Nitroglycerin-controlled circulation in orthognathic surgery.
Significant blood loss is a potential complication of maxillary osteotomies and maxillary and mandibular osteotomies. Controlling circulation by lowering blood pressure is a technique that has been used successfully to avoid this problem. Of the various agents available, nitroglycerin was chosen because of its known beneficial cardiovascular effects and its lack of toxicity as compared with sodium nitroprusside. Nine patients undergoing either maxillary or maxillary/mandibular osteotomies were anesthetized with halothane, N2O, O2, and supplemental doses of a muscle relaxant and narcotic. Nitroglycerin was used to lower mean arterial pressure during periods of potential increased blood loss. Estimated blood loss was 439 +/- 1.19 ml. The hemoglobin and hematocrit fell slightly from 13.8 +/- 1.74 g/dl and 41.2 +/- 5.11% to 12.04 +/- 1.8 g/dl and 35.6 +/- 4.9%. Attenuation of the pulmonary hypoxic vasoconstriction reflex was also seen, as was evidenced by a decrease in PaO2 after nitroglycerin administration. It was concluded that nitroglycerin is a safe and efficacious agent for controlled circulation during maxillary osteotomy surgery.