surgery

sometimes Acute severe hyponatremia
occurs following elective surgical procedures. It is usually
the result of the combination of appropriate postoperative stimulation
of antidiuretic hormone and injudicious administration of excess free
water in the first few postoperative days. Totally sodium-free intravenous
fluids (e.g., dextrose and water) should be given with great caution postoperatively,
since occasionally the resulting hyponatremia can be associated
with sudden death from a flaccid heart or with severe permanent
brain damage. The condition is usually best treated by withholding free
water and allowing the patient to reequilibrate spontaneously. At levels
below 115 meq/L, seizures or mental obtundation may mandate treatment
with hypertonic sodium solutions. This must be done with extreme care
because the risk of fluid overload with acute pulmonary or cerebral edema
is high.
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