CPR courses and semi-automatic defibrillators--life saving in cardiac arrest?

OBJECTIVES: The aim was to assess the knowledge of life-supporting first-aid in both cardiac arrest survivors and relatives, and their willingness to have a semi-automatic external defibrillator in their homes and use it in an emergency. MATERIAL AND METHODS: Cardiac arrest survivors, their families, friends, neighbours and co-workers were interviewed by medical students using prepared questionnaires. Their knowledge and self-assessment of life-supporting first-aid, their willingness to have a semi-automatic defibrillator in their homes and their willingness to use it in an emergency before and after a course in cardiopulmonary resuscitation (CPR) with a semi-automatic external defibrillator was evaluated. Courses were taught by medical students who had received special training in basic and advanced life support. RESULTS: Both patients and relatives, after a course of 2-3 h, were no longer afraid of making mistakes by providing life-supporting first-aid. The automated external defibrillator (AED) was generally accepted and considered easy to handle. CONCLUSION: We consider equipping high-risk patients and their families with AEDs as a viable method of increasing their survival in case of a recurring cardiac arrest. This, of course, should be corroborated by further studies.     

High acceptance of a home AED programme by survivors of sudden cardiac arrest and their families

PURPOSE: The feasibility and acceptance of providing sudden cardiac arrest survivors with life supporting first aid training and automated external defibrillators (AEDs) at their homes is unknown. Preliminary experiences are reported here. METHODS: Trained medical students provided life supporting first aid courses including AED training to cardiac arrest survivors. Patients were asked to invite relatives and friends to such training sessions at their home. Laerdal Little Anne and Heartstart AED Trainer were used. An AED was placed at the patients' disposal. A refresher course took place 1 year later. Questionnaires were used to evaluate the project. RESULTS: Since 1999, 88 families have been trained and provided with an AED. Immediately after the training 90% (66% "agree", 24% "maybe yes") believed they would perform first aid correctly, 1 year later 98% did so (68% "agree", 29% "maybe yes") (p=0.03). Families considered feeling much safer having an AED at home. The handling of an AED was regarded to be easy and AEDs would even be used on strangers. Only on one occasion an AED was used in a real emergency situation. CONCLUSION: Providing patients and relatives with life support first aid and AED training at their homes is feasible and has raised no major objections by the family members. All have considered handling of an AED much simpler than providing basic life support and therefore none think that it would be a major problem to use it in case of an emergency. This still has to be proven.     

Evaluation of M-AID, a first aid application for mobile phones

BACKGROUND: When performed effectively, cardiopulmonary resuscitation (CPR) by bystanders reduces mortality due to sudden cardiac arrest. Telemedicine applications offer a means by which bystanders can get specific instructions for handling the emergency situation. M-AID, a first aid application for mobile phones, uses an intelligent algorithm of 'yes' or 'no' questions to judge the ongoing situation and give the user detailed instructions. The aim of this study was to evaluate the benefit of this mobile phone application in a scenario of sudden cardiac arrest. METHODS: One hundred and nineteen volunteers were assigned at random either to the test or the control group. All participants were confronted with the same scenario of acute coronary syndrome leading to cardiac arrest. The participants were either equipped with a mobile phone running the software (test group) or had to handle the situation without support (control group). The participants received a certain amount of credits for each action taken according to a pre-defined protocol and these credits were added to a score and compared between the groups. Participants were divided into subgroups according to their medical and technical experience. RESULTS: The test group generally achieved a slightly higher average score that was not statistically significant (21.11 versus 19.97; p=0.302). In contrast, the performance of the individuals in the control group was significantly faster (2.41 min versus 4.24 min; p<0.001). Use of the mobile phone software did not enhance the chance of survival. Subgroup analysis showed that experienced mobile phone users performed significantly better than non-experienced individuals, but not as well as participants with advanced first aid knowledge. CONCLUSIONS: Experience in the use of mobile phones is a prerequisite for the efficient use of the tested M-AID version. This application cannot replace skills acquisition by practical training. In a subgroup with experience in mobile phone use and basic knowledge in CPR, the device improved performance of CPR.     

