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Introduction: Advances in early defibrillation access, key to the “Chain of Survival”, will depend on innovations in defibrillation waveforms, because of their impact on device size and weight. This study compared standard monophasic waveform automatic external defibrillators (AEDs) to an innovative biphasic waveform AED. Material and methods: Impedance-compensated biphasic truncated exponential (ICBTE) and either monophasic truncated exponential (MTE) or monophasic damped sine (MDS) AEDs were prospectively, randomly assigned by date in four emergency medical services. The study design compared ICBTE with MTE and MDS combined. This subset analysis distinguishes between the two classes of monophasic waveform, MTE and MDS, and compares their performance to each other and to the biphasic waveform, contingent on significant overall effects (ICBTE vs. MTE vs. MDS). Primary endpoint: Defibrillation efficacy with ⩽ 3 shocks. Secondary endpoints: shock efficacy with ⩽ 1 shock, ⩽ 2 shocks, and survival to hospital admission and discharge. Observations included return of spontaneous circulation (ROSC), refibrillation, and time to first shock and to first successful shock. Results: Of 338 out-of-hospital cardiac arrests, 115 had a cardiac aetiology, presented with ventricular fibrillation, and were shocked by an AED. Defibrillation efficacy for the first “stack” of up to 3 shocks, for up to 2 shocks and for the first shock alone was superior for the ICBTE waveform than for either the MTE or the MDS waveform, while there was no difference between the efficacy of MTE and MDS. Time from the beginning of analysis by the AED to the first shock and to the first successful shock was also superior for the ICBTE devices compared to either the MTE or the MDS devices, while again there was no difference between the MTE and MDS devices. More ICBTE patients achieved ROSC pre-hospital than did MTE patients. While the rates of ROSC were identical for MTE and MDS patients, the difference between ICBTE and MDS was not significant. Rates of refibrillation and survival to hospital admission and discharge did not differ among the three populations. Conclusions: ICBTE was superior to MTE and MDS in defibrillation efficacy and speed and to MTE in ROSC. MTE and MDS did not differ in efficacy. There were no differences among the waveforms in refibrillation or survival.

In the management of cardiac arrest there is ongoing controversy concerning the optimal dose of epinephrine. To obtain the best available evidence regarding the current optimal dose, we performed a meta-analysis. We searched the Medline database online and reviewed citations in relevant articles to identify studies that met preset inclusion criteria (prospective, randomized, double-blind). Five trials were identified. The pooled odds ratio for return of spontaneous circulation favours the experimental dose. The pooled odds ratio for hospital discharge failed to demonstrate a statistically significant beneficial effect of high and/or escalating doses of epinephrine in comparison with standard dose of epinephrine. The possibility that patients who have already sustained irreversible neurologic injury will be resuscitated carries potential adverse social and economic implications.

Guidelines on how to initiate and continue car-diopulmonary resuscitation (CPR) after sudden deathfor hearts ‘‘too good to die’’ have been enthusiasti-cally dissiminated by the American Heart Association(AHA) and the European Resuscitation Council(ERC) [1,2].The tragedy of modern resuscitative medicine isthat occasionally the patient can be left with ‘‘a braintoo bad to live’’ [Cerebral Performance Category(CPC) IV]. Consequently, the early and accurate pre-diction of irreversible anoxic brain damage has anenormous socio-economic significance for an individ-ual patient. Although relatives should be involved inthis discussion whenever possible, they should neverfeel that they have to take sole responsibility for ma-king the decision. A number of clinical scales, electro-physiological techniques and laboratory tests havebeen developed to predict outcome in individual pa-tients after cardiac arrest, but their influence on thedecision to withdraw life support in daily practice isunclear.The purpose of this survey is to address the follow-ing questions:Who initiates the decision to withdraw life support?What medical factors influence this decision?Are there international differences with regard towithdrawing or withholding potentially ineffectiveadvanced life support after cardiac arrect? [3]1.1.

