Chest Compressions For Cardiac Arrest Research Articles

Manual mastery vs. mechanized magic: current opinions on manual vs. mechanical chest compressions.

Mechanical chest compression devices are increasingly deployed during cardiopulmonary resuscitation. We discuss the data supporting the use of mechanical chest compression devices during cardiac arrest and provide an opinion about the future of the technology. Multiple randomized trials investigating the use of mechanical chest compression devices for out-of-hospital cardiac arrest have not demonstrated improved outcomes. There is little prospective evidence to support the use of mechanical chest compression devices in other settings. Data from observational studies do not support the routine use of mechanical chest compression devices for in-hospital cardiac arrest, but there may be a role for mechanical chest compressions for cardiac arrest in procedural areas and cardiac arrest prior to cannulation for extracorporeal membrane oxygenation. Mechanical chest compression devices offer a solution to some of the human limiting factors of resuscitation, but have failed to demonstrate meaningful improvement in outcomes from cardiac arrest. Routine use of mechanical chest compression devices during cardiac arrest is not supported by evidence.

Under pressure – Association of the arm position and leading circulatory structure behind the pressure point in cardiopulmonary resuscitation patients

BackgroundThoracic computed tomography scans (CT) are used by several study groups to investigate the circulatory structures (heart and vessels) located behind the pressure point for chest compressions. Yet, it remains unclear how the positioning of these structures is influenced by factors such as intubation, the respiratory cycle and arm positioning. MethodsWe retrospectively analyzed data of adult patients with in- or out-of-hospital cardiac arrest who underwent thoracic CT imaging within one year before or up to six months after arrest. A region of interest (ROI) behind the pressure point was defined. The largest structure within this region was defined as “leading circulatory structure”, which was the primary outcome. Airway status (intubated versus spontaneous breathing), respiratory cycle (inspiration, expiration, resting expiratory position), and arm position (up over the head versus down beside the trunk) served as covariates in an ordinal regression model. ResultsAmong 500 initially screened patients, 411 (82.2 %) were included in the analysis. There was a significant association between the arm position and the leading circulatory structure behind the pressure point. However, no association was found with airway status or respiratory cycle. The most frequently identified leading circulatory structure was the left atrium (arms up: 41.8 %, down: 50.7 %), followed by the ascending aorta (up: 23.8 % vs. down: 16.7 %). The left ventricle was the leading structure in only one case (0.2 %, arms down). ConclusionThis study shows that arm position is significantly associated with the leading circulatory structure behind the pressure point for chest compressions in cardiac arrest.

Association of Pediatric Postcardiac Arrest Ventilation and Oxygenation with Survival Outcomes.

Rationale: Adult and pediatric studies provide conflicting data regarding whether post-cardiac arrest hypoxemia, hyperoxemia, hypercapnia, and/or hypocapnia are associated with worse outcomes. Objectives: We sought to determine whether postarrest hypoxemia or postarrest hyperoxemia is associated with lower rates of survival to hospital discharge, compared with postarrest normoxemia, and whether postarrest hypocapnia or hypercapnia is associated with lower rates of survival, compared with postarrest normocapnia. Methods: An embedded prospective observational study during a multicenter interventional cardiopulmonary resuscitation trial was conducted from 2016 to 2021. Patients ⩽18 years old and with a corrected gestational age of ≥37 weeks who received chest compressions for cardiac arrest in one of the 18 intensive care units were included. Exposures during the first 24 hours postarrest were hypoxemia, hyperoxemia, or normoxemia-defined as lowest arterial oxygen tension/pressure (PaO2) <60 mm Hg, highest PaO2 ⩾200 mm Hg, or every PaO2 60-199 mm Hg, respectively-and hypocapnia, hypercapnia, or normocapnia, defined as lowest arterial carbon dioxide tension/pressure (PaCO2) <30 mm Hg, highest PaCO2 ⩾50 mm Hg, or every PaCO2 30-49 mm Hg, respectively. Associations of oxygenation and carbon dioxide group with survival to hospital discharge were assessed using Poisson regression with robust error estimates. Results: The hypoxemia group was less likely to survive to hospital discharge, compared with the normoxemia group (adjusted relative risk [aRR] = 0.71; 95% confidence interval [CI] = 0.58-0.87), whereas survival in the hyperoxemia group did not differ from that in the normoxemia group (aRR = 1.0; 95% CI = 0.87-1.15). The hypercapnia group was less likely to survive to hospital discharge, compared with the normocapnia group (aRR = 0.74; 95% CI = 0.64-0.84), whereas survival in the hypocapnia group did not differ from that in the normocapnia group (aRR = 0.91; 95% CI = 0.74-1.12). Conclusions: Postarrest hypoxemia and hypercapnia were each associated with lower rates of survival to hospital discharge.

