In course of time the collateral branches of the vessel above and below the level of section enlarge and their inter-communication becomes more free, so that even when large trunks have been divided the vascular supply of the parts beyond may be completely restored. This is known as the development of the _collateral circulation_.
_Imperfect Collateral Circulation._--While the development of the collateral circulation after the ligation or obstruction from other cause of a main arterial trunk may be sufficient to prevent gangrene of the limb, it may be insufficient for its adequate nourishment; it may be cold, bluish in colour, and there may be necrosis of the skin over bony points; this is notably the case in the lower extremity after ligation of the femoral or popliteal artery, when patches of skin may die over the prominence of the heel, the b.a.l.l.s of the toes, the projecting base of the fifth metatarsal and the external malleolus.
If, during the period of reaction, the blood-pressure rises considerably, the occluding clot at the divided end of the vessel may be washed away or the ligature displaced, permitting of fresh bleeding taking place--_reactionary_ or _intermediary haemorrhage_ (p. 272).
In the event of the wound becoming infected with pyogenic organisms, the occluding blood-clot or the young fibrous tissue may become disintegrated in the suppurative process, and the bleeding start afresh--_secondary haemorrhage_ (p. 273).
(b) If an artery is only _partly cut across_, the divided fibres of the tunica muscularis contract and those of the tunica externa retract, with the result that a more or less circular hole is formed in the wall of the vessel, from which free bleeding takes place, as the conditions are unfavourable for the formation of an occluding clot. Even if a clot does form, when the blood-pressure rises it is readily displaced, leading to reactionary haemorrhage. Should the wound become infected, secondary haemorrhage is specially liable to occur. A further risk attends this form of injury, in that the intra-vascular tension may in time lead to gradual stretching of the scar tissue which closes the gap in the vessel wall, with the result that a localised dilatation or diverticulum forms, const.i.tuting a _traumatic aneurysm_.
(c) When the injury merely takes the form of a _puncture_ or _small incision_ a blood-clot forms between the edges, becomes organised, and is converted into cicatricial tissue which seals the aperture. Such wounds may also be followed by reactionary or secondary haemorrhage, or later by the formation of a traumatic aneurysm.
_Conditions which influence the Natural Arrest of Haemorrhage._--The natural arrest of bleeding is favoured by tearing or crushing of the vessel walls, owing to the contraction and retraction of the coats and the tendency of blood to coagulate when in contact with damaged tissue.
Hence the primary haemorrhage following lacerated wounds is seldom copious. The occurrence of syncope or of profound shock also helps to stop bleeding by reducing the force of the heart"s action.
On the other hand, there are conditions which r.e.t.a.r.d the natural arrest.
When, for example, a vessel is only partly divided, the contraction and retraction of the muscular coat, instead of diminishing the calibre of the artery, causes the wound in the vessel to gape; by completing the division of the vessel under these circ.u.mstances the bleeding can often be arrested. In certain situations, also, the arteries are so intimately connected with their sheaths, that when cut across they were unable to retract and contract--for example, in the scalp, in the p.e.n.i.s, and in bones--and copious bleeding may take place from comparatively small vessels. This inability of the vessels to contract and retract is met with also in inflamed and dematous parts and in scar tissue. Arteries divided in the substance of a muscle also sometimes bleed unduly. Any increase in the force of the heart"s action, such as may result from exertion, excitement, or over-stimulation, also interferes with the natural arrest. Lastly, in bleeders, there are conditions which interfere with the natural arrest of haemorrhage.
#Repair of a Vessel ligated in its Continuity.#--When a ligature is applied to an artery it should be pulled sufficiently tight to occlude the lumen without causing rupture of its coats. It often happens, however, that the compression causes rupture of the inner and middle coats, so that only the outer coat remains in the grasp of the ligature.
While this weakens the wall of the vessel, it has the advantage of hastening coagulation, by bringing the blood into contact with damaged tissue. Whether the inner and middle coats are ruptured or not, blood coagulates both above and below the ligature, the proximal clot being longer and broader than that on the distal side. In small arteries these clots extend as far as the nearest collateral branch, but in the larger trunks their length varies. The permanent occlusion of those portions of the vessel occupied by clot is brought about by the formation of granulation tissue, and its replacement by cicatricial tissue, so that the occluded segment of the vessel is represented by a fibrous cord. In this process the coagulum only plays a pa.s.sive role by forming a scaffolding on which the granulation tissue is built up. The ligature surrounding the vessel, and the elements of the clot, are ultimately absorbed.
