Blood flow to oral tissues: and experimental study with enflurane, sodium nitroprusside, and nitroglycerin

Hypotensive anesthesia is currently being used in oral and maxillofacial surgery to reduce blood loss and provide a relatively bloodless surgical field. Radioactively labeled microspheres were used to determine and compare the hemodynamic effects of sodium nitroprusside (SNP), nitroglycerin (NTG), and deep enflurane anesthesia on oral tissues during controlled hypotension when compared with controls. Sodium nitroprusside and NTG produced significant reductions in blood flow to the maxilla, mandible, and tongue, while deep enflurane anesthesia did not. In the masseter and suprahyoid muscles, increases in tissue blood flow were found with SNP and enflurane. Nitroglycerin produced no significant change in blood flow in the masseter and the suprahyoid. These results demonstrate that in spite of a similar cardiac index with all agents tested, local oral blood flow varied significantly with the different agents tested. These differences in tissue blood flow suggest that SNP and NTG may be preferable to deep enflurane anesthesia for maxillary osteotomies to achieve greater flow reduction and diminish blood loss.