The preparation exemplifying these points is in the museum of the Royal College of Surgeons, together with the ligature still carrying in its noose the portion of the artery it strangulated and brought away with it.
187. A ligature should always be round and small, provided it be sufficiently strong. The strength of a ligature is variously estimated; some surgeons trying it by the strength of their own fingers, others by what they conceive to be the resisting power of the coats of the artery, in which perhaps they may err. The only way in which a surgeon can hope to acquire correct information on this point is by trying on the dead body what force of fingers is required to cut the inner coats of arteries of various sizes; and then taking the least force required for this purpose, to ascertain whether he can easily pull the ligature over or off the divided end of the artery. If a surgeon will take the trouble to do this, he will find that he has estimated the necessary force much too highly, and that he is in more danger of breaking his ligature than of failing to secure the artery. Hemorrhage has, however, been known to occur from the ligature having slipped off the end of an artery, which had been divided in the operation for aneurism, although I have never seen it happen after amputation, where the vessels were tied with a small, firm ligature. It constitutes a valid objection to the division of the artery between the ligatures, when two are applied.
A ligature composed of one strong thread of dentists’ silk, well waxed, is sufficiently firm for the largest artery. It does not, however, much signify what may be the shape, size, form, or substance of ligatures, when they are applied to arteries in a sound state, provided they are not too large, are fairly and separately tied, and with a sufficient degree of force to retain the ligature in its situation until separated by the usual processes of nature, which generally take from fourteen to thirty days for their completion.
188. When arteries are unhealthy, the selection and proper application of a ligature are points of great importance. A larger although yet a small, round ligature should be fairly, evenly, and firmly, although not so forcibly applied as on a sound artery; without the intervention of any substance whatever between it and the cellular covering of the vessel. The secondary hemorrhages which are recorded by different writers as prone to occur, and which did take place, happened, I am disposed to believe, more from the application of improper ligatures than from any other cause; for the inner coat of an artery is so prone to take on the adhesive state of inflammation that if a strong, small ligature be applied in the manner directed, it is more than probable that the closure of the artery will be effected. Ulceration will, however, sometimes take place on the inner coat of the vessel, and slowly extend outward, undoing in its progress any steps which may have been begun for the consolidation of the extremity of the artery. When a secondary hemorrhage does occur from this or from any other cause, it is usually from the beginning of the second to the fourth week; but there is no security for the patient until after the ligature has come away, unless it is retained an inordinate length of time, from having included some substances which do not readily yield under irritation, such as the extremity of a nerve, or a slip of ligament which is not sufficiently compressed in the noose of the ligature.
Secondary hemorrhage may also take place from the extension of ulceration or sloughing to the artery from the surrounding parts, and perhaps as frequently as from any other cause; but when mortification occurs, there is no secondary hemorrhage, unless in that species which is called hospital gangrene. The advantages to be derived from the application of a strong, small ligature, from the least possible disturbance of the surrounding parts, and from absolute quietude, while the healing processes are going on, must be so obvious as to require no further observation. An undue interference with the ligature, by pulling at it, cannot be too earnestly deprecated at an early period; although, at a subsequent time, some force is occasionally required for its removal after amputation.
LECTURE XI.
THE FEMORAL ARTERY, ETC.
189. When the femoral artery is cut across in the upper part of the thigh, whether it be done by a cannon-shot, a musket-ball, or a knife, the patient does not always bleed to death at once, although he frequently dies after a time in consequence of the shock and the loss of blood.
At the battle of Toulouse a large shot struck an officer and two men immediately behind him, and nearly tore off the right thigh of each. The artery was divided about, or less than three inches below Poupart’s ligament. I saw the officer shortly afterward, in consequence of his surgeon saying it was a case for amputation at the hip-joint. The bleeding had ceased, the pulse was feeble; the countenance ghastly, bedewed with a cold sweat, and with every indication of approaching dissolution. The house being at an advanced point, and close to one of the French redoubts, the fire of round shot and musketry was so severe upon and around it as to induce me to remain, until the battery should be taken by the troops then advancing upon our flank. In order to occupy my time usefully, I returned to the officer, and found he had just expired. Desirous of seeing by what means the hemorrhage had been arrested, I cut down upon the artery, took it carefully out, and found that its divided end was irregularly torn; a slight contraction had taken place just above, but not sufficient to have been of the slightest utility in suppressing the bleeding, which was in fact prevented by an external coagulum, which filled up the ragged extremity of the vessel, and which in a few days, if he had lived, would have been removed with the purulent discharge, an internal one forming in the mean time, the extremity of the artery also contracting and retracting, so that a secondary hemorrhage might not have taken place, indeed would not in the generality of instances.
At Salamanca I had the opportunity of examining the thigh of a French soldier, whose femoral artery had been divided perhaps even higher up by a cannon-shot. He lived until the next morning, when I saw him, no operation whatever having been attempted, nor a tourniquet applied. He died exhausted, but not from any immediate bleeding, which, when once stopped, had not returned. The artery was in a similar state to the preceding one, with this slight difference, that the orifice was a little more contracted; the external coagulum filled up the ragged end of the artery, and was slightly compressed within by the contraction, which kept it in its place. The rest of the coagulum filled the hollow in the surrounding parts, which the retraction of the artery had occasioned. In this case, so unlike those I have hitherto noticed, the first natural cause giving rise to the suppression of the bleeding was the diminution of the power of the heart; the second, the formation of a coagulum in the hollow of the sheath left by the retraction of the artery. Contraction had begun, but had done nothing essential. (See Aph. 413.)