The principles and practice of modern surgery

The part played by the constituent elements of the blood in inflammation, suppuration, and other still more disastrous conditions is so great and so important that, before proceeding to discussion of these lesions, it seems necessary to set forth a resume of facts illustrating the importance of accurate knowledge concerning this most important fluid.

The total amount of blood in the human body has been variously estimated at from one-eleventh to one-twenty-fifth of the body weight, the average being about one-sixteenth. The amount which the body may lose and still retain vitality is very vague and differs not only with individuals, but very greatly under various conditions. Severe loss of blood is one to be atoned for as quickly as possible, and is to be prevented as far as it can be after accidents or during operation. For this reason the so-called bloodless method of operating upon limbs, by the use of the rubber bandage, constituted a great advance in surgery. For the same reason the use of hemostatic forceps is of equal value in operating upon other parts of the body; other things being equal the quickest and most satisfactory recoveries follow the bloodless operations, and it is an advantage to conserve this vital fluid as far as possible.

It has been roughly estimated that the blood is divided about as follows, between the different parts of the body: the heart, lungs, and large vessels holding one-fourth, the skeletal muscles one-fourth, the liver one-fourth, the remaining quarter being distributed over the balance of the body.

The blood varies within wide limits in its coagulability, and this variation occurs apparently even within conditions of health. In some patients the blood may be seen to coagulate almost as rapidly as it collects upon the surface, while in others the exposed parts continue to ooze, and the checking of hemorrhage is a difficult, sometimes almost impossible, matter. There are certain diseases in which the blood is known to have reduced power in this direction; for example, in the toxemias, especially those connected with biliary obstruction and jaundice. There were not a few of these cases of slow bleeding to death in days gone by, simply because the capillary hemorrhage could not be controlled. Recently, it has been shown that calcium chloride administered internally has a marked effect in favoring coagulation, and when opportunity is afforded it should be given for several days previous to operating and as part of the necessary preparation. It may be administered in doses of from 1 to 2 Gm., and should be given three or four times, at least, in twenty-four hours.

A test of the coagulation time, normally three to five minutes, but lengthened under circumstances like those mentioned above, even to an hour, will often prove of great value.

There are certain albumoses whose effect on coagulation of the blood is very suggestive and very mysterious. A very minute dose of cobra poison, for instance, will make the blood of an experimental animal remain fluid for days, unless this animal has been previously immunized against it, in which case coagulation takes place even more rapidly than normally. A trace of serum from an immunized rabbit is enough to prevent the fluidifying effect of the cobra poison, but quite insufficient to neutralize its toxic effects. The surgeon practically never desires to reduce coagulability of the blood, but frequently to increase it. When it is increased by natural conditions or those not easily controlled, then it may lead to thrombosis and produce trouble in that way.

Fibrin.

—Increase of fibrin, hyperinosis, accompanies the leukocytosis of inflammation and suppuration. It may be approximately estimated on the cover-glass by noting the closeness of the network resulting after fifteen minutes’ exposure. The inflammatory indication of leukocytosis may, therefore, be inferred from its determination, while the leukocytosis of malignant disease will not be so accompanied. Hyperinosis is most marked in pyogenic processes, pneumonia and rheumatism. Its opposite, hypinosis, is met with in pernicious anemia. There is no change in the percentage of fibrin in the ordinary anemias or chlorosis. In hemophilia and purpura hemorrhagica the coagulation time is greatly increased.

The Formed Elements of the Blood.

—The specialized elements of the blood which are of particular interest to the surgeon are the red and the white corpuscles. These may both vary in relative size within certain physiological limits. The red cells especially are not of uniform size and vary from 6 to 9 microns in diameter. There are also present in normal blood a small number of red cells having a diameter of only 6 microns, which are known as microcytes. In infancy there are present also so-called giant corpuscles, or megalocytes, with a diameter of 10 microns or more. Considerable variation occurs in disease, especially in the severe anemias. Red corpuscles ordinarily stain with acid dyes, which facilitate their examination and a computation of the number present. When present in unusually large number the condition is spoken of as a polycythemia; when in reduced number as oligocythemia. In several of the anemias variations in size, shape, and color occur, and in certain of them many of the red corpuscles are found to be nucleated. Red cells which are nucleated are known as erythroblasts, and according to their size are spoken of as microblasts, normoblasts, and megaloblasts. Again, under certain diseased conditions the ordinary discoid form of the cells becomes irregular and crenated, and to those which are thus altered is given the name of poikilocytes.

There is another form of degeneration which consists in death or necrobiosis of the cell, whereby it loses its capacity for staining, or, at all events, stains irregularly and abnormally. This is seen also in cases of severe anemia and in conditions where the blood has been altered by the addition of toxic material, such as chloroform, etc. Occasionally also the red cells show a tendency to a granular change, which is probably entirely degenerative.

