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

Advanced and Invasive Cardiopulmonary Resuscitation (CPR) Techniques as an Adjunct to Advanced Cardiac Life Support

BACKGROUND

Despite numerous promising innovations, the chance of survival from sudden cardiac arrest has remained virtually unchanged for decades. Recently, technological advances have been made, user-friendly portable devices have been developed, and advanced invasive procedures have been described that could improve this unsatisfactory situation.

METHODS

A selective literature search in the core databases with a focus on randomized controlled trials and guidelines.

RESULTS

Technical aids, such as feedback systems or automated mechanical cardiopulmonary resuscitation (CPR) devices, can improve chest compression quality. The latter, as well as extracorporeal CPR, might serve as a bridge to treatment (with extracorporeal CPR even as a bridge to recovery). Sonography may be used to improve thoracic compressions on the one hand and to rule out potentially reversible causes of cardiac arrest on the other. Resuscitative endovascular balloon occlusion of the aorta might enhance myocardial and cerebral perfusion. Minithoracostomy, pericardiocentesis, or clamshell thoracotomy might resolve reversible causes of cardiac arrest.

CONCLUSIONS

It is crucial to identify those patients who may benefit from an advanced or invasive procedure and make the decision to implement the intervention in a timely manner. As with all infrequently performed procedures, sound education and regular training are paramount.

Traumatic Injuries Following Mechanical versus Manual Chest Compression

Objective

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

Methods

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

Results

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

Conclusion

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

Wilderness Medical Society Clinical Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2019 Update

To provide guidance to clinicians, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and a balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations. This is the 2019 update of the Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2014 Update.

Controversial Issues: Pro Mechanical Cardiopulmonary Resuscitation

High-quality cardiopulmonary resuscitation, in particular chest compressions, is a key aspect of out-of-hospital cardiac arrest (OHCA) resuscitation. Manual chest compressions remain the standard of care; however, the extrication and transport of patients with OHCA undermine the quality of manual chest compressions and risk the safety of paramedics. Therefore, in circumstances whereby high-quality manual chest compressions are difficult or unsafe, paramedics should consider using a mechanical device. By combining high-quality manual chest compressions and judicious application of mechanical chest compressions, emergency medical service agencies can optimize paramedic safety and patient outcomes.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Military application of mechanical CPR devices: a pressing requirement?

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

Accidental hypothermia

Accidental hypothermia causes profound changes to the body's physiology. After an initial burst of agitation (e.g., 36-37°C), vital functions will slow down with further cooling, until they vanish (e.g. <20-25°C). Thus, a deeply hypothermic person may appear dead, but may still be able to be resuscitated if treated correctly. The hospital use of minimally invasive rewarming for nonarrested, otherwise healthy patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionized the management of hypothermic cardiac arrest, with survival rates approaching 100%. Hypothermic patients with risk factors for imminent cardiac arrest (i.e., temperature <28°C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS center. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanic CPR can be helpful. Intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern postresuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimize prehospital triage, transport, and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and postresuscitation care.

Swedish-Norwegian co-operation in the treatment of three hypothermia victims: a case report

BACKGROUND

Accidental hypothermia with cardiac arrest represents a challenge for pre-hospital rescuers as well as in-hospital staff. For pre-hospital personnel, the main focus is to get the patient to the correct destination without unnecessary delay. For in-hospital personnel early information is vital to assess the possibility for resuscitation with extracorporeal re-warming. The challenge is augmented when rescuers must cross national borders to reach and/or deliver the patients. We present a case where three adolescent boys suffered severe hypothermia after a canoeing accident in Sweden.

CASE PRESENTATION

Three 14-year-old boys were canoeing a mountain lake close to the Norwegian border when their boat capsized and they all fell into the cold water. The rescue operation was hampered by rough weather conditions, and immersion times spanned from 63 to 125 min. Flight times from the scene of accident to the nearest ECMO center in Norway (Trondheim) and Sweden (Umeå) were about 30 and 90 min respectively. Two of the victims showed no vital signs after retrieval from the water and had extremely low body temperatures. They were brought to Trondheim University Hospital where they were resuscitated successfully with extracorporeal re-warming. Unable to be weaned from ECMO in the initial phase, both patients were retrieved by mobile ECMO teams to Karolinska University Hospital, from where they were discharged to their homes with good outcomes, although with some sequelae. A third victim with moderate to severe hypothermia without cardiac arrest was treated at a local hospital, from where he after a short stay was discharged without physical sequelae.

CONCLUSION

These cases are a reminder of the traditional mantra that «no one is dead until warm and dead». Good communication between pre- and in-hospital staff can be vital for optimizing patient treatment when handling victims of severe hypothermia, and especially when there is multiple victims. Communication between neighboring countries, but even neighboring regions within the same country, can be challenging. We encourage regions similar to ours to review protocols regarding hypothermia management, making them more robust before incidents like this take place.

Accidental hypothermia-an update : The content of this review is endorsed by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM)

BACKGROUND

This paper provides an up-to-date review of the management and outcome of accidental hypothermia patients with and without cardiac arrest.

