Evaluation of LUCAS, a new device for automatic mechanical compression and active decompression resuscitation

Animal research in cardiac arrest

The purpose of this narrative review is to provide an overview of lessons learned from experimental cardiac arrest studies, limitations, translation to clinical studies, ethical considerations and future directions. Cardiac arrest animal studies have provided valuable insights into the pathophysiology of cardiac arrest, the effects of various interventions, and the development of resuscitation techniques. However, there are limitations to animal models that should be considered when interpreting results. Systematic reviews have demonstrated that animal models rarely reflect the clinical condition seen in humans, nor the complex treatment that occurs during and after a cardiac arrest. Furthermore, animal models of cardiac arrest are at a significant risk of bias due to fundamental issues in performing and/or reporting critical methodological aspects. Conducting clinical trials targeting the management of rare cardiac arrest causes like e.g. hyperkalemia and pulmonary embolism is challenging due to the scarcity of eligible patients. For these research questions, animal models might provide the highest level of evidence and can potentially guide clinical practice. To continuously push cardiac arrest science forward, animal studies must be conducted and reported rigorously, designed to avoid bias and answer specific research questions. To ensure the continued relevance and generation of valuable new insights from animal studies, new approaches and techniques may be needed, including animal register studies, systematic reviews and multilaboratory trials.

Injury pattern and clinical outcome in patients with and without chest wall injury after cardiopulmonary resuscitation

BACKGROUND

Cardiopulmonary resuscitation (CPR), although lifesaving may cause chest wall injury (CWI) because of the physical force exerted on the thorax. The impact of CWI on clinical outcome in this patient group is unclear. The primary aim of this study was to investigate the incidence of CPR-related CWI and the secondary aim to study injury pattern, length of stay (LOS), and mortality in patients with and without CWI.

METHODS

This is a retrospective study of adult patients who were admitted to our hospital due to cardiac arrest (CA) during 2012 to 2020. Patients were identified in the Swedish CPR Registry and those undergoing CT of the thorax within 2 weeks after CPR were included. Patients with traumatic CA, chest wall surgery prior or after CA were excluded. Demographic data, type and length of CPR, type of CWI, LOS on mechanical ventilator (MV), in intensive care unit (ICU) and in hospital (H), and mortality were studied.

RESULTS

Of 1,715 CA patients, 245 met the criteria for inclusion. The majority (79%) of the patients suffered from CWI. Chondral injuries and rib fractures were more common than sternum fractures (95% vs. 57%), and 14% had a radiological flail segment. Patients with CWI were older (66.5 ± 15.4 vs. 52.5 ± 15.2, p < 0.001). No difference was seen in MV-LOS (3 [0-43] vs. 3 [0-22]; p = 0.430), ICU-LOS (3 [0-48] vs. 3 [0-24]; p = 0.427), and H-LOS (5.5 [0-85] vs. 9.0 [1-53]; p = 0.306) in patients with or without CWI. Overall mortality within 30 days was higher with CWI (68% vs. 47%, p = 0.007).

CONCLUSION

Chest wall injuries are common after CPR and 14% of patients had a flail segment on CT. Elderly patients have an increased risk of CWI, and a higher overall mortality is seen in patients with CWI.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Left rib fractures during cardiopulmonary resuscitation are associated with hemodynamic variations in a pig model of cardiac arrest

Background

Chest compressions (CC) are the cornerstone of cardiopulmonary resuscitation (CPR). But CC are also known to cause injuries, specifically rib fractures. The effects of such fractures have not been examined yet. This study aimed to investigate hemodynamic effects of rib fractures during mechanical CPR in a porcine model of cardiac arrest (CA).

Methods

We conducted a retrospective hemodynamic study in 31 pigs that underwent mechanical CC. Animals were divided into three groups based on the location of rib fractures: No Broken Ribs group (n = 11), Left Broken Ribs group (n = 13), and Right Broken Ribs group (n = 7). Hemodynamic measurements were taken at 10 seconds before and 10, 30, and 60 seconds after rib fractures.

Results

Baseline hemodynamic parameters did not differ between the three groups. Systolic aortic pressure was overall higher in the Left Broken Ribs group than in the No Broken Ribs group at 10, 30, and 60 seconds after rib fracture (p = 0.02, 0.01, and 0.006, respectively). The Left Broken Ribs group had a significantly higher right atrial pressure compared to the No Broken Rib group after rib fracture (p = 0.02, 0.01, and 0.03, respectively). There was no significant difference for any parameter for the Right Broken Ribs group, when compared to the No Broken Ribs group.

Conclusion

An increase in main hemodynamic parameters was observed after left rib fractures while right broken ribs were not associated with any change in hemodynamic parameters. Reporting fractures and their location seems worthwhile for future experimental studies.

Cardiopulmonary Resuscitation May Not Stop Glutamate Release in the Cerebral Cortex

BACKGROUND

Cardiopulmonary resuscitation (CPR) may not be sufficient to halt the progression of brain damage. Using extracellular glutamate concentration as a marker for neuronal damage, we quantitatively evaluated the degree of brain damage during resuscitation without return of spontaneous circulation.

MATERIALS AND METHODS

Extracellular cerebral glutamate concentration was measured with a microdialysis probe every 2 minutes for 40 minutes after electrical stimulation-induced cardiac arrest without return of spontaneous circulation in Sprague-Dawley rats. The rats were divided into 3 groups (7 per group) according to the treatment received during the 40 minutes observation period: mechanical ventilation without chest compression (group V); mechanical ventilation and chest compression (group VC) and; ventilation, chest compression and brain hypothermia (group VCH). Chest compression (20 min) and hypothermia (40 min) were initiated 6 minutes after the onset of cardiac arrest.

RESULTS

Glutamate concentration increased in all groups after cardiac arrest. Although after the onset of chest compression, glutamate concentration showed a significant difference at 2 min and reached the maximum at 6 min (VC group; 284±48 μmol/L vs. V group 398±126 μmol/L, P =0.003), there was no difference toward the end of chest compression (513±61 μmol/L vs. 588±103 μmol/L, P =0.051). In the VCH group, the initial increase in glutamate concentration was suddenly suppressed 2 minutes after the onset of brain hypothermia.

CONCLUSIONS

CPR alone reduced the progression of brain damage for a limited period but CPR in combination with brain cooling strongly suppressed increases in glutamate levels.

Pediatric Chest Compression Improvement Via Augmented Reality Cardiopulmonary Resuscitation Feedback in Community General Emergency Departments: A Mixed-Methods Simulation-Based Pilot Study

BACKGROUND

Yearly, more than 20,000 children experience a cardiac arrest. High-quality pediatric cardiopulmonary resuscitation (CPR) is generally challenging for community hospital teams, where pediatric cardiac arrest is infrequent. Current feedback systems are insufficient. Therefore, we developed an augmented reality (AR) CPR feedback system for use in many settings.

OBJECTIVE

We aimed to evaluate whether AR-CPR improves chest compression (CC) performance in non-pediatric-specialized community emergency departments (EDs).

METHODS

We performed an unblinded, randomized, crossover simulation-based study. A convenience sample of community ED nonpediatric nurses and technicians were included. Each participant performed three 2-min cycles of CC during a simulated pediatric cardiac arrest. Participants were randomized to use AR-CPR in one of three CC cycles. Afterward, participants participated in a qualitative interview to inquire about their experience with AR-CPR.

RESULTS

Of 36 participants, 18 were randomized to AR-CPR in cycle 2 (group A) and 18 were randomized to AR-CPR in cycle 3 (group B). When using AR-CPR, 87-90% (SD 12-13%) of all CCs were in goal range, analyzed as 1-min intervals, compared with 18-21% (SD 30-33%) without feedback (p < 0.001). Analysis of qualitative themes revealed that AR-CPR may be usable without a device orientation, be effective at cognitive offloading, and reduce anxiety around and enhance confidence in the CC delivered.

CONCLUSIONS

The novel CPR feedback system, AR-CPR, significantly changed the CC performance in community hospital non-pediatric-specialized general EDs from 18-21% to 87-90% of CC epochs at goal. This study offers preliminary evidence suggesting AR-CPR improves CC quality in community hospital settings.

Traumatic Injuries Following Mechanical versus Manual Chest Compression

Objective

Survival after out-of-hospital cardiac arrest (OHCA) depends on multiple factors, mostly quality of chest compressions. Studies comparing manual compression with a mechanical active compression-depression device (ACD) have yielded controversial results in terms of outcomes and injury. The aim of the present study was to determine whether out-of-hospital ACD cardiopulmonary resuscitation (CPR) use is associated with more skeletal fractures and/or internal injuries than manual compression, with similar duration of cardiopulmonary resuscitation (CPR) between the groups.

