Enabling the control of reperfusion parameters in out-of-hospital cardiac arrest: First applications of the CARL system

Controlled automated reperfusion of the whole body after cardiac arrest: Device profile of the CARL system

BACKGROUND

Cardiac arrest is associated with high mortality rates and severe neurological impairments. One of the underlying mechanisms is global ischemia-reperfusion injury of the body, particularly the brain. Strategies to mitigate this may thus improve favorable neurological outcomes. The use of extracorporeal cardiopulmonary membrane oxygenation (ECMO) during CA has been shown to improve survival, but available systems are vastly unable to deliver goal-oriented resuscitation to control patient's individual physical and chemical needs during reperfusion. Recently, controlled automated reperfusion of the whoLe body (CARL), a pulsatile ECMO with arterial blood-gas analysis, has been introduced to deliver goal-directed reperfusion therapy during the post-arrest phase.

METHODS

This review focuses on the device profile and use of CARL. Specifically, we reviewed the published literature to summarize data regarding its technical features and potential benefits in ECPR.

RESULTS

Peri-arrest, mitigating severe IRI with ECMO, might be the next step toward augmenting survival rates and neurological recovery. To this end, CARL is a promising extracorporeal oxygenation device that improves the early reperfusion phase after resuscitation.

[Extracorporeal Cardiopulmonary Resuscitation(ECPR) - the Future?]

In recent years, invasive resuscitation methods utilizing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) have gained significant attention. Despite advances in traditional resuscitation measures, out-of-hospital cardiac arrest (OHCA) mortality remains high. In the context of extracorporeal cardiopulmonary resuscitation (ECPR), VA-ECMO therapy offers a promising approach by providing circulatory support during cardiac arrest, allowing time for diagnostic evaluation and targeted therapy. However, patient selection for ECPR remains a challenge, relying on various factors including initial rhythm, duration of no-flow and low-flow states, as well as presence of reversible causes.Recent studies such as the ARREST, Prague OHCA and INCEPTION trials have investigated the efficacy of ECPR in OHCA patients, yielding mixed results. While the ARREST trial demonstrated a survival benefit with ECPR, the Prague OHCA and INCEPTION trials showed varying outcomes, reflecting the complexity of patient selection and treatment strategies. Despite inherent risks and complications associated with ECPR, it may offer a potential survival advantage under optimal conditions.Future directions in ECPR involve the development of innovative treatment protocols such as the CARL therapy, which incorporates specialized ECMO systems and tailored perfusion solutions. Early studies indicate promising outcomes with CARL therapy, emphasizing the importance of a well-coordinated and structured approach to ECPR implementation.In summary, ECPR shows promise in improving survival rates for OHCA patients within a well-organized healthcare system. However, further research is needed to refine patient selection criteria and optimize treatment protocols, ultimately enhancing patient outcomes in cardiac arrest scenarios.

Innovation and disruptive science determine the future of cardiothoracic surgery

One of the currently most asked questions in the field of medicine is how any specialty in the future will evolve to ensure better health for the patients by using current, unparalleled developments in all areas of science. This article will give an overview of new and evolving strategies for cardiothoracic (CT) surgery that are available today and will become available in the future in order to achieve this goal. In the founding era of CT surgery in the 1950s and 1960s, there was tremendous excitement about innovation and disruptive science, which eventually resulted in a completely new medical specialty, i.e. CT surgery. Entirely new treatment strategies were introduced for many cardiovascular diseases that had been considered incurable until then. As expected, alternative techniques have evolved in all fields of science during the last few decades, allowing great improvements in diagnostics and treatment in all medical specialties. The future of CT surgery will be determined by an unrestricted and unconditional investment in innovation, disruptive science and our own transformation using current achievements from many other fields. From the multitude of current and future possibilities, I will highlight 4 in this review: improvements in our current techniques, bringing CT surgery to low- and middle-income countries, revolutionizing the perioperative period and treating as yet untreatable diseases. These developments will allow us a continuation of the previously unheard-of treatment possibilities provided by ingenious innovations based on the fundamentals of CT surgery.

Year in review: Highlights in ECLS Innovation and Technology, Anno 2022-2023

BACKGROUND

In the field of extracorporeal life support (ECLS), the rapid influx of novel technologies and innovative techniques presents an ongoing challenge for professionals to stay informed about these advancements. To address this issue and ensure the ECLS community remains up-to-date, we have compiled a concise overview of recent technological innovations in ECLS.

