Splenic Bed Research Articles

The responses of the spleen to nerve stimulation in relation to the frequency of splenic nerve discharge.

The response of the spleen is shown to be made up of at least three distinct components, 2 vascular and 1 capsular. Although the splenic capsular response is maximal at frequencies of nerve stimulation well below 10 impulses per second, the response of the splenic vascular bed is less than 70% maximum with stimulation at 10 impulses per second (imp. /s). In the decerebrate cat the splenic nerve fibres are normally active at between 0 and 5.6 imp. /s and in asphyxia or following vertebral occlusion this activity can rise as high as 10 imp. /s.

Splenic arterial patterns angiographic analysis and review.

A detailed analysis of the angiographic appearance of the splenic artery and its branches has been compiled by reviewing a series of 38 selective celiac arteriograms. Direct measurements from the serialographic films (usually in 2 projections) were tabulated and minimum, maximum and average values for such parameters as diameter at various points, total length and segmental length have been recorded. In addition, a compilation of the origins and incidences of visualization of branches was made and compared with the anatomical findings of Michels. Finally, radiologically estimated circulation times through the splenic bed were determined. Variations of these parameters were wide. For example, the length of the normal splenic artery varied, among patients, from 17.3 to 33 cm; the circulation time varied from 4 to 18 seconds. These variations may serve as a useful background in the evaluation of splenic arterial patterns in the future. The normal angiographic anatomy as well as significant abnormalities of the splenic artery and its branches produced by intrinsic or extrinsic disease, has been described and illustrated.

Complications following splenectomy with special emphasis on drainage.

OF THE MANY controversial problems that exist in surgery today, that of drainage versus nondrainage following splenectomy remains to be solved. Recently, a report by Cohn¹tended to incriminate drainage of the splenic bed as a possible source of increased postoperative complications of the local-infection type. In the past, no controlled studies have been offered to lend support to either proponents or opponents^2,3of postsplenectomy drainage. The paucity of statistical knowledge concerning this controversy has stimulated the present review of our experience. <h3>Material and Methods</h3> During the ten-year period, 1955 through 1964, splenectomy was performed on 106 patients. The indications and complications were analyzed. Particular interest was focused on whether the splenic bed was drained. The age of the patients ranged from 17 months to 74 years. The average for the entire group was 35.5 years, and there was a slight preponderance of male over female. <h3>Indication for</h3>

LOCAL INFECTIONS AFTER SPLENECTOMY: RELATIONSHIP OF DRAINAGE.

THOUGH ATTRACTING little attention in the surgical literature, the question of whether or not to drain the splenic bed following splenectomy is an important one because major local infectious complications, ie, subphrenic abscess, follow splenectomy. Many surgeons state unequivocally that the splenic bed should always be drained 1-4 but others do not practice this and claim excellent results. 6 Since these views seem to be based on empiricism, the following retrospective study was undertaken and presents the first analysis of a large series of splenectomies specifically for the postoperative local infectious complications. Clinical Material The clinical records of 130 patients undergoing splenectomy were reviewed. The operations were performed at the New England Deaconess Hospital and on the Surgical Services of the Boston City Hospital from 1954 to 1964. The age of patients ranged from 1½ to 70 years. There was a slight preponderance of men to women. Splenectomy was performed

DIFFERENTIAL EFFECTS OF HEAT ON SPLENIC AND RENAL VASCULAR BEDS.

The effects on vascular resistance of increasing blood temperature, from hypothermic to hyperthermic levels, were evaluated on denervated perfused spleens and kidneys in the dog. Temperature of the perfusate (blood) was increased for variable intervals of time from the hypothermic level of 32 C to the hyperthermic level of 42 C. The calculated resistance in the splenic vascular bed increased, whereas the resistance decreased in the renal vascular bed. It is concluded that heat has a differential effect in the splenic and renal vascular bed, causing vasoconstriction in the spleen and vasodilation in the kidney.

Effect of Salmonella typhosa endotoxin on perfused dog spleen.

