Mikael Holmberg

Effect of bystander cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients in Sweden

BACKGROUND Information from the Swedish Cardiac Arrest Registry was used to investigate: (a) The proportion of patients suffering an out-of-hospital cardiac arrest who were given bystander cardiopulmonary resuscitation (B-CPR). (b) Where and by whom B-CPR was given. (c) The effect of B-CPR on survival. METHOD a prospective, observational study of cardiac arrests reported to the Swedish Cardiac Arrest Registry. Analyses were based on standardised reports of out-of-hospital cardiac arrests from ambulance organisations in Sweden, serving 60% of the Swedish population. From 1983 to 1995 approximately 15-20% of the population had been trained in CPR. RESULTS Of 9877 patients, collected between January 1990 and May 1995, B-CPR was attempted in 36%. In 56% of these cases, the bystanders were lay persons and in 25% they were medical personnel. Most of the arrests took place at home (69%) and only 23% of these patients were given B-CPR in contrast to cardiac arrest in other places where 53% were given CPR. Survival to 1 month was significantly higher in all cases that received B-CPR (8.2 vs. 2.5%). The odds ratio for survival to 1 month with B-CPR was in a logistic regression analysis 2.5 (95% CI 1.9-3.1). CONCLUSIONS In Sweden, the willingness and ability to perform B-CPR appears to be relatively widespread. More than half of B-CPR was performed by laypersons. B-CPR resulted in a two to threefold increase in survival.

Survival after cardiac arrest outside hospital in Sweden

The voluntary Swedish Cardiac Arrest Registry has collected and analyzed 14,065 standardised reports on cardiac arrests up until May 1995. The reports have been collected from approximately half of Swedens ambulance districts, which cover 60% of the population. Resuscitation was attempted in 10,966 cases. The median age was 70 years. In 70.0% the arrest was witnessed, and in 43.3% the first recorded rhythm was VT/VF. Bystander-CPR was initiated in 32.3% of the cases. Most cardiac arrests took place at home (65.8%) and 67.1% were judged to be of cardiac origin. In 1692 cases (15.4%), the patient was admitted alive in hospital and 544 patients (5.0%) were alive after 1 month. Survival to 1 month in the subgroup which presented with VT/VF was 9.5%. We found no significant difference between survival in large cities and smaller communities. The survivors were analysed in relation to time to defibrillation and we found a strong correlation between a short time and increased survival.

Incidence, duration and survival of ventricular fibrillation in out-of-hospital cardiac arrest patients in Sweden

UNLABELLED The chance of survival from ventricular fibrillation (VF) is up to ten times higher than those with other cardiac arrest rhythms. To calculate the effect of out-of-hospital resuscitation organisations on survival, it is necessary to know the percentage of cardiac arrest patients initially in VF and the relationship between delay time to defibrillation and survival. AIM To study the incidence of VF at the time of cardiac arrest and on first ECG, the duration of VF and the relation between time to defibrillation and survival. METHOD The Swedish Cardiac Arrest Registry has collected standardised reports on out-of-hospital cardiac arrests from ambulance organisations in Sweden, serving 60% of the Swedish population. RESULTS In 14065 cases of out-of-hospital cardiac arrest collected between 1990 and 1995, resuscitation was attempted in 10966 cases. INCIDENCE The first ECG showed VF in 43% of all patients. The incidence of VF at the time of cardiac arrest was estimated to be 60-70% in all patients and 80-85% in the cases with probable heart disease. DURATION The estimated disappearance rate of VF was slow. Thirty minutes after collapse approximately 40% of the patients were in VF. SURVIVAL Overall survival to 1 month was only 1.6% for patients with non-shockable rhythms and 9.5% for patients found in VF. With increasing time to defibrillation, the survival rate fell rapidly from approximately 50% with a minimal delay to 5% at 15 min. CONCLUSIONS This study suggests a high initial incidence of VF among out-of-hospital cardiac arrest patients and a slow rate of transformation into a non-shockable rhythm. The survival rate with very short delay times to defibrillation was approximately 50%, but decreased rapidly as the delay increased.

The epidemiology of out-of-hospital 'sudden' cardiac arrest.

