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

LUCAS(™)2 in Danish Search and Rescue Helicopters

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparative effectiveness of standard CPR vs active compression-decompression CPR with CardioPump for treatment of cardiac arrest

BACKGROUND

Despite all of the studies conducted on cardiopulmonary resuscitation (CPR), the mortality rate of cardiac arrest patients is still high. This has led to a search for alternative methods. One of these methods is active compression-decompression CPR (ACD-CPR) performed with the CardioPump.

OBJECTIVE

The differences in the restoration of spontaneous circulation; the 1-, 7-, and 30-day survival rates; and hospital discharge rates between conventional CPR and ACD-CPR performed with CardioPump were investigated. In addition, the differences between the 2 methods with respect to complications were also investigated.

METHODS

Our study was a prospective, randomized medical device study with a case-control group. Cardiac arrest cases brought to our emergency medicine clinic by the 112 emergency ambulances from out of hospital and patients who had developed cardiac arrest inhospital clinics between April 2015 and September 2015 were included in our study. For randomization, standard CPR was performed on odd days of each month, and CPR using CardioPump was performed on the even days of each month.

RESULTS

A total of 181 patients were included in our study. The number of patients who received conventional CPR was determined as 86 (47.5%), and the number of patients who received CPR using the CardioPump was determined as 95 (52.5%). We did not identify any difference between conventional CPR and CardioPump ACD-CPR with respect to restoration of spontaneous circulation, discharge rates, and the 1-, 7-, and 30-day survival rates. (P=.384, P=.601, P=.997, P=.483, and P=.803, respectively) The complication rate was higher in the patient group that received conventional CPR (P<.001).

CONCLUSION

As a result of our study, we did not obtain any evidence supporting the replacement of conventional CPR with ACD-CPR performed using CardioPump.

Cardiopulmonary resuscitation using electrically driven devices: a review

In the treatment of sudden cardiac arrest (SCA) immediate resuscitation with chest compressions and ventilation is crucial for survival. As manual resuscitation is associated with several drawbacks, mechanical resuscitation devices have been developed to support resuscitation teams. These devices are able to achieve better perfusion of heart and brain in laboratory settings, but real world experience showed no significant improved survival in comparison to manual resuscitation. This review will focus on two mechanical resuscitation devices, the Lund University Cardiac Assist System (LUCAS) and AutoPulse devices and the actual literature available. In conclusion, the general use of mechanical resuscitation devices cannot be recommended at the moment.

Mechanical versus manual chest compressions for out-of-hospital cardiac arrest: a meta-analysis of randomized controlled trials

Recent evidence regarding mechanical chest compressions in out-of-hospital cardiac arrest (OHCA) is conflicting. The objective of this study was to perform a meta-analysis of randomized controlled trials (RCTs) to compare the effect of mechanical versus manual chest compressions on resuscitation outcomes in OHCA. PubMed, Embase, the Cochrane Central Register of Controlled Trials, and the ClinicalTrials.gov registry were searched. In total, five RCTs with 12,510 participants were included. Compared with manual chest compressions, mechanical chest compressions did not significantly improve survival with good neurological outcome to hospital discharge (relative risks (RR) 0.80, 95% CI 0.61–1.04, P = 0.10; I² = 65%), return of spontaneous circulation (RR 1.02, 95% CI 0.95–1.09, P = 0.59; I² = 0%), or long-term (≥6 months) survival (RR 0.96, 95% CI 0.79–1.16, P = 0.65; I² = 16%). In addition, mechanical chest compressions were associated with worse survival to hospital admission (RR 0.94, 95% CI 0.89–1.00, P = 0.04; I² = 0%) and to hospital discharge (RR 0.88, 95% CI 0.78–0.99, P = 0.03; I² = 0%). Based on the current evidence, widespread use of mechanical devices for chest compressions in OHCA cannot be recommended.

Levosimendan Improves Neurological Outcome in a Swine Model of Asphyxial Cardiac Arrest

BACKGROUND

In asphyxial cardiac arrest, the severe hypoxic stress complicates the resuscitation efforts and results in poor neurological outcomes. Our aim was to assess the effects of levosimendan on a swine model of asphyxial cardiac arrest.

