The effect of hypertonic (3%) saline with and without furosemide on plasma osmolality, sodium concentration, and brain water content after closed head trauma in rats.

Adding furosemide (F) to mannitol causes a greater decrease of brain volume, intracranial pressure, and brain water content (BW) as compared with mannitol alone. We examined whether adding F to hypertonic saline (HS) causes less increase of BW early after closed head trauma (CHT) as compared with HS alone. With institutional approval, 125 rats underwent sham surgery or CHT and then immediately received no treatment, HS (1.2 g/kg, 3% solution), or HS + F (2 mg/kg). In groups 1-10 (n = 8/group), the percent BW content was determined at 30, 60, or 120 minutes. In groups 11-14 (n = 8/group), physiologic values were determined at 0, 30, 60, and 120 minutes. At 120 minutes, the increase of BW caused by CHT (sham = 78.9 +/- 0.6% and CHT = 81.5 +/- 2.2%, mean +/- SD) was prevented by HS + F (78.0 +/- 0.8%) but not by HS (80.7 +/- 2.2%). Both HS and HS + F similarly increased plasma osmolality and sodium concentration. Post-CHT hypotension and acidosis (30 and 60 minutes) and decrease of hemoglobin concentration (120 minutes) were less with HS + F than with HS. We conclude that adding F to HS decreases BW without causing more increase of osmolality and Na than that caused by HS alone.