Anomalous ECG downloads from semi-automatic external defibrillators.

The coincidental print-out by two different Laerdal systems (subsequently called 'system A' and 'system B') of the same medical control module (MCM) for a Laerdal Heartstart 2000 semi-automatic external defibrillator (SAED) led to the discovery of three deficiencies in the information storage and printing processes. First, we noted that the impedance reported via system A was consistently higher. Second, we found the attachment of 'mysterious' ECG samples in the reports from system B, but not from system A. A third problem was the unpredictable (in)ability of system B to print out the information from the MCMs. Further investigations with help from the company suggested that the above-mentioned problems were caused by incompatibilities between the software in the different parts of equipment used (i.e. SAED devices, MCMs, printing systems and a computer program to store the information in a database). These observations demonstrate the need for strict medical supervision on all aspects of a SAED project, and for feed-back from clinicians to manufacturers.

Theoretical calculation of maximum attainable benefit of public access defibrillation in Belgium. Belgian Cardio Pulmonary Cerebral Resuscitation Study Group.

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 (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. 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.

The effect of semi-automatic external defibrillation by emergency medical technicians on survival after out-of-hospital cardiac arrest: an observational study in urban and rural areas in Belgium.

The introduction of semi-automatic external defibrillators (SAEDs) allowed emergency medical technicians (EMTs) to deliver electroshocks in cases of out-of-hospital ventricular fibrillation (VF) or ventricular tachycardia (VT), often many minutes before the arrival of the mobile intensive care unit (MICU) team. In this observational study we report on the results obtained by the EMTs from the fire departments of Gent, Aalter and Brugge. In Gent, an SAED project started in May 1991. By December 1995, the SAED's electrodes had been attached in 367 cardiac arrest patients. The first rhythm detected by the device was asystole or electromechanical dissociation (EMD) in 241 patients (66%): only 5 of these patients survived to hospital discharge (2%). In the remaining 126 VF/VT cases (34%) the survival rate was 21% (26/126). In 14 of these 26 patients the shock(s) delivered by the EMTs restored spontaneous circulation before the arrival of the MICU team, with only venous cannulation and/or intubation being performed by the MICU team. In 4 other VF patients, the shock(s) delivered by EMTs converted the VF, with the MICU team successfully taking care of VF/VT relapses or postcountershock EMD. In the remaining 8 VF/VT cases, only the MICU attempts could resuscitate the patient. The SAED project in Aalter was set up in April 1993. By December 1995, care was taken for only 21 patients. None of the 4 VF/VT patients and the 17 asystole/EMD patients survived. In Brugge, there were 240 cardiac arrest cases treated with SAED between January 1991 and December 1995. Among the 89 VF/VT cases, there were 20 survivors (22%): 8 cases survived thanks to SAED shock(s) delivered by EMTs, in 3 cases survival was due to the combination of SAED shock(s) by EMTs and extensive ALS treatment by the MICU team, and in 9 cases restoration of spontaneous circulation was only obtained after application of ALS techniques by the MICU team. This observational study seems to show a beneficial effect of the introduction of SAED in Gent and Brugge. In Aalter the number of treated cases is tool low to draw conclusions. Anyhow, the global survival rate in the three areas remains low. Therefore, more efforts are needed to strengthen the other links of the chain of survival (early access to the emergency medical services-system, early basic cardiopulmonary resuscitation and early advanced life support.

Do victims of an out-of-hospital cardiac arrest benefit from a training program for emergency medical dispatchers?

In this paper, we assessed the effects of a training course for emergency medical dispatchers on the handling of out-of-hospital cardiac arrest cases in the dispatch center of a two-tiered emergency medical services system. A total of 112 cardiac arrest cases were studied; 64 before and 48 after the training course. Before the course, all relevant information was obtained in 36% of cases, only partial information in 56% and no useful medical information in 8%. The corresponding figures after the training program were 62, 38 and 0%, respectively (2 x 3 chi2 test, P = 0.01). Trends towards an increase in the percentage of cases in which a second-tier team was sent immediately after the initial call (58 vs 75%; chi2 test, P = 0.06) and towards shorter overall intervals between receipt of the call and dispatch of the second-tier team (logrank test, P = 0.10) were noticed. Similarly, the survival rate increased from 2% before, to 8% after the training course (chi2 test with Yates' correction, P = 0.24). We conclude that our training program for emergency medical dispatchers produced some beneficial effects.

An audit of in-hospital crash team interventions outside critical care areas.

All in-hospital interventions by the crash team of our hospital were recorded and evaluated retrospectively from 1 January 1992 to December 1994 and prospectively for 1995. The most frequent diagnosis was some type of cardiac arrest with a maximal incidence of 32.4% in 1994. Intubation was required in 58.7% of the cases in 1995. Outcome is better on surgical wards and for emergencies in the catheter laboratory compared with medical wards. The inappropriate overruling of the 'do not attempt resuscitation' (DNAR) policy eventually resulted in one survivor. We identified at least five cardiac arrest patients with an unacceptable delay in advanced life support. Our in-hospital critical incident registry resulted in a better policy for appropriate and timely intensive care unit referral.