The red corpuscles have a certain degree of elasticity which helps them to pass through capillaries which are smaller even than their own diameter; after escaping from these the corpuscles regain their original form. In the presence of carbon dioxide they lose this elasticity and become distorted or crenate. The influence of high altitudes in increasing the number of corpuscles is known, but unexplained. For instance, a residence of less than a month in the mountains will cause an increase of from 2,000,000 to 3,000,000 corpuscles per cubic millimeter. It has been surmised that under the influence of oxygen red corpuscle formation is stimulated to greater activity; in other words, that the red marrow becomes more active in the production of the hematoblasts.

In general terms it may be said that the blood of a normal adult male contains 5,000,000 red corpuscles per cubic millimeter, and that of an adult female 4,500,000. These figures are, of course, approximate and variable. When the number is reduced to 3,000,000 by common consent the case will be regarded as oligocythemia, and when increased to 6,000,000 as one of polycythemia.

The latter condition is most evident in cases of newly born infants. The excess rapidly diminishes during the first week of extrauterine life. It is to be explained by the loss of fluid suffered by the infant upon the establishment of respiration. The proportion of red cells also varies according to the nutrition of the individual, the season of the year, the altitude (as above), and climate, and varies during menstruation, pregnancy, lactation, and at the climacteric. With the loss of red cells the number is reduced in proportion to the hemoglobin, although the change in one respect is not exactly proportionate to that in the other.

That the colorless corpuscles, or leukocytes, are not all of one kind has been recognized for nearly sixty years, and long ago they were divided into granular and nucleated cells. A vast impetus to the study of hemocytology was given by Ehrlich, in 1878, when he introduced the use of aniline dyes. The reader must be reminded that some of these, like eosin, are acid in reaction, and others, like methyl blue, are basic; while a third group has been supposed to be neutral in reaction, like a mixture of methyl blue and acid fuchsin; but it has been found that the so-called neutral dyes have really a slightly acid reaction. We may, therefore, divide the cells according to the reaction of the dyes with which they usually are distinguished into the acid and basic, or, more technically, into oxyphile, which includes neutrophile, and basophile.

This is not the place in which to go into any minute discussion of this subject nor further than should be of practical interest to the surgeon; nevertheless an examination of the blood by some common and routine procedure is so necessary in many surgical conditions that it is impossible to entirely avoid the subject in a work like this. I have accordingly condensed it and put the salient facts about leukocytes into the following table:

Classification of Leukocytes.

In normal blood by far the greater part of the leukocytes consists of A and D. Lymphocytosis means a relatively high percentage of C and D. Eosinophilia means an increase in the proportion of B. Basophile cells are not absolutely pathological, for they may be present in very small numbers in normal blood.

The number of leukocytes in normal blood will average about 7000 to 10,000 per cubic millimeter, the percentage of each variety being given in the above table. Leukocytes are sometimes diminished in number; under diseased conditions they are often increased, and these are then included under the term leukocytosis. Variations occur daily and almost hourly under normal conditions. Increase naturally occurs after digestion, when the number of leukocytes may be almost doubled, the same being due principally to lymphocytes which are washed into the blood system from the lymph nodes by the flow of lymph or chyle. In starvation, however, the number may be remarkably reduced and in the case of the fasting man, Succi, the leukocytes were reduced at the end of the first week to 860 per cubic millimeter. The rather unusual condition of reduction of the number of corpuscles is called leukopenia.

Leukocytosis is usually the rule in carcinoma, with increase in A and F; the more rapid the growth, the greater this increase. In sarcoma this is even more pronounced; when occurring without hyperinosis the probability of malignancy is greater. Non-malignant tumors produce no such changes.

The blood platelets or plaques first described by Bizzozero, in 1882, have no small interest for physiologists and pathologists, but little for the practising surgeon. They number perhaps 5,000,000 per cubic millimeter and sustain a fairly constant ratio to the red cells. Their surgical interest is limited to the role which they may play in the formation of thrombus.

The term phagocytosis has to do in a general way with those leukocytes which act as scavengers by removing from the blood its noxious elements, presumably by a process of ingestion and digestion (see Chapter III).

Examination and estimation of the various formed elements of the blood are very valuable to the surgeon in the study of the anemias, of acute inflammation when the presence of pus is suspected, in the presence of suspected cancer, and in the presence of such conditions as Hodgkin’s disease, the various disorders of the spleen, etc. The so-called primary anemias include only the pernicious anemias and chlorosis; all others are designated as secondary. This distinction is not for convenience only, but serves a useful purpose.

Pernicious anemias produce a reduction both of the red corpuscles and the hemoglobin, the former usually in a greater degree than the latter, so that the color index (see below) is usually plus. Many of the cells become nucleated and, in general, their size is increased. In chlorosis the reduction of the hemoglobin is relatively large and the color index is extremely low. In the secondary anemias the red cells and hemoglobin are reduced disproportionately, so that the color index is minus. There may or may not be a relative increase of leukocytes and of the nucleated red cells, but these latter are not so likely to be as large as those seen in primary anemias. The color index is obtained by dividing the percentage of the hemoglobin present by the percentage of the red cells.