It is difficult to assemble data from an out-of-hospital cardiac arrest since there is often lack of objective information. The true incidence of sudden cardiac death out-of-hospital is not known since far from all of these patients are attended by emergency medical services. The incidence of out-of-hospital cardiac arrest increases with age and is more common among men. Among patients who die, the probability of having a fatal event outside hospital decreases with age; i. e. younger patients tend to more often die unexpectedly and outside hospital. Among the different initial arrhythmias, ventricular fibrillation is the most common among patients with cardiac aetiology. The true distribution of initial arrhythmias is not known since several minutes most often elapse between collapse and rhythm assessment. Most patients with out-of-hospital cardiac arrest have a cardiac aetiology. Out-of-hospital cardiac arrests most frequently occur in the patients home, but the prognosis is shown to be better when they occur in a public place. Witnessed arrest, ventricular fibrillation as initial arrhythmia and cardiopulmonary resuscitation are important predictors for immediate survival. In the long-term perspective, cardiac arrest in connection with acute myocardial infarction, high left ventricular ejection fraction, moderate age, absence of other heart failure signs and no history of myocardial infarction promotes better prognosis. Still there is much to learn about time trends, the influence of patient characteristics, comorbidity and hospital treatment among patients with prehospital cardiac arrest.

Low chance of survival among patients requiring adrenaline (epinephrine) or intubation after out-of-hospital cardiac arrest in Sweden

AIM To relate the outcome of out-of-hospital cardiac arrest to whether medication with adrenaline (epinephrine) was given and whether patients were intubated. PATIENTS A national survey in Sweden between 1990-1995 among patients suffering out-of-hospital cardiac arrest and in whom resuscitation was attempted. Sixty per cent of ambulance organisations in Sweden participated. DESIGN Prospective evaluation. Survival was defined as survival 1 month after cardiac arrest. RESULTS In all, 14065 patients were included in the evaluation. Of these, resuscitation was attempted in 10966 cases. Among these adrenaline (epinephrine) was given in 42.4 and 47.5% were intubated. In an univariate analysis treatment with adrenaline (epinephrine) and intubation was associated with a lower survival when all patients were evaluated. In a multivariate analysis including age, sex, place of arrest, bystander-CPR, initial arrhythmia, arrest being witnessed and aetiology, treatment with adrenaline (epinephrine) (OR 0.43, CI 0.27-0.66) and intubation (OR 0.71, CI 0.51-0.99) were both independent predictors of a lower chance of survival. When separately analysing patients with bystander witnessed cardiac arrest found in ventricular fibrillation and requiring more than 3 defibrillatory shocks neither treatment with adrenaline (epinephrine) nor intubation was associated with survival. Among patients with a non-shockable rhythm treatment with adrenaline (epinephrine) was a significant independent predictor for lower survival (OR 0.30, CI 0.07-0.82). CONCLUSION In a national survey in Sweden including 10966 cases of out-of-hospital cardiac arrest the outcome was related to whether medication with adrenaline (epinephrine) was given and whether patients were intubated. Neither in total nor in any subgroup did we find results indicating beneficial effects of any of these two interventions. Whether treatment with adrenaline (epinephrine) or intubation will increase survival after out-of-hospital cardiac arrest needs to be confirmed in prospective randomised trials.

The problem of out-of-hospital cardiac-arrest prevalence of sudden death in Europe today

In Europe, 40% of all deaths of individuals who are 25-74 years of age are caused by cardiovascular disease. Cardiac disease is the underlying cause in two-thirds of out-of-hospital sudden deaths. The 28-day case fatality rate for the combined population of out-of-hospital coronary artery disease deaths and hospitalized acute myocardial infarction patients is approximately 50% in 29 of the regions included in the World Health Organization (WHO) Monitoring Trends and Determinants in Cardiovascular Disease registry. Of 14,065 patients included in the Swedish Cardiac Arrest Registry, resuscitation procedures were started in 10,966 patients. The remaining 3,099 were considered definitely dead; 70% were witnessed, cardiac arrests and 32.3% had been given bystander cardiopulmonary resuscitation (CPR). The incidence of ventricular tachycardia (VT)/ventricular fibrillation (VF) in all patients was 43%, in witnessed cases 54%, and in nonwitnessed cases, 31%. The initial incidence of VT/VF was calculated to be approximately 60% in the whole population and 80-85% in those with probable cardiac disease. Survival to 1 month was 5.0% in the total population, 9.5% for those with VT/VF on the first electrocardiogram compared with 1.6% for those not in VT/VF. Survival rate was also calculated in relation to delay time to first defibrillation. Survival was 50% when defibrillation was performed immediately and decreased gradually to 0% for those with a delay time of 20 minutes. The survival rate after bystander CPR was 2.6-fold higher than the rate for those where no treatment was given until the ambulance arrived.