A Novel Anatomic Landmark to Target the Left Ventricle During Chest Compressions in Cardiac Arrest.

BackgroundResuscitation guidelines recommend that chest compressions be performed over the lower sternum. Current computed tomography and magnetic resonance imaging studies suggest that the current area of compression does not target the left ventricle (LV). Using transthoracic ultrasound, we sought to identify potential anatomic landmarks that would result in compressions over the LV in the majority of our study participants.MethodologyWe recruited 64 healthy men and women (over the age of 40) from the Simulated Patient Program at the University of Saskatchewan. Using ultrasound, we identified the LV and the associated surface anatomy in terms of intercostal space (ICS) and parasternal or mid-clavicular lines. We also collected biometric data including body mass index, chest circumference, and the corresponding inter-nipple line ICS.ResultsThe LV was located along the left sternal border in 62 (96.9%) participants. The most frequent LV location was along the left sternal border at the sixth ICS in 26 (40.6%) participants, with 13 (20.3%) at the fifth and 10 (15.6%) participants at the seventh ICS. In two (3.1%) participants, the LV was found along the mid-clavicular zone at the fifth ICS. The area from the fifth to seventh ICS on the left sternal border, typically covered by an adult palm centered at the sixth ICS, overlaid 49 of 64 (76.6%, 95% confidence interval [CI]: 64.3-86.2%) identified LV locations. By comparison, centering the heel of the palm over the inter-nipple line at the left sternal border would cover the LV in 46 (71.9%, 95% CI: 59.2-82.4%) participants. ConclusionsA novel area of compression over the left sternal border at the inter-nipple line would result in compressions over the LV in nearly three-quarters of our study participants. Future research should investigate whether this proposed area of compression is applicable to a broader population including those with cardiac and thoracic disease.

Airway management during in-hospital cardiac arrest: An international, multicentre, retrospective, observational cohort study

AimTo determine the type of airway devices used during in-hospital cardiac arrest (IHCA) resuscitation attempts. MethodsInternational multicentre retrospective observational study of in-patients aged over 18 years who received chest compressions for cardiac arrest from April 2016 to September 2018. Patients were identified from resuscitation registries and rapid response system databases. Data were collected through review of resuscitation records and hospital notes. Airway devices used during cardiac arrest were recorded as basic (adjuncts or bag–mask), or advanced, including supraglottic airway devices, tracheal tubes or tracheostomies. Descriptive statistics and multivariable regression modelling were used for data analysis. ResultsThe final analysis included 598 patients. No airway management occurred in 36 (6%), basic airway device use occurred at any time in 562 (94%), basic airway device use without an advanced airway device in 182 (30%), tracheal intubation in 301 (50%), supraglottic airway in 102 (17%), and tracheostomy in 1 (0.2%). There was significant variation in airway device use between centres. The intubation rate ranged between 21% and 90% while supraglottic airway use varied between 1% and 45%. The choice of tracheal intubation vs. supraglottic airway as the second advanced airway device was not associated with immediate survival from the resuscitation attempt (odds ratio 0.81; 95% confidence interval 0.35–1.8). ConclusionThere is wide variation in airway device use during resuscitation after IHCA. Only half of patients are intubated before return of spontaneous circulation and many are managed without an advanced airway. Further investigation is needed to determine optimal airway device management strategies during resuscitation following IHCA.

