Effects of hypotensive anesthesia on reducing intraoperative blood loss, duration of operation and quality of surgical field during orthognathic surgery- a systematic review and meta-analysis of randomized controlled trials
Susie Lin DDS, MD*, Chuan-Fong Yao MD†, Yu-Ray Chen MD‡, Chit Chen MD§
Department of Plastic & Reconstructive Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan
Purpose:Purpose: The objective of the present study was to evaluate the efficacy of hypotensive anesthesia on reducing intraoperative blood loss, decreasing operation time and improving the quality of the surgical field in patients undergoing orthognathic surgery. A systematic review and meta-analysis of randomized controlled trials addressing these issues were carried out.
Methods: An electronic database search of PubMed, ProQuest, Google Scholar, Web of Science, and Medline was performed in August, 2015. The risk of bias was evaluated using the Jadad Scale and Delphi List. The predictor variable was hypotensive anesthesia, and the primary outcome variable was intraoperative blood loss during orthognathic surgery. The secondary outcome variables were the operation time and quality of surgical field during orthognathic surgery. Inverse variance statistical method and random effect model were used. Subgroup analysis was performed based on different types of osteotomies and whether local anesthesia was used in conjunction with hypotensive general anesthesia.
Results: Ten randomized controlled trials were included for analysis. Our meta-analysis indicated that when compared with control (normotensive) groups, hypotensive anesthesia reduced the intraoperative blood loss by a mean of about 169 ml [95% confidence interval (CI): -228, -109.8]. Hypotensive anesthesia was not shown to reduce the operation time for orthognathic surgery, but it did improve the quality of surgical field, -0.66 [95% CI: -1.05, -0.28]. Subgroup analysis indicated that for blood loss in double-jaw surgery, the weighted mean difference favored the hypotensive groups with a saving of 175 cc of blood [95% CI: -319.51, -30.51], but no statistically significant reduction in blood loss was found in anterior maxillary osteotomy. If local anesthesia with epinephrine was used in conjunction with hypotensive anesthesia, the reduction in intraoperative blood loss was increased to -254.93 ml [95% CI: -413.5, -96.4].
Conclusion: The present study showed hypotensive anesthesia provided a statistically significant reduction of intraoperative blood loss in double-jaw surgery. The use of local anesthesia in conjunction with hypotensive general anesthesia further reduced the amount of intraoperative blood loss for orthognathic surgery. Hypotensive anesthesia was effective in improving the quality of surgical field, however, it did not seem to reduce the operation time for orthognathic surgery.