METHODS

Asphyxial cardiac arrest was induced in 20 Landrace/Large White piglets, which were subsequently left untreated for four minutes. The animals were randomised to receive adrenaline alone (n=10, Group A) and adrenaline plus levosimendan (n=10, Group B). All animals were resuscitated according to the 2010 European Resuscitation Council guidelines. Haemodynamic variables were measured before arrest, during arrest and resuscitation, and during the first 30 minutes after return of spontaneous circulation (ROSC), while survival and neurologic alertness score were measured 24 hours later.

RESULTS

Return of spontaneous circulation was achieved in six animals (60%) from Group A and nine animals (90%) from Group B (p=0.303). During the first minute of cardiopulmonary resuscitation, coronary perfusion pressure was significantly higher in Group B (p=0.046), but there was no significant difference at subsequent time points until ROSC. Although six animals (60%) from each group survived after 24 hours (p=1.000), neurologic examination was significantly better in the animals of Group B (p<0.01).

CONCLUSIONS

The addition of levosimendan to adrenaline improved coronary perfusion pressure immediately after the onset of cardiopulmonary resuscitation and resulted in better 24-hour neurological outcome.

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 resuscitation assist devices]

In Germany 100,000-160,000 people suffer from out-of-hospital cardiac arrest (OHCA) annually. The incidence of cardiopulmonary resuscitation (CPR) after OHCA varies between emergency ambulance services but is in the range of 30-90 CPR attempts per 100,000 inhabitants per year. Basic life support (BLS) involving chest compressions and ventilation is the key measure of resuscitation. Rapid initiation and quality of BLS are the most critical factors for CPR success. Even healthcare professionals are not always able to ensure the quality of CPR measures. Consequently in recent years mechanical resuscitation devices have been developed to optimize chest compression and the resulting circulation. In this article the mechanical resuscitation devices currently available in Germany are discussed and evaluated scientifically in context with available literature. The ANIMAX CPR device should not be used outside controlled trials as no clinical results have so far been published. The same applies to the new device Corpuls CPR which will be available on the market in early 2014. Based on the current published data a general recommendation for the routine use of LUCAS™ and AutoPulse® CPR cannot be given. The preliminary data of the CIRC trial and the published data of the LINC trial revealed that mechanical CPR is apparently equivalent to good manual CPR. For the final assessment further publications of large randomized studies must be analyzed (e.g. the CIRC and PaRAMeDIC trials). However, case control studies, case series and small studies have already shown that in special situations and in some cases patients will benefit from the automatic mechanical resuscitation devices (LUCAS™, AutoPulse®). This applies especially to emergency services where standard CPR quality is far below average and for patients who require prolonged CPR under difficult circumstances. This might be true in cases of resuscitation due to hypothermia, intoxication and pulmonary embolism as well as for patients requiring transport or coronary intervention when cardiac arrest persists. Three prospective randomized studies and the resulting meta-analysis are available for active compression-decompression resuscitation (ACD-CPR) in combination with an impedance threshold device (ITD). These studies compared ACD-ITD-CPR to standard CPR and clearly demonstrated that ACD-ITD-CPR is superior to standard CPR concerning short and long-term survival with good neurological recovery after OHCA.

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.

Systematic review of the mechanisms driving effective blood flow during adult CPR

BACKGROUND

High quality chest compressions is the most significant factor related to improved short-term and long-term outcome in cardiac arrest. However, considerable controversy exists over the mechanisms involved in driving blood flow.

OBJECTIVES

The aim of this systematic review is to elucidate major mechanisms involved in effective compression-mediated blood flow during adult cardiopulmonary resuscitation (CPR).

DESIGN AND SETTING

Systematic review of studies identified from the bibliographic databases of PubMed/Medline, Cochrane, and Scopus.

SELECTION CRITERIA

All human and animal studies including information on the responsible mechanisms of compression-related blood flow.

DATA COLLECTION AND ANALYSIS

Two reviewers (MG, TX) independently screened all potentially relevant titles and abstracts for eligibility, by using a standardized data-worksheet.

