The mechanism of shock

Abstract

441have had hypophysectomy and who require further surgery can excrete increased amounts of endogenous adrenal steroids. In paraplegic subjects the adrenal response to injury in the paralysed segments is delayed in onset and reduced in extent (Osborn, Schoenberg, Murphy, Erdman, and Young, 1962), but after operations under full spinal anaesthesia the response is only delayed a little and the intensity is unaffected (Mattingly and Tyler, 1965).The pattern of urinary excretion of the individual metabolites of adrenal androgens and gluco-corticoids is different after surgical operation compared to ACTH stimulation in the same patients. Surgical operation only stimulates the release of cortisol and its metabolites, whereas ACTH stimulates all aspects of adrenocortical production (Johnston, 1964).These observations support the view that a humoral agent from the injured part may act as an initiator. Some of the many substances liberated in damaged tissues, such as histamine and 5-hydroxytryptamine, can stimulate adrenal activity directly. Other changes, such as a reduction in blood-volume or extracellular space, and changes in concentration of sodium and potassium, are important in antidiuretic hormone and aldosterone release.One result of the basic studies which have been reviewed here has been to increase greatly the understanding of the events taking place in every surgical patient. Surgery has undoubtedly become safer as a consequence because departure from normal can be appreciated and logical steps taken to correct such variations.Sir Walter Langdon Browne in 1931 likened the endocrine system to an orchestra. This analogy still holds and gains in significance as a result of recent studies. Just as the individual members of an orchestra respond quickly to the conductor's signal with united purpose towards a single goal, so the stimulus of injury elicits an immediate and full response from all the endocrine organs for the purpose of maintaining homeostasis and providing the optimum conditions for efficient and rapid repair.