The effect of nimodipine on cerebral oxygenation in patients with poor-grade subarachnoid hemorrhage.
OBJECTIVE
Nimodipine has been shown to improve neurological outcome after subarachnoid hemorrhage (SAH); the mechanism of this improvement, however, is uncertain. In addition, adverse systemic effects such as hypotension have been described. The authors investigated the effect of nimodipine on brain tissue PO2.


METHODS
Patients in whom Hunt and Hess Grade IV or V SAH had occurred who underwent aneurysm occlusion and had stable blood pressure were prospectively evaluated using continuous brain tissue PO2 monitoring. Nimodipine (60 mg) was delivered through a nasogastric or Dobhoff tube every 4 hours. Data were obtained from 11 patients and measurements of brain tissue PO2, intracranial pressure (ICP), mean arterial blood pressure (MABP), and cerebral perfusion pressure (CPP) were recorded every 15 minutes. Nimodipine resulted in a significant reduction in brain tissue PO2 in seven (64%) of 11 patients. The baseline PO2 before nimodipine administration was 38.4+/-10.9 mm Hg. The baseline MABP and CPP were 90+/-20 and 84+/-19 mm Hg, respectively. The greatest reduction in brain tissue PO2 occurred 15 minutes after administration, when the mean pressure was 26.9+/-7.7 mm Hg (p < 0.05). The PO2 remained suppressed at 30 minutes (27.5+/-7.7 mm Hg [p < 0.05]) and at 60 minutes (29.7+/-11.1 mm Hg [p < 0.05]) after nimodipine administration but returned to baseline levels 2 hours later. In the seven patients in whom brain tissue PO2 decreased, other physiological variables such as arterial saturation, end-tidal CO2, heart rate, MABP, ICP, and CPP did not demonstrate any association with the nimodipine-induced reduction in PO2. In four patients PO2 remained stable and none of these patients had a significant increase in brain tissue PO2.


CONCLUSIONS
Although nimodipine use is associated with improved outcome following SAH, in some patients it can temporarily reduce brain tissue PO2.
Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19107, USA.
Michael F
MF
Stiefel
Gregory G
GG
Heuer
John M
JM
Abrahams
Stephanie
S
Bloom
Michelle J
MJ
Smith
Eileen
E
Maloney-Wilensky
M Sean
MS
Grady
Peter D
PD
LeRoux
D000368:Aged; D001921:Brain / Q000098:blood supply; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000601:surgery*; D007427:Intracranial Pressure; D008297:Male; D008875:Middle Aged; D009553:Nimodipine / Q000008:administration & dosage / Q000494:pharmacology*; D010100:Oxygen / Q000032:analysis*; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000188:drug therapy*
D002121:Calcium Channel Blockers; D009553:Nimodipine; D010100:Oxygen