Effect of intraventricular sodium nitroprusside on cerebral hemodynamics and oxygenation in poor-grade aneurysm patients with severe, medically refractory vasospasm.

OBJECTIVE

Sodium nitroprusside (SNP) was recently suggested as a treatment for cerebral ischemia in patients with severe, medically refractory vasospasm after subarachnoid hemorrhage. In this study, we sought to objectify the effect on cerebral hemodynamics and oxygenation (PbrO2) when using intraventricular SNP as a last resort therapy in poor-grade patients with subarachnoid hemorrhage; severe, medically refractory vasospasm; and compromised cerebral blood flow.

METHODS

Thirteen of 185 consecutive patients with subarachnoid hemorrhage developed severe, medically refractory vasospasm and were treated with intraventricular SNP. All of these patients' neurological conditions were classified as Hunt and Hess Grade IV. SNP doses ranged from 10 to 40 mg with single-dose treatment and from 2 to 8 mg/h with continuous infusion. Angiography or PbrO2 measurement was used to assess the treatment effects.

RESULTS

In 6 of the 13 patients, SNP improved cerebral hemodynamics, as demonstrated by increased PbrO2 or decreased cerebral circulation time. Only 1 patient showed increased diameter of the spastic vessel, however. Maximum increase in PbrO2 ranged from 5 to 52 mmHg. Adverse effects were hypertension in five patients, vomiting in three patients, and cardiac arrhythmia in one patient. Cerebral infarctions caused by vasospasm occurred in 6 (46%) of the 13 patients. No differences between SNP responders and SNP nonresponders were noted.

CONCLUSION

In patients with severe, medically refractory vasospasm, intraventricular SNP may improve PbrO2 and cerebral blood flow, but the effect is highly variable. On the basis of the improvements we observed in 6 of 13 patients, intraventricular SNP administration is justified as a last resort therapy in patients with cerebral ischemia and impending infarction. Our findings suggest that SNP may be more effective when initiated early and administered continuously.