Methods

The cohort included all patients diagnosed with out-of-hospital cardiac arrest (OHCA) at a tertiary medical center between January 2018 and June 2019 who achieved return of spontaneous circulation (ROSC). The primary outcome measure was the incidence of skeletal fractures and/or internal injuries in the two groups. Secondary outcome measures were clinical factors contributing to skeletal fracture/internal injuries and to achievement of ROSC during CPR.

Results

Of 107 patients enrolled, 45 (42%) were resuscitated with manual chest compression and 62 (58%) with a piston-based ACD device (LUCAS). The duration of chest compression was 46.0 minutes vs. 48.5 minutes, respectively (p=0.82). There were no differences in rates of ROSC (53.2% vs.50.8%, p=0.84), cardiac etiology of OHCA (48.9% vs.43.5%, p=0.3), major complications (ribs/sternum fracture, pneumothorax, hemothorax, lung parenchymal damage, major bleeding), or any complication (20.5% vs.12.1%, p=0.28). On multivariate logistic regression analysis, factors with the highest predictive value for ROSC were cardiac etiology (OR 1.94;CI 2.00-12.94) and female sex (OR 1.94;CI 2.00-12.94). Type of arrhythmia had no significant effect. Use of the LUCAS was not associated with ROSC (OR 0.73;CI 0.34-2.1).

Conclusion

This is the first study to compare mechanical and manual out-of-hospital chest compression of similar duration to ROSC. The LUCAS did not show added benefit in terms of ROSC rate, and its use did not lead to a higher risk of traumatic injury. ACD devices may be more useful in cases of delayed ambulance response times, or events in remote locations.

Manual and Mechanical Induced Peri-Resuscitation Injuries-Post-Mortem and Clinical Findings

(1) Background: Injuries related to resuscitation are not usually systematically recorded and documented. By evaluating this data, conclusions could be drawn about the quality of the resuscitation, with the aim of improving patient care and safety. (2) Methods: We are planning to conduct a multicentric, retrospective 3-phased study consisting of (1) a worldwide literature review (scoping review), (2) an analysis of anatomical pathological findings from local institutions in North Rhine-Westphalia, Germany to assess the transferability of the review data to the German healthcare system, and (3) depending on the results, possibly establishing potential prospective indicators for resuscitation-related injuries as part of quality assurance measures. (3) Conclusions: From the comparison of literature and local data, the picture of resuscitation-related injuries will be focused on and quality indicators will be derived.

Pectus excavatum and mechanical chest compression of a dangerous bond

Pectus excavatum (PE) is a malformation of the chest characterized by a median depression of the sternum. The incidence of PE is between 0.1% and 0.8%. In the last decade mechanical chest compression devices (MCCD) became of particular interest in cardiopulmonary resuscitation. Different devices became available and this resulted in an increase in their use during CPR mainly for practical reasons. Despite their increasing use, little evidence existed for their effectiveness and little was known about complications. Skin lesions and fractures of sternum or ribs are the ones with the highest incidence. Whereas subdiaphragmatic lesions, in particular fatal liver injuries are uncommon and described only in few case reports. In a recent retrospective study, CT was used to determine the proper compression landmark and depth of cardiopulmonary resuscitation in PE patients. The authors showed that the mean Haller Index in PE patients was higher than in controls, thus exposing internal organs to a higher injury risk during standard CPR maneuvers. We report the first case, to our knowledge, of liver injury during mechanical CPR in a patient with PE. Awareness is being raised on tailoring mechanical CPR in patients with chest deformities. Further exploration is needed to determine if there is a strong correlation between mechanical CPR and organ damage in PE. We believe that this case highlights the importance of individualizing CPR techniques.

[Add-on-LUCAS2™ resuscitation at NEF Innsbruck]

Studienziel

Ziele sind die Verlaufsanalyse und der Vergleich mit ausschließlich manuell reanimierten Patienten sowie die Erfassung der Einflussfaktoren bei Patienten, bei denen die mechanische Thoraxkompressionshilfe Lund University Cardiac Assist System (LUCAS2^TM) als Add-on-Therapie am Notarzteinsatzfahrzeug (NEF) Innsbruck verwendet wurde.

Material und Methodik

Retrospektive Verlaufsdatenanalyse von Patienten im Studienzeitraum 01.01.2014 bis 31.12.2019 des NEF Innsbruck aus dem Deutschen Reanimationsregister (GRR), bei denen LUCAS2™ nach notärztlicher Anordnung als Add-on-Therapie verwendet wurde.

Ergebnis

Bei 653 Reanimationen kam es zu 123 Add-on-LUCAS2™-Anwendungen (18,8 %). Von allen Patienten überlebten 16,2 % die ersten 30 Tage. Mithilfe der Add-on-LUCAS2^TM Anwendung überlebten 7,3 % (9/123) aller Add-on-LUCAS2™-Reanimationen bzw. 1,4 % (n = 9) aller CPRs. Bei 8/9 Add-On-LUCAS2™-„30 Tage-Überlebenden“ war der Herz-Kreislauf-Stillstand (HKS) beobachtet, und eine Laien-CPR wurde durchgeführt. Als Primärrhythmus wiesen 8/9 Kammerflimmern auf.

Im Vergleich zur ausschließlich manuellen CPR wurde eine Add-on-LUCAS2™-Reanimation hoch signifikant (p < 0,001) häufiger bei jüngeren, bei männlichen Patienten, in der Öffentlichkeit, bei schockbarem Erstrhythmus und beim Transport eingesetzt sowie signifikant häufiger bei beobachteten HKS (p < 0,05).

Die 30-Tage-Mortalität bei additiver Lysetherapie betrug 100 %.

Diskussion

Durch die Verwendung der Add-on-LUCAS2™-CPR kann eine prozentuelle Erhöhung der Überlebensrate erzielt werden und erscheint somit vorteilhaft (1,4 % in dieser Studie). Durch diese kann bei Patienten mit günstigen Prognosefaktoren eine hochwertige HDM auch bei technisch aufwendiger Bergung (Drehleiter, Stiegenhaus, Transport im RTW) durchgeführt und somit ein Transport ermöglicht werden. Jedoch kommt es dabei zu einer höheren Aufnahmerate unter CPR und somit zur Verlagerung der Therapiezielentscheidung in den Schockraum.

Prognostic Impact of In-Hospital Use of Mechanical Cardiopulmonary Resuscitation Devices Compared with Manual Cardiopulmonary Resuscitation: A Nationwide Population-Based Observational Study in South Korea

Background and Objectives: This study analyzed the prognostic impact of mechanical cardiopulmonary resuscitation (CPR) devices in out-of-hospital cardiac arrest (OHCA) patients, in comparison to manual CPR. Materials and Methods: This study was a nationwide population-based observational study in South Korea. Data were retrospectively collected from 142,905 OHCA patients using the South Korean Out-of-Hospital Cardiac Arrest Surveillance database. We included adult OHCA patients who received manual or mechanical CPR in the emergency room. The primary outcome was survival at discharge and the secondary outcome was sustained return of spontaneous circulation (ROSC). Statistical analysis included propensity score matching and multivariate logistic regression. Results: A total of 19,045 manual CPR and 1125 mechanical CPR cases (671 AutoPulse^TM vs. 305 Thumper^TM vs. 149 LUCAS^TM) were included. In the matched multivariate analyses, all mechanical CPR devices were associated with a lower ROSC than that of manual CPR. AutoPulse^TM was associated with lower survival in the multivariate analysis after matching (aOR with 95% CI: 0.57 (0.33–0.96)), but the other mechanical CPR devices were associated with similar survival to discharge as that of manual CPR. Witnessed arrest was commonly associated with high ROSC, but the use of mechanical CPR devices and cardiac origin arrest were associated with low ROSC. Only target temperature management was the common predictor for high survival. Conclusions: The mechanical CPR devices largely led to similar survival to discharge as that of manual CPR in OHCA patients; however, the in-hospital use of the AutoPulse^TM device for mechanical CPR may significantly lower survival compared to manual CPR.

Will Automated Compressing Devices Save More Lives in Recalcitrant Ventricular Fibrillation Cardiac Arrest?