The knowledge and perceptions of medical personnel relating to outcome after cardiac arrest

OBJECTIVE: We sought to evaluate the knowledge of probable outcome by medical personnel for in-hospital and out-of-hospital cardiac arrests, and self-reported history of CPR training referrals for family members of cardiac patients. METHODS: One hundred people from each of three population lists were randomly selected at a large, urban school of medicine and affiliated medical center: (1) year III and IV medical students; (2) residents in family medicine, emergency medicine, internal medicine, anesthesia, and surgery; (3) attending physicians in the same departments. A questionnaire was distributed that elicited estimates of in-hospital and out-of-hospital cardiac arrest (IHCA and OHCA, respectively) survival rates, and CPR training referral history. Estimates were compared against published data for accuracy (IHCA: 5-20%; OHCA 1-10%) RESULTS: The overall response rate was 63%. Accurate in-hospital cardiac arrest estimates [% (95% CI)] of survival were provided by 51.1% (36.8-63.4%), 47.3% (35.9-58.7%), and 36.7% (23.2-50.2%) of students, residents, and attending physicians, respectively. Accurate out-of-hospital estimates of survival were provided by 51.1% (36.8-63.4%), 52.1% (40.6-63.5%), and 70.8% (57.9-83.7%), respectively. Most thought that family members of cardiac patients ought to be CPR trained (92.6%). However, few had referred any for training in the past year (16.5%). There was strong support across respondent groups for including death notification information in the ACLS training program, with 80.4% of all respondents in favor. CONCLUSIONS: This study demonstrates that medical experience is not associated with accurate estimates of cardiac arrest survival. Overwhelmingly, medical personnel believe family members should be trained to perform CPR, however, few refer family members for CPR training.     

Characteristics and outcome among patients suffering from in hospital cardiac arrest in relation to the interval between collapse and start of CPR

AIM: To describe survival after in-hospital cardiac arrest in relation to the interval between collapse and start of cardiopulmonary resuscitation (CPR). PATIENTS: All patients suffering in-hospital cardiac arrest in Sahlgrenska University Hospital in G?teborg, Sweden between 1994 and 1999 in whom resuscitative efforts were attempted and for whom the interval between collapse and start of CPR was known. METHODS: Prospective recording of various factors at resuscitation including the interval between collapse and start of CPR. Retrospective evaluation via medical records of patients' previous history, clinical situation prior to cardiac arrest and final outcome. RESULTS: Survival to discharge was 33% among the 344 patients in whom CPR was started within the first minute as compared with 14% among the 88 patients in whom CPR started more than 1 min after collapse (P=0.008). The corresponding figures for patients found in ventricular fibrillation was 50 versus 32% (NS); for patients found in pulseless electrical activity 9 versus 3% (NS) and for patients found in asystole 19 versus 0% (NS). Correcting for dissimililarties in the previous history and factors at resuscitation, the adjusted odds ratio and 95% confidence limits for being discharged from hospital when CPR was started within 1 min compared with a later start was 3.06 with 95% confidence limits of 1.59-6.31. CONCLUSION: Among patients with in-hospital cardiac arrest in whom the interval between collapse and start of CPR was known, we found that in 80% of the cases CPR was started within the first minute after collapse. Among these patients, survival to discharge was twice that of patients in whom CPR was started later. These results highlight the importance of immediate CPR after in-hospital cardiac arrest.     

Quality of life 6-months after cardiac arrest

BACKGROUND: Evaluation of outcome after cardiac arrest focuses mainly on survival. Survivors of cardiac arrest end up in different states of health and survival alone may not be a sensitive measure for successful cardiopulmonary resuscitation (CPR). OBJECTIVES: To evaluate health-related quality of life (HR-QOL) of cardiac arrest survivors with EQ-5D, a generic instrument developed by the EuroQol group. PATIENTS AND METHODS: From April 1997 to December 2000, all cardiac arrest adult patients admitted to an eight-bed medical/surgical (ICU) of a tertiary care hospital were enrolled. At 6-months after ICU discharge survivors attended a follow-up interview and answered EQ-5D questionnaire. A match-control group was created choosing for each survivor of cardiac arrest two controls, with similar age range (+/-5 years) and similar Apache II (+/-3 Apache II units), that were randomly selected among other ICU patients. RESULTS: From a total of 1106 patients, 97 (9%) patients were admitted after cardiac arrest. Forty-seven patients (48%) were discharged from ICU. Of these, 11 patients died in the ward. Thirty-six (37%) patients were discharged from hospital. Twelve patients died after hospital discharge but before 6-month evaluation. Five patients were not evaluated, three because they were living in distant locations and two for unknown reasons. Nineteen patients attended the follow-up consultation. Eight of these patients were actively working and six of them had managed to return to their previous activity. Eleven patients were retired and seven of these managed to return to their previous level of activity while four patients presented with anoxic encephalopathy: one with mild and one with moderate neurological dysfunction, two with severe anoxic neurological dysfunction. Although a higher percentage of cardiac arrest survivors reported more extreme problems in some dimensions than other ICU patients, no significant differences were found on HR-QOL, when evaluated by EQ-5D. CONCLUSIONS: When evaluated with EQ-5D at 6-months after ICU discharge, survivors of cardiac arrest exhibit a HR-QOL similar to other ICU survivors. These results agree with previous reports stating that CPR is frequently unsuccessful but if survival is achieved a fairly good quality of life can be expected.     

