[Feasibility and safety of acute hypervolemic hemodilution in neurosurgical patients]

To evaluate the preoperative effects of acute hypervolemic hemodilution (AHH) on intracranial pressure, cerebral oxygen supply-demand balance and cardiovascular functions of neurosurgical patients.

Approved by hospital ethics committee, a total of 80 ASA grade I/II patients at our hospital during 2009, of either gender aged 18-60 yrs, undergoing elective craniotomy were recruited. The subjects were randomly divided equally into 2 groups: group H (hemodilution) and group C (control) (n = 40 each). After induction, 6% hydroxyethyl starch solution was infused at the rate of 24 ml×kg(-1)×h(-1) in group H, while patients in group C received compound electrolyte solution at the rate of 6 ml×kg(-1)×h(-1). Central venous pressure (CVP), cardiac output index (CI), stroke volume variation (SVV) and cerebral spinal fluid pressure (CSFP) were recorded at the following time points: T(Base) (before induction), T(0) (after induction and hemodynamic stabilization), T(30) (after infusion for 30 min) and T(60) (after infusion for 60 min). Blood samples from radial artery and jugular bulb were collected and calculated for systemic vascular resistance index (SVRI) and cerebral oxygen uptake rate (CERO(2)). The dosing frequency of vasoactive drugs was also recorded.

CI in group H was significantly higher than that in group C (P < 0.01). No significant difference was found in both SjvO(2) and CERO(2) between groups and among different points of time (P > 0.05). At the end of AHH, CVP and CSFP were (12 ± 2.2) mm Hg and (20.0 ± 2.1) mm Hg respectively. They were significantly higher than that in group C (P < 0.01).

Preoperative AHH in craniotomy will increase CI and maintain the balance of cerebral oxygen supply. But its clinical application is limited in the patient with high intracranial pressure due to the simultaneous increases in CVP and CSFP.