PURPOSE

This overview focuses primarily on academically investigated and reported advancements in the ECLS domain. It underscores the importance of transparent communication regarding technological limitations in healthcare and advocates for collaboration between medical professionals and engineers to elevate patient care.

RESEARCH DESIGN

This manuscript presents a compilation of recent technological advancements in ECLS, with an emphasis on innovations that have been academically explored and documented. The research approach involves gathering information from scholarly sources, reports, and studies to provide a comprehensive overview.

STUDY SAMPLE

The study sample comprises a diverse range of recent technological innovations in the field of extracorporeal life support (ECLS). These innovations span various aspects of ECLS technology and have been investigated and reported on within the academic literature.

ANALYSIS

Data collection involved systematically reviewing academic literature, reports, and studies related to recent technological advancements in ECLS. The collected information was then analyzed to identify common trends, notable developments, and the impact of these innovations on patient care.

RESULTS

The compilation highlights several significant technological innovations within the ECLS domain. Notable advancements include the development of new dual lumen cannulae, innovative devices for left ventricular (LV) unloading, lightweight ECMO transport systems, streamlined driving consoles to facilitate patient mobility, intricate systems for extracorporeal cardiopulmonary resuscitation (ECPR), standardized driving consoles for networking, and non-invasive circuit pressure monitoring. Some of these innovations have obtained regulatory approvals for distribution in the United States and/or authorization for the European market.

CONCLUSIONS

The manuscript underscores the critical role of collaboration between clinicians, researchers, and industry in driving recent technological innovations within the ECLS field. It emphasizes the necessity of open communication about technological limitations and the potential for repurposing established technologies in novel ways. However, the resourcefulness of physicians in repurposing devices requires validation through comprehensive scientific and technical investigation. Thus, fostering broader collaboration among stakeholders is recommended to ensure the rigorous evaluation and validation of new applications for established ECLS devices.

Treatment of Refractory Cardiac Arrest by Controlled Reperfusion of the Whole Body: A Multicenter, Prospective Observational Study

Background: Survival following cardiac arrest (CA) remains poor after conventional cardiopulmonary resuscitation (CCPR) (6-26%), and the outcomes after extracorporeal cardiopulmonary resuscitation (ECPR) are often inconsistent. Poor survival is a consequence of CA, low-flow states during CCPR, multi-organ injury, insufficient monitoring, and delayed treatment of the causative condition. We developed a new strategy to address these issues. Methods: This all-comers, multicenter, prospective observational study (69 patients with in- and out-of-hospital CA (IHCA and OHCA) after prolonged refractory CCPR) focused on extracorporeal cardiopulmonary support, comprehensive monitoring, multi-organ repair, and the potential for out-of-hospital cannulation and treatment. Result: The overall survival rate at hospital discharge was 42.0%, and a favorable neurological outcome (CPC 1+2) at 90 days was achieved for 79.3% of survivors (CPC 1+2 survival 33%). IHCA survival was very favorable (51.7%), as was CPC 1+2 survival at 90 days (41%). Survival of OHCA patients was 35% and CPC 1+2 survival at 90 days was 28%. The subgroup of OHCA patients with pre-hospital cannulation showed a superior survival rate of 57.1%. Conclusions: This new strategy focusing on repairing damage to multiple organs appears to improve outcomes after CA, and these findings should provide a sound basis for further research in this area.

Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest - current status

PURPOSE OF REVIEW

Extracorporeal cardiopulmonary resuscitation (ECPR) is an emerging treatment for refractory cardiac arrest. In recent years, several randomized controlled trials have been published that aimed to address the efficacy and effectiveness of ECPR for out-of-hospital cardiac arrest (OHCA). Despite the lack of high-quality evidence concerning clinical effectiveness and cost-effectiveness, ECPR is increasingly implemented throughout the world. In this review, we aim to provide an overview of the current status of ECPR for OHCA.

RECENT FINDINGS

Randomized controlled trials showed diverging results, largely due to differences in selection criteria and study design. Single-center studies, performed in centers with extraordinary expertise and dedication consistently achieve a low-flow time of around 60 min, but such achievements are rarely reproduced outside these centers. Strict patient selection can improve outcome but simultaneously limits the caseload. Preliminary data suggest that outcome may also be improved by avoiding hyperoxia postresuscitation.

SUMMARY

The potential of ECPR to increase survival in selected patients in highly dedicated systems seems to be proven, the question remains whether ECPR for OHCA can be widely implemented successfully and can develop into a sustainable, commonplace resource-effective treatment.

