Effects of intravenous nitroglycerin on the intracranial pressure and volume pressure response

Ventricular fluid pressure (VFP) and volume-pressure response were measured during nitroglycerin (NTG) infusion in nine patients anesthetized with N2O and fentanyl. The patients' ventilation was controlled, and PaCO2 was kept at 32 +/- 4 mm Hg. When an infusion of 0.01% NTG was given intravenously to decrease the mean blood pressure to 95.1%, 84.7%, and 78.2% of control, the VFP increased from control levels of 9.94 +/- 2.14 mm Hg to 12.89 +/- 2.25, 15.6 +/- 2.85, and 14.43 +/- 3.45 mm Hg, respectively. The volume-pressure response showed a significant increase when blood pressure decreased to 84.7% and 78.2% of control. These results suggest that intravenous NTG caused an increase in the intracranial pressure and a decrease in the intracranial compliance.