Effects of hypotensive anesthesia compared to normotensive anesthesia in orthognathic surgery

Introduction: Orthognathic surgery is widely accepted for correcting dentofacial deformities. Due to the rich blood supply in the head and neck region, considerable bleeding can occur from the incised soft tissues and bone during orthognathic surgery. Hypotensive anesthesia is a method used in surgical practice by which blood pressure is decreased predictably and deliberately to reduce blood loss and improve surgical field. However, there is still uncertainty regarding its effectiveness and safety in orthognathic surgery. Methods: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis, and generated a summary of findings table using the GRADE approach. Results and Conclusions: We identified three systematic reviews, including 11 studies overall, which are randomized trials. We concluded that hypotensive anesthesia may reduce intraoperative blood loss and may improve the quality of surgical field, however, the certainty of the evidence has been assessed as low. On the other hand, orthognathic surgery with HA may make little or no difference in surgical time (low certainty evidence). Finally, no studies were found that reported adverse effects or mortality.