Leukocytosis becomes pathological in conditions of acute inflammation where the neutrophiles (A) show the greatest relative increase. The degree of leukocytosis depends on two different factors: the intensity or the virulence of the infection, and the vitality or resisting power of the individual. These vary within such wide limits that it is hard to predicate anything definite in a given case. In general the increase is supposed to be proportionate to the severity of the infection, though the greater the reactionary ability of the patient the larger the number of white cells. Where vitality is very low leukocytosis is less pronounced. It is possible to have toxemia to such a degree that the activity of the leukocytes seems to be destroyed. The following summary from Cabot puts things in very distinct form.

Infection mild, vital reaction good—small leukocytosis.

Infection less mild, vital reaction less good—moderate leukocytosis.

Infection severe, vital reaction good—very marked leukocytosis.

Infection severe, vital reaction poor—no leukocytosis.

From this it will appear that the absence of leukocytosis in cases where it naturally would be expected is a serious indication and justifies an unfavorable prognosis; or else it may be interpreted in evidently favorable cases as indicating infection of very mild grade.

There are but few diseases in which leukocytosis by itself (or for that matter any other indication which the ordinary examination or blood count may give) is wholly sufficient for diagnostic purposes. But a blood count and estimate of the amount of hemoglobin present will often be of such advantage to the surgeon that he may well afford to wait in order to secure them. This is rarely necessary in acute cases, but in chronic cases, and especially the anemias, he may gain great benefit by such investigation. In trichinosis, for example, eosinophilia is most pronounced, B forming even as high as 70 per cent. of the leukocytes present.

The anemias which are of particular interest to the surgeon may be classified as follows:

• 1. Anemias without marked leukocytosis.
• A. Characterized by oligocythemia.
• B. Characterized by diminution of hemoglobin.
• 2. Anemias with marked leukocytosis.
• A. Leukemia (leukocythemia).
• B. Pseudoleukemia (Hodgkin’s disease).

1. A. Anemias due to hemorrhage may assume one of two forms, that resulting from sudden and extensive loss of blood or that resulting from constant oozing. Example of the former is seen in hemorrhages of the stomach or intestines after perforating ulcer, etc. Examples of the latter are met with in hemophilia and in uterine hemorrhages, or in excessive menstruation where the loss of blood extends over a considerable length of time. It is known, moreover, that certain entozoa in the intestines will produce a chronic anemia. Thus the red corpuscles may be reduced to even less than 1,000,000 per cubic millimeter. Immediately after acute hemorrhage the hemoglobin percentage is still normal, but after a short time it becomes reduced. If such cases do not speedily end fatally, nucleated red corpuscles appear in the blood and the observer will recognize both normoblasts and megaloblasts. At the same time the bone-marrow, which is normally yellow, becomes red, vascular, and richly cellular, and seems to furnish these cells just mentioned. Certain drugs, like potassium chlorate and glycerin, affect also the number of red corpuscles, but such poisons as these cause not only disintegration of the red cells, but produce also jaundice and hemoglobinuria. Pernicious anemia sometimes interferes with or fatally complicates surgical treatment. It is characterized by the extreme changes already mentioned, with which it marches steadily to a fatal termination. Quincke has reported an instance in which their number was reduced to 43,000 per cubic millimeter, while the hemoglobin was reduced to 20 or 25 per cent. of the normal amount.

1. B. The best example of anemia which depends upon diminution of the hemoglobin content of the red cells is that known as chlorosis. In this there are few recognizable signs of destruction of corpuscles, even under chemical microscopic examination; consequently the blood picture is very simple. The color index is very low, yet similar conditions may also be seen in syphilis, tuberculosis, and cancer. The underlying feature of all of these cases is malnutrition.

Within a few years a peculiar form of intense anemia has been described by Banti and others, and is often spoken of as splenic anemia or Banti’s disease. It is characterized by three stages: first, of splenic enlargement and anemia; second, a transitional stage; third, a stage of ascites which increases up to death. It is quite closely allied to Hanot’s hypertrophic cirrhosis of the liver. It is quite generally regarded as an example of an infection by some as yet unknown organism. It is of interest to the surgeon because if the spleen is removed early there are fair prospects of recovery.

2. A. Anemias with marked leukocytosis include especially those first spoken of by Virchow as leukemia. Originally he applied the term to a particular alteration of the blood, but it is now made to cover a group of diseases, all of which are characterized by peculiar and more or less similar increase of white corpuscles. Sometimes these are increased to such an extent as to make the blood grossly resemble a mixture of blood and pus. This resemblance led some of the earlier observers to speak of the condition as “suppuration of the blood.” The number of leukocytes is sometimes enormously increased; 1 to 10 of the red cells is quite common and 1 to 5 not exceedingly rare. Cases have been known in which the white cells outnumbered the red. In well-marked cases of leukemia, the red cells will be somewhat diminished, while the white will number from 100,000 to 500,000 per cubic millimeter. Accompanying this change in the blood there are alterations in the spleen, the lymph nodes, and the bone-marrow, sometimes one predominating, sometimes another. It has been customary in fact to speak of splenic, lymphatic, and medullary leukemia, but these forms are not sharply differentiated and a pure type of either form is rare. In this country we speak mainly of lymphatic and splenomedullary forms, the latter being much more common. The latter is accompanied by enlargement of the spleen, while in the lymphatic form the lymph nodes are involved and may become as large as walnuts. In the lymphatic form over 90 per cent. belong to C and D; in the splenomedullary or splenomyelogenous form the increase of F and G is most marked, while A will be reduced to 50 per cent. and D to about 10 per cent. The red corpuscles are decreased in number, but not necessarily in an inverse ratio; their number may be reduced even to 2,000,000 in extreme cases.

