Automatic and manual mechanical external chest compression devices for cardiopulmonary resuscitation

Complication frequency of mechanical chest compression devices: A single-center, blinded study using retrospective data

Aim

Use of mechanical chest compression devices for patients with cardiac arrest is increasing. As cardiopulmonary resuscitation (CPR) guidelines and LUCAS are updated, the evidence requires updating.

Methods

This single-center, retrospective study observed adult patients with out-of-hospital cardiac arrest receiving CPR from emergency services. Patients were assigned to LUCAS or manual CPR groups, matched by propensity score, and evaluated through computed tomography images by a radiologist blinded to their data. The primary outcome was complications from chest compressions, and logistic regression was used to analyze their risk factors.

Results

Overall, 261 patients were selected and divided into manual and LUCAS groups (n = 69 each). The manual CPR group exhibited higher witnessed cardiac arrest percentages (p = 0.023) and shorter times from scene to emergency department (p = 0.001) and total CPR duration (p = 0.002), versus the LUCAS group. Complication rates showed no significant intergroup differences in overall CPR complications (p = 0.462); however, the LUCAS group reported more hemothorax incidents (p = 0.028), versus the manual group. Logistic regression indicated that female sex (odds ratio [OR] 3.743, 95 % confidence interval [CI] 1.333-10.506), older age (OR 1.089, 95 % CI 1.048-1.132), and longer CPR durations (OR 1.045, 95 % CI 1.006-1.085) significantly correlated with compression complications, whereas LUCAS use did not (OR 0.713, 95 % CI 0.304-1.673).

Conclusion

No association was observed between LUCAS use and the overall incidence of chest compression complications in adults with OHCA. LUCAS is associated with more hemothorax cases and longer transport time, versus manual CPR. Evaluating LUCAS's benefits necessitates multiple perspectives and further research.

What are ambulance crews' experiences of using a mechanical chest compression device for out-of-hospital resuscitation? A constructivist qualitative study utilising online focus groups

Introduction

Mechanical chest compression devices (MCCDs) provide chest compressions mechanically to a person in cardiac arrest. Those chest compressions would usually be provided manually. Previous studies into the use of MCCDs have focused on the quantitative outcomes, with little emphasis on the qualitative experiences of those using MCCDs.

Purpose

To collect and report ambulance crews' experiences of using MCCDs for out-of-hospital resuscitation attempts.

Methods

The philosophical approach was constructivist, the methodology qualitative and the data collection method online focus groups. Convenience sampling was used to recruit participants who met the inclusion criteria, which broadly were to have experience of using MCCDs for out-of-hospital resuscitation. There have been two types of MCCD used locally. Participants were included regardless of which type of device they had experience of. Similarly, participants were included whether they had active or passive experience of the devices. The focus groups were recorded, fully transcribed and then analysed using constant comparison.

Results

Four selective codes emerged. These were factors directly affecting ambulance crew members; practicalities of a resuscitation attempt; ambulance crew members' perceptions, experiences and thoughts; negatives of MCCDs.

Conclusion

The main perceptions arising from the participants' discussion in this work were that MCCD use could potentially provide psychological protection to ambulance crew members when reflecting on resuscitation attempts, and participants felt there is an overall reduction of cognitive load for ambulance crew members when using MCCDs for resuscitation attempts. There were particularly timely benefits expressed of MCCDs easing the physical fatigue of a resuscitation attempt when responding wearing personal protective equipment, as has been required during the COVID-19 pandemic. MCCDs were felt to be of benefit when transporting a patient in cardiac arrest but differences were expressed as to whether the LUCAS-2 in particular helps or hinders extrication of a patient.

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.

Monitoring cardiopulmonary resuscitation quality in emergency departments: a national survey in China on current knowledge, attitudes, and practices

BACKGROUND

To investigate current knowledge, attitudes, and practices for CPR quality control among emergency physicians in Chinese tertiary hospitals.

METHODS

Anonymous questionnaires were distributed to physicians in 75 tertiary hospitals in China between January and July 2018.

RESULTS

A total of 1405 respondents answered the survey without obvious logical errors. Only 54.4% respondents knew all criteria of high-quality CPR. A total of 91.0% of respondents considered CPR quality monitoring should be used, 72.4% knew the objective method for monitoring, and 63.2% always/often monitored CPR quality during actual resuscitation. The main problems during CPR were related to chest compression: low quality due to fatigue (67.3%), inappropriate depth (57.3%) and rate (54.1%). The use of recommended monitoring methods was reported as follows, ETCO2 was 42.7%, audio-visual feedback devices was 10.1%, coronary perfusion pressure was 17.9%, and invasive arterial pressure was 31.1%. A total of 96.3% of respondents considered it necessary to participate in regular CPR retraining, but 21.4% did not receive any retraining. The ideal retraining interval was considered to be 3 to 6 months, but the actual interval was 6 to 12 months. Only 49.7% of respondents reported that feedback devices were always/often used in CPR training.

CONCLUSION

Chinese emergency physicians were very concerned about CPR quality, but they did not fully understand the high-quality criteria and their impact on prognosis. CPR quality monitoring was not a routine procedure during actual resuscitation. The methods recommended in guidelines were rarely used in practice. Many physicians had not received retraining or received retraining at long intervals. Feedback devices were not commonly used in CPR training.

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/.