METHODS

The authors reviewed the relevant literature in their specialist field. Summaries were merged, discussed and approved to produce this narrative review.

RESULTS

The hospital use of minimally-invasive rewarming for non-arrested, otherwise healthy, patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionised the management of hypothermic cardiac arrest, with survival rates approaching 100 % in some cases. Hypothermic patients with risk factors for imminent cardiac arrest (temperature <28 °C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS-centre. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanical CPR can be helpful. Delayed or intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern post-resuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimise pre-hospital triage, transport and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and post-resuscitation care.

CONCLUSIONS

Based on new evidence, additional clinical experience and clearer management guidelines and documentation, the treatment of accidental hypothermia has been refined. ECLS has substantially improved survival and is the treatment of choice in the patient with unstable circulation or cardiac arrest.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia: 2014 update

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations. This is an updated version of the original Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia published in Wilderness & Environmental Medicine 2014;25(4):425-445.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations.

Surviving two hours of ventricular fibrillation in accidental hypothermia

BACKGROUND

Cardiac arrest as a consequence of deep accidental hypothermia is associated with high mortality. Standardized prehospital management as well as rewarming with extracorporeal circulation (ECC) are important factors to improve survival. The objective of this case report is to illustrate the importance of effective cardiopulmonary resuscitation (CPR) and ECC in a cardiac arrest following deep accidental hypothermia.

CASE REPORT

A 42-year-old man was found unresponsive to external stimuli and pulseless at an outdoor temperature of 1°C. CPR was started at the scene by laypersons, and the emergency medical services (EMS) arrived 5 minutes after the emergency call. Resuscitation according to International Liaison Committee on Resuscitation (ILCOR) guidelines was initiated by EMS. The first recorded rhythm was ventricular fibrillation (VF), which persisted, despite repeated defibrillation. The patient showed signs of severe hypothermia and, during ongoing CPR, was transported to hospital where on arrival the patient's rectal temperature was measured at 22°C. Resuscitation measures were continued and warming was started at the emergency room. Due to persistent VF and deep hypothermia, the patient was transferred to a cardiothoracic surgical unit for rewarming with ECC. At commencement of ECC, CPR had been going for approximately 130 minutes and a total of 38 defibrillations had been made. During this time interval the patients was pulseless. At a core temperature of 30°C, one defibrillation restored sinus rhythm and subsequently stable circulation was achieved. The patient received a further 24 hours of hypothermia treatment at 32-34°C. He was discharged to rehabilitation facilities after 3 weeks of hospital care. Three months after the cardiac arrest the patient was fully recovered, was back to work, and had resumed normal activities.

CONCLUSIONS

We demonstrate a case of cardiac arrest due to deep accidental hypothermia that stresses the importance of effective CPR and early-stage consideration of the use of ECC for safe and effective rewarming.

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.

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.

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.

[Coronary revascularization during cardiopulmonary resuscitation. The bridge code]

Cardiac arrest is one of the major current challenges, due to both its high incidence and mortality and the fact that it leads to severe brain dysfunction in over half of the survivors. The so-called coronary origin Bridge Code is presented, based on the international resuscitation recommendations (2005, 2010). In accordance with a series of strict predictive criteria, this code makes it possible to: (1) select refractory CPR patients with a high or very high presumption of underlying coronary cause; (2) evacuate the patient using mechanical chest compressors [LucasTM, Autopulse®], maintaining coronary and brain perfusion pressures; (3) allow coronary revascularization access during resuscitation maneuvering (PTCA during ongoing CPR); (4) induce early hypothermia; and (5) facilitate post-cardiac arrest intensive care. In the case of treatment failure, the quality of hemodynamic support makes it possible to establish a second bridge to non-heart beating organ donation.

Feasibility of initiating extracorporeal life support during mechanical chest compression CPR: a porcine pilot study

BACKGROUND

Recently, portable extracorporeal membrane oxygenation (ECMO) machines have become commercially available. This creates the potential to utilize extracorporeal life support (ECLS) for the treatment of sudden cardiac arrest in the emergency department, and potentially in the out-of-hospital setting.

OBJECTIVE

We sought to determine the feasibility of installing the ECMO circuit during delivery of mechanical chest compression CPR.

METHODS

We used 5 mixed-breed domestic swine with a mean mass of 26.0 kg. After induction of anesthesia, animals were instrumented with micromanometer-tipped transducers placed in the aorta and right atrium via the left femoral artery and vein. Ventricular fibrillation (VF) was induced electrically with a transthoracic shock and left untreated for 8 min. Then, mechanical chest compressions were begun (LUCAS, Jolife, Lund, Sweden) and manual ventilations were performed to maintain ETCO(2) between 35 and 45Torr. Compressions continued until ECMO flow was started. Ten minutes after induction of VF, drugs were given (epinephrine, vasopressin, and propranolol). ECMO installation was started via cutdown on the right external jugular vein and right femoral artery for placement of venous and arterial catheters while chest compressions continued. ECMO installation start time varied from 17 to 30 min after start of compressions and continued until ECG indicated a shockable rhythm. First rescue shocks were given at 22, 32, 35, 44, and 65 min.

