Blood Loss In Orthognathic Surgery Research Articles

Effectiveness of prophylactic tranexamic acid versus placebo or no intervention for reducing blood loss in healthy patients undergoing orthognathic surgery: a systematic review protocol.

The objective of this review is to evaluate the effectiveness of perioperative prophylactic tranexamic acid for reducing blood loss in orthognathic surgery in healthy patients. Orthognathic surgery can cause significant hemorrhage, which requires postoperative blood transfusions. The most widely studied pharmaceutical adjunct for reducing blood loss is tranexamic acid, a synthetic amino acid that reversibly inhibits plasminogen activation. It is widely used and validated in other surgical procedures to limit blood loss; however, it is not a gold standard in orthognathic surgery. We will include clinical trials comparing tranexamic acid to appropriate controls. The primary outcomes are intraoperative blood loss, change in hematocrit/hemoglobin level, and need for blood transfusion. Secondary outcomes include operating time, length of hospital stay, and adverse reactions. Studies of patients with pre-existing coagulopathies and those undergoing only minor orthognathic surgery (eg, genioplasty) will be excluded. We will search 3 electronic databases (PubMed, Embase, and Cochrane Library) from database inception. Titles, abstracts, and full-text papers will be assessed against the inclusion criteria by 2 independent reviewers. Risk of bias will be assessed using the Cochrane Risk of Bias 2.0 tool. Data will be extracted by 2 independent reviewers. Meta-analysis will be conducted for all outcomes where appropriate, with weighted mean differences used for intraoperative blood loss, changes in hematocrit/hemoglobin levels, operation time, and length of stay; and risk ratio for transfusion rates and adverse outcomes. Certainty of the evidence will be presented using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. PROSPERO CRD42022314403.

Gender-specific differences in haemostatic parameters and their influence on blood loss in bimaxillary surgery

ObjectiveThe objectives of this prospective cohort study were to establish gender-related differences in blood loss and haemostatic profiles associated with bimaxillary surgery. In addition, we aimed to identify if any gender differences could be established which might help predict blood loss volume.Materials and methodsFifty-four patients (22 males; 32 females) undergoing bimaxillary surgery for skeletal dentofacial deformities were eligible for inclusion. Blood samples were taken 1 day preoperatively and 48 h postoperatively for detailed gender-specific coagulation analysis incorporating global coagulation assays (endogenous thrombin potential) and specific coagulation parameters. Blood loss was measured at two different time points: (1) the end of surgery, visible intraoperative blood loss (IOB) using ‘subtraction method’; and (2) 48 h postoperatively perioperative bleeding volume (CBL-48 h) using ‘haemoglobin-balance method’ and Nadler’s formula. Correlation and regression analyses were performed to identify relevant parameters affecting the amount of blood loss.ResultsSignificant differences in IOB and CBL-48 h were observed (p < 0.001). Men had higher IOB versus women, lacking statistical significance (p = 0.056). In contrast, men had significantly higher CLB-48 h (p = 0.019). Reduced CBL-48 h was shown to be most closely associated with the level of Antithrombin-III being decreased in females.ConclusionsMale gender is associated with higher IOB and CBL-48 compared with females. Gender does not affect IOB regarding haemostatic profile but does correlate strongly with procedure length. Conversely, CBL-48 is closely associated with gender-specific imbalances in the anticoagulant system.Clinical relevanceKnowledge of gender-related differences will help clinicians establish predictive factors regarding excessive blood loss in orthognathic surgery and identify at-risk patients.

The effect of tranexamic acid on blood loss in orthognathic surgery: a randomized, placebo-controlled, equivalence study

Orthognathic surgery can cause substantial bleeding. Recent meta-analyses concluded that there is a statistically significant reduction in perioperative blood loss with the preventive use of tranexamic acid (TA). However, the mean reported difference in bleeding was moderate, and the clinical relevance of this blood-sparing effect remains debated. We therefore conducted a prospective, double-blind, randomized, placebo-controlled equivalence study of the effect of TA in patients undergoing Lefort I or bimaxillary osteotomies. Our main outcome measure was total blood loss on postoperative day 1. The equivalence margin was ± 250 ml for the difference in blood loss and its 95% confidence interval. One hundred and forty-seven patients were randomized, of which 122 underwent bimaxillary osteotomies. Blood loss in the treatment group was 682 ± 323 vs. 875 ± 492 ml. The mean difference in bleeding was -132 [-243; -21] ml as per-protocol, but -193 [-329; -57] ml in intention-to-treat: the limits of this confidence interval exceeded the margin of equivalence. Similar results were obtained when analysing only patients undergoing bimaxillary osteotomy. Haemoglobin decreased by 1.8 ± 1.2 g/dl with TA, vs. 2.6 ± 1.1 g/dl with placebo (p<0.001). Our study did not demonstrate equivalence between TA and placebo on perioperative blood loss in orthognathic surgery. TA may reduce blood loss but without evidence of clinical consequences.