MAIN RESULTS

Forty seven studies met the inclusion criteria. Because of the heterogeneity in outcome measures, quantitative synthesis of evidence was not feasible. Evidence was critically synthesized in order to answer the review questions, taking into account study heterogeneity and validity. The number of included studies per category is as follows: blood flow during chest compression, nine studies; blood flow during chest decompression, six studies; effect of chest compression on cerebral blood flow, eight studies; active compression-decompression CPR, 14 studies; and effect of ventilation on compression-related blood flow, 13 studies.

CONCLUSION

The evidence so far is inconclusive regarding the major responsible mechanism in compression-related blood flow. Although both 'cardiac pump' and 'thoracic pump' have a key role, the effect of each mechanism is highly depended on other resuscitation parameters, such as positive pressure ventilation and compression depth.

Mechanical cardiopulmonary resuscitation for patients with cardiac arrest

BACKGROUND

Although modern cardiopulmonary resuscitation (CPR) substantially decreases the mortality induced by cardiac arrest, cardiac arrest still accounts for over 50% of deaths caused by cardiovascular diseases. In this article, we address the current use of mechanical devices during CPR, and also compare the CPR quality between manual and mechanical chest compression.

METHODS

We compared the quality and survival rate between manual and mechanical CPR, and then reviewed the mechanical CPR in special circumstance, such as percutaneous coronary intervention, transportation, and other fields.

RESULTS

Compared with manual compression, mechanical compression can often be done correctly, and thus can compromise survival; can provide high quality chest compressions in a moving ambulance; enhance the flow of blood back to the heart via a rhythmic constriction of the veins; allow ventilation and CPR to be performed simultaneously.

CONCLUSION

Mechanical devices will be widely used in clinical practice so as to improve the quality of CPR in patients with cardiac arrest.

Passive leg raise (PLR) during cardiopulmonary (CPR) - a method article on a randomised study of survival in out-of-hospital cardiac arrest (OHCA)

BACKGROUND

It is estimated that about 275,000 inhabitants experience an out-of-hospital cardiac arrest (OHCA) every year in Europe. Survival in out-of-hospital cardiac arrest is relatively low, generally between five per cent and 10%. Being able to explore new methods to improve the relatively low survival rate is vital for people with these conditions. Passive leg raise (PLR) during cardiopulmonary resuscitation (CPR) has been found to improve cardiac preload and blood flow during chest compressions. The aim of our study is to evaluate whether early PLR during CPR also has an impact on one-month survival in sudden and unexpected out-of-hospital cardiac arrest (OHCA).

METHOD/DESIGN

A prospective, randomized, controlled trial in which all patients (≥18 years) receiving out-of hospital CPR are randomized by envelope to be treated with either PLR or in the flat position. The ambulance crew use a special folding stool which allows the legs to be elevated about 20 degrees. Primary end-point: survival to one month. Secondary end-point: survival to hospital admission to one month and to one year with acceptable cerebral performance classification (CPC) 1-2.

DISCUSSION

PLR is a simple and fast maneuver. We believe that the greatest benefit with PLR is when performed early in the process, during the first minutes of CPR and before the first defibrillation. To reach power this study need 3000 patients, we hope that this method article will encourage other sites to contact us and take part in our study.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01952197.

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.

Miniaturized mechanical chest compressor improves calculated cerebral perfusion pressure without compromising intracranial pressure during cardiopulmonary resuscitation in a porcine model of cardiac arrest

OBJECTIVE

One of the major goals of cardiopulmonary resuscitation (CPR) is to provide adequate oxygen delivery to the brain for minimizing cerebral injury resulted from cardiac arrest. The optimal chest compression during CPR should effectively improve brain perfusion without compromising intracranial pressure (ICP). Our previous study has demonstrated that the miniaturized mechanical chest compressor improved hemodynamic efficacy and the success of CPR. In the present study, we investigated the effects of the miniaturized chest compressor (MCC) on calculated cerebral perfusion pressure (CerPP) and ICP.