In these cases, besides the change in number and form of the leukocytes already described, there are frequently found in the blood very minute crystals first described by Charcot. These are small, often adherent to the leukocytes, and most frequently found when eosinophile cells predominate; their exact significance is not known. The pathology of leukemia is too remote from the purpose of this work to receive consideration here. Without asserting its germ character one may say that it is under suspicion, and that various observers have described appearances supposed to indicate a specific cause, probably a protozoön.

2. B. Pseudoleukemia.—This has, in time past, gone under many different names, of which the most common is Hodgkin’s disease (q. v.). Many speak of it as malignant lymphoma. This is doubtless a disease with a specific cause, as yet unrecognized, which produces very significant changes in the blood, especially in the white corpuscles. The spleen and lymph nodes are both involved, mainly the latter. The general blood changes are quite variable and one may find many types. As a rule, these comprise not so much an increase in the number of leukocytes as a decrease in the number of red cells by which an apparent leukocytosis is brought about; hence the expression pseudoleukemia. Many cases, however, will present a certain degree of actual leukocytosis, the proportion of the whites to the reds being about 40 to 50.

What interpretation in general is to be given to leukocytosis? A condition deserving this name is, first of all, essentially temporary. In acute infectious diseases it shows itself during the febrile stage and the principal increase is in the finely granular oxyphile cells. In such diseases as erysipelas, as well as pneumonia, it lasts but a short time after the crisis has been reached and the temperature has fallen. In diseases like acute appendicitis and acute peritonitis from any cause a marked leukocytosis may be regarded as indicating the presence of pus; it should be emphasized, however, that pus may be present without this indication, and it has been previously stated that such a fact is to be interpreted either as an example of a mild degree of infection or an exceedingly reduced vitality.

Differential Leukocyte Count.

—It seems to be now quite clearly demonstrated that the mere establishment of a certain degree of leukocytosis does not furnish the surgeon a reliable guide for determining the presence of pus, it being an index of reaction rather than of actual severity of any particular kind of infection. A much more reliable guide is found in the proportion of polynuclear cells to the total number of leukocytes counted, i. e., by what may be called a differential count. In order to make this reliable, the normal ratio should first be determined. This is put at a point between 68 and 80 per cent. by various writers. As Gibson (Annals of Surgery, April, 1906) says, 75 per cent. may be considered the best working average. This average should be maintained as the total number of leukocytes increases, or else there is a disproportion which becomes significant. With a moderate leukocytosis there is a notable increase in polynuclear cells, and it may be estimated that there is either a severe form of lesion or less resistance to absorption, or both.

Gibson has suggested the formation of a chart where the number 10,000 of leukocytes shall appear upon the same line with 75 per cent. as the average normal proportion of polynuclears. Then drawing a parallel line, which shall indicate on one side each 1000 in increase of the former and each advance of one in the percentage, it will be seen that 15,000 leukocytes will correspond to 80 per cent. of polynuclears, 20,000 to 85 per cent., etc. When upon this chart there is drawn a line between that dot which represents the total leukocytosis on one side and that on the other which indicates the percentage of polynuclears, then the more horizontal this line the less the disproportion, while the more marked the angle it makes with the base line the greater the disproportion appears. It furnishes an admirable graphic record which the eye appreciates at once.

It would appear, then, that a differential blood count made in this way, and thus recorded, affords the most valuable diagnostic and prognostic aid in acute surgical diseases, indicating especially the presence of suppuration or of gangrene.

Glycogen in the Blood and the Iodine Reaction.

—Glycogen occurs in the blood especially in three classes of cases: those where there is marked respiratory disturbance in certain of the anemias, and, what is of especial interest to the surgeon, toxemias, either of chemical or bacterial origin. It is usually present in the secondary and pernicious anemias as well as in acute and late leukemias. It is considered by some that in these cases it really indicates the occurrence of some bacterial infection. Especially is glycogen present in cases of suppuration and surgical sepsis, i. e., in those cases where leukocytosis is usually, but not invariably, present; indeed, it would seem to be a most significant indication. While the iodine test is more easily carried out than is a blood count, the latter affords more information. The reaction is reliable and its relative intensity gives an idea of the intensity of the inflammatory process. In many cases with obscure symptoms and without leukocytosis its presence will afford much aid in diagnosis. It is of great assistance also in distinguishing between a deep-seated pneumonia and serous pleurisy, since in the latter there is no reaction, or in distinguishing between pleurisy with effusion and empyema; again, in distinguishing gonorrheal arthritis from true rheumatism. In a case of strangulated hernia the presence of the iodine reaction would indicate that pressure had produced gangrene, whereas its absence would indicate a relatively lesser degree of destruction. It has been aptly said that the presence of iodine reaction indicates that the patient is seriously sick.