#Repair of Veins.#--The process of repair in veins is the same as that in arteries, but the thrombosed area may become ca.n.a.lised and the circulation through the vessel be re-established.
HaeMORRHAGE IN SURGICAL OPERATIONS
The management of the haemorrhage which accompanies an operation includes (a) preventive measures, and (b) the arrest of the bleeding.
#Prevention of Haemorrhage.#--Whenever possible, haemorrhage should be controlled by _digital compression_ of the main artery supplying the limb rather than by a tourniquet. If efficiently applied compression reduces the immediate loss of blood to a minimum, and the bleeding from small vessels that follows the removal of the tourniquet is avoided.
Further, the pressure of a tourniquet has been shown to be a material factor in producing shock.
In selecting a point at which to apply digital compression, it is essential that the vessel should be lying over a bone which will furnish the necessary resistance. The common carotid, for example, is pressed backward and medially against the transverse process (carotid tubercle) of the sixth cervical vertebra; the temporal against the temporal process (zygoma) in front of the ear; and the facial against the mandible at the anterior edge of the ma.s.seter.
In the upper extremity, the subclavian is pressed against the first rib by making pressure downwards and backwards in the hollow above the clavicle; the axillary and brachial by pressing against the shaft of the humerus.
In the lower extremity, the femoral is controlled by pressing in a direction backward and slightly upward against the brim of the pelvis, midway between the symphysis pubis and the anterior superior iliac spine.
The abdominal aorta may be compressed against the bodies of the lumbar vertebrae opposite the umbilicus, if the spine is arched well forwards over a pillow or sand-bag, or by the method suggested by Macewen, in which the patient"s spine is arched forwards by allowing the lower extremities and pelvis to hang over the end of the table, while the a.s.sistant, standing on a stool, applies his closed fist over the abdominal aorta and compresses it against the vertebral column.
Momburg recommends an elastic cord wound round the body between the iliac crest and the lower border of the ribs, but this procedure has caused serious damage to the intestine.
When digital compression is not available, the most convenient and certain means of preventing haemorrhage--say in an amputation--is by the use of some form of _tourniquet_, such as the elastic tube of Esmarch or of Foulis, or an elastic bandage, or the screw tourniquet of Pet.i.t.
Before applying any of these it is advisable to empty the limb of blood.
This is best done after the manner suggested by Lister: the limb is held vertical for three or four minutes; the veins are thus emptied by gravitation, and they collapse, and as a physiological result of this the arteries reflexly contract, so that the quant.i.ty of blood entering the limb is reduced to a minimum. With the limb still elevated the tourniquet is firmly applied, a part being selected where the vessel can be pressed directly against a bone, and where there is no risk of exerting injurious pressure on the nerve-trunks. The tourniquet should be applied over several layers of gauze or lint to protect the skin, and the first turn of the tourniquet must be rapidly and tightly applied to arrest completely the arterial flow, otherwise the veins only are obstructed and the limb becomes congested. In the lower extremity the best place to apply a tourniquet is the middle third of the thigh; in the upper extremity, in the middle of the arm. A tourniquet should never be applied tighter or left on longer than is absolutely necessary.
The screw tourniquet of Pet.i.t is to be preferred when it is desired to intermit the flow through the main artery as in operations for aneurysm.
When a tourniquet cannot conveniently be applied, or when its presence interferes with the carrying out of the operation--as, for example, in amputations at the hip or shoulder--the haemorrhage may be controlled by preliminary ligation of the main artery above the seat of operation--for instance, the external iliac or the subclavian. For such contingencies also the steel skewers used by Spence and Wyeth, or a special clamp or forceps, such as that suggested by Lynn Thomas, may be employed. In the case of vessels which it is undesirable to occlude permanently, such as the common carotid, the temporary application of a ligature or clamp is useful.