Efek Resusitasi Jantung Paru Menggunakan Mechanical Chest Compressions Terhadap Keselamatan Pasien Henti Jantung

Background: Cardiac arrest is the biggest cause of death. The number of patients who survived is low. Data in the UK shows only 7% of patients who survived. The key factor to increase the amount of survival is the quality of cadiopulmonary resuscitation (CPR). CPR that is done manually or by humans tends to be of inferior quality due to fatigue. Mechanical chest compressions use machines and pistons to compress the chest, so that the frequency and depth of chest compression quality for a long time. The purpose of this systematic review is to analyze research evidence of the effect CPR using mechanical chest compressions to survival cardiac arrest. Methods : Systematic review is used to analyze the effectiveness of mechanical chest compressions against cardiac arrest. The article is traced from the data base of science direct, pub med, and EBSCO with the main keywords are mechanical chest compressions and cardiac arrest. Search on google search using the keywords mechanical chest compressions for cardiac arrest. Researchers only take research in the form of randomized controlled trials (RCT), and there are no language restrictions. The interventions carried out were mechanical chest compressions, measured outcomes were survival cardiac arrest, and side effects of the action. The quality of the study was assessed using the critical appaisal skill program. Data was synthesized based on the implementer, the intervention carried out, the blinding process, the results, conclusions and side effects of the action. Results: Findings in the form of 4 articles with high quality. The entire article states there is no difference in survival cardiac arrest between mechanical chest compressions and manual chest compressions. Mechanical chest compressions have more adverse side effects than manual chest compressions. Conclusion: The results of a systematic review show that mechanical chest compressions are no better than manual chest compressions, so they are not recommended for use.

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

BackgroundTreating 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.MethodsIn 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.ResultsEighteen (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).ConclusionAortic 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.

Mechanical vs. Manual Chest Compressions for Cardiac Arrest.

Editor's note: This is a summary of a nursing care-related systematic review from the Cochrane Library. For more information, see http://nursingcare.cochrane.org.

Mechanical versus manual chest compressions for cardiac arrest.

Mechanical chest compression devices have been proposed to improve the effectiveness of cardiopulmonary resuscitation (CPR). 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. 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. 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. We used standard methodological procedures expected by Cochrane. 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. 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.

Continuous vs. Interrupted Chest Compressions for Cardiac Arrest.

Editor's note: This is a summary of a nursing care-related systematic review from the Cochrane Library. For more information, see http://nursingcare.cochrane.org.

The mechanism of blood flow during chest compressions for cardiac arrest is probably influenced by the patient's chest configuration.

AimMechanical assist devices are sometimes needed during resuscitation efforts of patients with prolonged cardiac arrest. Two such devices, the AutoPulse and the LUCAS, have different mechanisms of action. We propose that the effectiveness of mechanical assist devices is somewhat dependent on the configuration and compliance of the patient's chest wall.MethodsA previous study of patients with out‐of‐hospital cardiac arrest in Arizona reported that survivors were younger and many were observed to have narrow anterior–posterior chest diameters. These observations suggest that the predominant mechanism of blood flow during cardiopulmonary resuscitation of individuals with primary cardiac arrest is influenced by the patient's anterior–posterior chest diameter and compliance. It is proposed that in older individuals with an increased anterior–posterior chest diameter and decreased chest compliance that the AutoPulse, which works by increasing intrathoracic pressures, may be more effective. In contrast, the LUCAS device, which works predominately by compression of the sternum, is probably more effective in patients with narrower anterior–posterior diameters and a more compliant chest.ResultsThese hypotheses need to be confirmed by researchers who not only have access to the lateral chest roentgenograms of patients with cardiac arrest, to determine their anterior–posterior chest diameter, but also to the type of mechanical device that was used during resuscitation efforts and their patient's survival. If the observations herein proposed are confirmed, hospitals and paramedics may ideally need to have one of each type of mechanical chest compression unit and select the one to use depending on the patient's age and anterior–posterior chest diameter.ConclusionsThe mechanism of blood flow in patients with cardiac arrest is predominantly secondary to cardiac compression in younger patients with narrow anterior chest diameters and predominately secondary to the thoracic pump mechanism in older patients with emphysema.

