In many hospitals it is the policy to carry out cardiopulmonary resuscitation on both inpatients and outpatients if there is a witnessed event or a presumed recent cessation of normal cardiac output, consistent with a cardiac arrest or a severe arrhythmia. Some times, the problem is that the individual has fainted or had a vasovagal attack rather than a primary cardiac event. Other causes such as aspiration or choking also need to be distinguished and treated appropriately. In the excitement of an apparent cardiac arrest it may be difficult to determine the cause and time may be lost before artificial respiration and cardiac compressions are effectively applied by witnesses or medical personnel. Under these circumstances it is often impossible to know how long the patient experiences inadequate oxygen and effective circulation, and there is always a lkelihood that brain perfusion may be impaired during the critical 5-10 minutes of the crisis. Once it is suspected that the heart has no spontaneous beat or that the rhythm is too fast and irregular or too slow, defibrillation is likely to be required (if the machine is available). Epinephrinine or atropine are often needed, as are other cardiac rate controlling drugs, but sodium bicarbonate is not given routinely during the early minutes of the resuscitation. Brain damage is not uncommon, but a remarkably good recovery may ensue. Some neurological deficit may be acceptable when the alternative could easily be the victims death from the dangerous event.