Background

Postoperative hyponatremia is a frequent complication that is found in more than 4% of patients undergoing surgery. It is also an independent factor of in-hospital mortality. Until now, previous studies have focused on the first hours after surgery, so there is little information regarding hyponatremia in the late postoperative period.

Purpose

evaluate the frequency and characteristics of hyponatremia in the first postsurgical week.

Methodology

Patients undergoing major surgery over a period of 18 months were included. Sodium level was determined at 24 hours, third, fifth and seventh day of the procedure. Hyponatremia was classified according to surgery type and presence of clinical symptoms and outcomes were documented.

Results

280 patients were studied. 20 (7.1%) developed hyponatremia on the first postoperative day, 34 (12.1%) on the third, 30 (10.7%) on the fifth day, and 31 (11%) on the seventh day. On the first postoperative day, patients undergoing urological and gastrointestinal surgeries developed hyponatremia more frequently. None of the patients developed serious complications. There was no relationship between age, gender or type of solutions and the development of hyponatremia.

Conclusions

hyponatremia is a frequent complication of surgical procedures that can develop in the first seven postoperative days.

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