Incorrectly performed bystander CPR might compromise survival of the cardiac arrest patient. We therefore evaluated the outcome in 3306 out-of-hospital primary cardiac arrests of which 885 received bystander CPR. bystanders performed CPR correctly in 52%, incorrectly in 11%, 31% performed only external chest compressions (ECC) and 6% only mouth-to-mouth ventilation (MMV). The initial ECG in cases without bystander CPR was ventricular fibrillation in 28% (95% confidence interval: 27-30%); 45% (41-50%) and 39% (29-48%), respectively when bystander CPR was performed correctly or incorrectly; 43% (37-49%) when only ECC was applied and 22% (11-33%) when only MMV was practiced. Long term survival, defined as being awake 14 days after CPR, was 16% (13-19%) in patients with correct bystander CPR; 10% (7-14%) and 2% (0-9%), respectively when only ECC or only MMV was performed; 7% (6-8%) when no bystander was involved; 4% (0-8%) when bystander CPR was performed incorrectly. Bystander CPR might have a beneficial effect on survival by maintaining the heart in ventricular fibrillation by ECC. A negative effect of badly performed bystander CPR was not observed compared to cases which had not received bystander CPR.

The exact impact of the 'interval between cardiac arrest (CA) and the start of basic cardiopulmonary resuscitation (CPR) performed by bystanders' on outcome is not fully established. We retrospectively evaluated data with regard to response intervals of 1195 out-of-hospital CA interventions where bystander CPR was performed and continued by the eight mobile intensive care units (MICUs) participating in the Belgian Cerebral Resuscitation Registry between 1982 and 1990. Partial correlations between time elapsed from CALL to CPR by lay public and outcome were determined when the effect of response times of 1st and 2nd tier were removed. The following groups were studied: ventricular fibrillation (VF), asystole and electromechanical dissociation (EMD), non-witnessed and witnessed. Good outcome was represented by initial restoration of spontaneous circulation (ROSC successes) and by prolonged survival (CPR successes) being 22.7 and 9.7%, respectively. The mean time +/- S.E.M. between CALL and CPR initiated by lay people for the studied population (n = 1195) was 2.5 +/- 0.1 min. The partial correlation coefficient between prolonged survival and time passed between CALL and bystander CPR was negative for all types of CA, yet significance was reached only in the non-witnessed group. Using ROSC as the endpoint significance is achieved in all groups except the VF patients, where the intervention times were shorter. In our population, prolonged survival was independently and negatively influenced by a delay between CALL and any CPR in the non-witnessed CA group (n = 421).

Summary Aim of the study The admission blood glucose level after cardiac arrest is predictive of outcome. However the blood glucose levels in the post-resuscitation period, that are optimal remains a matter of debate. We wanted to assess an association between blood glucose levels at 12 h after restoration of spontaneous circulation and neurological recovery over 6 months. Materials and methods A total of 234 patients from a multi-centre trial examining the effect of mild hypothermia on neurological outcome were included. According to the serum glucose level at 12 h after restoration of spontaneous circulation, quartiles (Q) were generated: Median (range) glucose concentrations were for QI 100 (67–115 mg/dl), QII 130 (116–143 mg/dl), QIII 162 (144–193 mg/dl) and QIV 265 (194–464 mg/dl). Results In univariate analysis there was a strong non-linear association between blood glucose and good neurological outcome (odds ratio compared to QIV): QI 8.05 (3.03–21.4), QII 13.41 (4.9–36.67), QIII 1.88 (0.67–5.26). After adjustment for sex, age, “no-flow” and “low-flow” time, adrenaline (epinephrine) dose, history of coronary artery disease and myocardial infarction, and therapeutic hypothermia, this association still remained strong: QI 4.55 (1.28–16.12), QII 13.02 (3.29–49.9), QIII 1.37 (0.38–5.64). Conclusion There is a strong non-linear association of survival with good neurological outcome and blood glucose levels 12 h after cardiac arrest even after adjusting for potential confounders. Not only strict normoglycaemia, but also blood glucose levels from 116 to 143 mg/dl were correlated with survival and good neurological outcome, which might have an important therapeutic implication.

Objective: Assuming that a lay person performing cardiopulmonary resuscitation (CPR) will also use an automatic external defibrillator (AED) wherever available, we tried to estimate the maximal attainable benefit of public access defibrillation in some centres in Belgium. Methods: We analysed retrospectively the data from the Belgian Cardio Pulmonary Cerebral Resuscitation Registry collected between 1991 and June 1996. The majority of these emergency medical service (EMS) systems are two-tiered with an early defibrillation program for the first tier and a physician-staffed second tier. Results: The data show that, in 5543 registered cases, there were 1001 (18%) adults with non-traumatic ventricular fibrillation/ventricular tachycardia (VF/VT) as the first monitored rhythm. In this subgroup there were 419 (42%) cases who had lay CPR. The duration of lay CPR before the first defibrillation either by the first or the second tier is known in 357 cases. This duration was more than 5 min and 10 min, in 80% and 53% of the cases, respectively. The median (Q 1 , Q 3 ) lay CPR duration was 11 (7, 15) min. Survival to hospital discharge in this subgroup was achieved in 80/357 (22%) patients. Using Weaver's linear model for survival after witnessed VF/VT, an estimated increase of more than 30% in survival rate was calculated. Conclusion: It is concluded that in our EMS system, laymen reach a substantial number of VF/VT victims many minutes before the arrival of the professional EMS teams. Therefore, a substantial increase in the number of survivors could be expected if lay responders were prepared to use an AED.

