Venous blood

“ Venous hæmorrhage is far more common, and, taking into account the anatomical relations of the veins, and their great size (increased by cyanosis) in children, it seems remarkable that bleeding is so seldom fatal; in desperate cases a very small amount of blood is sufficient to cause suffocation. Venous bleeding will stop only when respiration becomes free, and this is not possible so long as blood is being sucked into the air-passages. ”

“ The serum, mostly composed of albumen, is a transparent, straw-colored fluid, having the odor and taste of blood. The whole quantity of blood in the body is estimated on an average to be about one-ninth of its entire weight. The distinctions between the arterial and the venous blood are marked, since in the arterial system the blood is uniformly bright red, and in the venous of a very dark red color The blood-corpuscles contain both oxygen and carbonic acid in solution. When carbonic acid predominates, the blood is dark red ”

“ Sometimes the blood enters it in greater or less quantity, it is even, more or less heavy according to the kind of death. But these varieties belong only to the hepatic veins, which enter into the vena cave inferior just below the heart; they arise from the greater or less reflux of blood that takes place there, as in all the great venous trunks; they consequently arise almost always from the lungs; so that when we see that they are loaded with blood, the right auricle consequently distended, we may also be sure that the liver contains more of this fluid than usual. ”

“ Venous bleeding (from a vein) occurs as a steady even stream of dark blood, not affected by the heart beat.
(c) Capillary hemorrhage is in the form of a steady stream oozing from the raw surface of a tissue. The color is intermediary, as both arterial and venous capillaries contribute to it.
Nature’s Efforts to Control Hemorrhage. When an [Pg 52] artery is severed, the inner and middle coats immediately retract and curl up within the lumen, partially closing up the cut end. ”

“ The patches of congestion, so characteristic of this disease in other organs, are not here observed. This may depend upon the peculiar disposition of the capillary system of the kidney. The blood has to pass through the Malpigian tufts, and may be purified, or altered in character, before it reaches the proper venous system of the organ.
In cases where purulent infection of the blood has been purposely produced, portions of the kidney will not unfrequently be found inflamed and firmer than natural ”

“ II. Hæmorrhage from venous paralysis. Of Piles. Black stools. Petechiæ. Consumption. Scurvy of the lungs. Blackness of the face and eyes in epileptic fits. Cure of hæmorrhages from venous inability. I. As the imbibing mouths of the absorbent system already described open on the surface, and into the larger cavities of the body, so there is another system of absorbent vessels, which are not commonly esteemed such, I mean the veins, which take up the blood from the various glands and capillaries, after their proper fluids or secretions have been separated from it. ”

“ The venous side of the vascular system, owing to the great size of the veins, has a large potential capacity, while many of the capillaries in each organ are empty and collapsed, except at those periods of vaso-dilatation and hyperaemia which accompany extreme activity of function. The vascular system cannot be regarded as a closed system, for the blood-plasma, , whenever the capillary pressure is increased, transudes through the capillar wallinto the tissuesgaces and enters the lymphatics. ”

“ Venous pulse occurs only at the lower extremity of the jugulars. It is very frequent in animals of the bovine species, and in thin animals is not necessarily a pathological symptom. It is due to reflux of blood in the anterior vena cava, under the influence of the expiratory effort; sometimes to emphysema, tuberculosis, etc.; in other cases to the return of blood towards the vena cava and jugulars at the moment of auricular systole, as a result of lesions of the tricuspid or auriculo-ventricular orifices. ”

“ Inflammation of veins is a very unmanageable disease; the exhibition of purgatives and antimonials will be prudent, in order to evacuate the bowels, produce diaphoresis, and diminish the force of the circulation; the pain will also be much relieved by the application of warm fomentations to the affected part. General depletion is not admissible unless at the very commencement of the disease, and local bleeding must be had recourse to with very great caution; for by copious abstraction of blood, gangrene may be induced, or at least hastened. ”

“ Under these last circumstances, we may find a vein partially obliterated at different points, leaving intervals where lymph or pus are secreted. If the purulent matter introduced is allowed to remain a short time only in the vein, no inflammation is produced (Experiment vi) . But when any irritating fluid is detained there in consequence of the blood coagulating around it, adhesive, ulcerative, or suppurative inflammation, will be excited (Experiments vii and viii) .
The slowness with which veins inflame when cut, tied, or bruised, has been made a subject of comment by different authors ”

“ The examination of the blood, or of the vessels, in such cases, will by no means invariably indicate the presence of foreign matter after it has once become thoroughly mixed with the blood, nor will inflammation of the vein through which the fluid passes, be by any means invariably produced.
When a foreign substance is introduced into an artery, any immediate effects upon the blood may naturally be looked for in the system of capillaries which it supplies. If the blood then coagulates, local symptoms alone, will, in the first instance, be produced, and the constitution will remain unaffected. ”

“ If you have a varicose vein, it will almost for certain be in the leg, and if it bursts, you will feel the hot stream of blood and rapidly become faint. When this occurs, lie down on the floor and elevate the leg as high as you{404} can. This alone may stop the bleeding. If it does not, press your finger on the spot, and then send or call out for assistance. The slightest pressure will stop bleeding from a vein.
In these cases of serious bleeding, send for a surgeon as soon as you have applied pressure. In all probability the vessel will have to be tied. ”