Effect of continuous infusion of dexmedetomidine on blood loss in orthognathic surgery: a retrospective study

BackgroundPatients with maxillofacial deformities require orthognathic surgeries to correct occlusion. The surgical procedure may lead to massive bleeding, which is associated with haematoma, respiratory obstruction, and asphyxia. Dexmedetomidine has been used in controlled hypotension and may reduce blood loss in orthognathic surgery. We conducted a retrospective cohort study to evaluate the effect of dexmedetomidine on blood loss in orthognathic surgeries.MethodsThe primary outcome examined was blood loss, and secondary outcomes were postoperative haemoglobin level; intraoperative heart rate and blood pressure (T1: at incision; T2: 30 min after incision; T3: 60 min after incision; T4: 120 min after incision); dosage of fentanyl, remifentanil, urapidil, and esmolol; operation time; and incidence of allogeneic blood transfusion.ResultsA total of 1247 patients were included in this study, and 540 patient pairs were matched via propensity score matching. There were significant decreases in mean blood loss, heart rate at T1–T4, blood pressure at T1, and remifentanil and esmolol dosage in the dexmedetomidine group compared with those in the control group. There was also a significant increase in the postoperative haemoglobin level of the dexmedetomidine group.ConclusionsContinuous infusion of dexmedetomidine can decrease blood loss in orthognathic surgery.Trial registration: ChiCTR1800018794 (retrospectively registered)Name of registry: Chinese Clinical Trial RegistryDate of registration: 2018/10/09URL: www.chictr.org.cn/showproj.aspx?proj=30612

Is hypotensive anaesthesia guided by invasive intraarterial monitoring required for orthognathic surgery? - A retrospective review of anaesthetic practice and intraoperative blood loss in orthognathic surgery in a tertiary hospital.

Background and Aims:Orthognathic surgeries for maxillofacial deformities are commonly performed globally and are associated with significant blood loss. This can distort the surgical field and necessitate blood transfusion with its concomitant risks. We aimed to review if invasive intraarterial (IA) line monitoring and/or hypotensive anaesthesia is required for orthognathic surgeries, and their effects on intraoperative blood loss and transfusion requirements.Methods:This was a retrospective observational study conducted in patients admitted for orthognathic surgeries in a public tertiary hospital. Anaesthetic techniques and intraoperative haemodynamics were studied for their effects on intraoperative blood loss.Results:The data from 269 patients who underwent orthognathic–bimaxillary surgeries was analysed. Inhalational anaesthetic combined with remifentanil was administered for 86.6%, total intravenous anesthesia to 11.2% patients, while the rest received inhalational anaesthesia. Hypotensive anaesthesia was achieved in 48 subjects (17.8%) and associated with shorter duration of surgery (349 vs 378 min, P = 0.02) and a trend towards lower blood loss (874 mL vs 1000 mL, P = 0.058) but higher transfusion requirement (81.3% vs 58.8%, P = 0.004). An IA line was used in 119 patients (44.2%) and was not associated with a higher probability of achieving hypotensive anaesthesia (19.3% vs 16.7%, P = 0.06). However, less blood loss (911 vs 1029 mL, P = 0.05) occurred compared to noninvasive blood pressure monitoring.Conclusion:Invasive blood pressure monitoring is as effective as noninvasive methods to achieve hypotensive anaesthesia. It does not aid in achieving lower target blood pressure. There is a lack of association between a reduction in blood loss and higher blood transfusion during hypotensive anaesthesiaand thiswill require further evaluation.

