Prone Versus Sitting Position in Neurosurgery-Differences in Patients' Hemodynamic Management.

OBJECTIVE: Neurosurgery in general anesthesia exposes patients to hemodynamic alterations in both the prone and the sitting position. We aimed to evaluate the hemodynamic profile during stroke volume-directed fluid administration in patients undergoing neurosurgery either in the sitting or the prone position.

METHODS: In 2 separate prospective trials, 30 patients in prone and 28 patients in sitting position were randomly assigned to receive either Ringer acetate (RAC) or hydroxyethyl starch (HES; 130 kDa/0.4) for optimization of stroke volume. After combining data from these 2 trials, 2-way analysis of variance was performed to compare patients' hemodynamic profile between the 2 positions and to evaluate differences between RAC and HES consumption.

RESULTS: To achieve comparable hemodynamics during surgery, a higher mean cumulative dose of RAC than HES was needed (679 mL ± 390 vs. 455 mL ± 253; P < 0.05). When fluid consumption was adjusted with weight, statistical difference was lost. Fluid administration did not differ between the prone and sitting position. Mean arterial pressure was lower and cardiac index and stroke volume index were higher over time in patients in the sitting position.

CONCLUSIONS: The sitting position does not require excess fluid treatment compared with the prone position. HES is slightly more effective than RAC in achieving comparable hemodynamics, but the difference might be explained by patient weight. With goal-directed fluid administration and moderate use of vasoactive drugs, it is possible to achieve stable hemodynamics in both positions.