The American journal of emergency medicine
-
Historical Article
Electrolytes and plasma volume regulation in hypovolemic shock.
The concept of hypovolemic shock and its effects on plasma volume were described in the 1700s. It has been left for more recent investigators to elucidate the role of plasma volume and its mechanisms of regulation and interaction with the interstitial and intracellular fluid spaces. ⋯ The merits and characteristics of the current fluids available for resuscitation are reviewed. The choices of fluid for resuscitation should be made with the overall goal of an efficient and effective restoration of circulating volume without producing excessive, avoidable, potentially harmful distortion of other organ systems and body fluid compartments.
-
Blood loss is followed by compensatory cardiovascular readjustments that favor the maintenance of blood flow to central vital organs rather than to peripheral tissues. The microcirculatory changes that occur in skeletal muscle in shock states are of major importance, since skeletal muscle is not only the largest cell mass of the body but also one of the major target organs for neurohumorally mediated compensatory vascular readjustments. Intravital microscopic studies show that the microvascular blood flow in skeletal muscle is intermittent in the early posthemorrhagic period. ⋯ Obstruction of many capillaries by white blood cells and their slow passage through other capillaries seem to be the main reasons for the maldistribution of capillary blood flow in shock. Red blood cell aggregates obstructing capillary blood flow are not seen. The heterogeneous tissue perfusion is accompanied by local variations in cellular hypoxic injury, as is evidenced by multifocal measurements of tissue oxygen tension and by cellular transmembrane potential registrations.(ABSTRACT TRUNCATED AT 250 WORDS)