Is there a hidden blood loss in orthognathic surgery and should it be considered? Results of a prospective cohort study

The aim of this prospective observational study was to investigate the parameter ‘hidden blood loss’ (HBL) in the context of orthognathic surgery, incorporating undetected bleeding volumes occurring intra- and postoperatively.Orthognathic bleeding volumes were recorded at three different time points. At the end of the operation the visible intraoperative blood loss (VBL) was measured. Additionally, the perioperative blood loss was calculated 24 h and 48 h postoperatively using the ‘haemoglobin balance method’.Analysis of the HBL was based on the difference between the visible intraoperative blood loss (VBL) and calculated blood loss (CBL), determined 48 h after surgery.82 patients (male 33, female 49) were included in this study, of whom 41 underwent bimaxillary surgery and of whom 41 underwent Bilateral Sagittal Split Osteotomy (BSSO). Statistically significant differences with reference to the absolute bleeding volumes were found when comparing the two treatment modalities. In terms of HBL, a bleeding volume of 287.2 ml (±265.9) in the bimaxillary group and 346.9 ml (±271.3) in the BSSO cohort was recorded. This accounted for 32.2% (bimaxillary surgery) and 62.6% (BSSO) of the CBL after 48 h (BIMAX vs. BSSO, p < 0.001).HBL is a valuable adjunct to record within the perioperative management of orthognathic surgery to further improve patient safety and postoperative outcomes.

Machine learning based prediction of perioperative blood loss in orthognathic surgery

The aim of this study was to evaluate, if and with what accuracy perioperative blood loss can be calculated by a machine learning algorithm prior to orthognathic surgery. The investigators implemented a random forest algorithm to predict perioperative blood loss. 1472 patients who underwent orthognathic surgery from 01/2006 to 06/2017 at our institution were screened and 950 patients were included and separated 80%/20% in a training set - utilized to generate the prediction model - and a testing set - utilized to estimate the accuracy of the model. The outcome variable was the correlation between actual perioperative blood loss and predicted perioperative blood loss in the testing set. Other study variables were the difference of actual and predicted perioperative blood loss and important factors influencing perioperative blood loss using random forest feature importance. Descriptive and bivariate statistics were computed and the P value was set at 0.05. There was a statistically significant correlation between actual perioperative blood loss and predicted perioperative blood loss (p < 0.001). The mean difference was 7.4 ml with a standard deviation of 172.3 ml. The results of this study suggest that the application of a machine-learning algorithm allows a prediction of perioperative blood loss prior to orthognathic surgery.

Effect of Intravenous Tranexamic Acid on Perioperative Blood Loss in Orthognathic Surgery

Effect of Intravenous Tranexamic Acid on Perioperative Blood Loss in Orthognathic Surgery

Limiting blood loss in orthognathic surgery with Esmolol as a hypotensive agent

Orthognathic surgery may be complicated by difficulty in achieving hemostasis because unlike soft tissue, the vessels traversing bone cannot be identified and isolated before osteotomy. In this study we evaluated the amount of blood loss and duration of surgery under deliberate hypotensive anesthesia in comparison to amount of blood loss and duration of surgery under normotensive anesthesia on patients undergoing orthognathic surgical procedures. A total of 16 cases undergoing orthognathic surgery were included in this clinical study.Patients were randomly grouped under normotensive (group I) or hypotensive group (group 2). Patients in hypotensive anesthesia group were given Esmolol to maintain mean arterial pressure in the range of 70-80 mm of Hg till osteotomy segments were fixed. There was more than 40% reduction in blood loss in orthognathic surgical procedures when induced hypotension was used, but there was not statistically significant (p=0.91) reduction in the operative time. Based on surgeons and anesthetist’s assessment fast acting agents like Esmolol can be used intraoperatively to induce hypotension as and when required.

Hypotensive anesthesia: Comparing the effects of different drug combinations on mean arterial pressure, estimated blood loss, and surgery time in orthognathic surgery