#Arrest of Haemorrhage.#--_Ligature._--This is the best means of securing the larger vessels. The divided vessel having been caught with forceps as near to its cut end as possible, a ligature of catgut or silk is tied round it. When there is difficulty in applying a ligature securely, for example in a dense tissue like the scalp or periosteum, or in a friable tissue like the thyreoid gland or the mesentery, a st.i.tch should be pa.s.sed so as to surround the bleeding vessel a short distance from its end, in this way ensuring a better hold and preventing the ligature from slipping.
If the haemorrhage is from a partly divided vessel, this should be completely cut across to enable its walls to contract and retract, and to facilitate the application of forceps and ligatures.
_Torsion._--This method is seldom employed except for comparatively small vessels, but it is applicable to even the largest arteries. In employing torsion, the end of the vessel is caught with forceps, and the terminal portion twisted round several times. The object is to tear the inner and middle coats so that they curl up inside the lumen, while the outer fibrous coat is twisted into a cord which occludes the end of the vessel.
_Forci-pressure._--Bleeding from the smallest arteries and from arterioles can usually be arrested by firmly squeezing them for a few minutes with artery forceps. It is usually found that on the removal of the forceps at the end of an operation no further haemorrhage takes place. By the use of specially strong clamps, such as the angiotribes of Doyen, large trunks may be occluded by pressure.
_Cautery._--The actual cautery or Paquelin"s thermo-cautery is seldom employed to arrest haemorrhage, but is frequently useful in preventing it, as, for example, in the removal of piles, or in opening the bowel in colostomy. It is used at a dull-red heat, which sears the divided ends of the vessel and so occludes the lumen. A bright-red or a white heat cuts the vessel across without occluding it. The separation of the slough produced by the charring of the tissues is sometimes attended with secondary bleeding.
_Haemostatics_ or _Styptics_.--The local application of haemostatics is seldom to be recommended. In the treatment of epistaxis or bleeding from the nose, of haemorrhage from the socket of a tooth, and sometimes from ulcerating or granulating surfaces, however, they may be useful. All clots must be removed and the drug applied directly to the bleeding surface. Adrenalin and turpentine are the most useful drugs for this purpose.
Haemorrhage from bone, for example the skull, may be arrested by means of Horsley"s aseptic plastic wax. To stop persistent oozing from soft tissues, Horsley successfully applied a portion of living vascular tissue, such as a fragment of muscle, which readily adheres to the oozing surface and yields elements that cause coagulation of the blood by thrombo-kinetic processes. When examined after two or three days the muscle has been found to be closely adherent and undergoing organisation.
#Arrest of Accidental Haemorrhage.#--The most efficient means of temporarily controlling haemorrhage is by pressure applied with the finger, or with a pad of gauze, directly over the bleeding point. While this is maintained an a.s.sistant makes digital pressure, or applies a tourniquet, over the main vessel of the limb on the proximal side of the bleeding point. A useful _emergency tourniquet_ may be improvised by folding a large handkerchief _en cravatte_, with a cork or piece of wood in the fold to act as a pad. The handkerchief is applied round the limb, with the pad over the main artery, and the ends knotted on the lateral aspect of the limb. With a strong piece of wood the handkerchief is wound up like a Spanish windla.s.s, until sufficient pressure is exerted to arrest the bleeding.
When haemorrhage is taking place from a number of small vessels, its arrest may be effected by elevation of the bleeding part, particularly if it is a limb. By this means the force of the circulation is diminished and the formation of coagula favoured. Similarly, in wounds of the hand or forearm, or of the foot or leg, bleeding may be arrested by placing a pad in the flexure and acutely flexing the limb at the elbow or knee respectively.
#Reactionary Haemorrhage.#--Reactionary or intermediary haemorrhage is really a recurrence of primary bleeding. As the name indicates, it occurs during the period of reaction--that is, within the first twelve hours after an operation or injury. It may be due to the increase in the blood-pressure that accompanies reaction displacing clots which have formed in the vessels, or causing vessels to bleed which did not bleed during the operation; to the slipping of a ligature; or to the giving way of a grossly damaged portion of the vessel wall. In the s.c.r.o.t.u.m, the relaxation of the dartos during the first few hours after operation occasionally leads to reactionary haemorrhage.