Mechanical chest compressions improve rate of return of spontaneous circulation and allow for initiation of percutaneous circulatory support during cardiac arrest in the cardiac catheterization laboratory

BackgroundPerforming advanced cardiac life support (ACLS) in the cardiac catheterization laboratory (CCL) is challenging. Mechanical chest compression (MCC) devices deliver compressions in a small space, allowing for simultaneous percutaneous coronary intervention and reduced radiation exposure to rescuers. In refractory cases, MCC devices allow rescuers to initiate percutaneous mechanical circulatory support (MCS) and extracorporeal life support (ECLS) during resuscitation. This study sought to assess the efficacy and safety of MCC when compared to manual compressions in the CCL. MethodsWe performed a retrospective analysis of patients who received ACLS in the CCL at our institution between May 2011 and February 2016. Baseline characteristics, resuscitation details, and outcomes were compared between patients who received manual and mechanical compressions. ResultsForty-three patients (67% male, mean age 58 years) required chest compressions for cardiac arrest while in the CCL (12 manual and 31 MCC). Patients receiving MCC were more likely to achieve return of spontaneous circulation (ROSC) (74% vs. 42%, p=0.05). Of those receiving MCC, twenty-two patients (71%) were treated with MCS. Patients receiving percutaneous ECLS were more likely to achieve ROSC (100% vs. 53%, p=0.003) and suffered no episodes of limb loss or TIMI major bleeding. There were no significant differences in 30-day survival or survival to hospital discharge between groups. ConclusionsUse of MCC during resuscitation of cardiac arrest in the CCL increases the rate of ROSC. Simultaneous implantation of MCS, including percutaneous ECLS, is feasible and safe during MCC-assisted resuscitation in the CCL.

Abstract 11888: Mechanical Circulatory Support Increases Return of Spontaneous Circulation in Patients Receiving Mechanical Chest Compressions for Cardiac Arrest in the Cardiac Catheterization Laboratory

Introduction: In the cardiac catheterization laboratory (CCL), use of a mechanical chest compression (MCC) device allows acute cardiac life support (ACLS) and percutaneous interventions to occur simultaneously. Use of MCC in the CCL ensures adequate chest compressions without relying on manual compression providers. This is especially important in the context of recent studies that have shown that therapies offered in the CCL increase survival in patients with cardiac arrest. Furthermore, mechanical circulatory support (MCS) has been shown to improve outcomes of patients with cardiac arrest, but it is not known whether emergent, percutaneous MCS initiation provides clinical efficacy in patients undergoing MCC-assisted ACLS in the CCL. Methods: We performed a retrospective analysis of patients who received MCC-assisted ACLS in the CCL at our institution between April 2014 and February 2016. Baseline characteristics, resuscitation characteristics, and clinical outcomes were compared between patients who were treated with MCS and those who were not. Unpaired two-sample t-tests were used to compare continuous variables. Fisher’s exact test was used to compare categorical variables. Results: Thirty-one patients received MCC-assisted ACLS in the CCL. Twenty-two patients (71%) were treated with MCS (14 external cardiac life support (ECLS), 3 Impella, 5 intra-aortic balloon pump (IABP)). Patients who received MCS were significantly more likely to achieve return of spontaneous circulation (ROSC) than those who did not receive MCS (95% v 22%, p = 0.00). Thirty-day survival was more common in the group receiving MCS (Table 1). The majority of patients who received MCS suffered cardiac arrest either outside the hospital or in the emergency department. Conclusions: The addition of percutaneous MCS to MCC-assisted ACLS increased the rate of ROSC. These findings support the use of emergent percutaneous MCS during MCC-assisted ACLS in the CCL.

