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.