As a rule, reactionary haemorrhage takes place from small vessels as a result of the displacement of occluding clots, and in many cases the haemorrhage stops when the bandages and soaked dressings are removed. If not, it is usually sufficient to remove the clots and apply firm pressure, and in the case of a limb to elevate it. Should the haemorrhage recur, the wound must be reopened, and ligatures applied to the bleeding vessels. Douching the wound with hot sterilised water (about 110 F.), and plugging it tightly with gauze, are often successful in arresting capillary oozing. When the bleeding is more copious, it is usually due to a ligature having slipped from a large vessel such as the external jugular vein after operations in the neck, and the wound must be opened up and the vessel again secured. The internal administration of heroin or morphin, by keeping the patient quiet, may prove useful in preventing the recurrence of haemorrhage.
#Secondary Haemorrhage.#--The term secondary haemorrhage refers to bleeding that is delayed in its onset and is due to pyogenic infection of the tissues around an artery. The septic process causes softening and erosion of the wall of the artery so that it gives way under the pressure of the contained blood. The leakage may occur in drops, or as a rush of blood, according to the extent of the erosion, the size of the artery concerned, and the relations of the erosion to the surrounding tissues. When met with as a complication of a wound there is an interval--usually a week to ten days--between the receipt of the wound and the first haemorrhage, this time being required for the extension of the septic process to the wall of the artery and the consequent erosion of its coats. When secondary haemorrhage occurs apart from a wound, there is a similar septic process attacking the wall of the artery from the outside; for example in sloughing sore-throat, the separation of a slough may implicate the wall of an artery and be followed by serious and it may be fatal haemorrhage. The mechanical pressure of a fragment of bone or of a rubber drainage tube upon the vessel may aid the septic process in causing erosion of the artery. In pre-Listerian days, the silk ligature around the artery likewise favoured the changes that lead to secondary haemorrhage, and the interesting observation was often made, that when the collateral circulation was well established, the leakage occurred on the _distal_ side of the ligature. While it may happen that the initial haemorrhage is rapidly fatal, as for example when the external carotid or one of its branches suddenly gives way, it is quite common to have one, two or more _warning haemorrhages_ before the leakage on a large scale, which is rapidly fatal.
The _appearances of the wound_ in cases complicated by secondary haemorrhage are only characteristic in so far that while obviously infected, there is an absence of all reaction; instead of frankly suppurating, there is little or no discharge and the surrounding cellular tissue and the limb beyond are dematous and pit on pressure.
The _general symptoms_ of septic poisoning in cases of secondary haemorrhage vary widely in severity: they may be so slight that the general health is scarcely affected and the convalescence from an operation, for example, may be apparently normal except that the wound does not heal satisfactorily. For example, a patient may be recovering from an operation such as the removal of an epithelioma of the mouth, pharynx or larynx and the a.s.sociated lymph glands in the neck, and be able to be up and going about his room, when, suddenly, without warning and without obvious cause, a rush of blood occurs from the mouth or the incompletely healed wound in the neck, causing death within a few minutes.
On the other hand, the toxaemia may be of a profound type a.s.sociated with marked pallor and progressive failure of strength, which, of itself, even when the danger from haemorrhage has been overcome, may have a fatal termination. The _prognosis_ therefore in cases of secondary haemorrhage can never be other than uncertain and unfavourable; the danger from loss of blood _per se_ is less when the artery concerned is amenable to control by surgical measures.
_Treatment._--The treatment of secondary haemorrhage includes the use of local measures to arrest the bleeding, the employment of general measures to counteract the accompanying toxaemia, and when the loss of blood has been considerable, the treatment of the bloodless state.
_Local Measures to arrest the Haemorrhage._--The occurrence of even slight haemorrhages from a septic wound in the vicinity of a large blood vessel is to be taken seriously; it is usually necessary to _open up the wound_, clear out the clots and infected tissues with a sharp spoon, disinfect the walls of the cavity with eusol or hydrogen peroxide, and _pack_ it carefully but not too tightly with gauze impregnated with some antiseptic, such as "bipp," so that, if the bleeding does not recur, it may be left undisturbed for several days. The packing should if possible be brought into actual contact with the leaking point in the vessel, and so arranged as to make pressure on the artery above the erosion. The dressings and bandage are then applied, with the limb in the att.i.tude that will diminish the force of the stream through the main artery, for example, flexion at the elbow in haemorrhage from the deep palmar arch.