Outcomes Similar With Interrupted and Continuous Chest Compressions in Cardiac Arrest

According to this study: * In patients treated by emergency medical services (EMS) providers for out-of-hospital cardiac arrest, rates of survival and favorable neurologic status were similar in those who received interrupted chest compressions and those who received continuous chest compressions. * An accompanying editorial suggests that, in light of these findings, the 2015 American Heart Association resuscitation guidelines for EMS providers may need to be revisited.

Carotid Doppler blood flow measurement during cardiopulmonary resuscitation is feasible: A first in man study

ObjectiveHigh quality chest compressions are the cornerstone of effective cardiopulmonary resuscitation (CPR). There is no available method of real time noninvasive hemodynamic measurement and feedback to inform rescuers of the efficacy of compressions. Ultrasound-based measures of blood flow may provide immediate, noninvasive hemodynamic information. Our objective was to determine the feasibility and safety of using ultrasound to measure blood flow on patients with cardiac arrest. MethodsStudy design This was a prospective cohort study in an emergency department setting. Subjects Included were patients receiving ongoing manual chest compressions for cardiac arrest. Excluded were those less than 18 years of age, incarcerated, pregnant, with neck injury, or obvious traumatic cause of arrest. Scan protocol Physicians recorded blood flow over the common carotid arteries during chest compressions with transverse and longitudinal color flow and Doppler using a portable ultrasound machine (CX30, Philips Healthcare., Andover, MA). Measurements Duration of scan time, and the median values for peak systolic (PSV), end-diastolic (EDV) and mean diastolic (MDV) carotid blood flow velocities were captured. Feasibility was defined as the proportion of eligible subjects upon whom ultrasound was initiated Safety was defined as availability of at least 5min of scanning time. ResultsNineteen patients (56% of eligible) where enrolled and had ultrasound measurements attempted during manual compressions. In one patient, scanning was not initiated because ongoing CPR efforts were terminated. Three patients were enrolled but had no images available for review. A total of 15 patients (78% of attempted) had ultrasound imaging saved. Most (n=10, 66%) had scanning times greater than 5min (median 5min 59s, interquartile range 3min 15s to 8min 25s), median PSV was 67cms−1 (IQR 55–106), median EDV was 18cms−1 (IQR 12–27), and median MDV was 14cms−1 (IQR 9–18). ConclusionsUltrasound measurement of common carotid artery blood flow during CPR is feasible. Further studies are necessary to correlate carotid blood flow to other hemodynamic measures and its effects on patient outcomes.

