Mechanical Chest Compression Devices - A Narrative Review

The delivery of high-quality manual chest compressions is rarely achieved in practice. Mechanical chest compression devices can consistently deliver high-quality chest compressions. The recent publication of large prehospital trials of these devices provides important new information about the role of these devices. The Circulation Improving Resuscitation Care (CIRC), LUCAS in cardiac arrest (LINC) and Prehospital Randomized Assessment of a Mechanical Compression Device (PARAMEDIC) trials have recently been published. All these large prehospital trials found that the routine use of mechanical compression devices in the prehospital setting did not improve survival rates compared to those observed with manual chest compressions. There remain limited data on the routine use of devices during in-hospital cardiac arrest. Observational studies report favourable outcomes with the use of mechanical devices in special circumstances, including as a bridge to advanced therapies such as extracorporeal membrane oxygenation. Mechanical cardiopulmonary resuscitation (CPR) results in similar survival rates to manual CPR in out of hospital cardiac arrest. There are insufficient data to support or refute the routine use of mechanical CPR devices during in-hospital cardiac arrest. Observational studies demonstrate the feasibility of using mechanical CPR when manual CPR is difficult or impossible, and as a bridge to advanced therapies.

Resuscitation highlights in 2011

Mechanical chest compression devices have the potential to help maintain high-quality cardiopulmonary resuscitation (CPR), but despite their increasing use, little evidence exists for their effectiveness. We aimed to study whether the introduction of LUCAS-2 mechanical CPR into front-line emergency response vehicles would improve survival from out-of-hospital cardiac arrest. The pre-hospital randomised assessment of a mechanical compression device in cardiac arrest (PARAMEDIC) trial was a pragmatic, cluster-randomised open-label trial including adults with non-traumatic, out-of-hospital cardiac arrest from four UK Ambulance Services (West Midlands, North East England, Wales, South Central). 91 urban and semi-urban ambulance stations were selected for participation. Clusters were ambulance service vehicles, which were randomly assigned (1:2) to LUCAS-2 or manual CPR. Patients received LUCAS-2 mechanical chest compression or manual chest compressions according to the first trial vehicle to arrive on scene. The primary outcome was survival at 30 days following cardiac arrest and was analysed by intention to treat. Ambulance dispatch staff and those collecting the primary outcome were masked to treatment allocation. Masking of the ambulance staff who delivered the interventions and reported initial response to treatment was not possible. The study is registered with Current Controlled Trials, number ISRCTN08233942. We enrolled 4471 eligible patients (1652 assigned to the LUCAS-2 group, 2819 assigned to the control group) between April 15, 2010 and June 10, 2013. 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 group (104 [6%] of 1652 patients) and in the manual CPR group (193 [7%] of 2819 patients; adjusted odds ratio [OR] 0·86, 95% CI 0·64-1·15). No serious adverse events were noted. Seven clinical adverse events were reported in the LUCAS-2 group (three patients with chest bruising, two with chest lacerations, and two with blood in mouth). 15 device incidents occurred during operational use. No adverse or serious adverse events were reported in the manual group. We noted no evidence of improvement in 30 day survival with LUCAS-2 compared with manual compressions. On the basis of ours and other recent randomised trials, widespread adoption of mechanical CPR devices for routine use does not improve survival. National Institute for Health Research HTA - 07/37/69.

CPR PRO® Device Reduces Rescuer Fatigue during Continuous Chest Compression Cardiopulmonary Resuscitation: A Randomized Crossover Trial Using a Manikin Model

Quality between mechanical compression on reducible stretcher versus manual compression on standard stretcher in small elevator

Quality of cardiopulmonary resuscitation before and during transport in out-of-hospital cardiac arrest

