12th. This bleeding from the lower end of the vessel, which is more or less of a venous color, and issues in a continuous stream, may be restrained by compression properly made on the course of the lower part of the wounded artery; but in no instance should recourse be had to a ligature on a distant part of the artery above the seat of injury, until every other possible effort to arrest the hemorrhage from the lower end of the vessel has failed.
13th. The great principles of surgery to be observed in cases of wounded arteries, and which ought never to be absent from the mind of the surgeon, are two in number:—
1. That no operation ought to be performed on a wounded artery unless it bleed.
2. That no operation is to be done for a wounded artery in the first instance but at the spot injured, unless such operation not only appears to be, but is impracticable.
183. The means adopted by nature for the suppression of hemorrhage have been investigated by Celsus, Rufus, Galen, Œtius, etc., down to Dr. Jones, the most important English writer on this subject; but the methods of inquiry they all adopted appear to have been insufficient and unequal to the object in view. They bled an animal until he died, and then reasoned on the manner or means by which the bleeding was suppressed, when it was in fact arrested by death. It is obvious, then, that it is only when nature has not been interfered with, and the patient has not died from bleeding continued to the last moment, but has, on the contrary, lived some time after the hemorrhage has ceased, that the processes by which its suppression has been accomplished can be fairly investigated. These processes essentially depend on the size and variations of structure in an artery, which have been shown to be dissimilar in large and small arteries, and not even quite alike in the upper and lower ends of the same artery—facts which were elicited from observations made on men on the field of battle during the Peninsular war, and consequently not liable to error. It was then proved that arteries of moderate dimensions, such as the middle part of the femoral or the axillary, tibial or brachial, and particularly all below these in size, are capable, by their own intrinsic powers, when completely divided, of arresting the passage of the blood through them without any assistance from art, or from the surrounding parts in which they are situated. The establishment of this fact overthrew at once the theory which relates to the importance of, and necessity for, the sheath of the vessel, and the offices it performs in suppressing hemorrhage in vessels of this size, and in a great measure that supposed to be derived from the formation of an external coagulum, the bouchon of the French.
184. When the femoral artery has been fairly divided in the lower part of the thigh, the patient has, in almost all the cases which have come under observation, either died without assistance, or the hemorrhage has ceased spontaneously. Having been thus arrested for twelve hours, the efforts of nature are usually sufficient to prevent its return from the upper, although not from the lower end of the vessel; but then it is of venous and not of arterial color—a fact I first demonstrated, and which is now acknowledged to be of the greatest importance. The great evil to be dreaded in such cases is not from hemorrhage from the upper end of the divided artery, but from the lower, and from mortification of the foot.
The upper end of an artery retracts on being divided, and this retraction is accompanied by a contraction of the cut extremity of the vessel, which assumes the shape of the neck of a French wine-bottle or Florence oil-flask. The contraction is confined in the first instance to its very extremity, so that the barrier opposing the flow of blood is formed by this part alone. The contraction, however, goes on increasing for the space of an inch; it is usually filled up with an internal coagulum of a round, pyramidal shape, adhering firmly to the contracted end of the artery, loose at its apex, and extending frequently as far as the first collateral branch, but rarely under any circumstances beyond two inches; the very orifice of the artery on the outside being in a few days covered by a layer of a yellowish green-colored substance or fibrin, which indicates its situation in a remarkable manner. Some of these processes are continued even after the external wound has healed; the artery generally goes on diminishing and contracting as far as it is useless, so that of three or four inches, from one to two may be impervious, the remainder being contracted, although still permeable by a probe. An accompanying nerve, where there is one, would do the reverse, the cut extremity would become enlarged or bulbous, gradually diminishing as it is traced upward, until it regains its proper size.
The processes adopted by nature for closing the lower end of a divided artery of the size of the femoral at the inferior part of the thigh are somewhat different from those employed at the upper or opposite extremity. The retraction or contraction of the lower end of a divided artery is neither so perfect nor so permanent as at its upper end, and the small internal coagulum is in many instances altogether wanting, or very defective in its formation. The closure of the lower orifice being less perfectly accomplished than of the upper, it is the more likely to suffer from secondary hemorrhage, which may be distinguished from that from the upper end of the artery at an early period after the accident, by the venous color of the blood, and from its flowing or welling out in a continuous stream, as water rises from a spring, and not with an arterial impulse.
The retracting and contracting powers in the lower end of a divided artery are nevertheless considerable, and are sufficient in some cases to nearly close the lower end of the femoral artery when divided by amputation above the knee. When the femoral artery is cut across, the lower portion of the vessel is emptied by its last efforts, combined with the action of the capillaries. When the collateral circulation is powerful, blood soon regurgitates into the artery, but the force of the regurgitation can be in no proportion to that of the propulsion at the other or upper divided end of the vessel, which will generally be able to resist this impulse, while the lower one often opens and bleeds after the lapse of a few days. In all the cases I have had an opportunity of examining, in which hemorrhage had taken place from the lower end of the artery, the following appearances were observable after the interval of from four to five days.
The same kind of yellowish-green matter marks and conceals the situation of the lower extremity of the artery in the wound as it does the upper. It is, however, thinner where it immediately covers the end of the artery, which in none of these cases was contracted in the conical manner described as taking place in the upper extremity. On the introduction of a probe with the greatest gentleness into the artery from below, it usually makes its appearance at a point on the yellow space, raising a thin portion as it protrudes. On laying open the artery, the orifice would seem to have been once closed by this layer of fibrin, but with a less degree of contraction than the upper end of the same artery; the layer still, however, forming an obstacle sufficient to cover and close three-fourths of the orifice, the blood having flowed through the remaining fourth, which had probably given way by accident; which accident is usually some sudden or continued motion being given to the extremity or part injured, and which motion it is imperatively necessary to avoid, when the lower end of a wounded artery has not been secured by ligature.