Mechanical versus manual chest compressions for cardiac arrest

This is the first update of the Cochrane review on mechanical chest compression devices published in 2011 (Brooks 2011). Mechanical chest compression devices have been proposed to improve the effectiveness of cardiopulmonary resuscitation (CPR). To assess the effectiveness of mechanical chest compressions versus standard manual chest compressions with respect to neurologically intact survival in patients who suffer cardiac arrest. We searched the Cochrane Central Register of Controlled Studies (CENTRAL; 2013, Issue 12), MEDLINE Ovid (1946 to 2013 January Week 1), EMBASE (1980 to 2013 January Week 2), Science Citation abstracts (1960 to 18 November 2009), Science Citation Index-Expanded (SCI-EXPANDED) (1970 to 11 January 2013) on Thomson Reuters Web of Science, biotechnology and bioengineering abstracts (1982 to 18 November 2009), conference proceedings Citation Index-Science (CPCI-S) (1990 to 11 January 2013) and clinicaltrials.gov (2 August 2013). We applied no language restrictions. Experts in the field of mechanical chest compression devices and manufacturers were contacted. 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 atraumatic cardiac arrest. Two review authors abstracted data independently; disagreement between review authors was resolved by consensus and by a third review author if consensus could not be reached. The methodologies of selected studies were evaluated by a single author for risk of bias. The primary outcome was survival to hospital discharge with good neurological outcome. We planned to use RevMan 5 (Version 5.2. The Nordic Cochrane Centre) and the DerSimonian & Laird method (random-effects model) to provide a pooled estimate for risk ratio (RR) with 95% confidence intervals (95% CIs), if data allowed. Two new studies were included in this update. Six trials in total, including data from 1166 participants, were included in the review. The overall quality of included studies was poor, and significant clinical heterogeneity was observed. Only one study (N = 767) reported survival to hospital discharge with good neurological function (defined as a Cerebral Performance Category score of one or two), demonstrating reduced survival with mechanical chest compressions when compared with manual chest compressions (RR 0.41, 95% CI 0.21 to 0.79). Data from four studies demonstrated increased return of spontaneous circulation, and data from two studies demonstrated increased survival to hospital admission with mechanical chest compressions as compared with manual chest compressions, but none of the individual estimates reached statistical significance. Marked clinical heterogeneity between studies precluded any pooled estimates of effect. Evidence from RCTs in humans is insufficient to conclude that mechanical chest compressions during cardiopulmonary resuscitation for cardiac arrest are associated with benefit or harm. Widespread use of mechanical devices for chest compressions during cardiac events is not supported by this review. More RCTs that measure and account for the CPR process in both arms are needed to clarify the potential benefit to be derived from this intervention.

Chest compressions may be safe in arresting patients with left ventricular assist devices (LVADs)

IntroductionThe number of patients with left ventricular assist devices (LVADs) is increasing each year. Despite a lack of evidence, many emergency medical systems and hospitals have recommended against performing chest compressions in these patients. This deviation from conventional resuscitation algorithms is secondary to concern that chest compressions could dislodge the LVAD. ObjectiveTo assess whether cannula dislodgment occurred in LVAD patients receiving chest compressions. MethodsWe retrospectively analyzed the outcomes of all LVAD patients who received chest compressions for cardiac arrest over a four year period in a large urban hospital. Eight cases were reviewed for both cannula integrity and outcomes. ResultsUsing autopsy and adequate flow through device as proxy for intact inflow/outflow cannulas, none of the eight patients receiving chest compressions had cannula dislodgment. Four of the 8 patients had return of neurologic function. ConclusionsIn this small retrospective case series, standard chest compressions in patients with LVADs did not cause cannula dislodgment. More research is necessary to determine the utility of chest compressions in the LVAD population.

Abstract 302: Chest Compressions Should Be Performed on Arresting Patients with Left Ventricular Assist Devices (LVAD)

Introduction: Patients with implanted Left ventricular assist devices (LVAD) are being assessed by an increasing number of health care providers. Despite a lack of evidence, many emergency medical systems and hospitals have discouraged providers from performing chest compressions in these patients when they present in cardiac arrest. This deviation from conventional resuscitation algorithms is secondary to concern that chest compressions could dislodge the LVAD. Objective: To determine the rate of cannula dislodgment for patients presenting in cardiac arrest with known implanted LVAD devices receiving standard chest compression cardiopulmonary resuscitation. Methods: We retrospectively analyzed the outcomes of all patients who received chest compressions for cardiac arrest over a 4 year period in a large urban hospital. Eight cases were reviewed for both cannula integrity and outcomes. Results: Using autopsy and adequate flow through device as proxy for intact inflow/outflow cannulas, none of the eight patients receiving chest compressions had cannula dislodgment. Four of the 8 patients had return of neurologic function. Two additional patients had return of effective circulation without return of neurologic function. One patient had documented flow on the device without return of native heart function. The final patient did not have documented flow during resuscitation but autopsy showed no dislodgment. Conclusions: In this small retrospective study, standard chest compressions in patients with LVADs appear to be safe, without evidence of cannula dislodgment. Standard chest compressions for LVAD patients in circulatory arrest should be performed.