Motivation and adult learning: a survey among hospital personnel attending a CPR course

AIM OF THE STUDY: A massive cardiopulmonary resuscitation (CPR) training programme is continued in most hospitals to make hospital personnel ready to take action in cases of cardiac arrest. Motivated course participants learn more and perform better than unmotivated course participants. This study investigates whether hospital personnel are motivated to participate in CPR courses and whether motivation correlates with important assumptions in adult learning. MATERIALS AND METHODS: A survey measuring learning motivation via the MSLQ instrument was performed among 361 hospital personnel before attending a CPR course. Assumptions of adult learning were identified and data were analysed in relation to these assumptions. RESULTS: Hospital personnel are generally motivated for learning CPR. Respondents who had been prepared for the course, who had participated in the decision about attending the course, who were working in high-risk area for cardiac arrest or were nursing personnel working in long-time close contact with patients were more motivated to CPR training than other hospital personnel. It seems like motivation correlates with adult learning assumptions such as the learners need to know, the learners self-concept, readiness to learn and orientation to learning. CONCLUSION: This study supports the assumption that CPR training should be based on an adult learning model. As preparedness, participation, readiness and relevance seem to be key factors, we may want to include these factors when training hospital personnel in CPR skills.     

Outcome from paediatric cardiac arrest associated with trauma

OBJECTIVE: To examine survival rates for paediatric trauma patients requiring cardiopulmonary resuscitation (CPR) in the pre-hospital setting, and to identify characteristics that may be associated with survival. DESIGN: Ten-year retrospective trauma database review. SETTING: An urban physician-led pre-hospital trauma service serving a population of approximately 7.5 million, in the United Kingdom. PATIENTS: Eighty paediatric trauma patients (15 years or less) who received pre-hospital resuscitation following cardiorespiratory arrest between July 1994 and June 2004. INTERVENTION: Pre-hospital cardiopulmonary resuscitation. MAIN OUTCOME MEASURE: Survival to hospital discharge. RESULTS: Eighty children met inclusion criteria for the study. Nineteen (23.8%) were discharged alive from the emergency department and seven children (8.75%) survived to hospital discharge. Of the seven survivors, one had spinal cord injury. Two suffered asphyxial injury associated with blunt trauma and three sustained hypoxic insults following drowning or burns/smoke inhalation. In one patient with known congenital cardiac disease the cause of cardiac arrest was likely to have been medical. CONCLUSION: This study confirms the poor outcome for children requiring pre-hospital CPR following trauma. However, the results are better in this physician-attended group than in other studies where physicians were not present. They also suggest that cardiac arrest associated with trauma in children has a better outcome than in adults. In common with adults treated in this system, those patients with hypovolaemic cardiac arrest did not survive (Ann Emerg Med 2006;48:240-4). A large proportion of the survivors suffered hypoxic or asphyxial injuries. Targeted aggressive out-of-hospital resuscitation in certain patient groups can produce good outcomes.     

Simulated pediatric cardiopulmonary resuscitation: initial events and response times of a hospital arrest team