It is easily obtained by staining a cover-glass with a blood smear in a gummy solution of iodine and potassium iodide. When the blood is normal all the cells take on a uniform, bright-yellow color, while the white cells stain more lightly than does their protoplasm. When the glycogen reaction is present, brown granules are seen in the protoplasm of the polynuclear leukocytes, which may often take on a different brown tint. Frequently brown particles are to be seen outside of the corpuscles, while occasionally the other forms of leukocytes show also the reaction.

The value of a careful blood examination is well illustrated by Plate I, prepared by Dr. Irving P. Lyon, in which are displayed the alterations of greatest interest to the surgeon.

HEMOGLOBIN.

The principal interest of the red blood corpuscles for the surgeon, aside from their relative number and shape, inheres in their relation to hemoglobin, and hemoglobin is of particular interest here because much can be learned by estimating the proportion in which it is present. Hemoglobin has, furthermore, an interest which reaches beyond the mere blood appearance, since it is considered to be the apparent source from which both the urinary and biliary pigments are produced. That the amount contained in the blood varies within wide limits under different conditions has long been known. When notably reduced in amount the condition is referred to as oligochromemia. The ideal normal standard is present in but a small proportion of cases, even in strong young men in the third decade of life. The average is considerably lower and can scarcely be placed above 90 per cent. Females show a smaller amount than males—3 or 4 per cent. less. In anemia its reduction is not usually proportionate to that in the number of red cells. After hemoglobin loss, as after surgical operations, much can be gained in the matter of prognosis by estimating the speed of its regeneration. With regard to how much actual hemoglobin loss a patient can bear, it seems to be more important to determine how much still remains in the body. The minimum is apparently 20 per cent. In three cases dying of collapse after operation, Mikulicz found only 15 per cent. remaining. The rapidity of regeneration is a fairly accurate indication of improvement in every other respect. Regeneration is interfered with by constitutional syphilis, and, on the other hand, is often apparently favored in cases of tuberculosis. In malignant tumors the average of hemoglobin is reduced to about 60 per cent., and in these cases also complete regeneration is materially retarded. Incomplete removal or recurrence of cancer prevents typical regeneration or restoration, while, after successful or radical removal, complete restoration to the previous standard, often with positive gain, is obtained. Thus, a woman who had gained thirty pounds after resection of a cancerous pylorus, showed, after three months, hemoglobin repair to the amount of 65 per cent. A prognostic significance often attaches to the accurate estimation of hemoglobin at intervals after removal of malignant tumors.

A very convenient method for the ready estimation of hemoglobin is afforded by the Tallquist color scale. It can be practised at the bedside and is sufficiently accurate for the surgeon’s general purposes.

THROMBOSIS.

Thrombosis is a term applied to the formation of a thrombus—i. e., a clot within the cavity of the heart or one of the bloodvessels—the term being limited to coagulation of blood within these natural cavities, and without specifying the exciting cause of the same. A clot so formed is called a thrombus. To be accurate, a distinction should be made between a thrombus, which is caused always before death—or, rather, during life—and the clot, which is essentially a postmortem affair. Our application, then, of the terms “thrombosis” and “thrombus” refers solely to that which takes place during life. In order to appreciate the conditions which lead to thrombosis it is necessary to fully appreciate the reciprocal conditions which must normally be maintained between the circulating blood and the walls of the vessels in which it flows. Fluidity of blood depends always upon integrity of the vessel wall. As long as its lining membrane is absolutely undisturbed and normal, moving blood will never coagulate within it, and the only thrombi that may be met within it are those which are propagated from a distance. Coagulation of blood is, for the main part, associated with the peculiar properties of fibrin.

Fibrin is produced from fibrinogen, a globulin which is held in solution under ordinary circumstances, which has certain peculiarities of its own. When the change occurs it is entirely consumed and none remains in the blood serum. Fibrinogen is split up by a peculiar ferment called thrombin into what we ordinarily speak of as fibrin and a small amount of a soluble globulin, which remains in solution in the serum. Thrombin is not a normal constituent of the blood, but is formed when it escapes, as the result of the reaction between certain calcium salts and a nucleoproteid, which has been called prothrombin. The latter arises from the disintegration of the leukocytes, especially the polynuclear, and the blood plaques, after the blood leaves the bloodvessels. Calcium salts seem absolutely necessary for coagulation; hence the value of the administration of calcium chloride in certain cases previous to operation. Another essential feature seems to be the absolute integrity of the endothelial lining of the bloodvessels, although for this fact there is no satisfactory explanation. If a portion of a vein is removed from the body after double ligation its contained blood will not coagulate for a long time. Blood which is kept circulating through the lungs and heart alone soon loses its coagulability; hence the liver seems to be concerned in some way in maintaining it. Certain other substances also seem to retard coagulation, such as the albumoses of snake venom, and certain synthetic, colloid, proteid-like substances, which can be introduced very gradually. If, however, they are introduced rapidly, or in large quantities, thrombosis occurs promptly. We have much to learn about the coagulation of the blood, but the above facts are at least suggestive to the surgeon.