We present a 55-year-old male that developed ventricular fibrillation cardiac arrest in the setting of ST-elevation acute myocardial infarction with recalcitrant and persistent ventricular fibrillation arrest that was successfully resuscitated with a good neurological outcome. The persistent chest compressions were performed in our intensive care unit with an automated chest compression system. The patient required defibrillations and nonstop chest compressions which were the key factors for his survival. This is an example we should consider in all our intensive care units. It's time for a paradigm shift in replacing the compressor of a code team with an automated system. The out-of-hospital evidence in acute care is compelling to bring this technology that has been proven crucial in transports from hospital areas, ambulances, helicopters, and ships to the inpatient ICU bedside. In ventricular tachycardia and ventricular fibrillation (Vt/Vf), the electrical storm created is the perfect example of the need to have the best compressions to provide the best care possible with the best survival and neurological outcomes.

Safety of mechanical and manual chest compressions in cardiac arrest patients: A systematic review and meta-analysis

AIM

Summarise the evidence regarding the safety of mechanical and manual chest compressions for cardiac arrest patients.

METHODS

Two investigators separately screened the articles of EMBASE, PubMed, and Cochrane Central databases. Cohort studies and randomized clinical trials (RCTs) that evaluated the safety of mechanical (LUCAS or AutoPulse) and manual chest compressions in cardiac arrest patients were included. A meta-analysis was performed using a random effects model to calculate the pooled odds ratios (ORs) and their 95% confidence intervals (CIs). The primary outcome was the rate of overall compression-induced injuries. The secondary outcomes included the incidence of life-threatening injuries, skeletal fractures, visceral injuries, and other soft tissue injuries.

RESULTS

The meta-analysis included 11 trials involving 2,818 patients. A significantly higher rate of overall compression-induced injuries was found for mechanical compressions than manual compressions (OR, 1.29; 95% CI, 1.19-1.41), while there was no significant difference between the two groups in respect of the rate of life-threatening injuries. Furthermore, both modalities shared similar incidences of sternal fractures, vertebral fractures, lung, spleen, and kidney injuries. However, compared to mechanical compressions, manual compressions were shown to present a reduced risk of posterior rib fractures, and heart and liver lesions.

CONCLUSIONS

The findings suggested that manual compressions could decrease the risk of compression-induced injuries compared to mechanical compressions in cardiac arrest patients. Interestingly, mechanical compressions have not increased the risk of life-threatening injuries, whereas additional high-quality RCTs are needed to further verify the safety of mechanical chest devices.

TRIAL REGISTRY

INPLASY; Registration number: INPLASY2020110111; URL: https://inplasy.com/.

Devices to enhance organ perfusion during cardiopulmonary resuscitation

INTRODUCTION

The recommended method of cardiopulmonary resuscitation (CPR) has been closed-chest cardiac compressions, but the development of CPR adjunctive devices has called into question the efficacy and role of these adjunctive devices. In this review, we provide a comprehensive evaluation and discussion on the commercially available noninvasive CPR adjuncts used during out-of-hospital cardiac arrest (OHCA).

AREAS COVERED

We review the three most common CPR adjunctive devices: the piston mechanism, the load distributing band, and the impedance threshold device. All three CPR adjunctive devices have preclinical data to support their use during cardiac arrest. In clinical trials, limited data show improvement in survival and neurologic recovery for these devices, and there is insufficient high-level evidence to support their use over manual chest compressions. However, there is a role for them when adequate manual chest compressions are not feasible.

EXPERT OPINION

The commercially available CPR adjuncts do not consistently show improved outcomes in the literature. There is still a need for research and development into innovative solutions to improve OHCA survival and neurologic recovery. Efforts focused on increasing the speed of CPR initiation and increasing perfusion to the cerebral and coronary vasculature have the potential to advance resuscitative practices.

Standardized post-resuscitation damage assessment of two mechanical chest compression devices: a prospective randomized large animal trial

BACKGROUND

Mechanical chest compression devices are accepted alternatives for cardiopulmonary resuscitation (CPR) under specific circumstances. Current devices lack prospective and comparative data on their specific cardiovascular effects and potential for severe thoracic injuries.

OBJECTIVES

To compare CPR effectiveness and thoracic injuries of two mechanical chest compression devices in pigs.

STUDY DESIGN

Prospective randomised trial.

ANIMALS

Eighteen male German landrace pigs.

METHODS

Ventricular fibrillation was induced in anaesthetised and instrumented pigs and the animals were randomised into two intervention groups. Mechanical CPR was initiated by means of LUCAS™ 2 (mCCD1) or Corpuls™ cpr (mCCD2) device. Advanced life support was applied for a maximum of 10 cycles and animals achieving ROSC were monitored for 8 h. Ventilation/perfusion measurements were performed and blood gas analyses were taken. Thoracic injuries were assessed via a standardised damage score.

RESULTS

Five animals of the mCCD1 group and one animal of the mCCD2 group achieved ROSC (p = 0.048). Only the mCCD1 animals survived until the end of the monitoring period (p < 0.01). MCCD1 animals showed less pulmonary shunt (p = 0.025) and higher normal V/Q (p = 0.017) during CPR. MCCD2 animals showed significantly more severe thoracic injuries (p = 0.046).

CONCLUSION

The LUCAS 2 device shows superior resuscitation outcomes and less thoracic injuries compared to Corpuls cpr when used for experimental CPR in juvenile pigs. Researchers should be aware that different mCCDs for experimental studies may significantly influence the respective outcome of resuscitation studies and affect comparability of different trials. Controlled human and animal CPR studies and a standardised post-resuscitation injury evaluation could help to confirm potential hazards.

TRIAL REGISTRATION

Trial approval number: G16-1-042-E4.

Shoulder strap fixation of LUCAS-2 to facilitate continuous CPR during non-supine (stair) stretcher transport of OHCAs patients

Early recognition and rapid initiation of high-quality cardiopulmonary resuscitation (CPR) are key to maximising chances of achieving successful return of spontaneous circulation in patients with out-of-hospital cardiac arrests (OHCAs), as well as improving patient outcomes both inside and outside hospital. Mechanical chest compression devices such as the LUCAS-2 have been developed to assist rescuers in providing consistent, high-quality compressions, even during transportation. However, providing uninterrupted and effective compressions with LUCAS-2 during transportation down stairwells and in tight spaces in a non-supine position is relatively impossible. In this study, we proposed adaptations to the LUCAS-2 to allow its use during transportation down stairwells and examined its effectiveness in providing high-quality CPR to simulated OHCA patients. 20 volunteer emergency medical technicians were randomised into 10 pairs, each undergoing 2 simulation runs per experimental arm (LUCAS-2 versus control) with a loaded Resusci Anne First Aid full body manikin weighing 60 kg. Quality of CPR compressions performed was measured using the CPRmeter placed on the sternum of the manikin. The respective times taken for each phase of the simulation protocol were recorded. Fisher’s exact tests were used to analyse categorical variables and median test to analyse continuous variables. The LUCAS-2 group required a longer time (~ 35 s) to prepare the patient prior to transport (p < 0.0001) and arrive at the ambulance (p < 0.0001) compared to the control group. The CPR quality in terms of depth and rate for the overall resuscitation period did not differ significantly between the LUCAS-2 group and control group, though there was a reduction in both parameters when evaluating the device’s automated compressions during transport. Nevertheless, the application of the LUCAS-2 device yielded a significantly higher chest compression fraction of 0.76 (p < 0.0001). Our novel adaptations to the LUCAS-2 device allow for uninterrupted compressions in patients being transported down stairwells, thus yielding better chest compression fractions for the overall resuscitation period. Whether potentially improved post-OHCA survival rates may be achieved requires confirmation in a real-world scenario study.

Automated mechanical cardiopulmonary resuscitation devices versus manual chest compressions in the treatment of cardiac arrest: protocol of a systematic review and meta-analysis comparing machine to human

INTRODUCTION

Cardiac arrest is a leading cause of death in industrialised countries. Cardiopulmonary resuscitation (CPR) guidelines follow the principles of closed chest compression as described for the first time in 1960. Mechanical CPR devices are designed to improve chest compression quality, thus considering the improvement of resuscitation outcomes. This protocol outlines a systematic review and meta-analysis methodology to assess trials investigating the therapeutic effect of automated mechanical CPR devices at the rate of return of spontaneous circulation, neurological state and secondary endpoints (including short-term and long-term survival, injuries and surrogate parameters for CPR quality) in comparison with manual chest compressions in adults with cardiac arrest.