A novel mechanical chest compressor with rapid deployment in all population cardiopulmonary resuscitation

Cardiopulmonary resuscitation (CPR) resuscitates patients suffering from cardiac arrest. Mechanical chest compression CPR highlights the need for high CPR quality to facilitate survival and neurological recovery. However, current CPR devices cannot be used on pregnant women or infants. These devices’ long re-setup times interrupt CPR and can cause cerebral ischemia. This study designed a novel device with a crank-sliding mechanism. The polar coordinate system (r, θ, z) shortened the setup time and enabled adjustment without moving the patient. We compared our device with commercial products (e.g., LUCAS-2) by quantifying the compression pressure. Control groups for manual CPR of trained physicians and untrained citizens were recruited. We used Resusci Anne products as models. Our results indicated that our design exhibited performance similar to that of LUCAS-2 in adults (557.8 vs. 623.6 mmHg, p = 0.217) and met the current CPR standard guidelines. Notably, our device is applicable to pregnant women [565 vs. 564.5 (adults) mmHg, p = 0.987] and infants [570.8 vs. 564.5 (adults) mmHg, p = 0.801] without lowering the compression quality. The overall compression quality and stability of mechanical chest compression CPR were favorable to those of manual CPR. Our device provides an innovative prototype for the next generation of CPR facilities.

Load distributing band device for mechanical chest compressions: An Utstein-categories based analysis of survival to hospital discharge

PURPOSE

The role of load distributing band device (LDB, AutoPulse®, Zoll Medical Corporation, Chelmsford, MA, USA) in out-of-hospital cardiac arrest is still a matter of debate, with few studies reaching conflicting results available in literature. We sought to assess whether the use of the LBD device could affect survival to hospital discharge in the different Utstein categories.

MATERIALS AND METHODS

All consecutive patients enrolled in our provincial cardiac arrest registry (Pavia CARe) from January 2015 to December 2017 were included and pre-hospital data were computed as well as survival to hospital discharge.

RESULTS

Among 1401 resuscitation attempts, the LDB device was used in 235 (17%) patients. The LDB device was significantly more used for shockable cardiac arrest (42.6% vs 13.7%, p < 0.001). The rate of ROSC and of survival to hospital discharge in the LDB group compared to the manual group was 40% vs 17% (p < 0.001) and 10% vs 7% (p = 0.2), respectively. However, after correction for independent predictors of LDB use, LDB device was a strong independent predictor of survival to hospital discharge only for non-shockable witnessed OHCA [n = 624/1401, OR 11.9 (95% CI 1.5-95.2), p = 0.02]. In this categories of patients LDB group showed longer resuscitation time [49.3 min (IQR 37-71) vs 23.6 (IQR 15-35), p < 0.001] and a higher rate of conversion to a shockable rhythm (33/83 = 40% vs 29/541 = 5%, p < 0.001).

CONCLUSION

Utstein categories-based analysis showed that the LDB device positively affect survival to hospital discharge for non-shockable witnessed cardiac arrests with a neutral effect for shockable rhythms.

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.

Blood flow maintenance by cardiac massage during cardiopulmonary resuscitation: Classical theories, newer hypotheses, and clinical utility of mechanical devices

The mechanisms by which closed chest cardiac massage produces and maintains blood flow during cardiopulmonary resuscitation are still debated. To date, two main theories exist: the "cardiac pump", which assumes that blood flow is driven by direct cardiac compression and the "chest pump", which hypothesizes that blood flow is caused by changes in intrathoracic pressure. Newer hypotheses including the "atrial pump", the "lung pump", and the "respiratory pump" were also proposed. We reviewed studies supporting these different theories as well as the clinical evidences on the utility of mechanical devices proposed to optimize cardiopulmonary resuscitation, in view of their pathophysiological assumptions with regard to the underlying theory. On the basis of current evidence, a single theory is probably not sufficient to explain how cardiac massage produces blood flow. This suggests that different simultaneous mechanism might be involved. The relative importance of these mechanisms depends on several factors, including delay from collapse to starting of resuscitation, compression force and rate, body habitus, airway pressure, and presenting electrocardiogram. The complexity of the physiologic events occurring during cardiopulmonary resuscitation, together with the need of adequate training for a correct and prompt utilization of mechanical devices, might also partially explain the disappointing results of these devices in most clinical studies.

Update on mechanical cardiopulmonary resuscitation devices

PURPOSE OF REVIEW

The aim of this review is to update and discuss the use of mechanical chest compression devices in treatment of cardiac arrest.

RECENT FINDINGS

Three recently published large multicenter randomized trials have not been able to show any improved outcome in adult out-of-hospital cardiac arrest patients when compared with manual chest compressions.

SUMMARY

Mechanical chest compression devices have been developed to better deliver uninterrupted chest compressions of good quality. Prospective large randomized studies have not been able to prove a better outcome compared to manual chest compressions; however, latest guidelines support their use when high-quality manual chest compressions cannot be delivered. Mechanical chest compressions can also be preferred during transportation, in the cath-lab and as a bridge to more invasive support like extracorporeal membrane oxygenation.

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.

Chest compression duration influences outcome between integrated load-distributing band and manual CPR during cardiac arrest

BACKGROUND

The Circulation Improving Resuscitation Care (CIRC) Trial found equivalent survival in adult out-of-hospital cardiac arrest (OHCA) patients who received integrated load-distributing band CPR (iA-CPR) compared to manual CPR (M-CPR). We hypothesized that as chest compression duration increased, iA-CPR provided a survival benefit when compared to M-CPR.