METHODS

Ventricular fibrillation was electrically induced and untreated for 7min in 13 male domestic pigs weighing 39±3kg. The animals were randomized to receive mechanical chest compression with the MCC (n=7), or the Thumper device (n=6). CPR was performed for 5min before defibrillation attempt by a single 150J shock. At 2.5min of CPR, the epinephrine at a dose of 20μg/kg was administered. Additional epinephrine was administered at an interval of 3min thereafter. If resuscitation was not successful, CPR was resumed for an additional 2min prior to the next defibrillation until successful resuscitation or for a total of 15min. Post-resuscitated animals were observed for 2h.

RESULTS

Significantly greater intrathoracic positive and negative pressures during compression and decompression phases of CPR were observed with the MCC when compared with the Thumper device. The MCC produced significantly greater coronary perfusion pressure and end-tidal carbon dioxide. There were no statistically significant differences in systolic and mean ICP between the two groups; however, both of the measurements were slightly greater in the MCC treated animals. Interestingly, the diastolic ICP was significantly lower in the MCC group, which was closely related to the significantly lower negative intrathoracic pressure in the animals that received the MCC. Most important, systolic, diastolic and mean calculated CerPP were all significantly greater in the animals receiving the MCC.

CONCLUSIONS

In the present study, mechanical chest compression with the MCC significantly improved calculated CerPP but did not compromise ICP during CPR. It may provide a safe and effective chest compression during CPR. Protocol number: P1205.

Addition of glucagon to adrenaline improves hemodynamics in a porcine model of prolonged ventricular fibrillation

OBJECTIVE

Cardiac arrest is a daunting medical emergency. The aim of the present study was to assess whether the combination of adrenaline and glucagon would improve initial resuscitation success, 48-hour survival, and neurologic outcome compared with adrenaline alone in a porcine model of ventricular fibrillation.

METHODS

Ventricular fibrillation was induced in 20 healthy Landrace/Large White piglets, which were subsequently left untreated for 8 minutes. The animals were randomized to receive adrenaline alone (n = 10, group C) and adrenaline plus glucagon (n = 10, group G). All animals were resuscitated according to the 2010 European Resuscitation Council guidelines. Hemodynamic variables were measured before arrest, during arrest and resuscitation, and during the first 60 minutes after return of spontaneous circulation. Survival and a neurologic alertness score were measured at 48 hours after return of spontaneous circulation.

RESULTS

Return of spontaneous circulation was achieved in 8 animals (80%) from group C and 10 animals (100%) from group G (P = .198). A significant gradual increase in coronary perfusion pressure and diastolic aortic pressure over time, which started 1 minute after the onset of cardiopulmonary resuscitation, was observed. Three animals (30%) from group C and 9 animals (90%) from group G survived after 48 hours (P = .006), whereas neurologic examination was significantly better in the animals of group G (P < .001).

CONCLUSIONS

In this porcine model of prolonged ventricular fibrillation, the addition of glucagon to adrenaline improves hemodynamics during resuscitation and early postresuscitation period and may increase survival.

Automatic chest compression devices--when do they make sense?

The current resuscitation guidelines of the European Resuscitation Council do not include automatic chest compression devices (ACDs) as standard equipment to support cardiopulmonary resuscitation attempts. One possible reason could be the lack of a list of indications and contraindications for the use of ACD systems. This review should give a summary of current studies and developments according to ACD systems and deliver a list of possible applications. Furthermore, we discuss some ethical problems with cardiopulmonary resuscitation attempts and, in particular, with ACD systems. The use of ACDs occurs instead of manual chest compression. Because of this, there is no reason for changing the current guidelines, especially termination recommendations while using ACD systems. From our point of view, ACDs are a very good supplement to the current standard of resuscitation according to the European Resuscitation Council guidelines.

Mechanical versus manual chest compression CPR under ground ambulance transport conditions

BACKGROUND

Novel mechanical chest compression devices offer the possibility to transport cardiac arrest patients with ongoing CPR and might shorten significantly the time delay to post-resuscitation care.

METHODS

We simulated an eight-minute cardiac resuscitation situation during ambulance transport using CPR training manikins. We compared teams consisting of two experienced resuscitators with the performance of a mechanical chest compression device (LUCAS).