METHODS AND ANALYSIS

A sensitive search strategy will be employed in established bibliographic databases from inception until the date of search, followed by forward and backward reference searching. We will include randomised and quasi-randomised trials in qualitative analysis thus comparing mechanical to manual CPR. Studies reporting survival outcomes will be included in quantitative analysis. Two reviewers will assess independently publications using a predefined data collection form. Standardised tools will be used for data extraction, risks of bias and quality of evidence. If enough studies are identified for meta-analysis, the measures of association will be calculated by dint of bivariate random-effects models. Statistical heterogeneity will be evaluated by I²-statistics and explored through sensitivity analysis. By comprehensive subgroup analysis we intend to identify subpopulations who may benefit from mechanical or manual CPR techniques. The reporting follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

ETHICS AND DISSEMINATION

No ethical approval will be needed because data from previous studies will be retrieved and analysed. Most resuscitation studies are conducted under an emergency exception for informed consent. This publication contains data deriving from a dissertation project. We will disseminate the results through publication in a peer-reviewed journal and at scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42017051633.

Cardiopulmonary resuscitation (CPR) during spaceflight - a guideline for CPR in microgravity from the German Society of Aerospace Medicine (DGLRM) and the European Society of Aerospace Medicine Space Medicine Group (ESAM-SMG)

BACKGROUND

With the "Artemis"-mission mankind will return to the Moon by 2024. Prolonged periods in space will not only present physical and psychological challenges to the astronauts, but also pose risks concerning the medical treatment capabilities of the crew. So far, no guideline exists for the treatment of severe medical emergencies in microgravity. We, as a international group of researchers related to the field of aerospace medicine and critical care, took on the challenge and developed a an evidence-based guideline for the arguably most severe medical emergency - cardiac arrest.

METHODS

After the creation of said international group, PICO questions regarding the topic cardiopulmonary resuscitation in microgravity were developed to guide the systematic literature research. Afterwards a precise search strategy was compiled which was then applied to "MEDLINE". Four thousand one hundred sixty-five findings were retrieved and consecutively screened by at least 2 reviewers. This led to 88 original publications that were acquired in full-text version and then critically appraised using the GRADE methodology. Those studies formed to basis for the guideline recommendations that were designed by at least 2 experts on the given field. Afterwards those recommendations were subject to a consensus finding process according to the DELPHI-methodology.

RESULTS

We recommend a differentiated approach to CPR in microgravity with a division into basic life support (BLS) and advanced life support (ALS) similar to the Earth-based guidelines. In immediate BLS, the chest compression method of choice is the Evetts-Russomano method (ER), whereas in an ALS scenario, with the patient being restrained on the Crew Medical Restraint System, the handstand method (HS) should be applied. Airway management should only be performed if at least two rescuers are present and the patient has been restrained. A supraglottic airway device should be used for airway management where crew members untrained in tracheal intubation (TI) are involved.

DISCUSSION

CPR in microgravity is feasible and should be applied according to the Earth-based guidelines of the AHA/ERC in relation to fundamental statements, like urgent recognition and action, focus on high-quality chest compressions, compression depth and compression-ventilation ratio. However, the special circumstances presented by microgravity and spaceflight must be considered concerning central points such as rescuer position and methods for the performance of chest compressions, airway management and defibrillation.

Skeletal and soft tissue injuries after manual and mechanical chest compressions

AIMS

To determine the rate of injuries related to cardiopulmonary resuscitation (CPR) in cardiac arrest non-survivors, comparing manual CPR with CPR performed using the Lund University Cardiac Assist System (LUCAS).

METHODS AND RESULTS

We prospectively evaluated 414 deceased adult patients using focused, standardized post-mortem investigation in years 2005 through 2013. Skeletal and soft tissue injuries were noted, and soft tissue injuries were evaluated with respect to degree of severity. We found sternal fracture in 38%, rib fracture in 77%, and severe soft tissue injury in 1.9% of cases treated with CPR with manual chest compressions (n = 52). Treatment with LUCAS CPR (n = 362) was associated with significantly higher rates of sternal fracture (80% of cases), rib fracture (96%), and severe soft tissue injury (10%), including several cases of potentially life-threatening injuries.

CONCLUSION

LUCAS CPR causes significantly more CPR-related injuries than manual CPR, while providing no proven survival benefit on a population basis. We suggest judicious use of the LUCAS device for cardiac arrest.

Study of the Effects of 3 h of Continuous Cardiopulmonary Resuscitation at 27°C on Global Oxygen Transport and Organ Blood Flow

Aims

Complete restitution of neurologic function after 6 h of pre-hospital resuscitation and in-hospital rewarming has been reported in accidental hypothermia patients with cardiac arrest (CA). However, the level of restitution of circulatory function during long-lasting hypothermic cardiopulmonary resuscitation (CPR) remains largely unknown. We compared the effects of CPR in replacing spontaneous circulation during 3 h at 27°C vs. 45 min at normothermia by determining hemodynamics, global oxygen transport (DO₂), oxygen uptake (VO₂), and organ blood flow.

Methods

Anesthetized pigs (n = 7) were immersion cooled to CA at 27°C. Predetermined variables were compared: (1) Before cooling, during cooling to 27°C with spontaneous circulation, after CA and subsequent continuous CPR (n = 7), vs. (2) before CA and during 45 min CPR in normothermic pigs (n = 4).

Results

When compared to corresponding values during spontaneous circulation at 38°C: (1) After 15 min of CPR at 27°C, cardiac output (CO) was reduced by 74%, mean arterial pressure (MAP) by 63%, DO₂ by 47%, but organ blood flow was unaltered. Continuous CPR for 3 h maintained these variables largely unaltered except for significant reduction in blood flow to the heart and brain after 3 h, to the kidneys after 1 h, to the liver after 2 h, and to the stomach and small intestine after 3 h. (2) After normothermic CPR for 15 min, CO was reduced by 71%, MAP by 54%, and DO₂ by 63%. After 45 min, hemodynamic function had deteriorated significantly, organ blood flow was undetectable, serum lactate increased by a factor of 12, and mixed venous O₂ content was reduced to 18%.

Conclusion

The level to which CPR can replace CO and MAP during spontaneous circulation at normothermia was not affected by reduction in core temperature in our setting. Compared to spontaneous circulation at normothermia, 3 h of continuous resuscitation at 27°C provided limited but sufficient O₂ delivery to maintain aerobic metabolism. This fundamental new knowledge is important in that it encourages early and continuous CPR in accidental hypothermia victims during evacuation and transport.

Comparison of hemodynamic effects and resuscitation outcomes between automatic simultaneous sterno-thoracic cardiopulmonary resuscitation device and LUCAS in a swine model of cardiac arrest

Introduction

Mechanical cardiopulmonary resuscitation (CPR) devices are widely used to rescue patients from cardiac arrest. This study aimed to compare hemodynamic effects and resuscitation outcomes between a motor-driven, automatic simultaneous sterno-thoracic cardiopulmonary resuscitation device and the Lund University cardiac arrest system (LUCAS).

Material and methods

After 2 minutes of electrically induced ventricular fibrillation (VF), Yorkshire pigs (weight 35–60 kg) received CPR with an automatic simultaneous sterno-thoracic CPR device (X-CPR group, n = 13) or the Lund University cardiac arrest system (LUCAS group, n = 12). Basic life support for 6 minutes and advanced cardiovascular life support for 12 minutes, including defibrillation and epinephrine administration, were provided. Hemodynamic parameters and resuscitation outcomes, including return of spontaneous circulation (ROSC), 24-hour survival, and cerebral performance category (CPC) at 24 hours, were evaluated.

Results

Hemodynamic parameters, including aortic pressures, coronary perfusion pressure, carotid blood flow, and end-tidal carbon dioxide pressure were not significantly different between the two groups. Resuscitation outcomes were also not significantly different between the groups (X-CPR vs. LUCAS; rate of ROSC: 31% vs 25%, p = 1.000; 24-hour survival rate: 31% vs 17%, p = 0.645; neurological outcome with CPC ≤2: 31% vs 17%, p = 0.645). Also no significant difference in incidence complications associated with resuscitation was found between the groups.

Conclusions

CPR with a motor-driven X-CPR and CPR with the LUCAS produced similar hemodynamic effects and resuscitation outcomes in a swine model of cardiac arrest.

An observational study on survival rates of patients with out-of-hospital cardiac arrest in the Netherlands after improving the 'chain of survival'

OBJECTIVES

To evaluate the impact of implemented procedures for out-of-hospital cardiac arrests (OHCAs) by determining patient outcome defined as the percentage return of spontaneous circulation at arrival at the emergency department, and 3-month and 1-year-survival rates.

