Blood Volume Measurement to Guide Fluid Therapy After Aneurysmal Subarachnoid Hemorrhage

Background and Purpose— Conventional parameters used to guide fluid therapy after aneurysmal subarachnoid hemorrhage (SAH) are poorly related to blood volume. In a prospective controlled study we assessed whether fluid management guided by daily measurements of blood volume (BV) reduces the incidence of severe hypovolemia compared to conventional fluid balance guided fluid therapy. Methods— We used Pulse Dye Densitometry to measure BV daily in 102 patients during the first 10 days after SAH. Fluid management was based on BV-measurements in the intervention group (n=54) and on fluid balance in the control group (n=48). Severe hypovolemia was defined as BV <50 mL/kg. Results— In the intervention group 6.7% of BV measurements were in the severe hypovolemic range and in the control group 17.1% (mean weighted difference 7.7%; 95% CI: 1.4 to 13.9%). In the intervention group 21 patients (39%) had 1 or more measurements with severe hypovolemia versus 26 (54%) of the controls (RR 0.7; 95% CI: 0.5 to 1.1). Conclusions— Guiding fluid management on daily measurements of blood volume reduces the incidence of severe hypovolemia after SAH. The effects on neurological outcome should be studied.