The dehydration frequently observed in surgical patients may be due to several possible causes acting singly or in combination. Excessive loss of fluid may occur from the upper part of the alimentary tract as the result of vomiting or of drainage from a duodenal, pancreatic, biliary or intestinal fistula. Prolonged gastrointestinal drainage by the Wangensteen or the Miller-Abbott tube has the same effect. Similar loss may take place from the lower part of the alimentary tract in the presence of diarrhea. Excessive perspiration may lead to water depletion in a patient subjected to an operative procedure in an overheated operating room, and the excessive sweating which often accompanies both primary and secondary shock may cause large losses of fluid. Finally, Davidson1 and Underhill and his associates2 have called attention to the water which may evaporate from a traumatized surface in an extensive burn.
The significance of dehydration lies