SummaryThese results demonstrate that local injection of the endotoxin S. typhosa into the splenic vascular bed of the dog, perfused at a constant flow, results in a progressive increase in calculated vascular resistance. The response of the splenic vasculature to lethal doses of endotoxin, furthermore, is unlike that of the intestine and resembles the response of other organs of the portal circulatory bed, the liver and stomach. Where a persistent venular constriction occurs in the intestine, only a transitory venoconstriction occurs in the spleen.

Pressure-flow relationships in the perfused dog spleen.

Isolated and nonisolated preparations of dog spleens were perfused at various rates by means of a blood pump inserted proximal to the splenic artery. Pressures were measured continuously and vascular resistances were calculated. In both preparations vascular resistance decreased as perfusion pressure gradient increased over a wide range (67–313 mm Hg). Pressures and resistances were consistently lower at each perfusion rate in the isolated preparations, presumably due to periarterial nerve transection. The data suggest that the fall in vascular resistance is primarily brought about by a passive opening of closed channels and a further distention of open vessels unrelated to neurogenic factors. There is no evidence that the smooth muscle of the perfused splenic vascular bed actively contracts as flow and pressure increase.

The response of the splanchnic bed of chronically splenectomized dogs to epinephrine and norepinephrine infusion.

AbstractThe infusion of 1-epinephrine for 10 minutes induced an increase in splanchnic blood flow with no change in mean arterial blood pressure. During the first half of the infusion the increase in blood flow of the splenectomized group was significantly below the increase noted in normal intact dogs (previous publication). It was suggested that this was due to a lack of splenic contribution to portal flow under the influence of epinephrine. Following the infusion the splenectomized dogs exhibited a marked reduction in blood flow while in intact dogs the flow returned to control values. It was concluded that the increase in resistance which was responsible for the lower flow rate was due to the removal of the splenic bed since the splenic mesenteric systems comprise a parallel circuit. No change in flow was observed during norepinephrine infusion. However, a similar depression in flow to that seen in animals given epinephrine was noted after the infusion was stopped.

Leukocyte mobilization in normal, splenectomized, and leukemic rats after replacement transfusion.

Abstract 1.1. Leukocyte removal was accomplished in rats by replacement transfusion of normal, splenectomized, and leukemic animals by normal rat blood rendered leukopenic by mechanical removal of leukocytes. 2.2. The normal rat mobilized leukocytes rapidly, so that severe leukopenia did not develop during the period of replacement transfusion and recovery to normal leukocyte levels occurred within 30 minutes. 3.3. Splenectomized rats, whether splenectomy was performed immediately before or 3 to 5 days before replacement transfusion, did not mobilize leukocytes as rapidly as the normal animal. It was evident that these animals had available leukocyte stores, however, since severe leukopenia was not induced. 4.4. Rats with Shay granulocytic chloroleukemia also had available leukocyte reserves, but marked decrease in leukocyte count was obtained by replacement transfusion. It was evident that the available leukocyte reserves in these animals were not increased in proportion to the circulating leukocyte level. 5.5. In all experiments the leukocytes mobilized as a result of sudden leukocyte removal were mature and of the same cell type as in the circulation of the animals. This suggested that the leukocyte reserves of the rat consist of a premixed population of granulocytes and lymphocytes, rather than individual granulocytic and lymphocytic storage depots. 6.6. It was suggested that the immediately available leukocyte reserves of the rat consist of both granulocytes and lymphocytes stored within vascular channels and that the splenic vascular bed constitutes only one portion of that leukocyte "pool."

Measurement of blood volumes in the splanchnic bed of the dog.

Measurements of the distribution of blood volumes between the splanchnic and peripheral beds of dogs have been made. The splanchnic blood volume was found to be 21% of the total blood volume. The fractionation of the splanchnic blood volume between hepatic, splenic and mesenteric beds indicated that these contained approximately 30, 30 and 40%, respectively. There were certain difficulties which precluded precise measurement of the splanchnic fractions.