DESIGN

Observational study.

SETTING

Primary emergency medical care consisting of Advanced Life Support is given by ambulance nurses and secondary care by hospitals within the mid-western part of the Netherlands covering 750 000 inhabitants.

PARTICIPANTS

433 of 500 consecutive patients with OHCA were included in the study over a 1.5 -year period.

OUTCOME MEASURES

Analysis included number of patients with return of spontaneous circulation (ROSC) when handed over to the emergency department, survival at 3 months and 1 year including a comparison with global outcome rates. We further considered the influence of gender, delays, bystander Basic Life Support, use of an automated external defibrillator, initial rhythm and mechanical thorax compression in combination with Boussignac tube ventilation.

RESULTS

13% (67/500) of the initial patient population was excluded from the analysis as reanimation in these patients was aborted due to expressed wish not to be resuscitated. Resuscitation was started by bystanders, police and/or first responders in 312/433 (72%) cases. An automated external defibrillator was used in 198 of these 312 cases (63%) of which it defibrillated 108 times. Mechanical thorax compression in combination with Boussignac tube ventilation was necessary in 277/433 patients (64%). Spontaneous circulation returned in 96/277 (35%) patients of this group. In the overall studied population, ROSC percentage at arrival at the hospital was 214/433 (49%). The 3-month and 12-month-survival rates were 123/433 (28%) and 119/433 (27%), respectively.

CONCLUSIONS

Optimised 'chain of survival' for patients with OHCA resulted in ROSC in 49% of the cases and a 1-year-survival rate of 27% in the studied population.

Mechanical chest compressions for cardiac arrest in the cath-lab: when is it enough and who should go to extracorporeal cardio pulmonary resuscitation?

BACKGROUND

Treating patients in cardiac arrest (CA) with mechanical chest compressions (MCC) during percutaneous coronary intervention (PCI) is now routine in many coronary catheterization laboratories (cath-lab) and more aggressive treatment modalities, including extracorporeal CPR are becoming more common. The cath-lab setting enables monitoring of vital physiological parameters and other clinical factors that can potentially guide the resuscitation effort. This retrospective analysis attempts to identify such factors associated with ROSC and survival.

METHODS

In thirty-five patients of which background data, drugs used during the resuscitation and the intervention, PCI result, post ROSC-treatment and physiologic data collected during CPR were compared for prediction of ROSC and survival.

RESULTS

Eighteen (51%) patients obtained ROSC and 9 (26%) patients survived with good neurological outcome. There was no difference between groups in regards of background data. Patients arriving in the cath-lab with ongoing resuscitation efforts had lower ROSC rate (22% vs 53%; p = 0.086) and no survivors (0% vs 50%, p = 0.001). CPR time also differentiated resuscitation outcomes (ROSC: 18 min vs No ROSC: 50 min; p = 0.007 and Survivors: 10 min vs No Survivors: 45 min; p = 0.001). Higher arterial diastolic blood pressure was associated with ROSC: 30 mmHg vs No ROSC: 19 mmHg; p = 0.012).

CONCLUSION

Aortic diastolic pressure during CPR is the most predictive physiological parameter of resuscitation success. Ongoing CPR upon arrival at the cath-lab and continued MCC beyond 10-20 min in the cath-lab were both predictive of poor outcomes. These factors can potentially guide decisions regarding escalation and termination of resuscitation efforts.

Confirming the Clinical Safety and Feasibility of a Bundled Methodology to Improve Cardiopulmonary Resuscitation Involving a Head-Up/Torso-Up Chest Compression Technique

OBJECTIVES

Combined with devices that enhance venous return out of the brain and into the thorax, preclinical outcomes are improved significantly using a synergistic bundled approach involving mild elevation of the head and chest during cardiopulmonary resuscitation. The objective here was to confirm clinical safety/feasibility of this bundled approach including use of mechanical cardiopulmonary resuscitation provided at a head-up angle.

DESIGN

Quarterly tracking of the frequency of successful resuscitation before, during, and after the clinical introduction of a bundled head-up/torso-up cardiopulmonary resuscitation strategy.

SETTING

9-1-1 response system for a culturally diverse, geographically expansive, populous jurisdiction.

PATIENTS

All 2,322 consecutive out-of-hospital cardiac arrest cases (all presenting cardiac rhythms) were followed over 3.5 years (January 1, 2014, to June 30, 2017).

INTERVENTIONS

In 2014, 9-1-1 crews used LUCAS (Physio-Control Corporation, Redmond, WA) mechanical cardiopulmonary resuscitation and impedance threshold devices for out-of-hospital cardiac arrest. After April 2015, they also 1) applied oxygen but deferred positive pressure ventilation several minutes, 2) solidified a pit-crew approach for rapid LUCAS placement, and 3) subsequently placed the patient in a reverse Trendelenburg position (~20°).

MEASUREMENTS AND MAIN RESULTS

No problems were observed with head-up/torso-up positioning (n = 1,489), but resuscitation rates rose significantly during the transition period (April to June 2015) with an ensuing sustained doubling of those rates over the next 2 years (mean, 34.22%; range, 29.76-39.42%; n = 1,356 vs 17.87%; range, 14.81-20.13%, for 806 patients treated prior to the transition; p < 0.0001). Outcomes improved across all subgroups. Response intervals, clinical presentations and indications for attempting resuscitation remained unchanged. Resuscitation rates in 2015-2017 remained proportional to neurologically intact survival (~35-40%) wherever tracked.

CONCLUSIONS

The head-up/torso-up cardiopulmonary resuscitation bundle was feasible and associated with an immediate, steady rise in resuscitation rates during implementation followed by a sustained doubling of the number of out-of-hospital cardiac arrest patients being resuscitated. These findings make a compelling case that this bundled technique will improve out-of-hospital cardiac arrest outcomes significantly in other clinical evaluations.

Mechanical versus manual chest compressions for cardiac arrest

BACKGROUND

Mechanical chest compression devices have been proposed to improve the effectiveness of cardiopulmonary resuscitation (CPR).

OBJECTIVES

To assess the effectiveness of resuscitation strategies using mechanical chest compressions versus resuscitation strategies using standard manual chest compressions with respect to neurologically intact survival in patients who suffer cardiac arrest.

SEARCH METHODS

On 19 August 2017 we searched the Cochrane Central Register of Controlled Studies (CENTRAL), MEDLINE, Embase, Science Citation Index-Expanded (SCI-EXPANDED) and Conference Proceedings Citation Index-Science databases. Biotechnology and Bioengineering Abstracts and Science Citation abstracts had been searched up to November 2009 for prior versions of this review. We also searched two clinical trials registries for any ongoing trials not captured by our search of databases containing published works: Clinicaltrials.gov (August 2017) and the World Health Organization International Clinical Trials Registry Platform portal (January 2018). We applied no language restrictions. We contacted experts in the field of mechanical chest compression devices and manufacturers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), cluster-RCTs and quasi-randomised studies comparing mechanical chest compressions versus manual chest compressions during CPR for patients with cardiac arrest.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included five new studies in this update. In total, we included 11 trials in the review, including data from 12,944 adult participants, who suffered either out-of-hospital cardiac arrest (OHCA) or in-hospital cardiac arrest (IHCA). We excluded studies explicitly including patients with cardiac arrest caused by trauma, drowning, hypothermia and toxic substances. These conditions are routinely excluded from cardiac arrest intervention studies because they have a different underlying pathophysiology, require a variety of interventions specific to the underlying condition and are known to have a prognosis different from that of cardiac arrest with no obvious cause. The exclusions were meant to reduce heterogeneity in the population while maintaining generalisability to most patients with sudden cardiac death.The overall quality of evidence for the outcomes of included studies was moderate to low due to considerable risk of bias. Three studies (N = 7587) reported on the designated primary outcome of survival to hospital discharge with good neurologic function (defined as a Cerebral Performance Category (CPC) score of one or two), which had moderate quality evidence. One study showed no difference with mechanical chest compressions (risk ratio (RR) 1.07, 95% confidence interval (CI) 0.82 to 1.39), one study demonstrated equivalence (RR 0.79, 95% CI 0.60 to 1.04), and one study demonstrated reduced survival (RR 0.41, CI 0.21 to 0.79). Two other secondary outcomes, survival to hospital admission (N = 7224) and survival to hospital discharge (N = 8067), also had moderate quality level of evidence. No studies reported a difference in survival to hospital admission. For survival to hospital discharge, two studies showed benefit, four studies showed no difference, and one study showed harm associated with mechanical compressions. No studies demonstrated a difference in adverse events or injury patterns between comparison groups but the quality of data was low. Marked clinical and statistical heterogeneity between studies precluded any pooled estimates of effect.