BACKGROUND: Cardiopulmonary resuscitation (CPR) training programs exist to enhance knowledge and skills retention. However, they do not ensure that effective CPR will be performed by trainees or resuscitation teams. One aspect of CPR effectiveness is the ability of the team to respond to an emergency call in a timely manner. METHODS: We prospectively evaluated the time required for team members to respond to an emergency call and to initiate definitive treatment in our pediatric facility. The medical staff who responded had no prior knowledge of the simulated cardiac arrest (SCA) events. All events were recorded on audio-cassette tape to determine the sequence of events and response time of arrest team members. SCA scenarios represented examples of cardiac, hematologic, renal, respiratory, and pharmacologic pathophysiology. All participants were instructed to respond as though the SCA were an actual emergency. RESULTS: From December 1991 to January 1993, 37 SCAs were evaluated. Documentation began after a concise arrest scenario had been presented to a designated nursing representative who was to be the first rescuer on the scene. The rescuer first assessed the patient's condition, activated the cardiac arrest system (median elapsed time, MET, 0.50 minutes), and then initiated single-person CPR (MET 0.58 minutes). Administration of oxygen occurred at an MET of 2.25 minutes. The first member of the arrest team to respond was the pediatric resident (MET 3.17 minutes) followed by the respiratory therapist (MET 3.20 minutes), an ICU nurse (MET 3.58 minutes), a pharmacist (MET 3.42 minutes), and anesthesiology personnel (MET 4.70 minutes). DISCUSSION: The use of SCAs (termed "Mega Code") serves as an extension of Basic Life Support and Advanced Cardiac Life Support education and provides a valuable learning experience and quality assurance tool. Limitations that might influence patient outcome during an actual in-hospital arrest have led to refinements in our cardiac arrest procedures. Of particular note was the delay in oxygen administration, which may be linked to its omission from the 1986 and 1992 American Heart Association Basic Life Support Guidelines. CONCLUSION: We believe that BLS education for hospital employees should include and emphasize oxygen delivery for resuscitation.     

Infectious complications in survivors of cardiac arrest admitted to the medical intensive care unit

PURPOSE: To describe the incidence, associated factors and outcome of infectious complications in patients admitted to the medical intensive care unit (MICU) after cardiopulmonary resuscitation (CPR). MATERIALS AND METHODS: We identified a retrospective cohort of 56 patients consecutively admitted to MICU after CPR. We collected data on demographics, the first MICU day APACHE III score, mode and location of cardiac arrest, CPR duration, witnessed aspiration, prior antibiotics, the lowest first MICU day Glasgow coma score (GCS), new infections, duration of mechanical ventilation and mortality. RESULTS: Seventy-nine percent of the arrests occurred in the hospital. Pulseless electrical activity was the most common rhythm (52%). New infections developed in 46%. The most common infection was pneumonia (65%) and the most common pathogen Staphylococcus aureus (31%). Blood cultures were obtained in 40 patients during the first 48 h and pathogens were isolated in five (12.5%). Patients with infection were younger (53.7 vs. 70.4 years, P<0.001). Median first day GCS was eight in-patients with infection compared with ten in those without (P=0.032). Patients with infection had longer duration of mechanical ventilation (median 9 vs. 2 days, P=0.001) and MICU length of stay (median 8 vs. 3 days, P<0.001). Hospital mortality was 54% in-patients with infection versus 37% without (P=0.197). CONCLUSIONS: Infectious complications are common in survivors of cardiac arrest and are associated with increased morbidity.     

In-hospital cardiac arrest--an Utstein style report of seven years experience from the Sahlgrenska University Hospital

BACKGROUND: In-hospital cardiac arrest is one of the most stressful situations in modern medicine. Since 1997, there has been a uniform way of reporting - the Utstein guidelines for in-hospital cardiac arrest reporting. MATERIAL AND METHODS: We have studied all consecutive cardiac arrest in the Sahlgrenska University Hospital (SU) between 1994 and 2001 for who the rescue team was alerted in all 833 patients. The primary endpoint for this study was survival to discharge. RESULTS: Thirty-seven percent survived to hospital discharge. Among patients who were discharged alive, 86% were alive 1 year later. The survivors have a good cerebral outcome (94% among those who were discharged alive had cerebral performance category (CPC) score 1 or 2). The organization at SU is efficient; 80% of the cardiac arrest had CPR within 1 min. Time from cardiac arrest to first defibrillation is a median of 2 min. Almost two-thirds of the patients were admitted for cardiac related diagnoses. CONCLUSION: The current study is the largest single-centre study of in hospital cardiac arrest reported according to the Utstein guidelines. We report a high survival for in-hospital cardiac arrest. We have pointed out that a functional chain of survival, short intervals before the start of CPR and defibrillation are probably contributing factors for this.     