RESULTS

CPR-performance by two experienced resuscitators demonstrated ambivalent results. Whereas mean compression rate was within the recommended range (103/min, 95% CI: 93-113/min), mean compression depth was closely below the actually recommended compression depth of >5 cm (49.7 mm, 95% CI: 46.1-53.3mm). Nevertheless, only a mean of two thirds (67%) of all compressions were classified as manually correct (defined as sternal compression depth >5 cm). In contrast, the LUCAS device showed a constant and reliable CPR performance (99.96% correctly applied chest compressions correctly applied within the device programmed parameters, P = 0.0162) with almost no variance between the different sequences.

CONCLUSION

The LUCAS CPR device represents a reliable alternative to manual CPR in a moving ambulance vehicle during emergency evacuation. Furthermore, it needs less human resources and is safer for the EMS personnel.

Detection of a spontaneous pulse in photoplethysmograms during automated cardiopulmonary resuscitation in a porcine model

INTRODUCTION

Reliable, non-invasive detection of return of spontaneous circulation (ROSC) with minimal interruptions to chest compressions would be valuable for high-quality cardiopulmonary resuscitation (CPR). We investigated the potential of photoplethysmography (PPG) to detect the presence of a spontaneous pulse during automated CPR in an animal study.

METHODS

Twelve anesthetized pigs were instrumented to monitor circulatory and respiratory parameters. Here we present the simultaneously recorded PPG and arterial blood pressure (ABP) signals. Ventricular fibrillation was induced, followed by 20 min of automated CPR and subsequent defibrillation. After defibrillation, pediatric-guidelines-style life support was given in cycles of 2 min. PPG and ABP waveforms were recorded during all stages of the protocol. Raw PPG waveforms were acquired with a custom-built photoplethysmograph controlling a commercial reflectance pulse oximetry probe attached to the nose. ABP was measured in the aorta.

RESULTS

In nine animals ROSC was achieved. Throughout the protocol, PPG and ABP frequency content showed strong resemblance. We demonstrate that (1) the PPG waveform allows for the detection of a spontaneous pulse during ventilation pauses, and that (2) frequency analysis of the PPG waveform allows for the detection of a spontaneous pulse and the determination of the pulse rate, even during ongoing chest compressions, if the pulse and compression rates are sufficiently distinct.

CONCLUSIONS

These results demonstrate the potential of PPG as a non-invasive means to detect pulse presence or absence, as well as pulse rate during CPR.

Percutaneous Assist Device for Cardiopulmonary Resuscitation

Persistent cardiac arrest is often caused by coronary ischemia. Urgent revascularization during on-going resuscitation with the support of percutaneous left ventricular assist devices (PVAD) may be feasible and can have the potential to improve the prognosis. Transport during resuscitation is a challenge that may be overcome with the use of cardiopulmonary resuscitation devices. In the catheterization laboratory, rapid deployment of PVAD may reduce ischemia, contribute to electrical stabilization of the heart, and facilitate definite treatment with percutaneous coronary intervention. After revascularization, PVAD therapy may promote myocardial recovery and improve vital organ perfusion in a critical phase.

The study protocol for the LINC (LUCAS in cardiac arrest) study: a study comparing conventional adult out-of-hospital cardiopulmonary resuscitation with a concept with mechanical chest compressions and simultaneous defibrillation

Background

The LUCAS™ device delivers mechanical chest compressions that have been shown in experimental studies to improve perfusion pressures to the brain and heart as well as augmenting cerebral blood flow and end tidal CO_2, compared with results from standard manual cardiopulmonary resuscitation (CPR). Two randomised pilot studies in out-of-hospital cardiac arrest patients have not shown improved outcome when compared with manual CPR. There remains evidence from small case series that the device can be potentially beneficial compared with manual chest compressions in specific situations. This multicentre study is designed to evaluate the efficacy and safety of mechanical chest compressions with the LUCAS™ device whilst allowing defibrillation during on-going CPR, and comparing the results with those of conventional resuscitation.

Methods/design

This article describes the design and protocol of the LINC-study which is a randomised controlled multicentre study of 2500 out-of-hospital cardiac arrest patients. The study has been registered at ClinicalTrials.gov (http://clinicaltrials.gov/ct2/show/NCT00609778?term=LINC&rank=1).

Results

Primary endpoint is four-hour survival after successful restoration of spontaneous circulation. The safety aspect is being evaluated by post mortem examinations in 300 patients that may reflect injuries from CPR.