Other measures for combating the local sepsis, such as the irrigation method of Carrel, may be considered.
If the wound involves one of the extremities, it may be useful; and it imparts confidence to the nurse, and, it may be, to the patient, if a Pet.i.t"s tourniquet is loosely applied above the wound, which the nurse is instructed to tighten up in the event of bleeding taking place.
_Ligation of the Artery._--If the haemorrhage recurs in spite of packing the wound, or if it is serious from the outset and likely to be critical if repeated, ligation of the artery itself or of the trunk from which it springs, at a selected spot higher up, should be considered. This is most often indicated in wounds of the extremities.
As examples of proximal ligation for secondary haemorrhage may be cited ligation of the hypogastric artery for haemorrhage in the b.u.t.tock, of the common iliac for haemorrhage in the thigh, of the brachial in the upper arm for haemorrhage from the deep palmar arch, and of the posterior tibial behind the medial malleolus for haemorrhage from the sole of the foot.
_Amputation_ is the last resource, and should be decided upon if the haemorrhage recurs after proximal ligation, or if this has been followed by gangrene of the limb; it should also be considered if the nature of the wound and the virulence of the sepsis would of themselves justify removal of the limb. Every surgeon can recall cases in which a timely amputation has been the means of saving life.
The _counteraction of the toxaemia_ and the _treatment of the bloodless state_, are carried out on the usual lines.
#Haemorrhage of Toxic Origin.#--Mention must also be made of haemorrhages which depend upon infective or toxic conditions and in which no gross lesion of the vessels can be discovered. The bleeding occurs as an oozing, which may be comparatively slight and unimportant, or by its persistence may become serious. It takes place into the superficial layers of the skin, from mucous membranes, and into the substance of such organs as the pancreas. Haemorrhage from the stomach and intestine, attended with a brown or black discoloration of the vomit and of the stools, is one of the best known examples: it is not uncommonly met with in infective conditions originating in the appendix, intestine, gall-bladder, and other abdominal organs. Haemorrhage from the mucous membrane of the stomach after abdominal operations--apparently also due to toxic causes and not to the operation--gives rise to the so-called _post-operative haematemesis_.
#Const.i.tutional Effects of Haemorrhage.#--The severity of the symptoms resulting from haemorrhage depends as much on the rapidity with which the bleeding takes place as on the amount of blood lost. The sudden loss of a large quant.i.ty, whether from an open wound or into a serous cavity--for example, after rupture of the liver or spleen--is attended with marked pallor of the surface of the body and coldness of the skin, especially of the face, feet, and hands. The skin is moist with a cold, clammy sweat, and beads of perspiration stand out on the forehead. The pulse becomes feeble, soft, and rapid, and the patient is dull and listless, and complains of extreme thirst. The temperature is usually sub-normal; and the respiration rapid, shallow, and sighing in character. Abnormal visual sensations, in the form of flashes of light or spots before the eyes; and rushing, buzzing, or ringing sounds in the ears, are often complained of.
In extreme cases, phenomena which have been aptly described as those of "air-hunger" ensue. On account of the small quant.i.ty of blood circulating through the body, and the diminished haemoglobin content of the blood, the tissues are imperfectly oxygenated, and the patient becomes extremely restless, gasping for breath, constantly throwing about his arms and baring his chest in the vain attempt to breath more freely. Faintness and giddiness are marked features. The diminished supply of oxygen to the brain and to the muscles produces muscular twitchings, and sometimes convulsions. Finally the pupils dilate, the sphincters relax, and death ensues.
Young children stand the loss of blood badly, but they quickly recover, as the regeneration of blood takes place rapidly. In old people also, and especially when they are fat, the loss of blood is badly borne, and the ill effects last longer. Women, on the whole, stand loss of blood better than men, and in them the blood is more rapidly re-formed. A few hours after a severe haemorrhage there is usually a leucocytosis of from 15,000 to 30,000.