METHODS

A pre-planned secondary analysis of OHCA of presumed cardiac etiology from the randomized CIRC trial. Chest compressions duration was defined as the total number of minutes spent on compressions during resuscitation and identified from transthoracic impedance and accelerometer data recorded by the EMS defibrillator. Logistic regression was used to model the interaction between treatment and duration of chest compressions and was covariate-adjusted for trial site, patient age, witnessed arrest, and initial shockable rhythm. Primary outcome was survival to hospital discharge.

RESULTS

We enrolled 4231 subjects and of those, 2012 iA-CPR and 2002 M-CPR had complete outcome and duration of chest compressions data. While covariate-adjusted odds ratio for survival to hospital discharge was 1.86 in favor of iA-CPR (95% CI 1.16-3.0), there was an interaction between duration and study arm. When this was factored into the multivariate equation, the odds ratio for survival to hospital discharge showed a significant benefit for iA-CPR vs. M-CPR for chest compression duration greater than 16.5 min.

CONCLUSION

After adjusting for compression duration and duration-treatment interaction, iA-CPR showed a significant benefit for survival to hospital discharge vs. M-CPR in patients with OHCA if chest compression duration was longer than 16.5 min.

Evaluation of Zoll Medical's ResQCPR System for cardiopulmonary resuscitation

Cardiac arrest remains a leading cause of death, currently affecting more than 250,000 Americans annually. As recommended by the American Heart Association, the current standard of care for patients with an out-of-hospital cardiac arrest (OHCA) includes manual cardiopulmonary resuscitation (S-CPR). Survival with favorable neurological function for all patients following OHCA and treated with S-CPR averages <6%. The ResQCPR System is intended to provide greater circulation to the heart and brain compared with S-CPR, thereby increasing the likelihood of survival. A recent Phase III, multicenter randomized study demonstrated a 50% increase in survival to hospital discharge with favorable neurologic function in subjects with an OHCA of presumed cardiac etiology treated with the ResQCPR System compared with conventional CPR. The ResQCPR System has been recently approved by the FDA as a CPR adjunct to improve the likelihood of survival in adult patients with non-traumatic cardiac arrest.

Traumatic injuries after mechanical cardiopulmonary resuscitation (LUCAS2): a forensic autopsy study

AIM

The aim of our study was to compare traumatic injuries observed after cardiopulmonary resuscitation (CPR) by means of standard (manual) or assisted (mechanical) chest compression by Lund University Cardiopulmonary Assist System, 2nd generation (LUCAS2) device.

METHODS

A retrospective study was conducted including cases from 2011 to 2013, analysing consecutive autopsy reports in two groups of patients who underwent medicolegal autopsy after unsuccessful CPR. We focused on traumatic injuries from dermal to internal trauma, collecting data according to a standardised protocol.

RESULTS

The study group was comprised of 26 cases, while 32 cases were included in the control group. Cardiopulmonary resuscitation performed by LUCAS2 was longer than manual CPR performed in control cases (study group: mean duration 51.5 min; controls 29.4 min; p = 0.004). Anterior chest lesions (from bruises to abrasions) were described in 18/26 patients in the LUCAS2 group and in 6/32 of the control group. A mean of 6.6 rib fractures per case was observed in the LUCAS2 group, but this was only 3.1 in the control group (p = 0.007). Rib fractures were less frequently observed in younger patients. The frequency of sternal factures was similar in both groups. A few trauma injuries to internal organs (mainly cardiac, pulmonary and hepatic bruises), and some petechiae (study 46%; control 41 %; p = 0.79) were recorded in both groups.

CONCLUSION

LUCAS™2-CPR is associated with more rib fractures than standard CPR. Typical round concentric skin lesions were observed in cases of mechanical reanimation. No life-threatening injuries were reported. Petechiae were common findings.

Mechanical chest compression with a medical parallel manipulator for cardiopulmonary resuscitation

BACKGROUND

Chest compression is the primary technique in emergency situations for resuscitating patients who have a cardiac arrest. Even for experienced personnel, it is difficult to perform chest compressions at the correct compression rate and depth.

METHODS

We describe a new translational three-revolute-revolute-revolute (3-RRR) parallel manipulator designed for delivering chest compressions. The kinematic and chest analyses have been carried out analytically. The motion of the parallel manipulator while performing chest compressions was simulated under experimental conditions and the results were verified in MSC ADAMS software.

RESULTS

Simulation and experimental results had more or less similar results. The proposed parallel manipulator was able to achieve 120 compressions/min (cpm) with a depth in the range 38-51 mm during cardio-pulmonary resuscitation (CPR).

CONCLUSIONS

The design of the manipulator makes it easy to deploy for performing chest compressions at the correct compression rate and depth, as outlined in the 2010 resuscitation guidelines.

CPR-related injuries after manual or mechanical chest compressions with the LUCAS™ device: a multicentre study of victims after unsuccessful resuscitation

AIM

The reported incidence of injuries due to cardiopulmonary resuscitation using manual chest compressions (manual CPR) varies greatly. Our aim was to elucidate the incidence of CPR-related injuries by manual chest compressions compared to mechanical chest compressions with the LUCAS device (mechanical CPR) in non-survivors after out-of-hospital cardiac arrest.

METHODS

In this prospective multicentre trial, including 222 patients (83 manual CPR/139 mechanical CPR), autopsies were conducted after unsuccessful CPR and the results were evaluated according to a specified protocol.

