The amount of blood loss during maxillofacial orthognathic surgery

Accurate estimation of blood loss for predicting the need for transfusion during bimaxillary orthognathic surgery is important for maxillofacial surgeons and anesthesiologists. The aim of the present study was to determine blood loss in subjects who underwent maxillofacial orthognathic surgery in terms of age, gender and operative time. The present descriptive study was carried out in Chamran Hospital, Shiraz University of Medical Sciences, from 2011 to 2012. A total of 68 patients were selected using convenient sampling technique. Patients with smoking habits and addiction to opioids and those using medications affecting coagulation were excluded. All the surgeries were performed by the same surgical team under controlled hypotensive general anesthesia and infusion of tranexamic acid. Surgical blood loss was measured by counting the number of gauze pads saturated with blood and the amount of blood in the surgical suction unit. Data were analyzed with descriptive statistical methods at α=0.05. The study sample consisted of 61 subjects (25 males and 36 females) with a mean age of 23.7±5.9 years and average weight of 60.2±12.2 kg. All the subjects completed the study. The average surgical blood loss was 525.1±223.1 mL and the average operative time was 246.9±52.5 minutes. The average surgical blood loss for women and men were 465.8±161.6 and 610.4±271.0 mL, respectively, during a mean operative time of 255.8±54.9 minutes. The correlation coefficient between blood loss and operative time was 0.62 (p value < 0.05), demonstrating an increase in blood loss with a increase in operative time. Based on the results of this study, there was greater intraoperative blood loss only in patients with longer operative time. It is suggested that this factor be taken into account for estimating the amount of blood lost and prediction of the need for replacing lost blood.