Elements of Surgery. Robert Liston

When the heart, or the vessels within the pericardium, have been divided, it can be readily understood how life should be immediately destroyed, since the blood effused into the cavity of the pericardium by its pressure completely arrests the action of the heart. But occasionally punctured wounds, in such situations, have not been followed by instant death. In such cases, alarming symptoms occur at the time, but subside, and the patient may for some time suffer no uneasiness, but afterwards expires suddenly during muscular exertion, or perhaps in a fit of violent passion. Blood must have been effused into the pericardium at the first, causing symptoms of, or actual, syncope; but then the aperture in the vessel had become obstructed by coagulum before blood had been poured out in such quantity as to effectually prevent the actions of the heart; at a future period the coagulum gives way, and the subsequent effusion is limited only by the pericardial cavity being completely filled. In wounds, hemorrhage is the symptom which most alarms the bystanders, and which demands immediate attention; but, to operate successfully, the surgeon must divest himself of all fear, and learn to look boldly on the open and bleeding mouths of arteries. Effusion of blood ceases spontaneously, even from considerable vessels, on faintness supervening, and thus many lives are saved; but as soon as reaction commences it generally recurs, and may prove fatal, unless proper measures be resorted to.

      When an artery is divided, its extremity retracts within the sheath, it also contracts, and coagulation occurs; thus the orifice is obstructed, and a temporary barrier formed to further hemorrhage. The tube, however, is permanently closed by effusion of lymph from its orifice, and consolidation of the surrounding parts.

      The circumstances which follow division of an artery are these:—The immediate effect is retraction of its ends within the investing sheath, and a simultaneous contraction of the coats, so as to diminish the calibre. From the superior orifice there is necessarily a profuse flow of blood, which is discharged through the sheath that formerly enclosed that part of the vessel which has retracted. After considerable effusion of blood, the flow becomes slower and less profuse; particles of blood adhere to those filaments which previously connected the artery to the sheath, but which were lacerated by the sudden retraction of the divided extremity; these particles coagulate, and lessen the canal through which the blood is discharged, whilst they present an irregular surface, on which the blood continues to be deposited and to coagulate; and thus the aperture in the sheath is ultimately closed. This external coagulum is found to commence at the extremity of the artery, where it is of a cylindrical form, and shuts up the mouth of the vessel; it then extends along the canal in the sheath, frequently assuming a conical form; and, if a free discharge has been allowed for the blood, it will terminate at the cut margin of the sheath, otherwise it will be found continuous with the coagulum blocking up the external wound. Also, when hemorrhage has been resisted by the shutting of the external wound, blood is infiltrated into the cellular tissue around the bleeding point, and there coagulates; but this circumstance can be productive of little or no pressure on the parietes of the vessel, so as to assist those other natural means which obstruct it. The flow of blood through the divided vessel being prevented, the circulating fluid necessarily passes through the nearest collateral branches, leaving the blood in the extremity of the larger trunk in a state of comparative rest; consequently, coagulation occurs in this situation. The internal coagulum, however, is small, and not sufficient to occupy completely the cavity of the vessel; it is of a conical form, its apex being towards the heart, and opposite to the first collateral branch, and its base resting on the external coagulum, and there adhering to the internal surface of the artery. But, whilst this latter process is advancing, the capillary vessels supplying the cut margins of the artery have begun to act; they throw out coagulating lymph, and continue to do so until their secretion has completely filled the vessel immediately opposite to its divided margins; thus a third and more effectual coagulum is formed,—one of plastic matter, situated between the external and internal coagula of blood, and in general closely adherent to them. Lymph is also effused externally to the artery and its sheath, forming a dense stratum, which separates the extremity of the vessel from the external wound; it becomes organised, forms granulations, and thus the parts are consolidated, and the wound cicatrised. When the artery is permanently obstructed by the adhesion of its cut margins, the external coagulum can be dispensed with, and is gradually absorbed. Afterwards all the newly formed parts are condensed, and diminish in size; the artery contracts, its internal surface finally embraces the coagulated blood which lay loose in its canal; its coats appear to be thickened, and it is firm and hard. Ultimately, in consequence of the continuance of absorption, it becomes much more attenuated, so as scarcely to differ from the surrounding cellular tissue. Similar changes occur in the lower extremity of the divided artery; in general it retracts farther, its orifice is more contracted, and, the flow of blood being much less profuse than in the superior, the natural means for its temporary closure are sooner accomplished. When an artery has been divided close to the origin of a collateral branch, no bloody coagulum can form internally, for the blood in that situation is necessarily in a state of constant motion.

