Blood coagulation

“ A maniac was restored to reason by the blood of a calf, and the most extravagant hopes were entertained. But many fatal accidents occurring, experiments upon human beings were forbidden by law, and transfusion soon fell into disuse. It has, however, been successfully practiced in several cases within the last few years, and is a method still in repute for saving lives.
COAGULATION.—When blood is exposed to the air, it coagulates. This is caused by the solidifying of the fibrin, which entangling the disks, forms the "clot." The remaining clear, yellow liquid is the serum. ”

“ The coagulation of the blood, while it is a matter of fundamental importance in physiology, has peculiar interest for the surgeon, on account of the special feature of coagulability of inflammatory exudations and the part played by lymph in the healing of wounds and various other pathological phenomena, such as the sealing of divided arteries by blood-clot. ”

“ Now we know, from the experiment with the ox's jugular, that coagulation is propagated with extreme slowness, if at all, from a clot in blood perfectly undisturbed. The earlier coagulation of the main mass of the stirred blood was, therefore, not caused by propagation of the process from a layer upon the surface of the jar, but must have been the result of the brief agency of the glass rod. ”

“ The addition of an anticoagulant to the blood does not render it any less efficient as a hæmostatic agent. In all cases the coagulation time of the patient’s blood is found to be reduced after transfusion, whether sodium citrate be used as an anticoagulant or not. ”

“ Occasionally a distinct acceleration in the clotting, compared with the normal, may be observed. Wright has further ascertained in his excellent researches, that the clotting time can be influenced by drugs: calcium chloride, carbonic acid raise, citric acid, alcohol and increased respiration diminish the clotting power of the blood.
Recently Hayem has repeatedly called attention to a condition, that is probably closely connected with the coagulability of the blood. Although coagulation has set in, the separation of the serum from the clot occurs only very slightly or not at all. ”

“ This fact, which, taken by itself, might appear of little consequence, assumes considerable importance when considered as one of the inherent properties of the blood, at all times ready, under favourable circumstances, to be called into action in the living body. The conditions under which pus will determine the coagulation of the blood, and those under which it will circulate in the living vessels, require to be accurately ascertained, before we can rightly interpret the discordant evidence which we at present have upon this point. ”

“ Presumably the transfused [46] blood supplies directly the deficient factor in the coagulation complex, and it has been shown by Bernheim (1917) that the transfusion even of quite a small amount of blood will almost immediately stop the bleeding. In addition to comparative certainty and rapidity in action, transfusion has the advantage that it will replace the blood which has been lost, for often the patient has reached a stage at which he is in danger of his life from actual anæmia. ”

“ If there be a loss of tissue brought about by severe injury to the skin and the deeper tissues, there is usually an extravasation of blood from the severed vessels. Along with the exuded serum this fills up the breach in the tissues and the whole is rapidly formed into a fibrinous mass due to the disintegration of the polymorpho-nuclear leukocytes setting free their ferment. The ferment thus set free brings about the coagulation of the serum, which acts as a protective and temporary scaffolding to the injured tissues. ”

“ The danger is always greater if the blood is drawn from a different genus and unfitted to live in the blood of the recipient. Disease germs are especially dangerous if adapted to colonize the serosa of the vessel and destroy its epithelium. A decrease of the density of the blood favors coagulation, a lowering of one thousandth rendering it syrupy, and various chemical agents induce or favor coagulation, thus acetic acid, valerianic acid, alcohol, the salts of iron, and above all the salts of lime act in this way. ”

“ Fill three tumblers each two thirds full of water and set them in a warm place. Pour into one of the tumblers, and thoroughly mix with the water, two tablespoonfuls of the blood containing the Epsom salts. After an interval of half an hour add blood to the second tumbler in the [pg 038] same manner, and after another half hour add blood to the third. The water dilutes the salts so that coagulation is no longer prevented. Jar the vessel occasionally as coagulation proceeds; and if the clot is slow in forming, add a trace of some salt of calcium (calcium chloride) . ”

“ The immediate effect of the bleeding is to alarm the patient and family, no matter how slight it may be, inducing heart palpitation and other nervous symptoms. A small bleeding is not attended with any bad result, but large ones give rise to the symptoms of shock (sometimes immediate death) combined with anemia following the loss of blood. When the bleeding is large, blood by the mouthful may be ejected with each cough, and in these instances of such profuse bleeding is shown by dizziness, faintness, cold extremities, excessive pallor, sweating and rapid, small feeble pulse. ”

“ We had all joined with her in prayer, at her own request; she then consented to the operation. After a small quantity of the saline fluid had been injected, her p. 82husband’s sister offered to be blooded, as soon as the transfusion of blood was proposed. The transfusion was commenced, but no more than a teacupful could be borne, as a most startling effect was produced; the eyes having in an instant become red and staring to a frightful extent. Mr. L. saw this, and stopped the process instantaneously. Her breathing was quick and laborious. The pulse merely fluttered, and then stopped. ”

“ Greater success is claimed by Hooker, who reported that in five cases of pyogenic infection the results were distinctly favourable. He used immunized blood, but has formed the impression that the transfusion even of normal blood is of value in septicæmia by correcting the anæmia and helping to restore the normal resistance. ”

“ There are certain general pathological or occasional conditions of the body in which the blood during life does not coagulate at all or only imperfectly, as in scurvy and in the case of the menstrual blood. Also blood in a serous cavity, especially if it be abundant or there exists inflammation, is found not to coagulate or only imperfectly. Post mortem the blood remains liquid long after death in cases of death by drowning, asphyxia, etc., and in such cases hemorrhage may be free in a wound made some time after death. ”

