Fundamental studies on maintenance of the circulation in cardiac asystole by the mechanocardiac pulsator.

Cardiac asystole which manifests itself as a ventricular fibrillation or cardiac standstill is an accident occurring in approximately 0.1 per cent of all surgical interventions.’ It has been reported that 87 per cent of cardiac arrests occur in the operating room.6 In many medical institutions of the world, the customary approach to the problem is time consuming and conservative. All too frequently transparietal intracardiac injections of analeptics are used and are nearly always unsuccessful. If by chance they do restore heart function, it is doubtful as to whether the heart was in arrest in the first place. The alternative approach which is gaining popularity with surgeons with respect to cardiac resuscitation is that heart massage should be the exclusive treatment. In the event of a mistaken diagnosis of cardiac asystole, the intervention would still be justified as the better choice of two evils. Unfortunately, it is not always possible to restore adequate circulation of the blood before anoxia has done irreparable damage to the brain. It is now universally accepted that the critical time period whereby circulation can be detained without permanent damage to the central nervous system is four minutes. Statistical studies done by various authors”6 concerning this time rule has proved that survival with or without neurological sequelae is above 80 per cent when the circulation has been promptly restored. Failing to restore circulation within this time limit brought the survival rate down to approximately 30 per cent, mortality increasing for every extra minute of time that was delayed. It is understood that survival is not assured even when massage is done within the four-minute period. There are numerous factors which will determine the outcome of cardiac massage, such as the state of the heart itself, whether it be in failure, intoxicated by overdosage of anesthetics, anoxia, etc. Furthermore, the technique of the operator doing the massage and the maintenance of adequate blood pressure by intravenous infusions of vasoconstrictors should be given consideration. The object of this paper is to study primarily the methods of heart massage and to give some thought concerning the use of vasoconstrictors and plasma expanders as ancillary agents to maintain adequate blood flow during cardiac asystole. The primary cause for inadequate blood flow during manual massage is incorrect technique and fatigue of the operator. This sufficed to justify a study of the alternative possibilities to overcome the varying performance of the human factor in play. To this purpose cardiac mas-