Exclusion of a patient assessment interval and extension of the CPR interval both mitigate post-resuscitation myocardial dysfunction in a swine model of cardiac arrest

AIM OF STUDY: Interruptions in cardiopulmonary resuscitation (CPR), particularly as guided by automated external defibrillators, have been implicated in poor survival from cardiac arrest. Interruptions of CPR may be reduced by eliminating repetition of shocks between periods of CPR, elimination of the interval for patient assessment before CPR, and extension of the periods of CPR. MATERIALS AND METHODS: The effects of exclusion of a 30s post-shock assessment interval prior to CPR and use of a longer interval (180s versus 90s) of CPR on resuscitation and post-resuscitation function were assessed in a factorial design using an established swine model of cardiac arrest. Repetitive shocks were excluded. Ventricular fibrillation was induced ischemically and maintained untreated for 5min. RESULTS: All subjects were resuscitated, 95% survived 3 days, and 97% of survivors had full neurological recovery. Exclusion of the assessment interval reduced the delay to first return of spontaneous circulation by 33.1s (P=0.004) and the delay to sustained resuscitation by 99.2s (P=0.004), reduced post-resuscitation ECG ST elevation by 0.12mV (P=0.03), and alleviated transient post-resuscitation ejection fraction reduction (P<0.0001). Extension of the CPR interval reduced transient post-resuscitation fractional area change impairment (P=0.003). CONCLUSIONS: Exclusion of an interval for assessment of airway, breathing and signs of circulation mitigates post-resuscitation dysfunction in a swine model of cardiac arrest. Extension of the period of CPR independently provides measurable, though less comprehensive, mitigation as well.     

Treatment of out-of-hospital cardiac arrest with LUCAS, a new device for automatic mechanical compression and active decompression resuscitation

Lund University Cardiopulmonary Assist System (LUCAS) is a new gas-driven CPR device providing automatic chest compression and active decompression. This is a report of the first 100 consecutive cases treated with LUCAS due to out-of-hospital cardiac arrest (58% asystole, 42% ventricular fibrillation (VF)). Safety aspects were also investigated and it was found that LUCAS can be used safely regarding noise levels and oxygen concentrations within the ambulance. A crash test (10G) showed no displacement of the device from the manikin. Of the 71 patients with witnessed cardiac arrest, 39% received bystander CPR. In those 28 patients where LUCAS-CPR was initiated more than 15 min after the ambulance alarm and in the 29 unwitnessed cases, none survived for 30 days. Of the 43 witnessed cases treated with LUCAS within 15 min, 24 had VF and 15 (63%) of these cases achieved a stable return of spontaneous circulation (ROSC) and 6 (25%) of them survived with a good neurological recovery after 30 days; 5 (26%) of the 19 patients with asystole achieved ROSC and 1 (5%) survived for over 30 days. One patient where ROSC could not be achieved was transported with on-going LUCAS-CPR to the catheter laboratory and after PCI for an occluded LAD a stable ROSC occurred, but the patient never regained consciousness and died 15 days later. To conclude, establishment of an adequate cerebral circulation as quickly as possible after cardiac arrest is mandatory for a good outcome. In this report patients with a witnessed cardiac arrest receiving LUCAS-CPR within 15 min from the ambulance call had a 30-day survival of 25% in VF and 5% in asystole, but if the interval was more than 15 min, there were no 30-day survivors.     

Preliminary study of the relationship between the cardiopulmonary arrest time and its consequences in trauma patients

The proposal of this research was to obtain parameters to start or maintain cardiopulmonary resuscitation (CPR) in victims of trauma. The duration of the cardiac arrest and the CPR of the survivors was described, as well as the cerebral performance and the mortality of these victims 24, 48 and 72 hours after these events had happened. With the results of this characterization the relation between duration of cardiac arrest time, CPR and mortality were described. Data for this report were collected in Hospital das Clínicas da Faculdade de Medicina da Universidade de S?o Paulo emergency department. A big amount of the victims (93.4%) presents severe trauma and main cause of death was brain injury. Survival at 72 hours after CPR was 10%. The assessment, during the 72 hour period, of the survivors from cardiac arrest of traumatic cause has shown bad cerebral performance of those victims in that period of time. The survivor after the first episode of CPR was strongly related to cardiac arrest time when compared with CPR time. The time of cardiac arrest < or = 4 minutes and CPR < or = 20 minutes was related to survival more than 72 hours.     

