Comparison of three different hypotensive anesthesia techniques for orthognathic surgery on postoperative nausea and vomiting (PONV), intraoperative blood loss and quality of surgical field
Susie Lin D.D.S., M.D.*, Chieh Chen M.D.†, Chuan-Fong Yao M.D.‡, Ying-An Chen M.D.§, Yu-Ray Chen M.D
Purpose: In this clinical study, three hypotensive anesthesia protocols for orthognathic surgery were compared. These three anesthesia protocols differed by the sequence and the amount of Sevoflurane and Propofol used for the maintenance of hypotensive anesthesia during orthognathic surgery.The primary outcomes measured were the postoperative nausea and vomiting (PONV) rate, intraoperative blood loss, and quality of surgical field during orthognathic surgery. The purpose of this study was to determine the PONV rate and the most appropriate anesthesia protocol for patients undergoing orthognathic surgery in our patient population.
Patients and Methods: Sixty-three consecutive orthognathic surgery patients were recruited and assigned to three study groups. All patients were scheduled to undergo combined maxillary and mandibular orthognathic surgery between June and Augment of 2015. For patients in group 1, sevoflurane at 2-2.5 minimum alveolar concentration (MAC) was the sole maintenance anesthetic agent use. For group 2, Propofol anesthesia via Target Controlled Infusion (TCI) at 3-4 ug/ml for effect organ concentration was used in addition to a reduced dose of Sevoflurane at 1.3 MAC. For group 3, patients received Sevoflurane initially as in group 1, until fixation of the osteotomized segments was complete. It was then switched to TCI with Propofol until completion of the operation.
Results: The amount of Sevoflurane used for groups 1, 2 and 3 were 107.67 ml ±26.93, 51.76 ml ±8.99, and 82 ml ±20.05, respectively. PONV rates for groups 1, 2 and 3 were 28.6%, 9.5% and 14.3%, respectively. The intraoperative blood loss for groups 1, 2, and 3 were 707.14 ml ± 290.74, 917.62 ml ± 380.3, and 750.0 ml ±331.84, respectively. The difference in intraoperative blood loss, however, were not statistically significant (p = 0.110). For the quality of surgical field assessment, Fromme’s ordinal scale (0-5) was used. The scores for groups 1, 2 and 3 were 1.325±0.44, 2.04±0.49, 1.45±0.53, respectively, and the results were statistically significant (p = 0.003). Patients in group 1 had the highest PONV rate, but the lowest mean blood loss and best visibility of the surgical field. For group 2, patients had the lowest PONV rate, but the mean blood loss was the highest among all three groups, and the quality of surgical field rating was the worst. For group 3, patients experienced low PONV rate and excellent quality of surgical field during orthognathic surgery and the amount of intraoperative blood loss was reasonable. None of the patients in this study required allogenic blood transfusion.
Conclusion: Different anesthetic techniques can result in different PONV rates. The hypotensive anesthesia protocol used in group 3 provides the benefits of excellent visibility of surgical field during orthognathic surgery and low PONV rate. The PONV rates in our patient population are, in general, lower than the rates reported in the literature. We attribute the low PONV rates to eliminating the use of opioids for postoperative pain control, and preemptive use of anti-emetic agent against PONV.