      If the hemorrhage is suppressed artificially, either by ligature, or by otherwise well-applied pressure, no external coagulum is formed; there appears only the internal bloody coagulum, the lymphatic effusion, and consolidation of the compressed part. The natural contraction and retraction cannot occur in vessels partially divided; hemorrhage, therefore, is more violent and dangerous from a partial than from a complete section. Again, transverse wounds are more dangerous than longitudinal; in the latter, the edges of the wound are spontaneously approximated on account of the structure of the vessels, whilst, from the same cause, the margins of the latter continue separate, and, in fact, the aperture is a complete circle; the lips of an oblique wound will be more or less apart, in proportion as it approaches to the transverse direction. When an artery has been punctured, the wound in the sheath perhaps does not correspond with that in the vessel; blood, therefore, accumulates between the vessel and its sheath, and there coagulates. The wound is thus compressed, its edges kept in contact, and the farther escape of blood prevented; the lips of the incision are then agglutinated by effused lymph, and cicatrisation occurs. This, however, cannot be expected to take place unless methodical pressure has been applied from the first. Even from small punctures blood is effused under the sheath and into the neighbouring cellular tissue, rapidly, and in such quantity as to prevent adhesion. The effusion continues, and a false aneurism is formed. If a considerable part of the circumference has been divided, the lymph may be, and generally is, superabundant, and often to such an extent as to close up the canal of the artery at that point; but, if the aperture is minute and in a longitudinal direction, lymph will seldom be effused in greater quantity than is sufficient for the cicatrisation; and, though it should be superabundant, it is afterwards removed by the absorbents. In all cases, the cellular tissue round the wounded point is much thickened and condensed by the deposition of lymph, but this gradually disappears after cicatrisation has been completed. Sometimes, and generally when the wound has been transverse and large, the process of adhesion is disturbed, and suppuration occurs; in this case the wound in the vessel communicates with the fistulous track in the externally effused lymph, and may be the source of troublesome hemorrhage. In other instances of extensive transverse wounds, the undivided slip ulcerates, and the artery becomes obliterated, by means of the same natural processes that occur in complete division. In cases of laceration of an artery, when its coats have been forcibly torn rather than divided, little or no bleeding takes place. The vessel retracts; the lacerated margins of its inner coat become puckered up, so as to contract greatly the orifice of the vessel; the lacerated sheath is pulled out to a point, and closed at a little distance from the divided inner coats. If a large artery is torn asunder in the dead body, this stretching out and contraction of the sheath will prevent injection passing; in short, the immediate effects of the injury are such as to favour the instant formation of coagula, by which the hemorrhage is arrested until the orifices of the vessel be permanently closed by the adhesive process. Thus, in instances where the whole of an extremity has been torn off, the patients have generally lost but a very small quantity of blood.

      From wounds of veins the blood flows, not in a sub-saltatory but in a uniform stream: its colour is dark, and the flow is easily suppressed. The common opinion is, that to place a ligature on a vein is dangerous, and to be scrupulously avoided. The process of reparation, besides, in a wounded vein, is different from that in an artery. Veins are less disposed to the secreting action by which adhesion is perfected; and, when inflamed, the inflammation