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This trial compared blinded 10 mg aliquots of adrenaline with placebo in 194 cardiac arrest patients treated in hospital using American Heart Association guidelines. In-hospital and out-of-hospital arrests were included. Of the 339 eligible patients a large proportion (145 (45%)) were not randomised and received open 1 mg aliquots of adrenaline. This group is also analysed. Supervising physicians gave significant preference for males, patients with no previous cardiac history and without multiple organ disease to be given open 1 mg adrenaline. Patients in asystole at the time of consideration for entry were preferentially placed in the trial group (114 (69%) vs. 170 (88%)) and patients in ventricular fibrillation were preferentially given open 1 mg adrenaline (31 (21%) vs. 24 (12%) P < 0.03). The most beneficial rhythm changes which led to survival were sinus rhythm and ventricular tachycardia. Analysis of rhythm changes resulting from the dosing showed a significant (P = 0.01) change to a beneficial rhythm with 10 mg adrenaline but not for 1 mg adrenaline or placebo. This was not reflected by an improvement in immediate survival. No significant differences in immediate survival (IS) or hospital discharge (HD) exists between open 1 mg adrenaline (IS 14 (9.7%), HD 3 (2%)) or the 10 mg adrenaline (IS 9 (9.6%), HD 0) vs. placebo (IS 7 (7%), HD 0) trial arms. Patients reaching the point of use of adrenaline have a uniformly poor immediate survival (8.8%) and hospital discharge rate (0.9%). Dosing with 10 mg or 1 mg adrenaline does not influence outcome compared with placebo.

Defibrillation of patients with primary ventricular fibrillation (VF) results in a variety of rhythm changes. We analysed these changes in rhythm in 200 patients, using the American Heart Association's recommendation of two defibrillations prior to drug therapy. Sixty-three (31.5%) patients were immediate survivors with 38 (19%) being discharged from hospital alive. There was no difference between the age of immediate survivors (66.5 years, S.D. = 11.2) and non-survivors (68.3 years, S.D. = 13.7, P = 0.37). Immediate survivors were significantly more likely to be discharged alive from hospital if they were younger (70.0 years, S.D. 8.5 vs. 62.1 years, S.D. 15.8, P = 0.014). Increasing delays to the initiation of basic life support (CPR) and to defibrillation were associated with significantly less likelihood of cardioversion to sinus rhythm (P < 0.005 and P < 0.002, respectively). Those patients who stayed in VF were not more likely to be defibrillated into asystole or electro-mechanical dissociation. Seventeen percent (34) of patients were defibrillated to sinus rhythm after the first defibrillation and 14% (19) after the second, with similar hospital discharge rates (62% and 58%, respectively). Sixty percent (32) of patients in sinus rhythm, after two defibrillations, were discharged alive, compared to only 4% (6) of those patients not in sinus rhythm after two defibrillations. Our data provide new information on rhythm changes during resuscitation and supports the need for the earliest possible initiation of basic life support and defibrillation to improve survival from cardiac arrest due to ventricular fibrillation.

Serum catecholamines were measured during continued prolonged cardiopulmonary resuscitation and after 10 mg increments of intravenous epinephrine. This was part of an ongoing trial of 10 mg epinephrine versus placebo. Eight patients were in the placebo arm and seven in the epinephrine arm and the rhythms were two ventricular fibrillation, nine asystole and four electromechanical dissociation. Data were analysed by time from onset of the cardiac arrest and samples were analysed for levels of DHPG (dihydroxyphenylglycol) nor-epinephrine, epinephrine, DOPA (dihydroxyphenylalanine) and DOPAC (dihydroxyphenyl acetic acid). There was a significant (P < 0.001) difference between arterial and venous samples of epinephrine but not the other catecholamines. High levels of catecholamines were maintained in all time phases except for nor-epinephrine where significant (P < 0.0003) reduction occurred progressively after 20 min. Non-steady state kinetics were suggested between epinephrine and nor-epinephrine and DHPG and nor-epinephrine for the first 20 min. Very large increases in epinephrine were achieved with administered 10 mg epinephrine and this resulted in high DHPG levels supporting the experimental belief that exogenously administered epinephrine induces myocardial release of nor-epinephrine. This data supports the known effects of CPR on catecholamine release. It provides data on the other neurotransmitter hormones and supports the relationships shown in other animal and human data. It is suggested that supplementation with epinephrine during CPR may be unnecessary and the levels reached may be deleterious. Nor-adrenaline supplementation may be necessary after prolonged CPR.

Survival from ventricular fibrillation and asystole is influenced by variables measured during resuscitation that affect both immediate survival and discharge from hospital. These variables have been used to develop a formula to calculate an individuals chances of immediate survival and hospital discharge. It has allowed this heterogenous group to be subdivided into groups which can be compared both within and between institutions for the purposes of audit and evaluation of resuscitation protocols. This study evaluates the addition of clinical parameters to the prognostic index. One hundred twelve immediate survivors of ventricular fibrillation or asystole were examined immediately after resuscitation and clinical parameters measured and recorded. At the same time parameters previously described were recorded. The increase in the numbers of survivors improved the reliability (area under the receiver operator curve (ROC) improved from 0.79 to 0.83) of the index for predicting hospital discharge. Addition of the clinical variables of conscious state, respiratory state, blood pressure and pulse rate improved the prognostic index further to an ROC area of 0.86. This ensures that the predictive power of the new index is now highly reliable for predicting hospital discharge after successful resuscitation from ventricular fibrillation and asystole.

Despite advances in resuscitation, the ability to predict survival at cardiac arrests remains unsophisticated. We identified the factors determining outcome of all cardiopulmonary resuscitations performed at our institution over a 4-year period, and used a Cox multivariate regression model to design prognostic indices to assess the probability of successful resuscitation and hospital discharge. Cardiac arrests (710) were studied, and 193 (28%) were successfully resuscitated. The most influential variables, judged by the size and significance of their logistic regression coefficients, were rhythm, resuscitation delay, and age (for successful resuscitation), and rhythm, performance of intubation and defibrillation, defibrillation delay, and age (for survival until discharge). The combination of these in a prognostic index reliably predicted both outcome (area under the receiver operating curve of 0.78), and survival until discharge (area under the curve of 0.80).

Resuscitation for cardiac arrest was monitored over 4 years to examine the effect on survival of a change in the ventricular fibrillation (VF) protocol to include the routine early use of "high-dose" intravenous or transbronchial adrenaline. A significant reduction in the immediate survival of patients with VF was seen when the protocol was changed (22% after the change, 43% before). Prior predictors of poor response were similar in each group, except for the number of witnessed arrests, delay until cardiopulmonary resuscitation, and occurrence of endotracheal intubation, but multiple logistic regression showed the use of adrenaline to be an independent predictor of outcome. Early high-dose adrenaline was associated with a reduction in immediate survival in patients with persistent VF.