Assuming that a lay person performing cardiopulmonary resuscitation (CPR) will also use an automatic external defibrillator (AED) wherever available, we tried to estimate the maximal attainable benefit of public access defibrillation in some centres in Belgium.We analysed retrospectively the data from the Belgian Cardio Pulmonary Cerebral Resuscitation Registry collected between 1991 and June 1996. The majority of these emergency medical service (EMS) systems are two-tiered with an early defibrillation program for the first tier and a physician-staffed second tier.The data show that, in 5543 registered cases, there were 1001 (18%) adults with non-traumatic ventricular fibrillation/ventricular tachycardia (VF/VT) as the first monitored rhythm. In this subgroup there were 419 (42%) cases who had lay CPR. The duration of lay CPR before the first defibrillation either by the first or the second tier is known in 357 cases. This duration was more than 5 min and 10 min, in 80% and 53% of the cases, respectively. The median (Q1, Q3) lay CPR duration was 11 (7, 15) min. Survival to hospital discharge in this subgroup was achieved in 80/357 (22%) patients. Using Weaver's linear model for survival after witnessed VF/VT, an estimated increase of more than 30% in survival rate was calculated.It is concluded that in our EMS system, laymen reach a substantial number of VF/VT victims many minutes before the arrival of the professional EMS teams. Therefore, a substantial increase in the number of survivors could be expected if lay responders were prepared to use an AED.

In the current climate of rising healthcare cost, resuscitation efforts performed outside the hospital are critically evaluated because of their limited success rate in some settings. As part of a quality assurance program between the 1st January 1991 and 31st December 1993, six centres of the Belgian CPCR study group prospectively registered cardiac arrest (CA) patients and their treatment according to the Ustein Style recommendations. In the group (n = 511) of patients initially found in ventricular fibrillation (VF) a significantly better survival rate was observed for those patients who received a 1st defibrillatory shock by the 1st tier (n = 142 (27.8%)) as compared to those defibrillated after arrival of the 2nd tier (n = 369 (72.2%)). Median time to delivery of the first shock was significantly shorter (5 min) in the 1st tier group. In a second part of the study we describe long-term management of the 28 surviving VF patients, treated by the single EMS system of Brugge between 1st January 1991 and 30th April 1995: only 6 patients eventually received an implantable cardioverter defibrillator (ICD), whereas coronary revascularization was performed in 9 patients, and 3 patients were discharged on amiodarone only. Satisfactory long-term survival after out-of-hospital VF can be achieved by an early shock followed by advanced life support and appropriate definitive treatment.

Incorrectly performed bystander CPR might compromise survival of the cardiac arrest patient. We therefore evaluated the outcome in 3306 out-of-hospital primary cardiac arrests of which 885 received bystander CPR. bystanders performed CPR correctly in 52%, incorrectly in 11%, 31% performed only external chest compressions (ECC) and 6% only mouth-to-mouth ventilation (MMV). The initial ECG in cases without bystander CPR was ventricular fibrillation in 28% (95% confidence interval: 27-30%); 45% (41-50%) and 39% (29-48%), respectively when bystander CPR was performed correctly or incorrectly; 43% (37-49%) when only ECC was applied and 22% (11-33%) when only MMV was practiced. Long term survival, defined as being awake 14 days after CPR, was 16% (13-19%) in patients with correct bystander CPR; 10% (7-14%) and 2% (0-9%), respectively when only ECC or only MMV was performed; 7% (6-8%) when no bystander was involved; 4% (0-8%) when bystander CPR was performed incorrectly. Bystander CPR might have a beneficial effect on survival by maintaining the heart in ventricular fibrillation by ECC. A negative effect of badly performed bystander CPR was not observed compared to cases which had not received bystander CPR.