Chest compression (CC) is a significant emergency medical procedure for maintaining circulation during cardiac arrest. Although CC produces the necessary blood flow for patients with heart arrest, improperly deep CC will contribute significantly to the risk of chest injury. In this paper, an optimal CC closed-loop controller for a mechanical chest compressor (OCC-MCC) was developed to provide an effective trade-off between the benefit of improved blood perfusion and the risk of ribs fracture. The trade-off performance of the OCC-MCC during real automatic mechanical CCs was evaluated by comparing the OCC-MCC and the traditional mechanical CC method (TMCM) with a human circulation hardware model based on hardware simulations. A benefit factor (BF), risk factor (RF) and benefit versus risk index (BRI) were introduced in this paper for the comprehensive evaluation of risk and benefit. The OCC-MCC was developed using the LabVIEW control platform and the mechanical chest compressor (MCC) controller. PID control is also employed by MCC for effective compression depth regulation. In addition, the physiological parameters model for MCC was built based on a digital signal processor for hardware simulations. A comparison between the OCC-MCC and TMCM was then performed based on the simulation test platform which is composed of the MCC, LabVIEW control platform, physiological parameters model for MCC and the manikin. Compared with the TMCM, the OCC-MCC obtained a better trade-off and a higher BRI in seven out of a total of nine cases. With a higher mean value of cardiac output (1.35L/min) and partial pressure of end-tidal CO2 (15.7mmHg), the OCC-MCC obtained a larger blood flow and higher BF than TMCM (5.19 vs. 3.41) in six out of a total of nine cases. Although it is relatively difficult to maintain a stable CC depth when the chest is stiff, the OCC-MCC is still superior to the TMCM for performing safe and effective CC during CPR. The OCC-MCC is superior to the TMCM in performing safe and effective CC during CPR and can be incorporated into the current version of mechanical CC devices for high quality CPR, in both in-hospital and out-of-hospital CPR settings.

<b>Background:</b> Nutritional disorders still represent a major problem faced by developing countries. Surveying such problems is a step towards planning proper interventions, which contributes significantly to declines in under-five mortality rates. <b>Aims:</b> To study the state of nutritional trends in children under five years of age, attending a primary healthcare center in Al Shoula district, Iraq, in 2006 and 2012. Demographic features and feeding practices that may have had an effect on the nutritional status of children were also studied. <b>Subjects and methods:</b> Two cross-sectional surveys were conducted on children aged two to five years, in a primary healthcare center in Baghdad. Children attending for immunization were included (500 in 2006 and 570 in 2012), their mothers were interviewed, and the body mass index of the child was calculated. Children who were overweight and obese were identified, according to the Centers for Disease Control and Prevention charts, as those suffering from stunting. Nutritional parameters were compared between the two study groups, using the chi-square test, as well as various epidemiological factors that may have affected the outcomes. <b>Results:</b> The prevalence of both types of nutritional disorders (stunting and overweight and obesity) declined remarkably according to the 2012 survey; overweight and obesity declined from 20% to 7.2%, while stunting decreased from 51.2% to 30.9%. The age group showing the highest rate of improvement were the four to five year olds, as well as children from lower-income families. A higher rate of breastfeeding was reported in 2012, and breastfed babies suffered the least from both types of nutritional disorders, in both study groups. Overall, the study findings showed a high prevalence of stunting (30.9%), together with a significant level of overweight and obesity (7.2%). <b>Conclusion:</b> Children in Iraq suffer from high rates of stunting. With a moderately high rate of obesity, there is an urgent need to evaluate local data available and plan for an active intervention to combat these nutritional problems.

Chest compression quality during cardiopulmonary resuscitation (CPR) is defined by adequate rate and depth, with complete chest recoil. Other metrics are duty cycle, or the recently introduced release velocity. However, the relationship between metrics is not sufficiently understood. Our aim was to design and validate tools for the automated annotation and analysis of compression metrics during manual CPR in a simulated manikin setting. Eleven volunteers delivered chest compressions on a manikin equipped with a distance sensor to measure chest displacement. Compression depth signal was acquired during 2-min sessions, with different chest stiffness and target compression rates. The annotated metrics for each compression were: compression and decompression duration (T c , T d ), compression depth (d p ), duty cycle (DC), compression velocity (CV), and release velocity (RV). We annotated 31451 compressions in 132 recordings, and analyzed the distributions of the annotated metrics: d p decreased with increasing rate and stiffness. DC, CV and RV increased with rate, and differed with stiffness. CV and RV showed a strong linear correlation with the ratio dp/T c and dp/Td, respectively. The study provided a reliable framework for the characterization of chest compressions during manual CPR, and could be extended to human data.

Extracorporeal Cardiopulmonary Resuscitation: Prehospital or In-Hospital Cannulation?

