[7] Ether Narcosis by the Rectum.—Cunningham and Lahey have revived the almost abandoned method of rectal ether narcosis, after improving the technique. The rectal tube is introduced for ten to fifteen inches and ether vapor is then forced in until considerable gas is pressed around the rectal tube, keeping the forefinger in the rectum opposite the tube until it causes pain and hastens the expulsion of the rectal gases. It is essential that the rectum be distended to the point of keeping closed around the tube, since unless the gas normally in the bowel be first removed the patient absorbs the ether much more slowly, presumably because of its dilution. At the first introduction of the ether vapor the patient may feel a natural discomfort and desire to defecate, but in a short time this sensation disappears; the breath becomes ether-ladened in from one to five minutes, he becomes drowsy, the breathing stertorous, and he passes into complete surgical narcosis without any excitement.
The apparatus used consists of a bottle seven inches in height, of which five inches are used for ether space and the balance for vapor. The afferent tube which leads to the bottom of the ether ends in a bulb, with small perforations, so that the air escapes in several bubbles. This bottle is placed in a water-bath at a temperature between 80° and 90°. By keeping the ether warm, without boiling, the air forced through it is more easily saturated.
The same care must be given to see that the tongue does not fall over the larynx as when ether is given by the mouth. Should narcosis be too pronounced the tube should be disconnected and ether gas forced out of the bowel by abdominal massage. Oxygen may be given through the same tube if desired, while artificial respiration and stimulation are practised as usual when needed. After completion of the operation the ether vapor should be completely expelled by pressure.
The advantages of the method are that but a small amount of ether is used, there is no stage of excitement, vomiting is rare, bronchial secretion is prevented, and recovery is rapid. It has been shown that six volumes per cent. of ether are required in the blood for the production of complete anesthesia. The rapidity with which the latter can be produced depends upon the rapid production of this percentage. This result is attained more readily by the rectum than by the lungs. For the production of narcosis by this method the rectum should be previously and thoroughly emptied.
CHLOROFORM.
It is important that pure chloroform should be secured for anesthetic purposes. It should be kept in dark bottles, and in the dark, as it is liable to undergo decomposition in the presence of sunlight. It is less volatile than ether, and mixtures of the two drugs are not stabile, since the ether is likely to evaporate first. In its anesthetic effects it resembles ether, acting first upon the perceptive and last upon the motor centres.
The British Chloroform Committee estimate that from 1 to 2 per cent. of chloroform in the inspired air is sufficient for anesthetic purposes, and may be safely used; that 5 per cent. is more than adequate, and that anything stronger than 2.5 per cent. is dangerous.
The effect of chloroform upon the heart is to quicken and then slacken it. The former action is due to a depression of the vagus centre, while subsequent slowing is due partly to vagus stimulation and partly to direct weakening of the heart muscle. While chloroform does not materially affect the excitability either of the vagus or accelerator nerves its main effect is on the strength of the heart action, and is less marked on the auricles than on the ventricles. Ether has a more marked tendency to raise blood pressure than chloroform, while the latter is likely to be more responsible for sudden falls in blood pressure even after its administration has ceased.
The question of the relative dangers of the two drugs has engaged the attention of investigators the world over, and one of the side questions to be discussed is whether chloroform kills by arresting the circulation or the respiration. Chloroform produces a fall in blood pressure (see [Chapter XVII]) but as long as the blood pressure within the brain, and especially the medulla, is maintained this effect is of secondary importance; but when the respiratory centres lack their natural stimulus, and respiration becomes irregular, then, as it were, the patient “bleeds into his own vessels.” It is under these circumstances that adrenalin produces its most marked and prompt effect.
The first effect of chloroform inhalations is to raise blood pressure, but this is soon followed by lowered tension. The pupils may dilate slightly at first, but usually contract and remain contracted during anesthesia. When they dilate suddenly means should be adopted to avert the danger threatened, as the relaxation of the iris is the first visible relaxation of death. While the pupils react to light there is little danger.[8]