To the Editor.—Haas and Glick in their article in the Archives (113:597-600, 1978), have provided some interesting data on vasopressin plasma levels in surgical patients before, during, and after operation. But their accurate method of assaying vasopressin concentrations was applied in a rather uncontrolled setting in a heterogenous population of patients undergoing a variety of procedures and receiving different drugs before, during, and after the operation. Sparse details of fluid management were given and only a superficial attempt was made to correlate the large swings and individual variations of vasopressin levels with clinical events.
The authors conceded that the increase in vasopressin was probably unrelated to the state of hydration. It is, therefore, not apparent how their data lead them to their admonition regarding "the importance of avoidance of overly zealous hydration." Obviously, overzeal is not a desired attribute in any form of therapy, but this admonition may be