AUTHORS' CONCLUSIONS

The evidence does not suggest that CPR protocols involving mechanical chest compression devices are superior to conventional therapy involving manual chest compressions only. We conclude on the balance of evidence that mechanical chest compression devices used by trained individuals are a reasonable alternative to manual chest compressions in settings where consistent, high-quality manual chest compressions are not possible or dangerous for the provider (eg, limited rescuers available, prolonged CPR, during hypothermic cardiac arrest, in a moving ambulance, in the angiography suite, during preparation for extracorporeal CPR [ECPR], etc.). Systems choosing to incorporate mechanical chest compression devices should be closely monitored because some data identified in this review suggested harm. Special attention should be paid to minimising time without compressions and delays to defibrillation during device deployment.

Effect of compression waveform and resuscitation duration on blood flow and pressure in swine: One waveform does not optimally serve

BACKGROUND

Chest compression (CC) research primarily focuses on finding the 'optimum' compression waveform using a variety of compression efficacy metrics. Blood flow is rarely measured systematically with high fidelity. Using a programmable mechanical chest compression device, we studied the effect of inter-compression pauses in a swine model of cardiac arrest, testing the hypothesis that a single 'optimal' CC waveform exists based on measurements of resulting blood flow.

METHODS

Hemodynamics were studied in 9 domestic swine (∼30 kg) using multiple flow probes and standard physiological monitoring. After 10 min of ventricular fibrillation, five mechanical chest compression waveforms (5.1 cm, varying inter-compression pauses) were delivered for 2 min each in a semi-random pattern, totaling 50 compression minutes. Linear Mixed Models were used to estimate the effect of compression waveform on hemodynamics.

RESULTS

Blood flow and pressure decayed significantly with time in both arteries and veins. No waveform maximized blood flow in all vessels simultaneously and the waveform generating maximal blood flow in a specific vessel changed over time in all vessels. A flow mismatch between paired arteries and veins, e.g. abdominal aorta and inferior vena cava, also developed over time. The waveform with the slowest rate and shortest duty cycle had the smallest mismatch between flows after about 30 min of CPR.

CONCLUSIONS

This data challenges the concept of a single optimal CC waveform. Time dependent physiological response to compressions and no single compression waveform optimizing flow in all vessels indicate that current descriptions of CPR don't reflect patient physiology.

Estimation of the variations in mechanical impedance between the actuator and the chest, and the power delivered to the chest during cardiopulmonary resuscitation using machine-embedded sensors

Background

To reduce the risk of patient damage and complications during the cardiopulmonary resuscitation (CPR) process in emergency situations, it is necessary to monitor the status of the patient and the quality of CPR while CPR processing without additional bio-signal measurement devices. In this study, an algorithm is proposed to estimate the mechanical impedance (MI) between an actuator of the CPR machine and the chest of the patient, and to estimate the power delivered to the chest of the patient during the CPR process.

Methods

Two sensors for force and depth measurement were embedded into a custom-made CPR machine and the algorithm for MI and power estimation was implemented. The performance of the algorithm was evaluated by comparing the results from the kinetic model, the conventional discrete Fourier transform (DFT), and the proposed method.

Results

The estimations of the proposed method showed similar increasing/decreasing trends with the calculations from the kinetic model. In addition, the proposed method showed statistically equivalent performance in the MI estimation, and at the same time, showed statistically superior performance in the power estimation compared with the calculations from the conventional DFT. Furthermore, the MI and power estimation could be performed almost in real-time during the CPR process without excessive hands-off periods, and the intensity of random noise contained in the input signals did not seriously affect the MI and power estimations of the proposed method.

Conclusion

We expect that the proposed algorithm can reduce various CPR-related complications and improve patient safety.

Cardiac Arrest in the Catheterization Laboratory

BACKGROUND

Cardiac arrest in the Catheterization Lab is a rare and unique scenario that is often logistically challenging. It often has dire prognosis especially in patients suffering from severe pre-existing illnesses (high risk patient) such as acute myocardial infarction with cardiogenic shock, or patients undergoing high risk procedures. As the number of complex interventional procedures increases, cardiac arrest in the cath lab will become more common and optimal management of this scenario is critical for both the patient and operator.

CONCLUSION

In this review, we will discuss the special challenges during the resuscitation efforts in cath lab, especially with tradition chest compression. We will discuss the alternative options including mechanical compression devices and Invasive Percutaneous Mechanical Circulatory Support Devices. Finally, we will offer management suggestions on selecting the appropriate circulatory support device based on clinical and anatomic risks.

Prompt use of mechanical cardiopulmonary resuscitation in out-of-hospital cardiac arrest: the MECCA study report

INTRODUCTION

Early use of mechanical cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) may improve survival outcomes. Current evidence for such devices uses outcomes from an intention-to-treat (ITT) perspective. We aimed to determine whether early use of mechanical CPR using a LUCAS 2 device results in better outcomes.

METHODS

A prospective, randomised, multicentre study was conducted over one year with LUCAS 2 devices in 14 ambulances and manual CPR in 32 ambulances to manage OHCA. The primary outcome was return of spontaneous circulation (ROSC). Secondary outcomes were survival at 24 hours, discharge from hospital and 30 days.

RESULTS

Of the 1,274 patients recruited, 1,191 were eligible for analysis. 889 had manual CPR and 302 had LUCAS CPR. From an ITT perspective, outcomes for manual and LUCAS CPR were: ROSC 29.2% and 31.1% (odds ratio [OR] 1.09, 95% confidence interval [CI] 0.82-1.45; p = 0.537); 24-hour survival 11.2% and 13.2% (OR 1.20, 95% CI 0.81-1.78; p = 0.352); survival to discharge 3.6% and 4.3% (OR 1.20, 95% CI 0.62-2.33; p = 0.579); and 30-day survival 3.0% and 4.0% (OR 1.32, 95% CI 0.66-2.64; p = 0.430), respectively. By as-treated analysis, outcomes for manual, early LUCAS and late LUCAS CPR were: ROSC 28.0%, 36.9% and 24.5%; 24-hour survival 10.6%, 15.5% and 8.2%; survival to discharge 2.9%, 5.8% and 2.0%; and 30-day survival 2.4%, 5.8% and 0.0%, respectively. Adjusted OR for survival with early LUCAS vs. manual CPR was 1.47 after adjustment for other variables (p = 0.026).

CONCLUSION

This study showed a survival benefit with LUCAS CPR as compared to manual CPR only, when the device was applied early on-site.

Military application of mechanical CPR devices: a pressing requirement?

Maintaining high-quality chest compressions during cardiopulmonary resuscitation following cardiac arrest presents a challenge. The currently available mechanical CPR (mCPR) devices are described in this review, coupled with an analysis of the evidence pertaining to their efficacy. Overall, mCPR appears to be at least equivalent to high-quality manual CPR in large trials. There is potential utility for mCPR devices in the military context to ensure uninterrupted quality CPR following a medical cardiac arrest. Particular utility may be in a prohibitive operational environment, where manpower is limited or where timelines to definitive care are stretched resulting in a requirement for prolonged resuscitation. mCPR can also act as a bridge to advanced endovascular resuscitation techniques should they become more mainstream therapy.

Prehospital randomised assessment of a mechanical compression device in out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised trial and economic evaluation

BACKGROUND

Mechanical chest compression devices may help to maintain high-quality cardiopulmonary resuscitation (CPR), but little evidence exists for their effectiveness. We evaluated whether or not the introduction of Lund University Cardiopulmonary Assistance System-2 (LUCAS-2; Jolife AB, Lund, Sweden) mechanical CPR into front-line emergency response vehicles would improve survival from out-of-hospital cardiac arrest (OHCA).

OBJECTIVE

Evaluation of the LUCAS-2 device as a routine ambulance service treatment for OHCA.

DESIGN

Pragmatic, cluster randomised trial including adults with non-traumatic OHCA. Ambulance dispatch staff and those collecting the primary outcome were blind to treatment allocation. Blinding of the ambulance staff who delivered the interventions and reported initial response to treatment was not possible. We also conducted a health economic evaluation and a systematic review of all trials of out-of-hospital mechanical chest compression.