Prognostic impact of lung computed tomography density in cardiogenic shock patients with veno-arterial extracorporeal membrane oxygenation

BACKGROUND

Pulmonary complications often occur in patients receiving veno-arterial extracorporeal membrane oxygenation (VA ECMO). However, the prognostic impact of lung damage has not been fully elucidated.

METHODS

This single-center retrospective observational study targeted patients with cardiogenic shock who received VA ECMO between 2012 and 2021. This study included 65 patients who underwent chest computed tomography (CT) on VA ECMO, followed by escalation to central mechanical circulatory support (MCS) with left ventricular venting. The average density of lung CT images was measured using region-of-interest methods, and the primary endpoint was 180-day all-cause death after escalation to the central MCS.

RESULTS

Twenty-two patients (34%) developed 180-day all-cause death. According to the Cox regression analysis, age (hazard ratio [HR], 1.08; 95% confidence interval [CI], 1.03-1.14; p = 0.001), ischemic etiology (HR, 5.53; 95% CI, 2.09-14.62; p < 0.001), duration of VA ECMO support (HR, 1.19; 95% CI, 1.00-1.40; p = 0.045), and lung CT density (≥ -481 Hounsfield unit [HU]) (HR, 6.33; 95% CI, 2.26-17.72; p < 0.001) were independently associated with all-cause death. Receiver operating characteristic curve analysis determined that lung CT density ≥ -481 HU is an optimal cutoff value for predicting all-cause death (area under the curve [AUC], 0.72). The 180-day overall survival rate for patients with high lung CT density (≥ -481 HU) was significantly lower than that for those with low lung CT density (< -481 HU) (44.4% vs. 81.6%, respectively, p = 0.002).

CONCLUSIONS

Higher lung CT density could be a useful predictor of death in patients with VA ECMO requiring central MCS escalation.

Extracorporeal Cardiopulmonary Resuscitation

BACKGROUND

Around the world, survival rates after cardiac arrest range between <14% for in-hospital (IHCA) and <10% for outof- hospital cardiac arrest (OHCA). This situation could potentially be improved by using extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (CPR), i.e. by extracorporeal cardiopulmonary resuscitation (ECPR).

METHODS

A selective literature search of Pubmed and Embase using the searching string ((ECMO) OR (ECLS)) AND (ECPR)) was carried out in February 2023 to prepare an up-to-date review of published trials comparing the outcomes of ECPR with those of conventional CPR.

RESULTS

Out of 573 initial results, 12 studies were included in this review, among them three randomized controlled trials comparing ECPR with CPR, involving a total of 420 patients. The survival rates for ECPR ranged from 20% to 43% for OHCA and 20% to 30.4% for IHCA. Most of the publications were associated with a high degree of bias and a low level of evidence.

CONCLUSION

ECPR can potentially improve survival rates after cardiac arrest compared to conventional CPR when used in experienced, high-volume centers in highly selected patients (young age, initial shockable rhythm, witnessed cardiac arrest, therapy-refractory high-quality CPR). No general recommendation for the use of ECPR can be issued at present.

Effects of Prolonged Serum Calcium Suppression during Extracorporeal Cardiopulmonary Resuscitation in Pigs

Controlled reperfusion by monitoring the blood pressure, blood flow, and specific blood parameters during extracorporeal reperfusion after cardiac arrest has the potential to limit ischemia-reperfusion injury. The intracellular calcium overload as part of the ischemia-reperfusion injury provides the possibility for the injury to be counteracted by the early suppression of serum calcium with the aim of improving survival and the neurological outcome. We investigated the effects of prolonged serum calcium suppression via sodium citrate during extracorporeal resuscitation using the CARL protocol (CARL-controlled automated reperfusion of the whole body) compared to a single-dose approach in a porcine model after prolonged cardiac arrest. A control group (N = 10) was resuscitated after a 20 min cardiac arrest, initially lowering the intravascular calcium with the help of a single dose of sodium citrate as part of the priming solution. Animals in the intervention group (N = 13) received additional sodium citrate for the first 15 min of reperfusion. In the control group, 9/10 (90.0%) animals survived until day 7 and 7/13 (53.8%) survived in the intervention group (p = 0.09). A favorable neurological outcome on day 7 after the cardiac arrest was observed in all the surviving animals using a species-specific neurological deficit score. The coronary perfusion pressure was significantly lower with a tendency towards more cardiac arrhythmias in the intervention group. In conclusion, a prolonged reduction in serum calcium levels over the first 15 min of reperfusion after prolonged cardiac arrest tended to be unfavorable regarding survival and hemodynamic variables compared to a single-dose approach in this animal model.