Sevoflurane, an inhalational hypotensive anesthetic agent with a vasodilatory property, has been commonly used as a single agent to induce hypotension and effectively decrease blood loss in orthognathic surgery. However, it is common for patients to receive other hypotensive anesthetic agents in combination with sevoflurane. The purpose of our retrospective cohort study is to investigate whether administering an additional hypotensive agent has greater effect at reducing mean arterial pressure (MAP), estimated blood loss (EBL) and surgery time during orthognathic surgery. 57 subjects, aged 0-89 of both genders, who underwent orthognathic surgery were investigated in this study. Each patient's anesthesia records were reviewed to record the following variables of interest: EBL, duration of surgery, and MAP reduction in %. 41 subjects were placed in Group I and they received sevoflurane alone. 16 subjects were placed in Group II and they received sevoflurane plus a "supportive" agent. These "supportive" agents were esmolol, labetalol, metoprolol, nicardipine, and dexmedetomidine. The significant differences between two groups were assessed by using ANCOVA and p<0.05 was regarded as significant. Wilcoxon signed-rank test was used to look for differences in surgery time. Subjects in Group II experienced a greater reduction in MAP during surgery than subjects in Group I, 27.30% and 20.44%, respectively (p=0.027). There was no significant difference for sex (p=0.417) or age group (p=0.113) in estimated blood loss, however. The mean surgery time in Group I was 1.93, 2.77, and 4.54h with respect to LeFort, BSSO/IVRO, and double jaw surgery. Patients in Group II had a mean surgery time of 1.73, 2.07, and 5.64h with respect to LeFort, BSSO/IVRO, and double jaw surgery. No statistically significant difference was demonstrated in surgery time between Group I vs. Group II (p>0.05). Subjects in Group II experienced, on average, more blood loss than subjects in Group I, 355.50ml and 238.90ml, respectively. The use of multi-drug combination may offer significant advantage of reducing patients' mean arterial pressure. However, this has no significant effect on reducing blood loss or surgery time in comparison to sevoflurane alone.

Factors influencing intraoperative blood loss in orthognathic surgery

This retrospective study aimed to identify factors of importance for intraoperative blood loss relative to total blood volume in patients undergoing orthognathic surgery. The study included 356 patients treated consecutively at a Danish university hospital between 1 January 2010 and 31 December 2012. Inclusion criteria were (1) patient age ≥18 years and (2) patient undergoing a three-piece Le Fort I osteotomy, a bilateral sagittal split osteotomy, or a combination of the two. The patient-specific relative blood loss was calculated as a percentage by dividing the intraoperative blood loss by the estimated preoperative total blood volume, and then correlated with body mass index (BMI), age, sex, operating time, and treatment modality in a multivariate stepwise regression analysis. Operating time (P<0.001), BMI (P<0.001), and treatment modality (P<0.001) had a significant impact on relative blood loss; no significant effect of age or sex was observed. The coefficient of determination of relative blood loss was R2=0.34. In conclusion, this study introduces relative blood loss as a patient-specific measure of intraoperative blood loss. Average relative blood loss in this patient sample was 6.5%. Extensive surgery, a prolonged operating time, and reduced BMI significantly increase the intraoperative relative blood loss in patients undergoing orthognathic surgery.

Tranexamic acid reduces intraoperative blood loss in orthognathic surgery.

Medline, Embase and the reference lists of identified articles were also scanned for relevant papers. Only randomised controlled trials in English were considered. Two reviewers extracted data independently and study quality was assessed using the Jadad score. Meta-analysis was conducted. Four RCTs with a total of 183 patients were included. Intraoperative blood loss in the tranexamic acid group was statistically reduced (weighted mean difference [WMD] = -93.56, 95% CI = -132.59-54.52, P < .00001). No statistical difference was seen in the postoperative levels of haemoglobin and haematocrit (WMD = 0.50, 95% CIs = -0.43-1.43, P = .29 and WMD = 0.18, 95% CIs = -1.64-1.99, P = .85, respectively). This meta-analysis confirms that tranexamic acid can effectively reduce intraoperative blood loss in orthognathic surgery, especially by intravenous administration. But tranexamic acid cannot affect postoperative levels of haemoglobin and haematocrit.

The effect of tranexamic acid on blood loss in orthognathic surgery: a meta-analysis of randomized controlled trials

The objective of this article was to evaluate the efficacy of tranexamic acid on blood loss in orthognathic surgery. A meta-analysis was performed. The PubMed and EMBASE electronic databases were searched until June 30, 2012. Eligible studies were restricted to randomized controlled trials (RCTs). Four RCTs with 183 patients were included. The results showed that intraoperative blood loss in the tranexamic acid group was statistically reduced (weighted mean difference [WMD] = -93.56, 95% CI = -132.59-54.52, P < .00001). However, the postoperative levels of hemoglobin (Hb) and hematocrit (Hct) have no significant difference compared with placebo groups (WMD = 0.50, 95% CIs = -0.43-1.43, P = .29 and WMD = 0.18, 95% CIs = -1.64-1.99, P = .85, respectively). This meta-analysis confirms that tranexamic acid can effectively reduce intraoperative blood loss in orthognathic surgery, especially by intravenous administration. But, tranexamic acid cannot affect postoperative levels of Hb and Hct.