RESULTS

ECMO was successfully installed in all five animals without incident. It was necessary to briefly discontinue chest compressions during the most delicate part of inserting the catheters into the vessels. ECMO also allowed for very rapid cooling of the animals and facilitated post-resuscitation hemodynamic support. Only the 65-min animal did not attain return of spontaneous circulation (ROSC).

CONCLUSION

Mechanical chest compression may be a suitable therapeutic bridge to the installation of ECMO and does not interfere with ECMO catheter placement.

Prolonged closed cardiac massage using LUCAS device in out-of-hospital cardiac arrest with prolonged transport time

Saving more human lives through more effective reanimation measures is the goal of the new international guidelines on cardiopulmonary resuscitation as the decisive aspect for survival after cardiovascular arrest is that basic resuscitation should start immediately. According to the updated guidelines, the greatest efficacy in cardiac massage is only achieved when the right compression point, an adequate compression depth, vertical pressure, the correct frequency, and equally long phases of compression and decompression are achieved. The very highest priority is placed on restoring continuous circulation. Against this background, standardized continuous chest compression with active decompression has contributed to a favorable outcome in this case. The hydraulically operated and variably adjustable automatic Lund University Cardiac Arrest System (LUCAS) device (Jolife, Lund, Sweden) undoubtedly meets these requirements. This case report describes a 44-year-old patient who – approximately 15 min after the onset of clinical death due to apparent ventricular fibrillation – received cardiopulmonary resuscitation, initially by laypersons and then by the emergency medical team (manual chest compressions followed by situation-adjusted LUCAS compressions). Sinus rhythm was restored after more than 90 min of continuous resuscitation, with seven defibrillations. Interventional diagnostic workup did not reveal a causal morphological correlate for the condition on coronary angiography. After a 16-day period of hospital convalescence, with preventive implantation of an implantable cardioverter defibrillator and several weeks of rehabilitation, the patient was able to return home with no evidence of health impairment.

Vital organ blood flow with the impedance threshold device

OBJECTIVE

The purpose of this study is to review cardiopulmonary resuscitation hemodynamics and vital organ blood flow in animal models with the use of the impedance threshold device (ITD) and to correlate these findings with the results of human clinical trials.

RESULTS

Animal studies have demonstrated near normalization of cerebral blood flow and an increase between 50% and 100% in cardiac blood flow with use of the ITD. Coincident coronary perfusion pressure is significantly increased with the ITD. Results of human clinical trials generally reflect the data seen in animal models, with near normal blood pressure during active compression-decompression cardiopulmonary resuscitation and the ITD, near doubling of blood pressure with standard cardiopulmonary resuscitation plus the ITD, and significantly increased short-term survival rates.

CONCLUSIONS

Improved vital organ perfusion with ITD use during cardiopulmonary resuscitation is an important advance in resuscitation. Incorporation of the ITD into protocols that improve other aspects of the care of patients during cardiac arrest and after successful resuscitation should result in further benefit from the ITD.

Clinical consequences of the introduction of mechanical chest compression in the EMS system for treatment of out-of-hospital cardiac arrest—A pilot study

AIM

To evaluate the outcome among patients suffering from out-of-hospital cardiac arrest (OHCA) after the introduction of mechanical chest compression (MCC) compared with standard cardiopulmonary resuscitation (SCPR) in two emergency medical service (EMS) systems.

METHODS

The inclusion criterion was witnessed OHCA. The exclusion criteria were age < 18 years, the following judged etiologies behind OHCA: trauma, pregnancy, hypothermia, intoxication, hanging and drowning or return of spontaneous circulation (ROSC) prior to the arrival of the advanced life support (ALS) unit. Two MCC devices were allocated during six-month periods between four ALS units for a period of two years (cluster randomisation).

RESULTS

In all, 328 patients fulfilled the criteria for participation and 159 were allocated to the MCC tier (the device was used in 66% of cases) and 169 to the SCPR tier. In the MCC tier, 51% had ROSC (primary end-point) versus 51% in the SCPR tier. The corresponding values for hospital admission alive (secondary end-point) were 38% and 37% (NS). In the subset of patients in whom the device was used, the percentage who had ROSC was 49% versus 50% in a control group matched for age, initial rhythm, aetiology, bystander-/crew-witnessed status and delay to CPR. The percentage of patients discharged alive from hospital after OHCA was 8% versus 10% (NS) for all patients and 2% versus 4%, respectively (NS) for the patients in the subset (where the device was used and the matched control population).

CONCLUSION

In this pilot study, the results did not support the hypothesis that the introduction of mechanical chest compression in OHCA improves outcome. However, there is room for further improvement in the use of the device. The hypothesis that this will improve outcome needs to be tested in further prospective trials.