What did we learn from the time registration in the Belgian Cardio-Pulmonary-Cerebral Resuscitation registry?

It is well known that in a case of cardiac arrest a fast intervention is essential for the survival of the victim. All research on resuscitation therefore contains some reference to intervention times. In the past it was difficult to compare the results of different studies. This problem has however been overcome by the publication of the Utstein Guidelines, as these guidelines emphasize on a correct and complete time registration with uniform definitions of the different time intervals. As the Belgian Cardio-Pulmonary-Cerebral Resuscitation Study Group tries to collect all these time intervals we are able to present the complete performance of the interventions for cardiac arrest of five registration centres and to identify weak points in our 'chain of survival'.

Clinical status before and during cardiopulmonary resuscitation versus outcome in two consecutive databases. Belgian CPCR Study Group.

The outcome of out-of-hospital cardiac arrest is very much determined by uncontrollable precardiopulmonary resuscitation (CPR) conditions. Two consecutively registered databases containing variables related to pre-arrest, arrest and CPR are similarly analysed to produce and validate a simple clinical algorithm for acute decision making during CPR. The outcome results in the two different time periods remained nearly unchanged. The simultaneous and persistent absence of ventricular fibrillation, gasping and light-reactive pupils after arrival of the second tier was strongly associated with a poor outcome. Unresponsiveness of these variables to a full and optimal trial of advanced life support can in itself be considered as an index for irreversible myocardial and neurological damage.

Utstein style cardiopulmonary-cerebral resuscitation registry for out-of-hospital cardiac arrests between 1991 and 1993. The Belgian CPCR Study Group.

A global overview of the latest results (1991-1993) from the Belgian Cardio-Pulmonary-Cerebral-Resuscitation Study Group is presented in accordance with the Utstein style recommendations and compared with similar reports. Simple clinical research data requested in a standardized document generate better quality assurance because of the additional attention that accompanies scientific investigations. We hope that our results will stimulate more institutions to scrutinize their cardiopulmonary resuscitation efforts using similar endpoints and denominators. Summaries of these data enable clinicians to challenge conventional but untested therapeutic wisdom, and help to formulate rewarding hypotheses and algorithms with regard to fate and to process factors surrounding the incidence and treatment of cardiac arrests.

The 'early access' link in the chain of survival for cardiac arrest victims in Ghent, Belgium.

Without early access to the emergency medical services (EMS) system, the chances of surviving an out-of-hospital cardiopulmonary arrest (CPA) are poor. The aim of this study was to evaluate this first link in the chain of survival in Ghent. Therefore, we reviewed the data from the registry on all CPA cases treated by our mobile intensive care unit (MICU) and the tape recordings from the local EMS dispatch centre of 100 consecutive non-traumatic CPA cases that occurred after January 1, 1993. Alarm signs before the collapse were recorded in 39 cases. In only 54% (21 out of 39) a pre-arrest call to the EMS system was made. In only four cases (10%) was the MICU at the patient's side when the collapse occurred. The delay between collapse and call in the 79 cases in which no call to the EMS system was made before the collapse was estimated to be 3 min or less for only 49% (39 out of 79). To evaluate the processing of the call in the EMS dispatch centre, we examined all 100 cases with regard to whether or not the first tier (emergency medical technicians) and the second tier (MICU) were dispatched simultaneously upon the first call. We found that in 41 cases the MICU was not sent immediately. The most important reasons were minimal information available for the EMS system (n = 8), underestimation of the emergency of the call by the dispatcher (n = 10) and underestimation of the pre-alarm signs by a general practitioner (n = 7). This analysis shows that all aspects of the first link of the chain of survival need improvement.

Glycemia in the post-resuscitation period. The Cerebral Resuscitation Study Group.

An association between high glycemia on admission after resuscitation from an out-of-hospital cardiac arrest and poor neurological recovery has been reported. It remains controversial whether the high glycemia on admission causes the poor outcome or is just an epiphenomenon. The Cerebral Resuscitation Study Group therefore registered the glycemia on admission in 417 patients resuscitated after an out-of-hospital cardiac arrest. Our data confirm that a high glycemia on admission is related to a poor outcome. There is no relationship between the glycemia on admission and the duration of cardiopulmonary resuscitation (CPR). However, there is a positive but weak correlation between the dose of adrenaline administered during CPR and the glycemia on admission. This indicates that the higher glycemia on admission in patients with a poor outcome may, at least in part, be due to CPR parameters, such as the amount of adrenaline used, that are linked with a bad prognosis. However, it cannot be excluded that a high glycemia contributes to the brain damage after cardiac arrest.