Fluid Loss in Rats With Tourniquet Shock 1

Abstract

Release of a high unilateral tourniquet producing complete interruption of blood flow to a hind limb of the rat for about 5 hours almost invariably results in fatal shock. The development of shock is accompanied by progressive edema of the limb. The main object of the following experiments was to determine the magnitude and the rapidity of the fluid loss in the injured extremity. METHODSAdult white male rats weighing about 150 to 300 grams were used. These were anesthetized with sodium pentobarbital, given intraperitoneally in dosage of 25 to 35 mgm. per kgm. of body weight (0.3 to 0.4 ml. of a 2 per cent solution). Circulation in the left lower extremity was then entirely occluded by 2 tightly wound rubber band tourniquets. The first was placed around the knee in order to obtain extension of the leg. This facilitated the application of the second tourniquet, which was placed as high as possible in the groin, anchorage being obtained over a redundant segment of skin drawn down beneath the rubber band.Constriction was maintained for 5 hours and 10 minutes, at the end of which time the rats were alert and showed complete outward recovery from the anesthesia. The animals were then sacrificed by decapitation, either without release of tourniquet, or at fixed time intervals after release, i.e., 15 minutes, 30 minutes, and 1, 2 and 3 hours. The experiments were performed with small groups of rats sacrificed at different periods by random selection, until there was a total of 20 rats for each time interval.In each group there were 1 or more control rats which developed shock after removal of tourniquet and went on to death. Since these yielded only little blood at the time of death, an additional group of 11 rats was sacrificed at 5 to 6 hours following removal of constriction, in order to obtain sufficiEnt blood for chemical determinations. In 18 rats sacrificed by ether at various intervals after tourniquet release, the figures for fluid loss were of the same order as those obtained from decapitated animals.There were a few deaths apparently due to anesthesia. In addition, several rats which chewed their leg before or after removal of tourniquet were discarded. Food and water were withheld for a period of about 10 hours be-1 Aided by a grant from the Elisabeth Severance Prentiss Foundation.fore anesthesia was given, and also during the course ot the experiments. The latter were performed at room temperature during the summer and autumn seasons.The amount of fluid lost in the leg following removal of tourniquet was determined by the method of bisection (1, 2). An anterior midline incision was made from sternum to symphysis pubis and follow.ed by evisceration. A similar posterior midline incision extended down across the base of the tail. The spine was then transected at about the level of the first or second lumbar vertebra, and the lower extremities separated by bilateral paravertebral incisions passing through the hip joints.The difference in weight between the normal and the edematous extremity gave the gain in wei...

Determinants of Pancreatic Microcirculation in Acute Pancreatitis in Rats

“…The hemodynamic changes observed during acute pancreatitis, i.e., arterial hypotension and reduction of cardiac output, are attributed to hypovolemia due to massive fluid loss into the tissues and release of vasoactive substances and inflammatory mediators [16,29,30]. In the tourniquet shock model, hypotension is also induced by fluid sequestration in combination with release of vasoactive substances and inflammatory mediators [16,18]. We demonstrated that arterial hypotension due to tourniquet shock enhances progressive capillary perfusion failure during…”

“…With fixed tourniquets, preparation was finished and baseline measurements were taken. Release of the tourniquets after 4.0 hr, simultaneous with induction of pancreatitis, was accompanied with an immediate fall in arterial blood pressure (65 { 4 mm Hg 5 min after release) due to massive fluid sequestration and liberation of inflammatory mediators [16,18]. Pancreatitis was induced in all animals at 4.0 hr after start of preparation, except in animals allocated to group HYP.…”

Arterial Pressures in Tourniquet Shock

“…Arterial pressure in rats with fatal tourniquet shock shows 3 main phases: (1) an abrupt fall immediately after tourniquet release, ( 2 ) sustained hypotension within a relatively nlarrow range during most of the shock state, and ( 3 ) a terminal more or less rapid decline associated with death. Only in the terminal period does profound hypotension intervene, with levels below 40 mm.…”

Immunoelektrophoretische Untersuchungen der Proteinverteilung im postischämischen Ödem des Hundes im Vergleich zu Serum und Lymphe

“…Wir nehmen an, dab die ErhShung des osmotisehen Gewebsdruckes ein entscheidender Faktor bei der (~demgenese ist, was durch unsere Untersuchungen an Ratten und Hunden belegt wurde [20,25]. B. nach Embolektomien, nicht hinreichend erkl/~ren, t{ier wird nur ein kleines operationsbedingtes Gewebstraum~ gesetzt, das nicht mit dem AusmaB des C)dems korrelierbar ist.…”