Conclusion

This large multicentre study will contribute to the evaluation of mechanical chest compression in CPR and specifically to the efficacy and safety of the LUCAS™ device when used in association with defibrillation during on-going CPR.

The effects of a newly developed miniaturized mechanical chest compressor on outcomes of cardiopulmonary resuscitation in a porcine model*

OBJECTIVE

When the duration of cardiac arrest is prolonged, reperfusion of the vital organs by effective chest compression is the most important intervention for successful resuscitation. We investigated the effects of a newly developed miniaturized chest compressor on the outcomes of cardiopulmonary resuscitation.

DESIGN

Prospective, randomized, controlled experimental study.

SETTING

University-affiliated animal research laboratory.

SUBJECTS

Thirty male domestic pigs.

INTERVENTIONS

Ventricular fibrillation was induced in 30 male domestic pigs weighing 35 ± 2 kg. Cardiopulmonary resuscitation was initiated after 7 mins of untreated ventricular fibrillation. The animals were randomized to receive mechanical chest compression with a miniaturized chest compressor, a LUCAS device or a Thumper device. After 5 mins of cardiopulmonary resuscitation, a 150-J defibrillation was delivered. If resuscitation was not successful, cardiopulmonary resuscitation was continued for 2 mins before the next defibrillation. The protocol was continued until successful resuscitation or for a total of 15 mins of cardiopulmonary resuscitation. The animals were observed for 72 hrs after resuscitation.

MEASUREMENTS AND MAIN RESULTS

The miniaturized chest compressor generated significantly greater coronary perfusion pressure, end-tidal PCO2, carotid blood flow, and intrathoracic negative pressure, with significantly lower compression depth and fewer rib fractures when compared with both the LUCAS and Thumper devices. Both the miniaturized chest compressor and LUCAS devices required lower numbers of defibrillation for successful resuscitation when compared with the Thumper device. This was associated with lower prevalence of recurrent ventricular fibrillation and better postresuscitation myocardial and neurological function when compared with the Thumper device.

CONCLUSIONS

The miniaturized chest compressor improves hemodynamic efficacy and the success of cardiopulmonary resuscitation with significantly less injury, which is as effective as the LUCAS device. It may provide a new option for cardiopulmonary resuscitation.

Single rescuer exertion using a mechanical resuscitation device: a randomized controlled simulation study

OBJECTIVES

The goal of this experimental study was to investigate rescuer exertion when using "Animax," a manually operated hand-powered mechanical resuscitation device (MRD) for cardiopulmonary resuscitation (CPR), compared to standard basic life support (BLS).

METHODS

This was a prospective, open, randomized, crossover simulation study. After being trained, 80 medical students with substantial knowledge in BLS performed one-rescuer CPR using either the MRD or the standard BLS for 12-minute intervals in random order. The main outcome parameter was the heart rate pressure product (RPP) as an index of cardiac work. Secondary outcome parameters were physical exhaustion quantified by the Borg scale (measurement of perceived exertion), Nine Hole Peg Test (NHPT; measurement of fine motor skills), and capillary lactate concentration during testing.

RESULTS

While no significant difference could be found for the RPP, a significantly increased mean heart rate during the final minute of standard BLS compared to the MRD was found (139 ± 22 beats/min vs. 135 ± 26 beats/min, p = 0.027). By contrast, subjective exertion using the MRD was rated significantly higher on the Borg scale (15.1 ± 2.4 vs. 14.6 ± 2.6, p = 0.027). Mean serum lactate concentration was significantly higher when the MRD was used compared to standard BLS (3.4 ± 1.5 mmol/L vs. 2.1 ± 1.3 mmol/L, p ≤ 0.001).

CONCLUSIONS

Use of the MRD leads to a RPP of the rescuers comparable to standard BLS. These findings suggest that there is no clinically relevant reduction of exertion if this MRD is used by a single rescuer. If this kind of MRD is used for CPR, frequent changeovers with a second rescuer should be considered as the guidelines suggest for standard CPR.