Causes.

—The underlying cause of all thrombi is, then, alteration of the endothelium. In consequence, when it is desirable to produce coagulation artificially, advantage may be taken of this fact, and mechanical injury to the vessel walls may be quickly followed by the desired results. Advantage is also taken of this fact in surgery, especially in certain methods of treating aneurysm, by rude handling, by needling, by the introduction of horsehairs, fine wire, etc. A venous thrombosis is certainly favored by the thinness of the venous walls, by which poorer protection is afforded to their lining endothelium, and infection more easily occurs. Arterial thrombosis is favored when cardiac vigor is impaired and vessel walls are thickened so as to obstruct the blood current. This occurs particularly in syphilitic endarteritis, where the intima suffers most, and final occlusion is due to the thrombus thus formed. Arteriosclerosis does not, by itself, often produce this trouble; it comes rather with atheromatous and calcareous degenerations. The local ischemia which is occasioned by ergotism, by pellagra (due to use of certain kinds of maize), by the vasomotor spasm of Raynaud’s disease (see under Gangrene), by too long-continued constriction, or by frostbite, causes results comparable to those produced experimentally in parts supplied by a terminal artery, e. g., in the kidney after temporary occlusion of its artery. All the tissues involved undergo profound alterations, in which thrombosis figures very largely and may lead to gangrene.

While such endothelial lesions are essential, there are, nevertheless, numerous other accessory causes which should be mentioned. These comprise:

A. The presence of foreign bodies, as, for example, needles, hooklets of echinococci, parasites, particles of tumors, fragments from the heart valves, and, most of all, that which is essentially a foreign body, a clot which has come from some other point. Around such foreign particles will quickly group themselves a relatively large number of leukocytes, thus affording another example of phagocytosis, soon to be described. Mere slowing of blood stream without some such mechanical irritation is not sufficient to produce coagulation. If, for instance, a section of vein is isolated between two ligatures, the ligation being aseptically done and the surroundings of the vein wall disturbed as little as possible, the blood thus shut up within the vein remains fluid indefinitely. If, however, the vessel wall is separated from its surroundings, so that its nourishment is compromised, the contained fluid quickly coagulates.

B. Necrosis, gangrene, etc., lead to quick involvement of the endothelium of the vessels contained within the involved part, and consequently to quick coagulation of the blood which they contain.

C. Temperature has also an influence in the same direction, and extremes in either direction, or drying of vessels which may happen to be exposed to the air for some time, lead to the same results.

D. Inflammatory and degenerative processes occurring in and about the vessel walls tend always to produce coagulation. This is well seen in the influence exerted by the so-called atheromatous ulcers—i. e., the degeneration of certain areas in the walls of large vessels.

E. Microörganisms and their products are perhaps the most frequently effective of all the accessory causes of thrombosis. In other words, in all the surgical infectious diseases we may expect to find more or less, sometimes extensive, thrombosis in the vessels of the affected part. This may so far shut off circulation as to produce temporary or permanent edema, or it may lead to gangrene, which may be local or may terminate the life of the patient.

Thrombi are classified as:

• 1. Primary; and
• 2. Propagated.

The primary thrombus is one which has originated at the spot where it has been first produced, and is usually co-extensive with its cause. The propagated thrombus may be one which has been carried to a considerable distance, and is met with at a point widely different from that where it originated, or one which has extended along the vascular channel in which it was first formed, but far beyond the limits of its prime cause. When a thrombus attaches itself to a part of the vessel wall it is called parietal or valvular, because it does not completely occlude the vessel; when it involves the entire circumference of the vessel, but does not completely occlude it, it is spoken of as annular. The obstructive thrombus is that which completely fills a given vessel and shuts off all circulation through it.

The propagated thrombus extends usually in both directions, and always much farther in veins than in arteries. Thus, thrombi may be met with extending from the ankles even into the inferior vena cava. The venous valves may on one hand excite coagulation, or on the other tend to fix the coagula more firmly in their place. In arteries thrombi usually extend only to the first collateral channel on the cardiac side, but occasionally they spread farther. The cause of a primary thrombus is to be sought at the site of its lodgement; the cause of propagated thrombi is often observed at a wide distance from the effect.

Thrombosis is, again, to be spoken of as—

• a. Marasmic;
• b. Mechanical or traumatic;
• c. Infective.

a. The marasmic forms are due to essential alterations in the constituents of the blood, which are due mainly to starvation or wasting disease. Marasmic thrombi seldom give rise to serious disturbance during life until the condition is so complex and grave that the patient is at death’s door. Postmortem evidences of marasmic thrombi, however, are often found, and yet have but little surgical significance. They are seen perhaps as often in the cranial sinuses as anywhere.

b. Thrombi of mechanical or traumatic origin are those, for instance, which are due to the presence of foreign bodies, to stagnation of blood as the result of ischemia or local anemia, to compression by tumors, etc.

c. Infective thrombi are those distinctly due to the injurious effects of micro-organisms, and are those mainly concerned in the various manifestations of sepsis which are of interest to surgeons.

