[CHAPTER IV]
When Does Human Life End?
The moment human life begins in the human fetus is a subject of dispute, but the moment human life ends is a mystery—we have no method of determining exactly just when the soul leaves the body. Daily throughout the world the priest reaches a patient who has just died. Conditional absolution, extreme unction, baptism might have been administered if there were signs of life, but the heart and lungs are still, "the patient is dead," and the priest leaves without doing anything. Yet it is always probable that the patient does not die at once even in a case of decapitation.
Bichat, at the beginning of the last century, called the brain, lungs, and heart "the tripod of life," and from time immemorial we have based our judgment of the presence of somatic death on the lack of consciousness, respiration, and circulation in the patient. The heart, however, beats after consciousness and respiration cease (and sometimes respiration continues after the pulse cannot be felt), and this cardiac activity may go on for more than a half hour after all the normal clinical signs of death have appeared—after respiration has quit, when no heart-sounds can be heard by the stethoscope and muscular relaxation indicates death.
The stimulus of the heart-beat probably starts at the juncture of the superior vena cava with the right auricle of the heart. Some biologists think that in this spot life takes its last stand before the final retreat, but that fact is disputed of late. In the hospital of the Rockefeller Institute for Medical Research in New York, Dr. G. Canby Robinson[60] made records from about eight patients before and during the actual stopping of the heart, using the electrocardiograph, which can be employed without disturbing the patient. He thus found—only in one case, however—that the heart may beat for a half hour after all vascular and circulatory sounds have ceased to be audible. In a letter to me Dr. Robinson said: "Undoubtedly the heart continues to show activity sufficient to be recorded by the string galvanometer very frequently after respiration has ceased, both in man and the lower animals; but this does not necessarily mean that it continues to be an efficient pump, maintaining the circulation. Undoubtedly also in other instances the cardiac activity ceases before the respiration, but I have never obtained electrocardiographic records of such cases."
Crile's experiments upon dogs show that it is possible to resuscitate these animals after they have been apparently dead for periods of time up to seven and a half minutes. The cessation of the blood circulation causes degenerations in the nerve cells and fibres, and these lesions may last even if the animal has been resuscitated. Crile thinks the human respiratory centre may survive anemia from thirty to fifty minutes; the vasomotor and cardiac centres, about twenty to thirty minutes; the spinal cord, eight to ten minutes; the motor cortex, eight to ten minutes; the portion of the brain used in conscious activity as such, six to seven minutes. The higher neurons have been stimulated into reflex activity twenty-five minutes after complete clinical cardiac cessation of activity.
In any attempt to resuscitate a person apparently dead the maintenance of the blood circulation is the chief end. If, however, the blood is not oxygenated the circulation will not go on automatically. Artificial respiration is used, and the active principle of the adrenal gland is injected to stimulate the heart. If the heart has stopped in diastole,—that is, when distended with blood,—this distention must be relieved by cardiac massage, commonly through an opening in the thoracic wall. Intratracheal insufflation of oxygen is also to be employed, as a rule.
In Essays in Pastoral Medicine[61] I mentioned several cases of resuscitation after what had appeared to be certain death. Two of these had been "dead" for forty-five minutes before they were revived temporarily. Wayne Babcock[62] reported a number of new cases of his own. One was a resuscitation which lasted for forty-three hours, and which was begun twenty-five minutes after respiration had ceased. The patient was a very fat negress who had collapsed after the use of scopolamine. A man whose arm had been torn off died from shock in the operating-room. After fifteen minutes of artificial respiration the circulation started again, and he was kept alive for six hours in this manner, but he died as soon as the artificial respiration was discontinued. An exactly similar case was kept alive for seven hours by artificial respiration. One of Babcock's cases was a woman of eighty-seven years of age, who apparently died on the table during an operation for strangulated hernia. After ten minutes of cardiac and respiratory cessation she was revived. She died four days later of peritonitis. A man fifty-six years of age undergoing the same operation ceased breathing and his heart stopped. He was completely revived and cured.