Transport with ongoing resuscitation: a comparison between manual and mechanical compression

AIM

In special circumstances it may be necessary to transport out-of-hospital cardiac arrest patients with ongoing resuscitation to the hospital. External mechanical chest compression devices could be an alternative for these resuscitations. The study compares manual chest compression with external mechanical devices and a semiautomatic device in transport conditions using a resuscitation manikin.

METHODS

Manual chest compressions were compared with LUCAS 2, AutoPulse and animax mono devices using the Ambu Man Wireless MegaCode manikin (10 series each). The measurements were performed in a standard ambulance vehicle during transport on a predefined track of 5.0 km.

RESULTS

Mean compression frequencies in the manual group (117 ± 18 min(-1)) and in the animax mono group (115 ± 10 min(-1)) were significantly higher than in the LUCAS 2 group (100 min(-1), p=0.02) and the AutoPulse group (80 min(-1), p<0.01). Both mechanical devices worked absolutely constantly. Only the animax mono group reached with 51.2 mm the recommended compression depth. The quality of manual compressions decreased considerably during braking or change manoeuvres while the mechanical devices continued to work constantly.

CONCLUSIONS

During a patient transport with ongoing resuscitation, external mechanical compression devices may be a good alternative to manual compression because they increase the safety of the rescuer and patient. Yet, in this study only animax mono reached the guideline specifications regarding chest compressions' frequency and depth. Concerning constancy, the mechanical devices work reliably and more independently from motion influences. Further studies are necessary to evaluate the effectiveness of these devices in patient transport.

Passive leg raising during cardiopulmonary resuscitation results in improved neurological outcome in a swine model of prolonged ventricular fibrillation

OBJECTIVE

The objective was to evaluate whether passive leg raising during cardiopulmonary resuscitation in a porcine model of prolonged ventricular fibrillation improves hemodynamics, return of spontaneous circulation, 24-hour survival, and neurological outcome.

METHODS

Ventricular fibrillation was induced in 20 healthy Landrace/Large White piglets, which were subsequently left untreated for 8 minutes. Ten animals were randomly assigned into the control group and were resuscitated according to the 2005 European Resuscitation Council guidelines, and 10 piglets were assigned into the passive leg raising group and were resuscitated with the legs passively raised at 45° with the aid of a special purpose-made metallic device. End points were either return of spontaneous circulation or asystole.

RESULTS

Return of spontaneous circulation was observed in 6 and 9 animals from the control and the passive leg raising group, respectively (P = .121; odds ratio = 0.16; 95% confidence interval, 0.01-1.87). Just prior to the first defibrillation attempt, coronary perfusion pressure was significantly higher in the passive leg raising group (22.8 ± 9.5 vs 10.6 ± 6.5 mm Hg, P < .004); but no subsequent significant differences were observed. Although all animals that restored spontaneous circulation survived for 24 hours, neurologic alertness score was significantly better in the animals treated with passive leg raising (90 ± 10 vs 76.6 ± 12.1, P = .037).

CONCLUSIONS

Passive leg raising during cardiopulmonary resuscitation significantly increased coronary perfusion pressure in the minute prior to the first shock. Return of spontaneous circulation and 24-hour survival rate were comparable between groups. However, the animals in the passive leg raising group exhibited significantly higher neurological scores.

Novel adhesive glove device (AGD) for active compression-decompression (ACD) CPR results in improved carotid blood flow and coronary perfusion pressure in piglet model of cardiac arrest

OBJECTIVE

ACD-CPR improves coronary and cerebral perfusion. We developed an adhesive glove device (AGD) and hypothesized that ACD-CPR using an AGD provides better chest decompression resulting in improved carotid blood flow as compared to standard (S)-CPR.

DESIGN

Prospective, randomized and controlled animal study.

METHODS

Sixteen anesthetized and ventilated piglets were randomized after 3 min of untreated VF to receive either S-CPR or AGD-ACD-CPR by a PALS certified single rescuer with compressions of 100 min(-1) and C:V ratio of 30:2. AGD consisted of a modified leather glove exposing the fingers and thumb. A wide Velcro patch was sewn to the palmer aspect of the glove and the counter Velcro patch was adhered to the pig's chest wall. Carotid blood flow was measured using ultrasound. Data (mean±SD) was analyzed using one way ANOVA and unpaired t-test; p-value ≤ 0.05 was considered statistically significant.