While the ordinary evidences of thrombosis are most often looked for in the veins of the extremities, in the lungs, and in the cranial sinuses, it must not be forgotten that thrombosis may occur equally easily in the portal system of vessels; in which case we find the most marked expressions in this system and in the liver. In cases also of pyemia proceeding from lesions in the rectum or in the bowels there are evidences of infection, abscess, etc., in the liver, but not in the lungs, to which point infective thrombi from other sources are promptly carried.

The ultimate fate of a thrombus depends entirely upon the presence or absence of bacteria. If septic, it invariably breaks down. If aseptic, it may undergo one or more of the following metamorphoses:

A. Decolorization.—This is noted particularly in the red thrombi, and is due to disintegration of the red corpuscles, their coloring matter being diffused and resorbed or transformed into hematoidin. It would be a mistake, however, to suppose that all light-colored thrombi are those which, originally red, have been decolorized. The possibility of white thrombi must always be remembered.

B. Organization.—This is the result of time, and means a metamorphosis into solid vascular connective tissue. Newly formed, minute, vascular loops project from the vasa vasorum into the thrombus, and it becomes thus vascularized, while the completion of the organization is due, in the main, to spindle-cell connective tissue, which is formed by wandering cells that penetrate into the thrombus from without. This gives the organized thrombus a certain resemblance to a sponge, and makes the original vein resemble a cranial sinus, since its interior is spanned by bands of connective tissue. Typical illustrations of this kind are seen, for instance, where the iliac veins join to form the inferior cava, by which a certain amount of obstruction to venous return is produced without its being total. The length of time required for these changes is indefinite. They begin, however, within a short time after ligature of a vein, and proceed with a rapidity varying according to circumstances.

C. Calcification.—Calcium salts are occasionally deposited in thrombi, usually not until they have undergone considerable contraction and alteration; as the result of which we have formation of small masses, essentially minute calculi, to which the name of phleboliths has been given. These phleboliths are not infrequently found in more or less occluded and much distended varicose veins of the extremities, and they prohibit the occurrence of softening.

D. Softening.—This is the most serious termination of the thrombotic accident, and is usually due to the agency of infecting organisms. A non-infectious form is, however, recognized, by which there is a metamorphosis of original clot into an oily or pulpy fluid, usually dark colored, but in the white thrombi often yellowish white, reminding one crudely of pus. The discovery of such material under these circumstances has led in time past to the supposition that pus, as such, was found floating in the blood—a condition that does not exist except under extraordinary circumstances. It is with infection of thrombi and consequent softening, however, that surgeons have most to deal, and the paramount importance to them of such disturbances is emphasized in the article under Pyemia.

A closely allied topic to that above considered is the subject of thrombophlebitis. This means, in effect, inflammation of one or more veins, which is directly due to the presence therein of thrombi. Such a condition is, in its strict sense, an inflammation, since it is always an infectious process. If in the veins of a non-infected region simple thrombi form, they may be occluded by organization of the included masses, but such a process never extends beyond the immediate area involved. On the other hand, if the process is essentially an infectious one, either from without or from within, then both vessel and its contained thrombi succumb completely to the infectious process, which is also essentially a spreading one; and this is limited only by mechanical barriers, by conservative suppuration, or often only by the life of the individual. Excellent examples of thrombophlebitis are seen in the involved uterine sinuses in cases of puerperal septicemia, and in the cranial sinuses after infected compound fractures, or particularly after disease originating in the middle ear has extended to them.

Thrombosis is, at times, a distinctly surgical condition, and often a surgical complication of febrile and other diseases, especially typhoid, in which it constitutes a serious complication and prolongs convalescence for a period of several months. If foreseen it can scarcely be prevented, and when present calls for treatment varying with the location of the lesion and the exciting causes. In the earlier stage anything like rude manipulation or massage is very unfortunate, since soft clots might thus be broken up and distributed to other parts of the body. Absolute physiological rest combined with the application of silver ointment, of ichthyol-mercurial ointment, which should be covered with some non-absorbent material, will probably give the best results. If the lower limbs are affected it may be well to elevate the feet so as to favor return of blood through vessels not yet obstructed. After a certain length of time the thrombi may be regarded as at least adherent if not organized, and massage will prove an important remedy, since by it the lymphatics will be better enabled to take up the fluids which have leaked from the bloodvessels and produced the edema which always characterizes these cases. Sluggishness of circulation is nearly always followed by more or less laxness of tissue, or actual hypertrophy, and a limb thus involved may never regain its original size or flexibility. Veins once compromised, if not occluded, frequently become varicose, or varicosities develop in adjoining veins and still further complicate the case. For such difficulty the measures discussed in the chapter on the Veins may be later required.

In every fresh case of thrombosis or thrombophlebitis great care should be taken in order that by no means shall the clots be disengaged and float away. The dangers correspond to those existing in variocele and nevi, often treated by the older methods of injection of coagulating material. In one instance reported, a child died within half an hour after the injection of an iron salt into a small nevus of the face. Coagulation was excited to a point far beyond the limits intended.