RESULTS

Among the patients included, 75.9% in the manual CPR group and 91.4% in the mechanical CPR group (p=0.002) displayed CPR-related injuries. Sternal fractures were present in 54.2% of the patients in the manual CPR group and in 58.3% in the mechanical CPR group (p=0.56). Of the patients in the manual CPR group, there were 64.6% with at least one rib fracture versus 78.8% in the mechanical CPR group (p=0.02). The median number of rib fractures among patients with rib fractures was 7 in the manual CPR group and 6 in the mechanical CPR group. No CPR-related injury was considered to be the cause of death.

CONCLUSION

In patients with unsuccessful CPR after out-of-hospital cardiac arrest, rib fractures were more frequent after mechanical CPR but there was no difference in the incidence of sternal fractures. No injury was deemed fatal by the pathologist.

Mechanical versus manual chest compressions for cardiac arrest

BACKGROUND

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).

OBJECTIVES

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.

SEARCH METHODS

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.

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 atraumatic cardiac arrest.

DATA COLLECTION AND ANALYSIS

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.

MAIN RESULTS

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.

AUTHORS' CONCLUSIONS

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.

CPR PRO® device reduces rescuer fatigue during continuous chest compression cardiopulmonary resuscitation: a randomized crossover trial using a manikin model

BACKGROUND

The performance of high-quality chest compressions with minimal interruptions is one of the most important elements of the "Chain of Survival."

OBJECTIVES

To evaluate the impact of a novel CPR PRO(®) (CPRO) device for manual chest compression on rescuer fatigue, pain, and cardiopulmonary resuscitation (CPR) quality.

METHODS

Randomized crossover trial of 24 health care professionals performing continuous chest compression CPR for 10 min with a CPRO device and conventional manual CPR (MCPR). Data about chest compressions were recorded using a manikin. Rescuers' physiologic signs were recorded before and after each session, and heart rate (HR) data were tracked continuously. Fatigue was assessed with ratings of perceived exertion, and pain questionnaire.

RESULTS

All subjects completed 10 min of CPR with both methods. Significantly more rest breaks were taken during MCPR sessions (1.7 ± 2 vs. 0.21 ± 0.72). Subjects' perceived exertion was higher after MCPR, as well as the average (120.7 ± 16.8 vs. 110.8 ± 17.6) and maximal HR (134.3 ± 18.5 vs. 123.42 ± 16.5) during testing. Subjects reported more pain in the hands, especially the wrist, after performing MCPR. Average depth of compressions was higher with the CPRO device (4.6 ± 7.0 vs. 4.3 ± 7.9) and declined more slowly over time. Other CPR quality parameters, such as the correct position and complete release of pressure, were also better for CPRO CPR.

CONCLUSIONS

CPRO device reduces rescuer fatigue and pain during continuous chest compression CPR, which results in a higher quality of CPR in a simulation setting.

Obstacles delaying the prompt deployment of piston-type mechanical cardiopulmonary resuscitation devices during emergency department resuscitation: a video-recording and time-motion study

BACKGROUND

The quality of cardiopulmonary resuscitation (CPR) is important to survival after cardiac arrest. Mechanical devices (MD) provide constant CPR, but their effectiveness may be affected by deployment timeliness.

OBJECTIVES

To identify the timeliness of the overall and of each essential step in the deployment of a piston-type MD during emergency department (ED) resuscitation, and to identify factors associated with delayed MD deployment by video recordings.

METHODS

Between December 2005 and December 2008, video clips from resuscitations with CPR sessions using a MD in the ED were reviewed using time-motion analyses. The overall deployment timeliness and the time spent on each essential step of deployment were measured.

RESULTS

There were 37 CPR recordings that used a MD. Deployment of MD took an average 122.6 ± 57.8s. The 3 most time-consuming steps were: (1) setting the device (57.8 ± 38.3s), (2) positioning the patient (33.4 ± 38.0 s), and (3) positioning the device (14.7 ± 9.5s). Total no flow time was 89.1 ± 41.2s (72.7% of total time) and associated with the 3 most time-consuming steps. There was no difference in the total timeliness, no-flow time, and no-flow ratio between different rescuer numbers, time of day of the resuscitation, or body size of patients.

CONCLUSIONS

Rescuers spent a significant amount of time on MD deployment, leading to long no-flow times. Lack of familiarity with the device and positioning strategy were associated with poor performance. Additional training in device deployment strategies are required to improve the benefits of mechanical CPR.

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 mechanical chest compressions versus standard manual chest compressions with respect to neurologically intact survival in patients who suffer cardiac arrest.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Studies (CENTRAL) on The Cochrane Library, MEDLINE, EMBASE, Science Citation abstracts, Biotechnology and Bioengineering abstracts and Clinicaltrials.gov in November 2009. No language restrictions were applied. Experts in the field of mechanical chest compression devices and manufacturers were contacted.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Two authors (SCB and LJM) abstracted data independently. Disagreement between reviewers was resolved by consensus and a third author (BB) if consensus could not be reached. The methodologies of selected studies were evaluated for risk of bias by a single author (SCB). The primary outcome was survival to hospital discharge with good neurologic outcome. We used the DerSimonian & Laird method (random-effects model) to provide a pooled estimate for relative risk with 95% confidence intervals.

