The effect of very early cisternal irrigation on basilar artery spasm after SAH in the rat model.

The authors have investigated the effect of very early irrigation of the cerebrospinal fluid (CSF) space in the haemorrhage rat model of vasospasm. Fifteen rats had basilar cistern irrigation with physiological saline for 3 hours after subarachnoid haemorrhage (SAH), and fifteen control rats had subarachnoid haemorrhage without irrigation of clot. The changes in basilar arteries diameters were determined by angiograms obtained from the rats. The post haemorrhage angiograms showed significant basilar artery spasm in both groups (P less than or equal to 0.0005, t-test). However in the last angiogram the basilar artery diameter was found to have the same value measured before subarachnoid haemorrhage in the irrigation group whereas no obvious change was observed in the control group. In the irrigation group the mean diameter of the basilar artery in the last angiogram was 0.412 mm. (0.30 mm to 0.50 mm). None of the animals, treated by cisternal irrigation, showed angiographic vasospasm while the latter group did (P less than or equal to 0.0005). Animals treated with physiological saline irrigation had a median clot grade of 0.40 (range grade 0 to 2); control rats had a median grade 2.86 (range grade 1 to 4, P less than 0.001, Mann-Withney U test), on the brain stem, indicating significant reduction of clot by lavage. In conclusion, performance of experimental physiological saline irrigation at a very early time after subarachnoid haemorrhage prevents the arteriographic and morphological changes of both acute and late vasospasms.