or reversed, even minutes or hours post mortem, as also reported in the isolated porcine brain using BrainEx technology³. To date, translating single-organ interventions to intact, whole-body applications remains hampered by circulatory and multisystem physiological challenges. Here we describe OrganEx, an adaptation of the BrainEx extracorporeal pulsatile-perfusion system and cytoprotective perfusate for porcine whole-body settings. After 1 h of warm ischaemia, OrganEx application preserved tissue integrity, decreased cell death and restored selected molecular and cellular processes across multiple vital organs. Commensurately, single-nucleus transcriptomic analysis revealed organ- and cell-type-specific gene expression patterns that are reflective of specific molecular and cellular repair processes. Our analysis comprises a comprehensive resource of cell-type-specific changes during defined ischaemic intervals and perfusion interventions spanning multiple organs, and it reveals an underappreciated potential for cellular recovery after prolonged whole-body warm ischaemia in a large mammal.

Manganese Porphyrin Promotes Post Cardiac Arrest Recovery in Mice and Rats

Introduction Cardiac arrest (CA) and resuscitation induces global cerebral ischemia and reperfusion, causing neurologic deficits or death. Manganese porphyrins, superoxide dismutase mimics, are reportedly able to effectively reduce ischemic injury in brain, kidney, and other tissues. This study evaluates the efficacy of a third generation lipophilic Mn porphyrin, MnTnBuOE-2-PyP5+, Mn(III) ortho meso-tetrakis (N-n-butoxyethylpyridinium-2-yl)porphyrin (MnBuOE, BMX-001), in both mouse and rat models of CA. Methods Forty-eight animals were subjected to 8 min of CA and resuscitated subsequently by chest compression and epinephrine infusion. Vehicle or MnBuOE was given immediately after resuscitation followed by daily subcutaneous injections. Body weight, spontaneous activity, neurologic deficits, rotarod performance, and neuronal death were assessed. Kidney tubular injury was assessed in CA mice. Data were collected by the investigators who were blinded to the treatment groups. Results Vehicle mice had a mortality of 20%, which was reduced by 50% by MnBuOE. All CA mice had body weight loss, spontaneous activity decline, neurologic deficits, and decreased rotarod performance that were significantly improved at three days post MnBuOE daily treatment. MnBuOE treatment reduced cortical neuronal death and kidney tubular injury in mice (p < 0.05) but not hippocampus neuronal death (23% MnBuOE vs. 34% vehicle group, p = 0.49). In rats, they had a better body-weight recovery and increased rotarod latency after MnBuOE treatment when compared to vehicle group (p < 0.01 vs. vehicle). MnBuOE-treated rats had a low percentage of hippocampus neuronal death (39% MnBuOE vs. 49% vehicle group, p = 0.21) and less tubular injury (p < 0.05) relative to vehicle group. Conclusions We demonstrated the ability of MnBuOE to improve post-CA survival, as well as functional outcomes in both mice and rats, which jointly account for the improvement not only of brain function but also of the overall wellbeing of the animals. While MnBuOE bears therapeutic potential for treating CA patients, the females and the animals with comorbidities must be further evaluated before advancing toward clinical trials.

Immediate complete revascularization showed better outcome in out-of-hospital cardiac arrest survivors with left main or triple-vessel coronary diseases

This study aimed to evaluate the prevalence of left main or triple vessel coronary artery disease (CAD) in comatose out-of-hospital cardiac arrest (OHCA) survivors and assessed their outcome based on the revascularization strategy. This multicenter, retrospective, observational registry-based study was conducted at 9 Korean tertiary care hospitals. Adult comatose OHCA survivors with left main or triple vessel CAD documented by immediate (≤ 2 h) coronary angiography after return of spontaneous circulation between 2011 and 2019 were included. The primary outcome was neurologically intact survival at 1-month. Among 727 OHCA patients, 150 (25%) had left main or triple vessel CAD and underwent complete (N = 32), incomplete (N = 78), and no immediate (N = 40) revascularization, respectively. The rate of neurologically intact survival at 1 month was significantly different among the groups (53%, 32%, and 23% for complete, incomplete, and no immediate revascularization groups, respectively; P = 0.02). After adjustment using the inverse probability of treatment weighting, complete revascularization was associated with neurologically intact survival at 1 month (odds ratio, 2.635; P = 0.01). Left main or triple vessel CAD is not uncommon in OHCA patients. The complete revascularization was associated with better outcome. Further clinical trials to confirm the best revascularization strategy are needed.