Evaluation of the efficacy of tranexamic acid on blood loss in orthognathic surgery. A prospective, randomized clinical study

The purpose of this prospective, randomized, double blind study was to assess the effect of tranexamic acid on blood loss, quality of surgical field and duration of surgery in adolescent orthognathic surgery patients. 50 consecutive patients, scheduled for orthognathic surgery were included. The study group (n=25) received tranexamic acid 10mg/kg as a bolus preoperatively followed by 1mg/kg as a maintenance dose intra operatively; the control group (n=25) received placebo (normal saline). All patients received moderate hypotensive anaesthesia with nitroglycerin and had surgery according to a standard protocol. Intra operative blood loss, duration of surgery, quality of surgical field, blood transfusion and complications, if any, were recorded. The mean total blood loss was 166.1±65.49ml in the study group and 256.4±77.80ml in the control group. The results showed statistically significant reduction in blood loss (p<0.001) and improved quality of surgical field (p<0.001) in the study group. There was no significant difference in duration of surgery and transfusion requirements between the two groups. In conclusion, preoperative and intra operative administration of the antifibrinolytic agent, tranexamic acid, is effective in controlling blood loss and improving the quality of the surgical field.

Blood Loss Following Orthognathic Surgery Varies Widely and Sometimes Transfusions are Needed

Blood loss in orthognathic surgery: a systematic review. Piñeiro-Aguilar A, Somoza-Martín M, Gandara-Rey JM, García-García A. J Oral Maxillofac Surg 2011;69(3):885-92. Thomas B. Dodson, DMD, MPH PURPOSE/QUESTION: To determine the range of information available to help surgeons better prepare themselves, their patients, and the auxiliary support for orthognathic surgery and transfusion requirements Information not available Systematic review Level 2: Limited-quality, patient-oriented evidence Grade C: Consensus, disease-oriented evidence, usual practice, expert opinion, or case series for studies of diagnosis, treatment, prevention, or screening.

Does Tranexamic Acid in an Irrigating Fluid Reduce Intraoperative Blood Loss in Orthognathic Surgery? A Double-Blind, Randomized Clinical Trial

The aim of this study was to investigate the efficacy of tranexamic acid in an irrigant fluid in decreasing intraoperative blood loss during orthognathic surgery. This was a prospective, randomized, double-blind, placebo-controlled trial of elective bimaxillary osteotomy. Forty patients were included in the study and 20 were randomly assigned to each group. Drawing of random lots determined whether 0.05% tranexamic acid in normal saline solution or normal saline was used as an irrigant fluid during surgery. All patients underwent hypotensive anesthesia and surgery according to standard protocol. Intraoperative blood loss, operative and hypotensive times, preoperative and postoperative hematocrit levels, transfusion of blood product, and amount of irrigant fluid were recorded. Parametric data were reported as mean ± standard deviation and nonparametric data were counted. Changes in parametric variables were analyzed using unpaired Student t test. Two-sided significance tests were used. P < .05 was accepted as statistically significant. Blood loss during bimaxillary surgery was not decreased significantly in the tranexamic acid group compared with the control group (832.5 ± 315.5 vs 917.5 ± 424.0 mL, respectively, P = .47). Tranexamic acid in an irrigant fluid does not significantly decrease intraoperative blood loss compared with placebo during orthognathic surgery.