Thrombophlebitis is essentially a surgical condition, occasionally terminating favorably by suppuration and spontaneous evacuation, but calling for surgical intervention whenever it can be recognized and the parts are accessible. The principles of treatment of these conditions are positive and unmistakable. They comprise evacuation of the infective material and disinfection of the involved cavities and tissues. Thus, in sinus phlebitis—i. e., thrombophlebitis of the lateral sinus—it has been made practicable not only to open the sinus in the mastoid region, but to expose the jugular vein in the neck, to ligate it, and to wash through from one opening to the other, effectually getting rid in this way of a long mass of infected thrombi. Only by such bold and radical measures in many of these instances may life be saved.

EMBOLISM.

Embolism means the transportation of any material by which a bloodvessel can be occluded or plugged from one part of the vascular system to some other. The underlying idea is that of transportation or carriage. An embolus is anything so transported, without implying its exact character. The name is even applied to so unsubstantial an affair as a minute bubble of air, which, however, in a tube containing a circulating fluid is a possible source of considerable disturbance. A single bubble thus carried would, by itself, be a trifling affair, but when numerous bubbles are thus transported the result is such local disturbance as may lead to loss of function. Thus, air embolism, so called, may provoke profound, even fatal, disturbances, as, when, with the returning blood stream through the cranial sinuses or one of the large veins in the neck, when opened by accident or operation, air is sucked in, it is carried to the right side of the heart, whose action is perhaps completely perverted because of the new and strange substance which thus enters it, so different from that for which its lining membrane is prepared and to which it reacts. The entrance of air into veins, which constitutes in effect air embolism, has been in time past a bugbear to surgeons, but nevertheless is a source of probable danger when large venous trunks in proximity to the heart are thus exposed. Air embolism is certainly a rarity. On the other hand, those substances which figure most often as emboli are vegetations from the valves of the heart; drops of fat; fragments of tumors; pieces of softened and disintegrated thrombi; foreign bodies, as hooklets of echinococcus cysts; and, perhaps most often of all, the microorganisms clinging to some minute fragment of thrombus which has been dislodged. Embolism is also produced experimentally by the artificial introduction into the circulating blood of cinnabar or small particles of pith or other material. Emboli differ in number and size from the smallest appreciable up to the largest, which may be met with in the larger venous trunks. They are dislodged from their primary site sometimes by accident, as by rude manipulation, injury, etc.; sometimes by undue cardiac activity, as when detached from a valve wall; sometimes by the process of softening of thrombus and a subsequent introduction into the blood stream as a result of some trifling motion; or even by spontaneous processes. Emboli also differ in numbers according to the nature of the primary lesion. In cases of so-called fat embolism fluidified fat is taken into the returning blood stream, carried to the heart, churned up with the contained blood, and distributed to the lungs in such a way that myriads of minute fat masses are distributed throughout the capillaries of the lungs, and free circulation of blood through them is thereby impeded.

It will thus be seen that the relations between thrombosis and embolism are most intimate, but that either one may occur without the occurrence of the other.

Among the viscera, with the exception possibly of the brain, the disastrous consequences of such processes as those just described are more apparent and indicative than in thrombosis and embolism of the mesenteric bloodvessels—a condition not so rare as journal articles would imply, yet, nevertheless, one seldom recognized either during life or after death. Its principal symptoms consist of intense abdominal pain, bloody diarrhea, subnormal temperature, sometimes with vomiting, perhaps in the latter stages vomiting of blood. Shock is usually also extremely marked. The consequence of this condition is almost inevitably gangrene of the intestine supplied by that particular portion of the mesenteric vessels. The pain comes on within a short time after the occurrence, and under the peculiar circumstances gangrene may be practically determined within a few hours. Some two hundred and fifty cases of this kind are now on record, and the condition is one well worth the prompt attention of the surgeon, because only by surgical intervention—i. e., by resection of the necrotic mass of intestine—can life possibly be saved. That when a limited portion of the intestine is involved the gangrenous part may be successfully removed has been proved by several operators. (See Chapter LII.)

It will thus be seen that embolism constitutes often a distinctly surgical condition for which unfortunately only radical measures are suitable. Many cases of gangrene of the toes and feet, extending to the legs, are produced by embolism of the femoral and popliteal arteries, similar conditions being noted less often in the upper extremities. Amputation offers the only resource in such instances, at the same time affording no guarantee against any similar embolic disturbance elsewhere. In only most exceptional instances is it possible, by resorting to moist heat, position, etc., to encourage circulation to such an extent as to obviate the necessity of amputation. (See Chapter V.)

Fat Embolism.

—Fat embolism as a distinct, sometimes fatal, surgical condition has received of late so much study as to be entitled to consideration by itself. By this term is meant a plugging of small arteries by minute drops of fat, which, having been set free somewhere about the periphery, are carried into the venous circulation and thence distributed to various parts of the system. Inasmuch as the capillaries of the lungs are often their first lodging place, fat embolism here is most often met with, and consequently recognized and studied. But it may occur in the brain, the choroid, the kidneys, or other parts, provided only that there has been sufficient ris a tergo on the part of the heart to force the fat globules through the pulmonary capillaries and into the systemic circulation.