MAIN RESULTS

Four trials, including data from 868 patients, 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 neurologic function (as defined as a Cerebral Performance Category score of 1 or 2), demonstrating reduced survival with mechanical chest compressions when compared with manual chest compressions (RR 0.41 (95% CI 0.21- 0.79). Data from other studies included in this review were used to calculate relative risks for having a return of spontaneous circulation (2 studies, N = 51, pooled RR 2.81, 95% CI 0.96 to 8.22) and survival to hospital admission (1 study, N = 17, RR 4.13, 95% CI 0.19 to 88.71) in patients who received mechanical chest compressions versus those who received manual chest compressions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from human RCTs to conclude that mechanical chest compressions during cardiopulmonary resuscitation for cardiac arrest is associated with benefit or harm. Widespread use of mechanical devices for chest compressions during cardiac is not supported by this review. More RCTs that measure and account for CPR process in both arms are needed to clarify the potential benefit from this intervention.

No difference in autopsy detected injuries in cardiac arrest patients treated with manual chest compressions compared with mechanical compressions with the LUCAS device--a pilot study

AIM

To compare the variety and incidence of internal injuries after manual and mechanical chest compressions during CPR.

METHODS

In a prospective pilot study conducted in two Swedish cities, 85 patients underwent autopsy after unsuccessful resuscitation attempts with manual or mechanical chest compressions, the latter with the LUCAS device. Autopsy was performed and the results were evaluated according to a specified protocol.

RESULTS

No injuries were found in 26/47 patients in the manual group and in 16/38 patients in the LUCAS group (p=0.28). Sternal fracture was present in 10/47 in the manual group and 11/38 in the LUCAS group (p=0.46), and there were multiple rib fractures (> or =3 fractures) in 13/47 in the manual group and in 17/38 in the LUCAS group (p=0.12). Bleeding in the ventral mediastinum was noted in 2/47 and 3/38 in the manual and LUCAS groups respectively (p=0.65), retrosternal bleeding in 1/47 and 3/38 (p=0.32), epicardial bleeding in 1/47 and 4/38 (p=0.17), and haemopericardium in 4/47 and 3/38 (p=1.0) respectively. One patient in the LUCAS group had a small rift in the liver and one patient in the manual group had a rift in the spleen. These injuries were not considered to have contributed to the patient's death.

CONCLUSION

Mechanical chest compressions with the LUCAS device appear to be associated with the same variety and incidence of injuries as manual chest compressions.

The effect of two different counting methods on the quality of CPR on a manikin--a randomized controlled trial

OBJECTIVES

To compare the quality of cardiopulmonary resuscitation (CPR) and rescuers' exhaustion using different methods of counting, and to establish an appropriate method of counting.

MATERIALS AND METHODS

Forty-eight subjects who had received formal training in basic life support (BLS) were recruited from doctors and nurses working in the Emergency Department of a university hospital. They performed 3 min of continuous chest compressions using two different methods of counting, one after the other, on an adult resuscitation manikin. The total number of compressions, the number of these considered satisfactory, the peak heart rate of subjects and the time to peak heart rate were all recorded. Perceived fatigue and discomfort was evaluated by self-reported survey results with use of a visual analogue scale (VAS).

RESULTS

The effective power of external chest compression and the mean compression depth when counting from 1 to 10, repeated three times, were greater than those achieved when counting from 1 to 30 during 3 min of CPR (67.48% vs. 57.81% and 44.52 mm vs. 40.48 mm, P<0.05). The exhaustion-score using the VAS (22.15 points) was lower and the time to peak heart rate (124.88 s) was longer when counting from 1 to 10, repeated three times, than when rescuers counted from 1 to 30.

CONCLUSIONS

Counting from 1 to 10 three times in Chinese as opposed to 1-30 results in better quality chest compressions. Counting from 1 to 10 three times was associated with less user feelings of fatigue, and a longer time to peak heart rate. These findings support the teaching of counting compressions 1-10 three times during CPR.

Evolution and new perspective of chest compression mechanical devices

Cardiac arrest is a major concern in health care, owing to its high incidence and mortality rates. Since the development of external cardiopulmonary resuscitation (CPR), there has been little advancement in nonpharmacologic therapies that have increased survival rates associated with cardiac arrest. Consequently, there has been much interest in the development of new techniques to improve the efficacy of CPR, particularly in the development of devices. Initially, many of the devices developed were not considered functional and failed to gain acceptance in the clinical setting. Recently, however, several devices have been developed which have progressed the administration of CPR and garnered acceptance in the clinical setting. In this article we will briefly review some of the more common mechanical devices developed to increase the safety and efficacy of CPR administration.

Video-recording and time-motion analyses of manual versus mechanical cardiopulmonary resuscitation during ambulance transport

INTRODUCTION

The quality of cardiopulmonary resuscitation (CPR) plays a crucial role in saving lives from out-of-hospital cardiac arrest (OHCA). Previous studies have identified sub-optimal CPR quality in the prehospital settings, but the causes leading to such deficiencies were not fully elucidated.

OBJECTIVE

This prospective study was conducted to identify operator- and ambulance-related factors affecting CPR quality during ambulance transport; and to assess the effectiveness of mechanical CPR device in such environment.

MATERIALS AND METHODS

A digital video-recording system was set up in two ambulances in Taipei City to study CPR practice for adult, non-traumatic OHCAs from January 2005 to March 2006. Enrolled patients received either manual CPR or CPR by a mechanical device (Thumper). Quality of CPR in terms of (1) adequacy of chest compressions, (2) instantaneous compression rates, and (3) unnecessary no-chest compression interval, was assessed by time-motion analysis of the videos.