Characteristics and outcome among patients having out of hospital cardiac arrest at home compared with elsewhere

Objective: To describe the characteristics and outcome of patients who have a cardiac arrest at home compared with elsewhere out of hospital. Patients: Subjects were patients included in the Swedish cardiac arrest registry between 1990 and 1999. The registry covers about 60% of all ambulance organisations in Sweden. Methods: The study sample comprised patients reached by the ambulance crew and in whom resuscitation was attempted out of hospital. There was no age limit. Crew witnessed cases were excluded. The patients were divided into two groups: cardiac arrest at home and cardiac arrest elsewhere. Results: Among a study population of 24 630 patients the event took place at home in 16 150 (65.5%). Those in whom the arrest took place at home differed from the remainder in that they were older, were more often women, less often had a witnessed cardiac arrest, were less often exposed to bystander cardiopulmonary resuscitation (CPR), were less often found in ventricular fibrillation, and had a longer interval between collapse and call for ambulance, arrival of ambulance, start of CPR, and first defibrillation. Of patients in whom the arrest took place at home, 11.3% were admitted to hospital alive, v 19.4% in the elsewhere group (p < 0.0001); corresponding figures for survival after one month were 1.7% v 6.2% (p < 0.0001). The adjusted odds ratio for survival after one month (at home v not at home; considering age, sex, initial arrhythmia, bystander CPR, aetiology, and whether the arrest was witnessed) was 0.40 (95% confidence interval 0.33 to 0.49; p < 0.0001). Conclusions: Sixty five per cent of out of hospital cardiac arrests in Sweden occur at home. The patients differed greatly from those with out of hospital cardiac arrests elsewhere, and fewer than 2% were alive after one month. Having an arrest at home was a strong independent predictor of adverse outcome. Further research is needed to identify the reasons for this.

A comparison between patients suffering in-hospital and out-of-hospital cardiac arrest in terms of treatment and outcome

Abstract. Herlitz J, Bång A, Ekström L, Aune S, Lundström G, Holmberg S, Holmberg M, Lindqvist J (Sahlgrenska University Hospital, Göteborg, Sweden). A comparison between patients suffering in‐hospital and out‐of‐hospital cardiac arrest in terms of treatment and outcome. J Intern Med 2000; 248: 53–60.

Rhythm changes during resuscitation from ventricular fibrillation in relation to delay until defibrillation, number of shocks delivered and survival

AIM To describe rhythm changes during the initial phase of resuscitation from ventricular fibrillation in relation to the interval between collapse and defibrillation, to survival and to bystander-initiated cardiopulmonary resuscitation (CPR). PATIENTS All patients who suffered out-of-hospital cardiac arrest between 1980 and 1992, who were reached by the emergency medical service system (EMS), in whom resuscitation attempts were initiated and who were found in ventricular fibrillation. RESULTS In all, 1216 patients were included in the study. Among patients who converted to a pulse-generating rhythm after the first defibrillation (n = 119) were 56% discharged from hospital as compared with 6% among patients who converted to asystole. The corresponding figures after the third defibrillation were 49% and 2%, respectively, and after the fifth defibrillation 28% and 7%, respectively. Among patients in whom the first defibrillation took place less than 5 min after collapse, 28% directly converted to a pulse-generating rhythm as compared with 3% when the first defibrillation took place 12 min or more after collapse. CONCLUSION Among patients who suffer out-of-hospital cardiac arrest and are found in ventricular fibrillation, there is a strong relationship between survival and initial rhythm changes after defibrillation. These rhythm changes are directly related to the interval between collapse and the first defibrillation.

Diurnal, weekly and seasonal rhythm of out of hospital cardiac arrest in Sweden

AIM To describe the diurnal, weekly and seasonal rhythm among patients suffering from out of hospital cardiac arrest in Sweden. METHODS All patients in Sweden between 1990 and 1999 participating in a National Registry covering 65% of all patients suffering from out of hospital cardiac arrest where cardiopulmonary resuscitation (CPR) was attempted. Only patients with a cardiac arrest of a cardiac aetiology and aged > 18 years were included in the survey. RESULTS 10,868 patients fulfilled inclusion criteria. In terms of the diurnal rhythm, there was a progressive increase in the development of cardiac arrest from 06:00 h, reaching a peak at about 10:00 h. Thereafter, there was a progressive decline until 05:00 h. The diurnal rhythm was more marked among patients aged > 65 years and among patients in whom the arrest occurred outside home. There was a weekly rhythm with an increased incidence of cardiac arrest on Mondays. This was particularly evident among patients aged < 66 years and among men. A cardiac arrest occurred most frequently in January and December. This was particularly observed in the large cities. CONCLUSION We found that out of hospital cardiac arrest of a cardiac etiology has a diurnal, weekly and seasonal rhythm occurring most frequently in the morning hours, on Mondays and in December and January. Age, sex and place of arrest influence these rhythms.