Clinical investigation of prolonged induced hypotension in head and neck surgery.

Thirty patients undergoing radical surgery for cancer of the head and neck were subjected to deliberate hypotension (60-80 mm Hg) for an average period of 275 minutes. Ten patients undergoing surgery of similar magnitude but without controlled hypotension formed a control group. Hypotensive patients excreted significantly less urine during surgery. There were no discernible differences between groups in respect of preand postoperative haemoglobin levels, blood volumes, blood urea nitrogen or serum glutamic oxaloacetic transaminase values, electrocardiographic or chest radiographic appearances, or in arterial blood-gas analysis made during surgery. One death occurred in the hypotensive group. The authors conclude that more sensitive indices than those utilized are necessary to assess adequacy of perfusion during deliberate hypotension.