Hypotensive anesthesia and autotransfusion in spinal surgery

Sixty-eight (68) spinal operations performed under normotensive anesthesia were compared with 77 procedures performed undr controlled hypotensive anesthesia. Procedures reviewed included Harrington instrumentation and fusion, dorsal arch resetion, laminectomies and other spinal fusions. Intraoperative and postoperative blood loss and blood replacement were found to be reduced by approximately 50% in the group undergoing controlled hypotensive anesthesia for each procedure reviewed. Tis reduction in blood loss was achieved with only a moderate reduction in blood pressure (20 mm Hg systolic). Reduction i systolic blood pressure of greater than 20 mm was not associated with greater reduction in blood loss. Deliberate hypotensin was coupled with hemodilution, lowering the hematocrit to 28% to 30% in order to increase cardiac output, increase tisse perfusion and decrease venous stasis. Autotransfusion has further reduced the need for homologous transfusion such thatthe combined techniques of hypotension and autotransfusion can eliminate the need for homologous blood transfusion in allbut the most unusual cases.