RESULTS

A total of 20 ambulance resuscitations were included. Compared to the manual group (n=12), the Thumper group (n=8) had similar no-chest compression interval (33.40% versus 31.63%, P=0.16); significantly lower average chest compression rate (113.3+/-47.1 min(-1) versus 52.3+/-14.2 min(-1), P<0.05), average chest compression rate excluding no-chest compression interval (164.2+/-43.3 min(-1) versus 77.2+/-6.9 min(-1), P<0.05), average ventilation rate (16.1+/-4.9 min(-1) versus 11.7+/-3.5 min(-1), P<0.05); and longer no-chest compression interval before getting off the ambulance (5.7+/-9.9s versus 18.7+/-9.1s, P<0.05). The majority of the no-chest compression interval was considered operator-related; only 15.3% was caused by ambulance related factors.

CONCLUSIONS

Many unnecessary no-chest compression intervals were identified during ambulance CPR, and most of this was operator, rather than ambulance related. Though a mechanical device could minimise the no-chest compression intervals after activation, it took considerable time to deploy in a system with short transport time. Human factors remained the most important cause of poor CPR quality. Ways to improve the CPR quality in the ambulance warrant further study.

A history of mechanical devices for providing external chest compressions

The importance of providing good quality chest compressions with limited interruptions has been emphasised by the Resuscitation Guidelines 2005. The difficulties of providing consistent, good quality, chest compressions manually are well documented and attempts have been made to devise mechanical means to achieve this. Many see the development of mechanical devices as a new phenomenon; however, as with many other components of resuscitation science, they have in fact been available for a number of years. This paper provides a brief historical review of some of the mechanical devices which have been invented over the last 45 years in order to deliver external chest compressions. It also suggests some reasons why these devices failed to become a regular part of resuscitation practice.

Cardiac arrest and resuscitation with an automatic mechanical chest compression device (LUCAS) due to anaphylaxis of a woman receiving caesarean section because of pre-eclampsia

We report a case of anaphylaxis with pulseless electrical activity (PEA)(verified by ECG and a radial intra-arterial line) in a 30-year-old woman who received 3G Promiten (dextran-1) and a prophylactic intra-venous infusion of Macrodex (dextran) for postoperative thromboembolism during caesarean section for pre-eclampsia in the 24th week of gestation. Manual chest compressions, followed by mechanical chest compressions (LUCAS, Jolife, Lund, Sweden), were performed for 50min before restoration of spontaneous circulation (ROSC). She awoke the next day with no sequelae. She had some suction cup marks on the sternum but otherwise no complications of the chest compressions. At follow up by phone 1 month later, she and her baby were doing well.

Use of an automatic mechanical chest compression device (LUCAS) as a bridge to establishing cardiopulmonary bypass for a patient with hypothermic cardiac arrest

We report the case of a victim of deep accidental hypothermia who was extracted from the ice and received 1.5 h of mechanical chest compression. This was followed with rapid rewarming on cardiopulmonary bypass and resulted in good physical and mental recovery. This management option should be considered for similar victims.

Chest compression rates during cardiopulmonary resuscitation are suboptimal: a prospective study during in-hospital cardiac arrest

BACKGROUND

Recent data highlight a vital link between well-performed cardiopulmonary resuscitation (CPR) and survival after cardiac arrest; however, the quality of CPR as actually performed by trained healthcare providers is largely unknown. We sought to measure in-hospital chest compression rates and to determine compliance with published international guidelines.

METHODS AND RESULTS

We developed and validated a handheld recording device to measure chest compression rate as a surrogate for CPR quality. A prospective observational study of adult cardiac arrests was performed at 3 hospitals from April 2002 to October 2003. Resuscitations were witnessed by trained observers using a customized personal digital assistant programmed to store the exact time of each chest compression, allowing offline calculation of compression rates at serial time points. In 97 arrests, data from 813 minutes during which chest compressions were delivered were analyzed in 30-second time segments. In 36.9% of the total number of segments, compression rates were <80 compressions per minute (cpm), and 21.7% had rates <70 cpm. Higher chest compression rates were significantly correlated with initial return of spontaneous circulation (mean chest compression rates for initial survivors and nonsurvivors, 90+/-17 and 79+/-18 cpm, respectively; P=0.0033).

CONCLUSIONS

In-hospital chest compression rates were below published resuscitation recommendations, and suboptimal compression rates in our study correlated with poor return of spontaneous circulation. CPR quality is likely a critical determinant of survival after cardiac arrest, suggesting the need for routine measurement, monitoring, and feedback systems during actual resuscitation.

Increased cortical cerebral blood flow with LUCAS; a new device for mechanical chest compressions compared to standard external compressions during experimental cardiopulmonary resuscitation

OBJECTIVE

LUCAS is a new device for mechanical compression and decompression of the chest during cardiopulmonary resuscitation (CPR). The aim of this study was to compare the efficacy of this new device with standard manual external chest compressions using cerebral cortical blood flow, cerebral oxygen extraction, and end-tidal CO2 for indirect measurement of cardiac output. Drug therapy, with adrenaline (epinephrine) was eliminated in order to evaluate the effects of chest compressions alone.

METHODS

Ventricular fibrillation (VF) was induced in 14 anaesthetized pigs. After 8 min non-intervention interval, the animals were randomized into two groups. One group received external chest compressions using a new mechanical device, LUCAS. The other group received standard manual external chest compressions. The compression rate was 100 min(-1) and mechanical ventilation was resumed with 100% oxygen during CPR in both groups. No adrenaline was given. After 15 min of CPR, external defibrillatory shocks were applied to achieve restoration of spontaneous circulation (ROSC). Cortical cerebral blood flow was measured continuously using Laser-Doppler flowmetry. End-tidal CO2 was measured using mainstream capnography.

