Randomized, Double-blind Trial of the Effect of Fluid Composition on Electrolyte, Acid-base, and Fluid Homeostasis in Patients Early After Subarachnoid Hemorrhage

Background: Hyper- and hyponatremia are frequently observed in patients after subarachnoidal hemorrhage, and are potentially related to worse outcome. We hypothesized that the fluid regimen in these patients is associated with distinct changes in serum electrolytes, acid-base disturbances, and fluid balance.

Methods: Thirty-six consecutive patients with SAH were randomized double-blinded to either normal saline and hydroxyethyl starch dissolved in normal saline (Voluven(®); saline) or balanced crystalloid and colloid solutions (Ringerfundin(®) and Tetraspan(®); balanced, n = 18, each) for 48 h. Laboratory samples and fluid balance were evaluated at baseline and at 24 and 48 h.

Results: Age [57 ± 13 years (mean ± SD; saline) vs. 56 ± 12 years (balanced)], SAPS II (38 ± 16 vs. 34 ± 17), Hunt and Hess [3 (1-4) (median, range) vs. 2 (1-4)], and Fischer scores [3.5 (1-4) vs. 3.5 (1-4)] were similar. Serum sodium, chloride, and osmolality increased in saline only (p ≤ 0.010, time-group interaction). More patients in saline had Cl >108 mmol/L [16 (89 %) vs. 8 (44 %); p = 0.006], serum osmolality >300 mosmol/L [10 (56 %) vs. 2 (11 %); p = 0.012], a base excess <-2 [12 (67 %) vs. 2 (11 %); p = 0.001], and fluid balance >1,500 mL during the first 24 h [11 (61 %) vs. 5 (28 %); p = 0.046]. Hyponatremia and hypo-osmolality were not more frequent in the balanced group.

Conclusions: Treatment with saline-based fluids resulted in a greater number of patients with hyperchloremia, hyperosmolality, and positive fluid balance >1,500 mL early after SAH, while administration of balanced solutions did not cause more frequent hyponatremia or hypo-osmolality. These results should be confirmed in larger studies.