Background and objective Patients undergoing coronary artery bypass grafting often require volume loading after operation. In this situation hypertonic saline may be beneficial in restoring the haemodynamic balance and removing excess extravascular fluid.

Methods Forty coronary artery bypass grafting patients were randomly assigned to receive either hypertonic saline 7.5% (20 patients) or 0.9% saline (20 patients) as a single dose of 4 mL kg−1 over 30 min in the postoperative rewarming phase in the intensive care unit.

Results Mean arterial pressure increased in the hypertonic saline group from 82 ± 10 (SD) to 104 ± 17 mmHg (P = 0.002 vs. the normal saline group), and the cardiac index rose from 2.3 ± 0.5 to 3.4 ± 0.8 L min−1 m2 (P = 0.002 vs. the normal group). The haemodynamic effect of hypertonic saline lasted only about 1 h. Diuresis was greater in the hypertonic saline group both at 1 h (hypertonic saline: 490 ± 274 vs. normal saline: 204 ± 130mL; P = 0.001) and 10 h (hypertonic saline: 1952 ± 554vs. normal saline: 1421 ± 514mL; P = 0.003).

Conclusions No adverse effects were seen. The hypertonic saline had a strong diuretic effect and may be beneficial in coronary artery bypass graft patients after operations. This is because of its value as a short-term plasma expander and the diuresis eliminates excessive fluid from the body. A larger study is needed to determine whether the benefits outweigh the possible side-effects in these patients.