中学校园普及心肺复苏的重要性研究

目的：通过心肺复苏（CPR）培训教育使中学生对心搏骤停者做出迅速反应,完成现场CPR急救,提高CPR知识的普及范围。方法：采用急救知识进校园的现场培训方式,以2010年颁布的新版心肺复苏指南为教材,开展多媒体讲座和现场操作示范教学培训活动,理论和操作相结合,特别注重培养学生的实际动手操作能力,使受训学生学会院前急救知识。结果：培训结束时进行考核,接受培训的学生一次通过考核合格率为98.4%。结论：现代心肺复苏术是最为简单有效、易于学习、易于掌握的救命技术,急救培训是向公众普及急救知识的一个好方法,具有可行性,通过对中学生进行CPR培训,进一步在公众中推广CPR急救知识和技能。     

Knowledge, skills and counselling behaviour of Belgian general practitioners on CPR-related issues.

General practitioners (GP) can identify potential cardiac arrest victims. They have the opportunity to inform cardiac patients and their families about the risk of sudden cardiac death and can motivate family members to attend a CPR-course. To study actual counselling practices concerning basic CPR-training a questionnaire was mailed to a representative sample of Belgian GPs (n = 1119). The level of CPR-training of the GPs was fairly good: 67% had received BLS training on a manikin and 63% had already attended a cardiac arrest event. A discrepancy was observed between the positive attitude towards CPR and the counselling of family members to attend a CPR-course (9%). GPs feared to inflict additional stress to the patient (32%) or the family (43%) or did not know where CPR courses were organised (37%). GPs are a primary target group for CPR-training and should learn how to counsel potential bystanders of a cardiac arrest to attend a CPR-course without inflicting additional anxiety on the patient or his family.     

Public perceptions and experiences of myocardial infarction, cardiac arrest and CPR in London

INTRODUCTION: The lay public have limited knowledge of the symptoms of myocardial infarction ("heart attack"), and inaccurate perceptions of cardiac arrest survival rates. Levels of CPR training and willingness to intervene in cardiac emergencies are also low. AIMS: To explore public perceptions of myocardial infarction and cardiac arrest; investigate perceptions of cardiac arrest survival rates; assess levels of training and attitudes towards CPR, and explore the types of interventions considered useful for increasing rates of bystander CPR among Greater London residents. METHODS: A quantitative interview survey was conducted with 1011 Greater London residents. Eight focus groups were also conducted to explore a range of issues in greater depth and validate trends that emerged in the initial survey. RESULTS: Chest pain was the most commonly recognised symptom of "heart attack". Around half of the respondents were aware that a myocardial infarction differs from a cardiac arrest, although their ability to explain this difference was limited. The majority overestimated that at least a quarter of cardiac arrest patients in London survive to hospital discharge. Few participants had received CPR training, and most were hesitant about performing the procedure on a stranger. CONCLUSIONS: Awareness and knowledge of CPR, and reactions to cardiac emergencies, reflect relatively low levels of CPR training in London. Publicising cardiac arrest survival figures may be instrumental in prompting members of the public to train in CPR and motivating those who have been trained to intervene in a cardiac emergency.     

Resuscitation Outcomes Consortium (ROC) PRIMED cardiac arrest trial methods part 1: rationale and methodology for the impedance threshold device (ITD) protocol

AIM: The primary aim of this study is to compare survival to hospital discharge with a modified Rankin score (MRS)< or =3 between standard cardiopulmonary resuscitation (CPR) plus an active impedance threshold device (ITD) versus standard CPR plus a sham ITD in patients with out-of-hospital cardiac arrest. Secondary aims are to compare functional status and depression at discharge and at 3 and 6 months post-discharge in survivors. MATERIALS AND METHODS: Design: Prospective, double-blind, randomized, controlled, clinical trial. Population: Patients with non-traumatic out-of-hospital cardiac arrest treated by emergency medical services (EMS) providers. Setting: EMS systems participating in the Resuscitation Outcomes Consortium. Sample size: Based on a one-sided significance level of 0.025, power=0.90, a survival with MRS< or =3 to discharge rate of 5.33% with standard CPR and sham ITD, and two interim analyses, a maximum of 14,742 evaluable patients are needed to detect a 6.69% survival with MRS< or =3 to discharge with standard CPR and active ITD (1.36% absolute survival difference). CONCLUSION: If the ITD demonstrates the hypothesized improvement in survival, it is estimated that 2700 deaths from cardiac arrest per year would be averted in North America alone.