Extracorporeal life support in adult patients with out-of-hospital cardiac arrest

The use of extracorporeal life support in cardiopulmonary resuscitation (CPR) of adult patients experiencing out-of-hospital cardiac arrest by the application of veno-arterial extracorporeal membrane oxygenation (ECMO) during cardiac arrest has been increasing over the past decade. This can be attributed to the encouraging results of extracorporeal CPR (ECPR) in multiple observational studies. To date, only one randomised controlled trial has compared ECPR to conventional advanced life support measures. Patient selection is crucial for the success of ECPR programmes. A rapid and organised approach is required for resuscitation, i.e. cannula insertion with ECMO pump initiation in combination with other aspects of post-cardiac arrest care such as targeted temperature management and early coronary reperfusion. The provision of an ECPR service can be costly, resource intensive and technically challenging, as limited studies have reported on its cost-effectiveness.

Hyperoxia during extracorporeal cardiopulmonary resuscitation for refractory cardiac arrest is associated with severe circulatory failure and increased mortality

Background

High levels of arterial oxygen pressures (PaO₂) have been associated with increased mortality in extracorporeal cardiopulmonary resuscitation (ECPR), but there is limited information regarding possible mechanisms linking hyperoxia and death in this setting, notably with respect to its hemodynamic consequences. We aimed therefore at evaluating a possible association between PaO₂, circulatory failure and death during ECPR.

Methods

We retrospectively analyzed 44 consecutive cardiac arrest (CA) patients treated with ECPR to determine the association between the mean PaO₂ over the first 24 h, arterial blood pressure, vasopressor and intravenous fluid therapies, mortality, and cause of deaths.

Results

Eleven patients (25%) survived to hospital discharge. The main causes of death were refractory circulatory shock (46%) and neurological damage (24%). Compared to survivors, non survivors had significantly higher mean 24 h PaO₂ (306 ± 121 mmHg vs 164 ± 53 mmHg, p < 0.001), lower mean blood pressure and higher requirements in vasopressors and fluids, but displayed similar pulse pressure during the first 24 h (an index of native cardiac recovery). The mean 24 h PaO₂ was significantly and positively correlated with the severity of hypotension and the intensity of vasoactive therapies. Patients dying from circulatory failure died after a median of 17 h, compared to a median of 58 h for patients dying from a neurological cause. Patients dying from neurological cause had better preserved blood pressure and lower vasopressor requirements.

Conclusion

In conclusion, hyperoxia is associated with increased mortality during ECPR, possibly by promoting circulatory collapse or delayed neurological damage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02361-3.

Features of Patients Receiving Extracorporeal Membrane Oxygenation Relative to Cardiogenic Shock Onset: A Single-Centre Experience

Background and Objectives: Extracorporeal membrane oxygenation (ECMO) can be helpful in patients with cardiogenic shock associated with myocardial infarction, and its early use can improve the patient survival rate. In this study, we report a mortality rate-difference analysis that examined the time and location of shock occurrence. Materials and Methods: We enrolled patients who underwent ECMO due to cardiogenic shock related to myocardial infarction and assigned them to either a pre- or post-admission shock group. The primary outcome was the 1-month mortality rate; a subgroup analysis was conducted to assess the effect of bailout ECMO. Results: Of the 113 patients enrolled, 67 (38 with pre-admission shock, 29 with post-admission shock) were analysed. Asystole was more frequently detected in the pre-admission shock group than in the post-admission group. In both groups, the commonest culprit lesion location was in the left anterior descending artery. Cardiopulmonary resuscitation was performed significantly more frequently and earlier in the pre-admission group. The 1-month mortality rate was significantly lower in the pre-admission group than in the post-admission group. Male sex and ECMO duration (≥6 days) were factors significantly related to the reduced mortality rate in the pre-admission group. In the subgroup analysis, the mortality rate was lower in patients receiving bailout ECMO than in those not receiving it; the difference was not statistically significant. Conclusions: ECMO application resulted in lower short-term mortality rate among patients with out-of-hospital cardiogenic shock onset than with in-hospital shock onset; early cardiopulmonary resuscitation and ECMO might be helpful in select patients.