Coagulation Hastened by “Painful” Stimulation
In the experiments on the action of stimuli which in the unanesthetized animal would cause pain, it will be recalled that faradic stimulation of a large nerve trunk (the stump of the cut sciatic) and operation under light anesthesia were the methods used to affect the afferent nerves. Elliott[6] found that repeated excitation of the sciatic nerve was especially efficient in exhausting the adrenal glands of their adrenin content, and also that this reflex persisted after removal of the cerebral hemispheres. It was to be expected, therefore, that with well-stored glands, sciatic stimulation, even in the decerebrate animal, would call forth an amount of adrenal secretion which would decidedly hasten clotting. The following case illustrates such a result:
Dec. 12.—A cat was anesthetized with ether at 3.45 and the left sciatic nerve was bared. Decerebration was completed at 3.57. The clotting time of the blood began to be tested six minutes later:
| 4.03 | 4 | minutes |
| .08 | 3.5 | “ |
| .13 | 3.5 | “ |
| .18 | 4.5 | “ |
| .23 to .25 | Stimulation of left sciatic. | |
| 4.26 | 2.5 | minutes |
| .29 | 3.5 | “ |
| .34 | 4 | “ |
| .40 | 5 | “ |
| .45 to .50 | Stimulation of left sciatic. | |
| 4.53 | 2.5 | minutes |
| .57 | 7 | “ |
| 5.06 | 7.5 | “ |
| .15 to .17 | Stimulation of left sciatic. | |
| 5.17 | 4 | minutes |
| .22 | 4.5 | “ |
| .27 | 5.5 | “ |
| .36 | 5.5 | “ |
| .46 | 7 | “ |
The results obtained in this case, which were similar to results in other cases, are represented graphically in [Fig. 32]. The coagulation time was becoming gradually more prolonged, but each excitation of the sciatic nerve was followed by a marked shortening. The strength of stimulation was not determined with exactness, but it is worthy of note that the current used in the first and the third stimulations was weaker than could be felt on the tongue, whereas that used in the second was considerably stronger, though it did not produce reflex spasms.
Figure 32.—Three shortenings of coagulation time after stimulation of the left sciatic nerve, at 4:23-:25, at 4:45-:50 (stronger), and at 5:15-:17.
Mere tying of the nerve is capable of producing a marked shortening of coagulation, as the following figures show:
Oct. 21.—10.57 cat under ether, and urethane given:
| 11.11 | 8.5 | minutes |
| .23 | 8.5 | “ |
| .32 to .35 | Left sciatic bared and tied. | |
| .37 | 1.5 | minutes |
| .41 | 5.5 | “ |
| .50 | 7 | “ |
| 12.02 | 8.5 | “ |
Stimulation of the crural nerve had similar effects, reducing the clotting time in one instance from a succession of 3, 3, and 3.5 minutes to 1.5 minutes shortly after the application of the current, with a return to 3.5 minutes at the next test.
Operative procedures performed under light anesthesia (i. e., with the more persistent reflexes still present), or reduction of anesthesia soon after operation, resulted in a remarkable shortening of the coagulation time:
Nov. 8.—A cat was etherized and tracheotomized. The abdomen was then opened and a ligature was drawn around the hepatic nerves. The operation was completed at 2.25. At 2.50 the etherization became light and the rate of clotting began to be faster:
| 2.50 | 6 | minutes |
| 3.00 | 5.5 | “ |
| .10 | 3.5 | “ |
| .15 | 3.5 | “ |
| .20 | 4.5 | “ |
| .30 | 7.5 | “ |
Nov. 11.—A female cat, very quiet, was placed in the holder at 1.55. The animal was not excited. At 2.10 etherization was begun; the animal was then tracheotomized, and the femoral artery was exposed.
| 2.21 | 4.5 | minutes | |
| .26 | 4.5 | “ | Anesthesia lessened. |
| .32 | 3.5 | “ | “ light. |
| .35 | Abdomen opened. | ||
| .47 | 1.5 | minutes. | |
| .52 | 1 | “ | |
| .55 | Ligature passed around hepatic nerves. | ||
| .57 | 1.5 | minutes. | Anesthesia light; corneal reflex present. |
| 3.02 | 3 | “ | |
| .07 | 3 | “ | Some hepatic nerves cut. |
| .12 | 4.5 | “ | Rest of hepatic nerves cut. |
| .22 | 5 | “ | |
The results of this experiment are shown graphically in [Fig. 33].
Figure 33.—Shortening of coagulation time during an operation under light anesthesia. At 2:35 the abdomen was opened, at 2:55 a ligature was passed around the hepatic nerves.
Nov. 13.—A cat was etherized at 1.55, tracheotomized, and the femoral artery laid bare. As soon as these preparations were completed, the ether was removed and anesthesia became light. The blood clotted thus:
| 2.08 | 6 | minutes | |
| .15 | 4 | “ | Anesthesia light. |
| .20 | 2 | “ | |
| .24 | 1 | “ | Etherization begun again. |
| .27 | 2.5 | “ | |
| .30 | 3.5 | “ | |
| .35 | 5.5 | “ | |
| .50 | 5.5 | “ |
In the foregoing and in other similar instances, a condition of surgical injury, whether just made or being made, was accompanied by more rapid clotting of blood when the degree of anesthesia was lessened. This condition was one which, if allowed to go further in the same direction, would result in pain. Both direct electrical stimulation and also surgical operation of a nature to give pain in the unanesthetized animal result, therefore, in faster clotting.
It is worthy of note that after decerebration clotting apparently occurred no faster because the abdomen had been opened, although in the decerebrate state etherization was suspended. The mechanism for reflex control of the adrenals may not be higher than the corpora quadrigemina, as Elliott has shown, but the discharge from the glands seems to be more certain to occur when the cerebrum is present and is permitted even slightly to operate.