Feasibility of HEMS performed prehospital extracorporeal-cardiopulmonary resuscitation in paediatric cardiac arrests; two case reports

INTRODUCTION

A broad range of pathophysiologic conditions can lead to cardiopulmonary arrest in children. Some of these children suffer from refractory cardiac arrest, not responding to basic and advanced life support. Extracorporeal-Cardiopulmonary Resuscitation (E-CPR) might be a life-saving option for this group. Currently this therapy is only performed in-hospital, often necessitating long transport times, thereby negatively impacting eligibility and chances of survival. We present the first two cases of prehospital E-CPR in children performed by regular Helicopter Emergency Medical Services (HEMS).

CASE PRESENTATIONS

The first patient was a previously healthy 7 year old boy who was feeling unwell for a couple of days due to influenza. His course deteriorated into a witnessed collapse. Direct bystander CPR and subsequent ambulance advanced life support was unsuccessful in establishing a perfusing rhythm. While doing chest compressions, the patient was seen moving both his arms and making spontaneous breathing efforts. Echocardiography however revealed a severe left ventricular impairment (near standstill). The second patient was a 15 year old girl, known with bronchial asthma and poor medication compliance. She suffered yet another asthmatic attack, so severe that she progressed into cardiac arrest in front of the attending ambulance and HEMS crews. Despite maximum bronchodilator therapy, intubation and the exclusion of tension pneumothoraxes and dynamic hyperinflation, no cardiac output was achieved.

INTERVENTION

After consultation with the nearest paediatric E-CPR facilities, both patients were on-scene cannulated by regular HEMS. The femoral artery and vein were cannulated (15-17Fr and 21Fr respectively) under direct ultrasound guidance using an out-of-plane Seldinger approach. Extracorporeal Life Support flow of 2.1 and 3.8 l/min was established in 20 and 16 min respectively (including preparation and cannulation). Both patients were transported uneventfully to the nearest paediatric intensive care with spontaneous breathing efforts and reactive pupils during transport.

CONCLUSION

This case-series shows that a properly trained regular HEMS crew of only two health care professionals (doctor and flight nurse) can establish E-CPR on-scene in (older) children. Ambulance transport with ongoing CPR is challenging, even more so in children since transportation times tend to be longer compared to adults and automatic chest compression devices are often unsuitable and/or unapproved for children. Prehospital cannulation of susceptible E-CPR candidates has the potential to reduce low-flow time and offer E-CPR therapy to a wider group of children suffering refractory cardiac arrest.

Development of an in-vitro model for extracorporeal blood pumps to study the effects of artificial pulsatility on human blood

Introduction

The application of extracorporeal circulation (ECC) systems is known to be associated with several implications regarding hemolysis, inflammation, and coagulation. In the last years, systems with pulsatile blood flow are increasingly used with the intention to improve hemodynamics in reperfusion. However, their implications on the aforementioned aspects remain largely unknown. To investigate the effects of pulsatility, this ex-vivo study was initiated.

Methods

Test circuits (primed with human whole blood) were set up in accordance with the recommendations of international standards for in-vitro evaluation of new components and systems of ECC. Diagonal pumps were either set up with non-pulsatile (n = 5, NPG) or pulsatile (n = 5, PG) pump settings and evaluated for 6 h. All analyses were conducted with human whole blood. Blood samples were repeatedly drawn from the test circuits and analyzed regarding free hemoglobin, interleukin 8 (IL-8), platelet aggregation and acquired von Willebrand syndrome (AVWS).

Results

After 1 h of circulation, a significant coagulation impairment (impaired platelet function and AVWS) was observed in both groups. After 6 h of circulation, increased IL-8 concentrations were measured in both groups (NPG: 0.05 ± 0.03 pg./mL, PG: 0.03 ± 0.01 pg./mL, p = 0.48). Pulsatile pump flow resulted in significantly increased hemolysis after 6 h of circulation (NPG: 37.3 ± 12.4 mg/100 L; PG: 59.6 ± 14.5 mg/100 L; p < 0.05).

Conclusion

Our results indicate that the coagulative impairment takes place in the early phase of ECC. Pulsatility did not affect the occurrence of AVWS ex-vivo. Prolonged durations of pulsatile pump flow led to increased hemolysis and therefore, its prolonged use should be employed cautiously in clinical practice with appropriate monitoring.