RESULTS

During CPR, the cortical cerebral blood flow was significantly higher in the group treated with LUCAS (p = 0.041). There was no difference in oxygen extraction between the groups. End-tidal CO2, an indirect measurement of the achieved cardiac output during CPR, was significantly higher in the group treated with the LUCAS device (p = 0.009). Restoration of spontaneous circulation was achieved in two animals, one from each group.

CONCLUSIONS

Chest compressions with the LUCAS device during experimental cardiopulmonary resuscitation resulted in higher cerebral blood flow and cardiac output than standard manual external chest compressions. These results strongly support prospective randomised studies in patients to evaluate this new device.

Skeletal chest injuries secondary to cardiopulmonary resuscitation

OBJECTIVE

To review the evidence on the incidence of rib and sternal fractures after conventional closed-chest compression in the treatment of cardiac arrest in adults and children, and after active compression-decompression cardiopulmonary resuscitation (ACD-CPR).

METHODS

Medline search and additional review of the cited literature in the articles found.

RESULTS

Reports on conventional CPR in adults suggest an incidence of rib fractures ranging from 13 to 97%, and of sternal fractures from 1 to 43%. Reports on CPR in children suggest an incidence of rib fractures of 0-2%, and no sternal fractures. ACD-CPR has been reported as causing rib fractures in 4-87%, and sternal fractures in 0-93% of cases.

CONCLUSIONS

Sound methodological studies on thoracic fractures due to chest compression do not exist and the available studies cannot be compared one with another. In infants and toddlers, manual CPR rarely causes skeletal chest injuries. In adults, sternal fractures occur in at least one-fifth and rib fractures as well as rib and/or sternal fractures in at least one-third of the patients during conventional CPR. There is no compelling evidence to show that an increased complication rate is associated with ACD-CPR. Rib or sternal fractures are unlikely to increase mortality, as they rarely cause severe internal organ damage. Further prospective studies are desirable to assess complications by post-mortem examinations that explicitly address them. In particular, clinical evaluation of mechanical CPR devices should be accompanied by a thorough assessment of the associated complications because data specific to this modality are not available.

Alternative cardiopulmonary resuscitation devices

Cardiopulmonary resuscitation (CPR) involving manual external chest compression combined with artificial respiration was first described in 1960 by Kouwenhoven et al. (Kouwenhoven W, Jude JR, Knickerbocker GG. Closed-chest cardiac massage. JAMA. 1960; 173:1064-7). In the four decades since then, there have been no widely accepted alternatives for this technique. Even with the subsequent worldwide adoption of CPR and other advanced cardiac life support measures, long-term survival after prehospital cardiac arrest is still typically only 5%, to 10%. The performance of CPR must therefore be improved to increase the rate of long-term survival. Currently under development are new, alternative techniques such as interposed abdominal compression (IAC), active compression-decompression (ACD), pneumatic and nonpneumatic circumferential chest compression, and minimally invasive cardiac massage. Many of these newer techniques, compared with standard manual CPR, appear to provide superior vital organ blood flow and increased blood pressure. To date, only IAC (in-hospital only) and ACD have been shown to improve long-term survival in clinical studies. Circumferential chest compression and minimally invasive cardiac massage, on the other hand, have not yet been adequately tested in large clinical trials. Despite the difficulty and expense in studying these CPR techniques, additional research is necessary to evaluate their effectiveness in improving survival after sudden cardiac arrest.

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

LUCAS is a new gas-driven CPR device providing automatic chest compression and active decompression. In an artificial thorax model, superior pressure and flow were obtained with LUCAS compared with manual CPR. In a randomized study on pigs with induced ventricular fibrillation significantly higher cardiac output, carotid artery blood flow, end-tidal CO(2), intrathoracic decompression-phase aortic- and coronary perfusion pressures were obtained with LUCAS-CPR (83% ROSC) compared to manual CPR (0% ROSC). In normothermic fibrillating pigs, the ROSC rate was 100% after 15 min and 38% after 60 min of LUCAS-CPR (no drug treatment). The ROSC rate increased to 75% if surface cooling to 34 degrees C was applied during the first 30 min of the 1-h resuscitation period. Experience with the first 20 patients has shown that LUCAS is light (6.5 kg), easy to handle, quick to apply (10-20 s), maintains a correct position, and works optimally during transport both on stretchers and in ambulances. In one hospital patient with a witnessed asystole where manual CPR failed, LUCAS-CPR achieved ROSC within 3 min. One year later the patient's mental capacity was fully intact. To conclude, LUCAS-CPR gives significantly better circulation during ventricular fibrillation than manual CPR.