SETTING

Four UK ambulance services (West Midlands, North East England, Wales and South Central), comprising 91 urban and semiurban ambulance stations. Clusters were ambulance service vehicles, which were randomly assigned (approximately 1 : 2) to the LUCAS-2 device or manual CPR.

PARTICIPANTS

Patients were included if they were in cardiac arrest in the out-of-hospital environment. Exclusions were patients with cardiac arrest as a result of trauma, with known or clinically apparent pregnancy, or aged < 18 years.

INTERVENTIONS

Patients received LUCAS-2 mechanical chest compression or manual chest compressions according to the first trial vehicle to arrive on scene.

MAIN OUTCOME MEASURES

Survival at 30 days following cardiac arrest; survival without significant neurological impairment [Cerebral Performance Category (CPC) score of 1 or 2].

RESULTS

We enrolled 4471 eligible patients (1652 assigned to the LUCAS-2 device and 2819 assigned to control) between 15 April 2010 and 10 June 2013. A total of 985 (60%) patients in the LUCAS-2 group received mechanical chest compression and 11 (< 1%) patients in the control group received LUCAS-2. In the intention-to-treat analysis, 30-day survival was similar in the LUCAS-2 (104/1652, 6.3%) and manual CPR groups [193/2819, 6.8%; adjusted odds ratio (OR) 0.86, 95% confidence interval (CI) 0.64 to 1.15]. Survival with a CPC score of 1 or 2 may have been worse in the LUCAS-2 group (adjusted OR 0.72, 95% CI 0.52 to 0.99). No serious adverse events were noted. The systematic review found no evidence of a survival advantage if mechanical chest compression was used. The health economic analysis showed that LUCAS-2 was dominated by manual chest compression.

LIMITATIONS

There was substantial non-compliance in the LUCAS-2 arm. For 272 out of 1652 patients (16.5%), mechanical chest compression was not used for reasons that would not occur in clinical practice. We addressed this issue by using complier average causal effect analyses. We attempted to measure CPR quality during the resuscitation attempts of trial participants, but were unable to do so.

CONCLUSIONS

There was no evidence of improvement in 30-day survival with LUCAS-2 compared with manual compressions. Our systematic review of recent randomised trials did not suggest that survival or survival without significant disability may be improved by the use of mechanical chest compression.

FUTURE WORK

The use of mechanical chest compression for in-hospital cardiac arrest, and in specific circumstances (e.g. transport), has not yet been evaluated.

TRIAI REGISTRATION

Current Controlled Trials ISRCTN08233942.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 11. See the NIHR Journals Library website for further project information.

Corpuls CPR Generates Higher Mean Arterial Pressure Than LUCAS II in a Pig Model of Cardiac Arrest

According to the European Resuscitation Council guidelines, the use of mechanical chest compression devices is a reasonable alternative in situations where manual chest compression is impractical or compromises provider safety. The aim of this study is to compare the performance of a recently developed chest compression device (Corpuls CPR) with an established system (LUCAS II) in a pig model. Methods. Pigs (n = 5/group) in provoked ventricular fibrillation were left untreated for 5 minutes, after which 15 min of cardiopulmonary resuscitation was performed with chest compressions. After 15 min, defibrillation was performed every 2 min if necessary, and up to 3 doses of adrenaline were given. If there was no return of spontaneous circulation after 25 min, the experiment was terminated. Coronary perfusion pressure, carotid blood flow, end-expiratory CO₂, regional oxygen saturation by near infrared spectroscopy, blood gas, and local organ perfusion with fluorescent labelled microspheres were measured at baseline and during resuscitation. Results. Animals treated with Corpuls CPR had significantly higher mean arterial pressures during resuscitation, along with a detectable trend of greater carotid blood flow and organ perfusion. Conclusion. Chest compressions with the Corpuls CPR device generated significantly higher mean arterial pressures than compressions performed with the LUCAS II device.

Mechanical Cardiopulmonary Resuscitation Device in an Accident and Emergency Department: A Case Report and Literature Review

We present a case of resuscitation of a 38-year-old lady with ventricular fibrillation using the Lund University Cardiopulmonary Assist System (LUCAS), a mechanical cardiopulmonary resuscitation (CPR) device. Return of spontaneous circulation was obtained after prolonged resuscitation but the patient eventually succumbed nine days after admission to the coronary care unit. The role of mechanical CPR devices in resuscitation in the accident and emergency department is discussed.

Life-Threatening and Suspicious Lesions Caused by Mechanical Cardiopulmonary Resuscitation

Chest compression devices for mechanical cardiopulmonary resuscitation (CPR) have become more common. Here, we report the case of a young woman who attempted resuscitated with LUCAS™2 after she was found unconscious at home. At autopsy, we found extensive intramuscular hemorrhages in posterior neck, between the scapulae, and in the lumbar region. Investigation of internal organs showed injuries to the lung, spleen, and kidney. The extension of the injuries gave rise to suspicion of homicide by smothering, which police investigation subsequently did not support. The pattern of injury could be attributed to automatic compression decompression CPR with LUCAS™2.The injuries may have been lethal had the patient survived. For the forensic pathologists, it is important to remain updated on developments in treatment techniques to avoid pitfalls when interpreting injury.Larger studies, prospective or retrospective, may be able to qualify the possible risks of automatic compression decompression CPR even further.

The Efficacy of LUCAS in Prehospital Cardiac Arrest Scenarios: A Crossover Mannequin Study

Introduction

High-quality cardiopulmonary resuscitation (CPR) is critical for successful cardiac arrest outcomes. Mechanical devices may improve CPR quality. We simulated a prehospital cardiac arrest, including patient transport, and compared the performance of the LUCAS™ device, a mechanical chest compression-decompression system, to manual CPR. We hypothesized that because of the movement involved in transporting the patient, LUCAS would provide chest compressions more consistent with high-quality CPR guidelines.

Methods

We performed a crossover-controlled study in which a recording mannequin was placed on the second floor of a building. An emergency medical services (EMS) crew responded, defibrillated, and provided either manual or LUCAS CPR. The team transported the mannequin through hallways and down stairs to an ambulance and drove to the hospital with CPR in progress. Critical events were manually timed while the mannequin recorded data on compressions.

Results

Twenty-three EMS providers participated. Median time to defibrillation was not different for LUCAS compared to manual CPR (p=0.97). LUCAS had a lower median number of compressions per minute (112/min vs. 125/min; IQR = 102–128 and 102–126 respectively; p<0.002), which was more consistent with current American Heart Association CPR guidelines, and percent adequate compression rate (71% vs. 40%; IQR = 21–93 and 12–88 respectively; p<0.002). In addition, LUCAS had a higher percent adequate depth (52% vs. 36%; IQR = 25–64 and 29–39 respectively; p<0.007) and lower percent total hands-off time (15% vs. 20%; IQR = 10–22 and 15–27 respectively; p<0.005). LUCAS performed no differently than manual CPR in median compression release depth, percent fully released compressions, median time hands off, or percent correct hand position.

Conclusion

In our simulation, LUCAS had a higher rate of adequate compressions and decreased total hands-off time as compared to manual CPR. Chest compression quality may be better when using a mechanical device during patient movement in prehospital cardiac arrest patient.

Corpuls cpr resuscitation device generates superior emulated flows and pressures than LUCAS II in a mechanical thorax model

The provision of sufficient chest compression is among the most important factors influencing patient survival during cardiopulmonary resuscitation (CPR). One approach to optimize the quality of chest compressions is to use mechanical-resuscitation devices. The aim of this study was to compare a new device for chest compression (corpuls cpr) with an established device (LUCAS II). We used a mechanical thorax model consisting of a chest with variable stiffness and an integrated heart chamber which generated blood flow dependent on the compression depth and waveform. The method of blood-flow generation could be changed between direct cardiac-compression mode and thoracic-pump mode. Different chest-stiffness settings and compression modes were tested to generate various blood-flow profiles. Additionally, an endurance test at high stiffness was performed to measure overall performance and compression consistency. Both resuscitation machines were able to compress the model thorax with a frequency of 100/min and a depth of 5 cm, independent of the chosen chest stiffness. Both devices passed the endurance test without difficulty. The corpuls cpr device was able to generate about 10-40% more blood flow than the LUCAS II device, depending on the model settings. In most scenarios, the corpuls cpr device also generated a higher blood pressure than the LUCAS II. The peak compression forces during CPR were about 30% higher using the corpuls cpr device than with the LUCAS II. In this study, the corpuls cpr device had improved blood flow and pressure outcomes than the LUCAS II device. Further examination in an animal model is required to prove the findings of this preliminary study.

