Hypertonic saline (7.5%) decreases perioperative weight gain following cardiac surgery.

OBJECTIVE

To compare the effects of 7.5% hypertonic saline (HS) and 0.9% normal saline (NS) on perioperative weight gain in cardiac surgical patients.

DESIGN

Prospective, randomized study.

SETTING

University teaching hospital.

PARTICIPANTS

Patients (n = 72) scheduled for elective coronary artery bypass graft surgery.

INTERVENTIONS

Patients were randomly assigned to receive either 7.5% HS (36 patients) or 0.9% NS (36 patients) as a single dose of 4 mL/kg over 30 minutes during the postoperative rewarming phase in the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

Weight gain until the first postoperative morning was significantly greater in the NS group than in the HS group (1.9 plus minus 1.4 kg, median, 2.1 kg; 0.8 plus minus 1.5 kg, median, 0.8 kg; p = 0.005). One-hour diuresis after the fluid infusion was significantly greater in the HS group compared with the NS group (501 plus minus 282 mL and 237 plus minus 173 mL; p < 0.001). In the linear regression model, the 2 most important factors affecting the perioperative weight gain were the volume of fluid infused postoperatively in the intensive care unit (4,098 plus minus 916 mL in the HS group and 4,589 plus minus 1,344 mL in the NS group) and the total diuresis after surgery (3,351 plus minus 1,035 mL in the HS group and 2,942 plus minus 846 mL in the NS group).

CONCLUSIONS

HS had an intense diuretic effect, which reduced intraoperative fluid retention. This effect was confirmed by the lesser increase in body weight measured on the first postoperative morning.