The principles and practice of modern surgery / by Roswell Park ... with 722 engravings and 60 full-page plates in colors and monochrome.

  • Roswell Park
Date:
1907
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Licence: Public Domain Mark

Credit: The principles and practice of modern surgery / by Roswell Park ... with 722 engravings and 60 full-page plates in colors and monochrome. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    namely, congestion and hypcrcviia. To begin with these, then, we must note, fii'st of ail, that congestion and hyperemia may be— A. Active; and B. Passive. They may also be spoken of as— 1. Acute; and 2. Chronic. Considering first the two latter distinctions, it will be fonnd that the acute hy])eremias are met with most often in consequence of sharp mechanical disturbances. I'lie chronic hyperemias, on the contrary, are conditions which in many individuals are more or less permanent. Note accurately here the proper significance of certain terms. Hyper- emia means, in effect, an oversupply of blood to the given part; the term should have only a local significance. When the entire body seems to be too well su])]>lied with blood, the condition is known as •plethora, the counterpart of which term is usually anemia. The direct counterpart of the term Jit/prremia should j^erhaps l)e isrhniiia, meaning a perverted blood supply in reduced amount. With jilethora and anemia as terms implying general conditions, with hyperemia and ischemia implying local con- ditions, there should be little room for confusion in phraseology. The active form of hyperemia used to be called fiuxion, a term now rarely used. Active hyperemia means an increased supply of arterial blood. In passive hi/peremia the oversupply is rather of venous blood. In the former case the condition seems due to overactivity of the heart, with such local tissue changes as permit it to occur. In passive hyperemia the blood current is slower—there is a tendency toward, and sometimes an actual, stagnation; all of which is usually due to obstruction of the return of blood to the heart. The conditions permitting these two results may be widely variant. Active Hyperemia.—Active hyperemia may be produced by purely nervous influ- ences, even those of emotional origin. The flushing of the face which is known as blushing is, perhaps, the most common illustration of this fact. It is well known also that this is, in some degree at least, the result of division of certain nerves which have to do with the regulation of the blood supply. The cervical sympathetic is the best known and most often studied of these, and the consequences of division of this nerve in the neck are stated in all the text-books on physiology. So also by electrical stimulation of certain nerves the parts supplied by them can be made to show a very active hyperemia, which will subside shortly after discontinuance of stimulation, pro- viding this has not been kept up too long. In active hyperemia there is absolute increase of intra-arterial tension, and under these circumstances pulsation may be noted in those small vessels in which commonly it is not seen nor felt. This is the explanation of the throb- bing pain complained of under many actively hyperemic conditions. This hyperemia affords the explanation of the clinical signs to which attention has already been called. The increased heat of the part is the result of greater access of blood, which prevents cooling by radiation and evaporation; the peculiar redness is due to the greater filling of the capillaries with the blood, which gives the peculiar hue to the skin and visible textures; while to the increased jiressure upon sensory nerves is also due the pain. The minuter changes occurring within the congested part call for more accurate descrij^tion. Whether or not there is actual dilatation of cajiillaries under these circumstances is a matter still under dispute, but of the dilatation of the larger vessels there can be no possible question. As hyperemia is to such a great extent brought about by action of the nervous system, it is well to divide it more accurately into the hyperemia of ])aralysis, or neuroparah/tir congestion, which is the result of a paralysis of the constrictor fibers of the vasomotor system, and into the hyperemia of irritation, or neurotonic congestion, which is due to the irritation of the dilators (Recklinghausen). Physiologists are fairly well agreed that as between the dilating and the constricting apparatus of the vasomotor system there is ordinarily preserved a certain degree of efpiilibrium; to which fact is probably due that normal condition of affairs inaugurated after temporary disturbance, since overaction in one direction succeeds reaction in the other. As Warren has illustrated this, our common treatment of frostbite by cold applications is a concession to this fact, since by the cold ap])lications we endeavor to limit the reaction wliich would otherwise follow after thawing out the frozen part.