The goal of this study was to evaluate the utility of extracorporeal membrane oxygenation (ECMO) to resuscitate patients following critical cardiac events in the catheterization laboratory. Retrospective review of medical records. Cardiac intensive care unit and cardiac catheterization laboratory at a tertiary care children's hospital. Pediatric patients cannulated emergently for ECMO in the cardiac catheterization laboratory (n = 22). ECMO was initiated emergently in the cardiac catheterization laboratory for progressive hemodynamic deterioration due to low cardiac output syndrome or catheter-induced complications. Twenty-two patients were cannulated for ECMO in the catheterization laboratory between 1996 and 2004. Median age was 33 months (range 0-192), median weight 14.8 kg (2.4-75), and median duration of ECMO 84 hrs (2-343). Indications included catheter-induced complication (n = 14), severe low cardiac output syndrome (n = 7), and hypoxemia (n = 1). Three patients (14%) were cannulated in the catheterization laboratory before catheterization for low cardiac output or hypoxemia. During cannulation, 19 patients (86%) were receiving chest compressions; median duration of cardiopulmonary resuscitation was 29 mins (20-57). Eighteen patients (82%) survived to discharge (five of whom underwent cardiac transplantation) and four (18%) died. Of 19 patients who received cardiopulmonary resuscitation during cannulation, 15 (79%) survived to discharge and nine (47%) sustained neurologic injury. There was no significant difference between survivors and nonsurvivors in age, weight, duration of cardiopulmonary resuscitation or ECMO support, pH, or lactate levels. ECMO is a technically feasible and highly successful tool in the resuscitation of pediatric patients following critical events in the cardiac catheterization laboratory.

Funding Acknowledgements Type of funding sources: None. Background Despite the increase of extracorporeal membrane oxygenation (ECMO) employment around the globe over the last decades, studies describing the emergency use of venoarterial (VA)-ECMO in the cardiac catheterization laboratory (CCL) are scarce. Purpose The aim of this study was to describe the patient population that received ECMO in the CCL of a tertiary care center and the associated complications and outcomes. Methods In this single-center retrospective study we reviewed the baseline clinical and laboratory characteristics, indications and outcomes of adult patients, who received VA-ECMO between 2011 and 2019. Results In the given time period, ECMO use in the CCL increased drastically. Mean age of the 83 patients was 58.3 ± 12.5 years, 78.3% were male. From 2011 to 2018 ECMO-use in the CCL increased drastically. The most common indication for ECMO implantation was cardiac arrest (66%), followed by cardiogenic shock (12%), high-risk PCI (11%), and procedure-related complications (10%). While 30-day mortality in the total study population was 69%, it varied greatly depending on the underlying indication for ECMO therapy (cardiac arrest 78%, cardiogenic shock 20%, high-risk PCI 44%, procedure-related complications 88%). The most commonly occurring complications were acute kidney injury (20%) and cannula site bleeding (20%), followed by extremity complications (19%), sepsis (18%), major bleeding (10%) and stroke (8%). Of interest, patients receiving ECMO therapy after in-hospital cardiac arrest showed greater survival rates (28.2%) as compared to patients after out of hospital cardiac arrest (18.2%; p=0.045). High serum lactate levels (p=0.018) and low baseline pH values (p=0.001) at baseline were associated with a significantly increased 30-day mortality after ECMO implantation. Conclusion The emergency use of VA-ECMO in the CCL increased over the last years and was associated with a high 30-day mortality in our study population. Still, a &amp;gt;20% survival rate in the group of patients with refractory cardiac arrest, an otherwise futile situation, suggests that VA-ECMO implantation is reasonable in selected patients. As high admission serum lactate levels and the baseline pH are strong predictors of outcome, such parameters may be used to guide decision making.

Neuromonitoring of Neonatal Extracorporeal Membrane Oxygenation Patients Using Serial Cranial Ultrasounds*