Mechanical devices for cardiopulmonary resuscitation: an update

Despite the promise and universal use of the Kouwenhoven technique for closed chest cardiac massage, this method has been shown repeatedly to suffer from lack of clinical efficacy. Although the Kouwenhoven technique can clearly save lives, the inherent inefficiency of this approach and the challenges related to teaching and retaining the skills needed to perform the technique correctly have limited its overall effectiveness. This has prompted the development of newer lifesaving CPR techniques and devices. Some of the advances, such as the vest approach, active compression-decompression, and the impedance threshold valve, offer a benefit when compared with the Kouwenhoven technique. It is clear, however, that challenges related to implementation of these newer approaches will determine their ultimate utility. It is not sufficient to have a better technique or device available. Challenges to implementation of the newer approaches include overcoming the inertia of a universal mindset on the already-familiar Kouwenhoven technique and creating a cost-effective justification for change. Each year, approximately 10 million people in the United States are trained in the Kouwenhoven technique. Americans spend nearly $500,000,000 annually on this form of CPR training and retraining. Given the less than 5% survival rate for the 300,000 patients who experience out-of-hospital cardiac arrest each year in the United States, the prudence of this societal investment when compared with other ways health care dollars are spent should be questioned. It is hoped that this mismatch between costs and benefits will be recognized and will lead to the adoption of more effective means to resuscitate patients.

Effectiveness of ventilation-compression ratios 1:5 and 2:15 in simulated single rescuer paediatric resuscitation

Current guidelines for paediatric basic life support (BLS) recommend a ventilation-compression ratio of 1:5 during child resuscitation compared with 2:15 for adults, based on the consensus that ventilation is more important in paediatric than in adult BLS. We hypothesized that the ratio 2:15 would provide the same minute ventilation as 1:5 during single-rescuer paediatric BLS due to the reduced time required to change between ventilations and compressions. Fourteen lay rescuers were trained with both ratios and thereafter performed single rescuer BLS for approximately 4 min with each of the two ratios in random order on a child-sized manikin with a built-in respiratory monitor. Quality of chest compressions was assessed by measurement of the rate, depth and position. There were no significant differences in tidal volumes or minute ventilation between the ratios. Nearly all chest compressions were within acceptable limits for depth and place with both methods, but the mean number of chest compressions per minute was 48+/-15% greater with ratio 2:15. In conclusion, there was no difference in ventilation, but nearly one and a half times as many compressions with a ratio of 2:15 than 1:5 for lay rescuers during single rescuer paediatric CPR. In order to simplify CPR training for laypersons, we recommend a 2:15 ratio for both single- and two-person, adult and paediatric layperson BLS.

Neurological outcome after experimental cardiopulmonary resuscitation: a result of delayed and potentially treatable neuronal injury?

BACKGROUND

In experimental cardiopulmonary resuscitation (CPR) aortic balloon occlusion, vasopressin, and hypertonic saline dextran administration improve cerebral blood flow. Free radical scavenger alpha-phenyl-N-tert-butyl-nitrone (PBN) and cyclosporine-A (CsA) alleviate neuronal damage after global ischemia. Combining these treatments, we investigated neurological outcome after experimental cardiac arrest.

METHODS

: Thirty anesthetized piglets, randomly allocated into three groups, were subjected to 8 min of ventricular fibrillation followed by 5 min of closed-chest CPR. The combined treatment (CT) group received all the above-mentioned modalities; group B was treated with balloon occlusion and epinephrine; and group C had sham balloon occlusion with epinephrine. Indicators of oxidative stress (8-iso-PGF(2 alpha)), inflammation (15-keto-dihydro-PGF(2 alpha)), energy crisis (hypoxanthine and xanthine), and anoxia/hypoxia (lactate) were monitored in jugular bulb venous blood. Neurological outcome was evaluated 24 h after CPR.

RESULTS

: Restoration of spontaneous circulation (ROSC) was more rapidly achieved and neurological outcome was significantly better in the CT group, although there was no difference in coronary perfusion pressure between groups. The jugular venous PCO2 and cerebral oxygen extraction ratio were lower in the CT group at 5-15 min after ROSC. Jugular venous 8-iso-PGF(2 alpha) and hypoxanthine after ROSC were correlated to 24 h neurological outcome

CONCLUSIONS

: A combination of cerebral blood flow promoting measures and administration of alpha-phenyl-N-tert-butyl-nitrone and cyclosporine-A improved 24 h neurological outcome after 8 min of experimental normothermic cardiac arrest, indicating an ongoing neuronal injury in the reperfusion phase.

Mechanical advances in cardiopulmonary resuscitation

Challenged by the continued high mortality rates for patients in cardiac arrest, the American Heart Association and the European Resuscitation Council developed a new set of guidelines in 2000 to help advance several new and promising cardiopulmonary resuscitation (CPR) techniques and devices. This is the first time these organizations have taken such a bold move, in part because of the poor results with standard closed-chest cardiac massage. The new techniques, interposed abdominal counterpulsation and active compression decompression CPR, each provide greater blood flow to the vital organs in animal models of CPR and lead to higher blood pressures in patients in cardiac arrest. In some clinical studies, both techniques have resulted in a significant increase in survival after cardiac arrest in comparison with standard CPR. Three of the four new CPR devices that were recommended in the new guidelines also provide superior vital organ blood flow and increased blood pressures in comparison with standard CPR. The three devices that improve the efficiency of CPR are the circumferential vest, an active compression decompression CPR device, and an inspiratory impedance valve used in combination with the active compression decompression CPR device. The fourth device type, one that compresses the thorax using an automated mechanical piston compression mechanism, was recommended to reduce the number of personnel required to perform CPR. However, no studies on the automated mechanical compression devices have showed an improvement in hemodynamic variables or survival in comparison with standard CPR. Taken together, these new technologies represent an important step forward in the evolution of CPR from a pair of hands to devices designed to enhance CPR efficiency. Each of these advances is described, and the recent literature about each of them is reviewed.