Abstract 213: Changing Hand Position During Manual Chest Compressions in Cardiac Arrest Affects the Hemodynamic Response: A Clinical Pilot Study

Introduction: Optimal hand position during manual chest compressions (MCC) in cardiac arrest is unknown, but current Guidelines recommend a hand position on the lower half of the sternum. Recent imaging studies suggest that significant inter-individual anatomical differences exist, which might cause altered hemodynamic responses during standard MCC. In this prospective pilot study we wanted to assess the feasibility of utilizing capnography to optimize MCC and identify the optimal hand position in out-of-hospital cardiac arrest (OCHA). Materials and methods: Patients treated by the physician-manned ambulance for non-traumatic OCHA between February and May 2011 were included. Continuous EtCO 2 was measured by sidestream capnography (Lifepak 12, Physio Control, WA, USA). The three minute intervention period was initiated after endotracheal intubation. In the first minute chest compression rate and depth was optimized with hand-position at the recommended point (P0). A two-minute test phase followed; 50 compressions performed at three different sternal positions two cm below P0; P1 midline, P2 two cm to the left, P3 two cm to the right. The hand-position with the highest EtCO 2 value was used during the remaining resuscitation effort. EtCO 2 values are given as means (range), and presented in kPa (1 kPa = 7.5 mmHg). Results: Variations in EtCO 2 values could be documented in 15 OHCA patients. Average EtCO 2 values for 11 patients with cardiac etiology were 4.5 (1.9, 8.3), 5.3 (2.3, 9.6), 5.1 (2.4, 10.3), and 5.1 (2.5, 9.1) for P0 - P3, respectively, and for four non-cardiac etiology patients 4.8 (0.8, 9.7), 5.3 (0.8, 10.7), 5.8 (0.7, 10.3), and 5.1 (0.4, 8.4) for P0 - P3, respectively. The optimal EtCO 2 value was found in P0 in three patients, and in alternative hand positions in 12 patients, with the following distribution; P1: five patients, P2: five patients, P3: one patient, and in one patient P1, P2 and P3 was equally good. Conclusions: Monitoring and optimizing CPR performance and interventions using capnography was feasible. We could demonstrate inter-individual differences affecting hemodynamics, and there were no indications that one specific hand position could be expected to give optimal cardiac output in all patients.

Mechanical chest compressions with trapezoidal waveform improve haemodynamics during cardiac arrest

Background During manual chest compressions for cardiac arrest the waveforms of chest compressions are generally sinusoidal, whereas mechanical chest compression devices can have different waveforms, including trapezoidal. We studied the haemodynamic differences of such waveforms in a porcine model of cardiac arrest. Methods Eight domestic pigs (weight 31 ± 3 kg) were anaesthetised and instrumented to continuously monitor aortic (AP) and right atrial pressure (RAP), carotid (CF) and cerebral cortical microcirculation blood flow (CCF). Coronary perfusion pressure (CPP) was calculated as the maximal difference between AP and RAP during diastole or decompression phase. After 4 min of electrically induced ventricular fibrillation, mechanical chest compressions were performed with four different waveforms in a factorial design, and in randomized sequence for 3 min each. Resulting differences are presented as mean with 95% confidence intervals. Results Mean AP and RAP were higher with trapezoid than sinusoid chest compressions, difference 5.7 (0.7, 11) and 6.3 (2.1, 11) mmHg, respectively. Flow measured as CF and CCF was also improved with trapezoidal waveform, difference 14 (2.8, 26) ml/min and 11 (5.6, 17)% of baseline, respectively, with a parallel, non-significant ( P = 0.08) trend for CPP. Active vs. passive decompression to zero level improved CF, but without even a trend for CPP. Conclusion Trapezoid chest compressions and active decompression to zero level improved blood flow to the brain. The compression waveform is an additional factor to consider when comparing mechanical and manual chest compressions and when comparing different compression devices.