RESULTS

Right atrial pressure (mmHg) during the decompression phase was lower during AGD-ACD-CPR (-3.32±2.0) when compared to S-CPR (0.86±1.8, p=0.0007). Mean carotid blood flow was 53.2±27.1 (% of baseline blood flow in ml/min) in AGD vs. 19.1±12.5% in S-CPR, p=0.006. Coronary perfusion pressure (CPP, mmHg) was 29.9±5.8 in AGD vs. 22.7±6.9 in S-CPR, p=0.04. There was no significant difference in time to ROSC and number of epinephrine doses.

CONCLUSION

Active chest decompression during CPR using this simple and inexpensive adhesive glove device resulted in significantly better carotid blood flow during the first 2 min of CPR.

Evaluation of coronary blood flow velocity during cardiac arrest with circulation maintained through mechanical chest compressions in a porcine model

Background

Mechanical chest compressions (CCs) have been shown capable of maintaining circulation in humans suffering cardiac arrest for extensive periods of time. Reports have documented a visually normalized coronary blood flow during angiography in such cases (TIMI III flow), but it has never been actually measured. Only indirect measurements of the coronary circulation during cardiac arrest with on-going mechanical CCs have been performed previously through measurement of the coronary perfusion pressure (CPP). In this study our aim was to correlate average peak coronary flow velocity (APV) to CPP during mechanical CCs.

Methods

In a closed chest porcine model, cardiac arrest was established through electrically induced ventricular fibrillation (VF) in eleven pigs. After one minute, mechanical chest compressions were initiated and then maintained for 10 minutes upon which the pigs were defibrillated. Measurements of coronary blood flow in the left anterior descending artery were made at baseline and during VF with a catheter based Doppler flow fire measuring APV. Furthermore measurements of central (thoracic) venous and arterial pressures were also made in order to calculate the theoretical CPP.

Results

Average peak coronary flow velocity was significantly higher compared to baseline during mechanical chests compressions and this was observed during the entire period of mechanical chest compressions (12 - 39% above baseline). The APV slowly declined during the 10 min period of mechanical chest compressions, but was still higher than baseline at the end of mechanical chest compressions. CPP was simultaneously maintained at > 20 mmHg during the 10 minute episode of cardiac arrest.

Conclusion

Our study showed good correlation between CPP and APV which was highly significant, during cardiac arrest with on-going mechanical CCs in a closed chest porcine model. In addition APV was even higher during mechanical CCs compared to baseline. Mechanical CCs can, at minimum, re-establish coronary blood flow in non-diseased coronary arteries during cardiac arrest.

Poor chest compression quality with mechanical compressions in simulated cardiopulmonary resuscitation: a randomized, cross-over manikin study

INTRODUCTION

Mechanical chest compression devices are being implemented as an aid in cardiopulmonary resuscitation (CPR), despite lack of evidence of improved outcome. This manikin study evaluates the CPR-performance of ambulance crews, who had a mechanical chest compression device implemented in their routine clinical practice 8 months previously. The objectives were to evaluate time to first defibrillation, no-flow time, and estimate the quality of compressions.

METHODS

The performance of 21 ambulance crews (ambulance nurse and emergency medical technician) with the authorization to perform advanced life support was studied in an experimental, randomized cross-over study in a manikin setup. Each crew performed two identical CPR scenarios, with and without the aid of the mechanical compression device LUCAS. A computerized manikin was used for data sampling.

RESULTS

There were no substantial differences in time to first defibrillation or no-flow time until first defibrillation. However, the fraction of adequate compressions in relation to total compressions was remarkably low in LUCAS-CPR (58%) compared to manual CPR (88%) (95% confidence interval for the difference: 13-50%). Only 12 out of the 21 ambulance crews (57%) applied the mandatory stabilization strap on the LUCAS device.

CONCLUSIONS

The use of a mechanical compression aid was not associated with substantial differences in time to first defibrillation or no-flow time in the early phase of CPR. However, constant but poor chest compressions due to failure in recognizing and correcting a malposition of the device may counteract a potential benefit of mechanical chest compressions.