ABSTRACT
Controlled hypotension helps to reduce blood loss during spinal surgery. The mean arterial pressure needs to be safe and adequate for perfusion of the spinal cord and other vital organs. A moderate degree of induced hypotension, usually a mean arterial pressure of 65 or 20mmHg below the baseline in normotensive subjects, is considered safe in nonmyelopathic patients. Induced hypotension, however, may contribute to spinal cord ischemia and neurological damage. The risk increases significantly in the presence of preoperative hypertension, hypocapnia, anemia, rapid blood loss, or a sudden drop in the blood pressure. The adverse effects may depend on the degree of hypotension induced and the specific drugs used to produce hypotension.