Development and validation of an improved mechanical thorax for simulating cardiopulmonary resuscitation with adjustable chest stiffness and simulated blood flow

Investigations of compressive frequency, duty cycle, or waveform during CPR are typically rooted in animal research or computer simulations. Our goal was to generate a mechanical model incorporating alternate stiffness settings and an integrated blood flow system, enabling defined, reproducible comparisons of CPR efficacy. Based on thoracic stiffness data measured in human cadavers, such a model was constructed using valve-controlled pneumatic pistons and an artificial heart. This model offers two realistic levels of chest elasticity, with a blood flow apparatus that reflects compressive depth and waveform changes. We conducted CPR at opposing levels of physiologic stiffness, using a LUCAS device, a motor-driven plunger, and a group of volunteers. In high-stiffness mode, blood flow generated by volunteers was significantly less after just 2min of CPR, whereas flow generated by LUCAS device was superior by comparison. Optimal blood flow was obtained via motor-driven plunger, with trapezoidal waveform.

The role of resuscitative endovascular balloon occlusion of the aorta (REBOA) as an adjunct to ACLS in non-traumatic cardiac arrest

Non-traumatic cardiac arrest is a major public health problem that carries an extremely high mortality rate. If we hope to increase the survivability of this condition, it is imperative that alternative methods of treatment are given due consideration. Balloon occlusion of the aorta can be used as a method of circulatory support in the critically ill patient. Intra-aortic balloon pumps have been used to temporize patients in cardiogenic shock for decades. More recently, resuscitative endovascular balloon occlusion of the aorta (REBOA) has been utilized in the patient in hemorrhagic shock or cardiac arrest secondary to trauma. Aortic occlusion in non-traumatic cardiac arrest has the effect of reducing the vascular volume that the generated cardiac output is distributed across. This augments myocardial and cerebral perfusion, increasing the probability of a return to a good quality of life for the patient. This phenomenon has been the subject of numerous animal studies dating back to the early 1980s; however, the human evidence is limited to several small case series. Animal research has demonstrated improvements in cerebral and coronary perfusion pressure during ACLS that lead to statistically significant differences in mortality. Several case series in humans have replicated these findings, suggesting the efficacy of this procedure. The objectives of this review are to: 1) introduce the reader to REBOA 2) review the physiology of NTCA and examine the current limitations of traditional ACLS 3) summarize the literature regarding the efficacy and feasibility of aortic balloon occlusion to support traditional ACLS.

Thoracic Spine Fracture in a Survivor of Out-of-Hospital Cardiac Arrest with Mechanical CPR

This is a report of a thoracic vertebral fracture in a 79-year-old male survivor of out-of-hospital cardiac arrest with chest compressions provided by a LUCAS 2 (Physio-Control Inc.; Lund Sweden) device. This is the first such report in the literature of a vertebral fracture being noted in a survivor of cardiac arrest where an automated compression device was used. Marshall RT , Kotecha H , Chiba T , Tennyson J . Thoracic spine fracture in a survivor of out-of-hospital cardiac arrest with mechanical CPR. Prehosp Disaster Med. 2016;31(6):684-686.

Cardiopulmonary Resuscitation Pattern Evaluation Based on Ensemble Empirical Mode Decomposition Filter via Nonlinear Approaches

Good quality cardiopulmonary resuscitation (CPR) is the mainstay of treatment for managing patients with out-of-hospital cardiac arrest (OHCA). Assessment of the quality of the CPR delivered is now possible through the electrocardiography (ECG) signal that can be collected by an automated external defibrillator (AED). This study evaluates a nonlinear approximation of the CPR given to the asystole patients. The raw ECG signal is filtered using ensemble empirical mode decomposition (EEMD), and the CPR-related intrinsic mode functions (IMF) are chosen to be evaluated. In addition, sample entropy (SE), complexity index (CI), and detrended fluctuation algorithm (DFA) are collated and statistical analysis is performed using ANOVA. The primary outcome measure assessed is the patient survival rate after two hours. CPR pattern of 951 asystole patients was analyzed for quality of CPR delivered. There was no significant difference observed in the CPR-related IMFs peak-to-peak interval analysis for patients who are younger or older than 60 years of age, similarly to the amplitude difference evaluation for SE and DFA. However, there is a difference noted for the CI (p < 0.05). The results show that patients group younger than 60 years have higher survival rate with high complexity of the CPR-IMFs amplitude differences.

Mechanical chest compression devices are associated with poor neurological survival in a statewide registry: A propensity score analysis

OBJECTIVE

To compare functional survival (discharge cerebral performance category 1 or 2) among victims of out-of-hospital cardiac arrest (OHCA) who had resuscitations performed using mechanical chest compression (mech-CC) devices vs. those using manual chest compressions (man-CC).

METHODS

Observational cohort of 2600 cases of OHCA from a statewide, prospectively-collected cardiac arrest registry (Utah Cardiac Arrest Registry to Enhance Survival). Comparison of functional survival among those receiving mech-CC vs man-CC was performed using a mixed-effects Poisson model with inverse probability weighted propensity scores to control for selection bias.

RESULTS

Overall, mech-CC was utilized in 405/2600 (16%) of the total arrests in Utah during this period. 371/405 (92%) were of the load-distributing band type (AutoPulse(®)) and 22/405 (5%) were mechanical piston devices (LUCAS™), while 12/405 (3%) employed other devices. The relative risk (RR) for functional survival comparing mech-CC to man-CC after propensity score adjustment was 0.41 (95% CI 0.24-0.70, p=0.001).

CONCLUSIONS

Mechanical chest compression device use was associated with lower rates of functional survival in this propensity score analysis, controlling for Utstein variables and early return of spontaneous circulation.

Combination of chest compressions and interposed abdominal compressions in a swine model of ventricular fibrillation

PURPOSE

The aim of this study was to investigate the effects of the combination of chest compressions and interposed abdominal compressions (IAC-CPR) in a swine model of ventricular fibrillation (VF).

METHODS

Twenty healthy female Landrace-Large White pigs were the study subjects. At the end of the eighth minute of VF, animals in the control group (Group A) received chest compressions at a rate of 100/min, while animals in the experimental group received chest compressions and simultaneous interposed abdominal compressions (CC-IAC - Group B), both at a rate of 100/min. The primary end point of the experiment was return of spontaneous circulation (ROSC). Secondary outcomes were 48-h survival rate and 48-h neurologic outcome.

RESULTS

Six animals (60%) from Group A and 9 animals (90%) from Group B achieved ROSC (P=.121). There was a statistically significant difference in systolic aortic pressure, mean aortic pressure, right atrial pressures, and end-tidal carbon dioxide (ETCO2) between the two groups during the first cycle of CPR, while during the second cycle, diastolic aortic pressure was significantly higher in Group B. Coronary perfusion pressure (CPP) values in group B were significantly higher compared with those in Group A during the first and second cycle of CPR. Neurologic examination was statistically significantly better in Group B (75.00±10.00 vs. 90.00±10.00, P=.037).

CONCLUSION

ROSC did not differ statistically significant in the IAC-CPR compared to the CPR group only, while CPP was significantly higher in IAC-CPR-treated animals.

LUCAS(™)2 in Danish Search and Rescue Helicopters

OBJECTIVE

Prehospital resuscitation is often challenging. Giving uninterrupted and effective compressions is relatively impossible during transportation. In 2012, The Royal Danish Air Force received a donation of 8 mechanical chest compression devices (LUCAS(™)2; Physio-Control/Jolife AB, Lund, Sweden) to be used onboard the Danish search and rescue (SAR) helicopters. The scope of this investigation was to establish whether or not mechanical chest compression devices should be considered a necessity onboard the Danish SAR helicopters.

METHODS

Data were compiled from SAR medical journals. From the data collected, observations were made as to when LUCAS(™)2 was used and what diagnosis the SAR physician made.

RESULTS

One thousand ninety missions were registered in the 24-month research period, and LUCAS(™)2 was used in 25 missions. Cardiac emergencies amounted for 25% of the missions.

CONCLUSION

The Danish SAR helicopters retrieved 33 drowned/hypothermic patients during the research period, and the LUCAS(™)2 was used in 11 of the patients requiring resuscitation. The LUCAS(™)2 was frequently used during other emergencies like sudden cardiac arrest. Cardiac emergencies were the predominant type of mission. LUCAS(™)2 is now considered mandatory on Danish SAR helicopters.