Both techniques are used in order to reduce the tension on the wall of the aneurysm thus decreasing the transmural pressure. This will facilitate its dissection and the application of the clip. Induced hypotension produces hypoperfusion in the organs of those patients with altered cerebral circulation, coronary disease, anemia, severe hypovolemia and advanced age.
Induced hypotension is used during the approach and surgical dissection of the aneurysm.
This range is different in hypertensive patients. Their autoregulation curve is shifted towards the right, requiring higher mean blood pressures in order to maintain an adequate CBF and to avoid zones of ischemic brain tissue. Induced hypotension is a relative contraindication in hypertensive patients. The limit of hypotension is not well defined. Some authors recommend that with intact autoregulation the limit should not be below 50 mmHg.