“ During the war it was found that transfusion enabled an exsanguinated patient better to withstand the attacks of pyogenic and putrefactive organisms in his wounds, but this was probably due to the improvement in the general circulation which resulted rather than to any bactericidal properties in the transfused blood. It is known that outside the body blood has considerable powers of inhibiting the growth of bacteria, but ordinarily it does not possess bactericidal properties. ”

“ A vicious circle is thus established, and the symptoms of shock become severe as the capillary stagnation becomes more pronounced.
A second factor which may also play its part in the loss of blood volume in the general circulation is the exudation of some of the plasma into the surrounding tissue spaces. As the stagnation increases, oxygenation decreases, and the walls and the capillaries become more permeable, so that some fluid is probably lost in this way. ”

“ There was no difference between the behavior of old and fresh specimens.
(3) No acceleration of coagulation in vitro was observed even with the highest concentrations tried, namely 25 and 50 per cent.
(4) Irrigations made with fresh dry coagulen in solution and sterile solution in ampoules on superficial bleeding from the foot-pads of 3 normal and peptonized dogs and local application to hemorrhages from dissected femoral arteries and bone and liver wounds of 3 dogs showed that coagulen was no more active than normal saline. ”

“ It should not therefore surprise us that to minds quite unacquainted with the therapeutical effects of blood-letting in disease, a death that follows a bleeding, however remote in point of time, should be credited to the operation rather than to the disease for which the operation was performed. An uncertain percentage of cases of many acute inflammations will recover, whether bled or not; an uncertain percentage of them will die, whether bled or not, and no matter how treated ”

“ Undoubtedly the ideal treatment for carbon monoxide poisoning is by putting the patient in a specially constructed chamber in which he can breathe oxygen under a pressure of about three atmospheres. By this means the carboxyhæmoglobin is dissociated and replaced by oxyhæmoglobin. An oxygen chamber is usually not available, though a very useful substitute may be tried in the shape of a Haldane’s oxygen mask. Failing this, there is evidence to show that a blood transfusion is an effective form of treatment. ”

“ In hemorrhages she produces a faintness, which occasions a coagulum in the open vessels; so that the further passage of blood through them is obstructed.
[37]
In wounds of the flesh and bones she discharges foreign matter by exciting an inflammation, and supplies the waste of both with new flesh and bone.
II. There are cases where the efforts of nature are too feeble to do service, as in malignant and chronic fevers.
III. There are cases where the efforts of nature are over proportioned to the strength of the disease, as in the cholera morbus and dysentery. ”

“ In any case of bleeding the patient may become weak or may faint, but unless the blood is flowing actively, this is not necessarily a serious sign, and the quiet condition of the circulation during the faint often assists nature in staying the bleeding, by allowing the blood to clot, and so block up any wound in a blood-vessel. ”

“ Upon the same principle alkaline applications may be made to dissolve coagulated blood; suppose, for the sake of illustration, that the bladder should become filled with coagulum through hemorrhage from the prostate gland, and that the most serious consequences were to be apprehended from the distention; in such an emergency, a dilute and tepid solution of potass, if injected through the catheter, might prove eminently serviceable ”

“ The danger in cholera is proportioned to the volume of the discharges rather than to their frequency, just as a single profuse hemorrhage is more serious than the loss of an equal amount of blood divided among several successive days. The special danger, however, is not, as in hemorrhage, from syncope, but from the progressive loss by drainage of the water of the blood, rendering it unfit to circulate, and therefore causing it to stagnate in the veins. ”

“ To remove the effusion during the inflammatory stage does not appear to be rational treatment unless the quantity is so excessive as to endanger the life of the patient. The fluid remains limpid unless exposed to air or contact with foreign substance. When, after a time, there is some coagulation, it is only of a thin layer which covers and protects the roughened surface of the pleura. A certain amount of effusion is useful; it separates and bathes in a bland fluid the tender and inflamed surfaces, and keeps at rest the affected portion of the lung. ”

“ A patient suffering from severe shock is unable to tolerate more than a very small quantity of fluid in his stomach without vomiting. Some success was attained by Oswald Robertson in treating cases of hæmorrhage by the method of “forced fluids,” large quantities being given by the mouth and by the rectum (245) . In many serious cases, however, this treatment is inapplicable, and it is clear that transfusion is more rapid and more certain in its effect. ”

“ A slight exciting cause is all that is necessary to produce their rupture. The primary cause is the false membrane, and, in some cases, vascular granulations, which have rapidly formed, perhaps in twenty-four hours—conditions eminently favorable to the production of hemorrhage. In cancerous, tubercular, and dyscrasial conditions of the blood, the blood-vessels are especially weak and easily give way, owing to the defective nutritive properties of the blood itself, just as, in typhoid fever, we have nasal and intestinal hemorrhage, and in typhus, petechiæ. ”

“ The experiment suggests that resistance to infection is heightened if two bodies can combat the infection present in one; but continuous transfusion is scarcely practicable in man.
Diphtheria.—In the later stages of some acute diseases due to a bacterial infection, the patient falls into a condition of acute toxæmia, the symptoms of which resemble in some ways those of shock. Harding has drawn attention to this condition in diphtheria; he has produced it experimentally in animals and has treated it by blood transfusion. ”

“ Moist dressings favour the removal of bacteria by promoting the escape of the inflammatory exudate, in which they are washed out.
Artificial Hyperaemia.#--When such direct means as the above are impracticable, much can be done to aid the tissues in their struggle by improving the condition of the circulation in the inflamed area, so as to ensure that a plentiful supply of fresh arterial blood reaches it. The beneficial effects of _hot fomentations and poultices_ depend on their causing a dilatation of the vessels, and so inducing a hyperaemia in the affected area. ”