THERE WAS A TIME NOT LONG AGO WHEN THE QUALity and quantity of chest compressions did not seem that important during resuscitation—at least not in comparison with early defibrillation. A ventricular tachyarrhythmia is the initiating event in more than 80% of patients who develop out-of-hospital, primary cardiac arrest during ambulatory electrocardiographic monitoring. Survival declines rapidly if defibrillation is not performed in the first few minutes (defibrillation phase) because myocardial adenosine triphosphate (ATP) levels begin to decrease as fibrillating myocardial cells continue to consume ATP at a nearly normal rate. As a result, ventricular fibrillation (VF) is the presenting rhythm in only 22% to 35% of out-of-hospital cardiac arrest cases when emergency medical services (EMS) personnel arrive on scene. By this time, myocardial ATP stores have often declined to critical levels and a defibrillation shock will usually terminate VF but frequently results in either asystole or pulseless electrical activity as cells run out of high-energy phosphate “fuel.” During this circulatory phase, a brief period of effective chest compression before defibrillation can boost myocardial ATP stores and increase the likelihood that a perfusing rhythm will follow defibrillation. Thus, the strategy for resuscitation from cardiac arrest has evolved from “shock first and often” to a time-critical, orchestrated approach of high-quality cardiopulmonary resuscitation (CPR), defibrillation, and postresuscitation care. This new approach highlights the importance of highquality, minimally interrupted chest compressions to maximize tissue oxygen delivery and intracellular high-energy phosphate levels. Conventional, closed-chest CPR is at best imperfect, producing hemodynamic change similar to that observed in cardiogenic shock. Minimal interruption of chest compression helps to maximize tissue oxygen delivery and, hence, myocardial high-energy phosphate levels. Aufderheide et al showed that both high-quality chest compression (adequate depth, force, and duration) and complete chest wall decompression are needed to maximize stroke volume and improve venous filling during the upstroke, respectively. The odds of survival from cardiac arrest increase when continuous, or nearly continuous, high-quality chest compressions are performed during resuscitation. Abella et al used a monitor/defibrillator with additional sensing capabilities to measure CPR quality (chest compression rate and depth, ventilation rate, and the fraction of cardiac arrest time without chest compressions) during resuscitation in 67 patients who experienced in-hospital cardiac arrest. The authors found that the quality of chest compression was inconsistent and often did not meet published guideline recommendations, even when performed by well-trained hospital staff. In a follow-up study, the same authors used a handheld recording device to measure chest compression rate as a surrogate for CPR quality in 3 different hospitals and found that higher chest compression rates correlated significantly with initial return of spontaneous circulation in 97 in-hospital patients with cardiac arrest. Thus, chest compression quantity and quality are critical determinants of survival from cardiac arrest. Positive pressure ventilation may not be necessary during the first few minutes of CPR because spontaneous agonal respirations often contribute to respiratory exchange of gases. Chest compression alone with a patent airway generates significant minute ventilation and the quantity of oxygen needed is reduced significantly during low blood flow states. Chandra et al assessed the time course of change in arterial blood gases during resuscitation in a canine experimental VF model and found that chest compression alone during CPR can maintain adequate gas exchange to sustain the oxygen saturation level above 90% for at least 4 minutes. Survival from out-of-hospital cardiac arrest is as good in humans when bystanders perform only chest compressions compared with when bystanders perform both chest compressions and mouth-to-mouth ventilation. In this issue of JAMA, Bobrow and colleagues provide an analysis based on a before and after comparison as well as a protocol compliance analysis of out-of-hospital

BackgroundThe effect of paramedic crew size in the resuscitation of patients with out-of-hospital cardiac arrest (OHCA) remains inconclusive. We hypothesised that teams with a larger crew size have better resuscitation performance including chest compression fraction (CCF), advanced life support (ALS), and teamwork performance than those with a smaller crew size.MethodsWe conducted a randomized controlled study in a simulation setting. A total of 140 paramedics from New Taipei City were obtained by stratified sampling and were randomly allocated to 35 teams with crew sizes of 2, 3, 4, 5, and 6 (i.e. 7 teams in every paramedic crew size). A scenario involving an OHCA patient who experienced ventricular fibrillation and was attached to a cardiopulmonary resuscitation (CPR) machine was simulated. The primary outcome was the overall CCF; the secondary outcomes were the CCF in manual CPR periods, time from the first dose of epinephrine until the accomplishment of intubation, and teamwork performance. Tasks affecting the hands-off time during CPR were also analysed.ResultsIn all 35 teams with crew sizes of 2, 3, 4, 5, and 6, the overall CCFs were 65.1%, 64.4%, 70.7%, 72.8%, and 71.5%, respectively (P = 0.148). Teams with a crew size of 5 (58.4%, 61.8%, 68.9%, 72.4%, and 68.7%, P<0.05) had higher CCF in manual CPR periods and better team dynamics. Time to the first dose of epinephrine was significantly shorter in teams with 4 paramedics, while time to completion of intubation was shortest in teams with 6 paramedics. Troubleshooting of M-CPR machine decreased the hands-off time during resuscitation (39 s), with teams comprising 2 paramedics having the longest hands-off time (63s).ConclusionLarger paramedic crew size (≧4 paramedics) did not significantly increase the overall CCF in OHCA resuscitation but showed higher CCF in manual CPR period before the setup of the CPR machine. A crew size of ≧4 paramedics can also shorten the time of ALS interventions, while teams with 5 paramedics will have the best teamwork performance. Paramedic teams with a smaller crew size should focus more on the quality of manual CPR, teamwork, and training how to troubleshoot a M-CPR machine.