“ Extensive effusions of serum, lymph, and pus, mixed in different proportions, will take place in the serous cavities of the body, and become infiltrated in the cellular membrane, accompanied with very slight indications of inflammatory action. The colouring matter of the blood will also sometimes become effused with its other parts; but when this is the case, the blood will be found to have lost its coagulating power: in this respect presenting a direct contrast to the effusion from a healthy wounded vessel. ”

“ It has been already shown that the blood, when in a natural condition, has a tendency to coagulate around pus, and, probably, many other fluids, even out of the body (Experiments i, v) , [Pg 8] and that this property is exercised in a still more remarkable manner in the living vessels (see Experiments vii, viii) . Foreign matter, even after it has got into the veins, may then, by the same means, be prevented from proceeding farther towards the centre of circulation. The process that takes place under such circumstances, is strictly analogous to union by the first intention. ”

“ In the close of malignant fevers, where bleeding has been omitted in the beginning of the disease, blood drawn from a vein is generally so dissolved, as to be beyond the reach of repeated bleedings to restore it to its natural texture. In this case, arteriotomy might probably be performed with advantage. The arteries, which retain their capacity of life longer than the veins, by being relieved from the immediate pressure of blood upon them, might be enabled so to act upon the torpid veins, as to restore their natural action, and thereby to arrest departing life. ”

“ The germs of boils and fevers often get into the blood, but the white cells usually kill them before they have a chance to grow into large numbers and make the body sick.
How to stop Bleeding.—Most of the larger arteries are deep in the flesh and seldom get cut. There are many veins just under the skin. If the blood comes out in spurts, it is from an artery; but if it flows steadily, it is from a vein. If the blood does not run out in a stream, it will stop without any special care. As soon as the blood gets to the air it forms a jellylike mass called a clot. ”

“ These changes may be expected in a more marked degree, when the obstruction depends upon coagulation of the blood, than when it arises from other causes, inasmuch as the coagulum usually extends to several veins at the same time.
In the experiments that have been made upon animals, it has been a matter of surprise that, while extreme pain was evinced upon the injection of irritating fluids into the veins, comparatively little or no suffering was produced, when similar experiments were performed upon the arteries. ”

“ If the coagulum be allowed to remain, the vein in which it is formed soon becomes thickened; but, as the experiments cited [Pg 4] prove, this thickening is the effect and not the cause of the stagnation of the vitiated blood in the vessel.
II. When blood coagulates in a serous cavity, a thin pellicle forms upon its surface, and, becoming thickened by deposition from the fibrin of the blood, forms a cyst, which completely circumscribes the effusion. ”

“ 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. ”

“ The two given below are translations from Védrènes’ version (Paris, 1876) , and they deal, the one with venesection and the other with the proper manner of arresting hemorrhage from a wound. Both the passages quoted represent only fragments, as sufficient space for more extensive extracts is not available.
Book II., Chapter X.—Bloodletting from a Vein.—Incising a vein for the purpose of drawing blood from it, is not a new procedure; but it is certainly a new thing to resort to bloodletting in almost all diseases. ”

“ When a clot of blood obstructs the vein he directs us to squeeze it out, or to dissolve it with oil or vinegar. When coldness of the body, occasioned whether by the temperature of the air, or the nature of the disease, prevents the flow of blood, he recommends fomentations and frictions. When a piece of fat or flesh blocks up the opening of the vein, he says there is no remedy for it but to cut it out or push it aside. When the object is to produce a sudden depletion he directs us to make a large incision in the vein, but a small one when it is intended to procure revulsion. ”

“ Hunter, "bleeding should be performed with great caution: even a quick, hard pulse, and sizy blood, are not always to be depended upon as sure indications of bleeding being the proper method of the resolution of the inflammation; more must be taken into the account. The kind of blood is of great consequence to be known; for although it should prove sizy, yet if it lies squat in the basin, and is not firm in texture, and if the symptoms at the same time are very violent, bleeding must be performed very sparingly, if at all ”

“ Some change must previously have passed in the blood, by which its coagulating power is impaired, or some unusual mechanical means must have been employed, before the pus can find its way in the course of the circulation. The contradictory statements which have been made by those who have injected pus into the veins, may thus be reconciled, by taking into account the power exercised by the blood in the experiments which have been made. ”

“ With regard to age, bleeding must not be practised before the fourteenth, nor after the seventieth year, unless some urgent necessity compel us. And upon the whole we must avoid bleeding those persons whose strength is reduced. In recent inflammations we must make the evacuation from the opposite parts, but in chronic from the adjoining. We abstract blood from many parts of the body, but more especially from the inner part of the elbow. But it is to be recollected that in general the artery lies below the inner vein called the alar ”

“ The coagulation of the blood in such cases (Exp. vii and viii) serves as a bond of union between the sides of the veins (which may be either temporary or permanent) , so as to prevent the entrance of any foreign matter into the circulation. When the blood thus coagulates in veins, changes may be produced analogous to those mentioned as occurring in serous cavities. If the quantity of blood be large, a thin pellicle is at first formed upon its surface (see Preparations 1523-25 and 1525-64, in the Museum of Guy's Hospital) . ”

“ On account of the smaller amount of elastic and muscular tissue in the wall of a vein, the contraction and retraction of its walls are less than in an artery, and so bleeding may continue for a longer period. On the other hand, owing to the lower blood-pressure the outflow goes on more slowly, and the gradually increasing pressure produced by the extravasated blood is usually sufficient to arrest the haemorrhage before it becomes serious. As an aid in diagnosing the source of the bleeding, it should be remembered that the rupture of a vein does not affect the pulsation in the limb beyond. ”