Blood Loss in Orthognathic Surgery: A Systematic Review

Intraoperative blood loss during orthognathic surgery is frequently abundant and sometimes requires blood transfusion. The aim of the present study was to conduct a systematic review of the published data regarding intraoperative blood loss during orthognathic surgical interventions, including Le Fort I osteotomy, mandibular ramus osteotomy, and both combined, to determine the range of information available to help surgeons better prepare themselves, their patients, and the auxiliary support needed for this type of surgery and the transfusion requirements. Selected reports from the PubMed and Cochrane Library databases for studies conducted from 1978 to 2008 were evaluated to determine whether they included information on the volume of bleeding during surgery and the factors that might have influenced the amount of bleeding. Of the 90 reports examined and evaluated, 7 were included in the critical analysis conducted as a part of the present systematic review. Referring to the reports used for statistical analysis of the volume of blood loss, the mean intraoperative bleeding volume was 436.11 mL, the mean of the standard deviations was ±207.89 mL, and mean surgery duration was 196.9 minutes. Our results have shown that the intraoperative bleeding observed in patients during Le Fort I or mandibular ramus osteotomies or both combined was less than the limits set for blood transfusion. However, bleeding was occasionally heavier, and surgeons should be prepared for heavier bleeding by reserving blood at a blood bank or by preparing an autotransfusion.

O.423 Tranexamic acid reduces blood loss in orthognathic surgery

The purposes of the study were to investigate and evaluate the differences detected by the patients between the traditional orthognathic approach and the surgery-first one in terms of level of satisfaction and quality of life.A total of 30 patients who underwent orthognathic surgery for correction of malocclusions were selected and included in this study. Fifteen patients were treated with the conventional orthognathic surgery approach, and 15 patients with the surgery-first approach. Variables were assessed through the Orthognathic Quality of Life Questionnaire and the Oral Health Impact Profile questionnaire and analyzed with 2-way repeated-measures analysis of variance.The results showed significant differences in terms of the Orthognathic Quality of Life Questionnaire (P <0.001) and the Oral Health Impact Profile (P <0.001) scores within groups between the first and last administrations of both questionnaires. Differences in the control group between first and second administrations were also significant. Questionnaire scores showed an immediate increase of quality of life after surgery in the surgery-first group and an initial worsening during orthodontic treatment in the traditional approach group followed by postoperative improvement.This study showed that the worsening of the facial profile during the traditional orthognathic surgery approach decompensation phase has a negative impact on the perception of patients’ quality of life. Surgeons should consider the possibility of a surgery-first approach to prevent this occurrence.

Prophylactic administration of Yunnan Baiyao capsule reduces intra-operative blood loss in orthognathic surgery

To evaluate the haemostatic efficacy and safety of prophylactic oral administration of Yunan Baiyao capsules on reduction of blood loss in bimaxillary orthognathic surgery. Eighty-seven patients scheduled for Le Fort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) were enrolled in the prospective, randomized, double-blind, placebo-controlled clinical study. Forty-three patients took prophylactic oral administration of Yunnan Baiyao capsules 3 days before operation, and 44 patients without Yunnan Baiyao administration served as control. The intraoperative blood loss during Le Fort I osteotomy and bilateral sagittal split ramus osteotomy was estimated and the safety of Yunnan Baiyao capsules was evaluated. The total blood loss in the Yunnan Baiyao group (330.5 +/- 134.4) ml was significantly lower than that of the control group (420.3 +/- 175.9) ml. The blood loss of Le Fort I osteotomy in the Yunnan Baiyao group (154.9 +/- 84.3) ml was also significantly lower than that of the control group (203.8 +/- 98.1) ml. The mean blood loss of BSSRO in the Yunnan Baiyao group was also lower than that of the control group, but the differences was not significant. The post-operative fibrinolysis was in the same level in both groups. Thromboemblic events or other side effects were not observed in this clinical trial. Prophylactic oral administration of Yunnan Baiyao capsules can effectively reduce the intra-operative blood loss in bimaxillary orthognathic surgery. Yunnan Baiyao capsule are an effective and safe haemostatic traditional Chinese medicine.

Limiting blood loss in orthognathic surgery by esmolol

Elective surgeries like orthognathic for correction of dentofacial deformities do not warrant blood transfusions. But orthognathic procedures often cause appreciable blood loss, most of which cannot be controlled by identification and ligation of blood vessels. Hypotensive anaesthesia could be the ideal way of reducing blood loss and associated transfusions. Numbers of pharmacological agents have been used for inducing hypotension which can bring down mean arterial blood pressure within the target of 65–70 mm Hg, i.e. lowering mean arterial blood pressure to 80% of pre operative value. This paper attempts to evaluate the effectiveness of esmolol in achieving hypotensive anaesthesia and thereby reducing blood loss in orthognathic surgery.