***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: BACKGROUND The mode of administration for tranexamic acid ( TXA ) to significantly reduce the decrease in hemoglobin ( Hb ) , number of transfusions , relevant costs , and side effects in patients undergoing primary unilateral total knee arthroplasty ( TKA ) has not been resolved . METHODS A total of 560 patients undergoing primary unilateral TKA were r and omized into 4 groups : intravenous group ( 140 patients receiving 2 doses of 20 mg/kg intravenous TXA ) , topical group ( 140 patients administered 3.0 g topical TXA ) , oral group ( 140 patients given 2 doses of 20 mg/kg oral TXA ) , and a control group ( 140 patients not given TXA ) . The primary outcomes included postoperative 48-hour Hb loss and drainage volume , number of transfusions , transfusion and TXA costs , and thromboembolic complications . Secondary outcomes were postoperative inpatient time and wound healing 3 weeks after TKA . RESULTS Baseline data among the 4 groups were similar . The 48-hour Hb loss and drainage volume in the intravenous , topical , and oral groups were significantly less ( P < .05 ) than those in the control group , and the latter had significantly more transfusions and transfusion costs than the other 3 groups ( P < .05 ) . The TXA cost was lowest in the oral group compared with that in the topical and intravenous groups ( P < .05 ) . No differences in thromboembolic complications , postoperative inpatient time , or wound healing were observed among the groups . However , wound dehiscence and continuous wound discharge occurred in the topical group . CONCLUSION All the 3 modes of TXA administration significantly reduced postoperative Hb loss , the number of transfusions , and transfusion costs compared with those in the control group . No pulmonary embolism or infection was observed . Oral TXA is recommended because it provided a similar clinical benefit and result ed in the lowest TXA cost compared with the other 2 modes of TXA administration In our department we use an enhanced recovery protocol for joint replacement of the lower limb . This incorporates the use of intravenous tranexamic acid ( IVTA ; 15 mg/kg ) at the induction of anaesthesia . Recently there was a national shortage of IVTA for 18 weeks ; during this period all patients received an oral preparation of tranexamic acid ( OTA ; 25 mg/kg ) . This retrospective study compares the safety ( surgical and medical complications ) and efficacy ( reduction of transfusion requirements ) of OTA and IVTA . During the study period a total of 2698 patients received IVTA and 302 received OTA .  After adjusting for a range of patient and surgical factors , the odds ratio ( OR ) of receiving a blood transfusion was significantly higher with IVTA than with OTA ( OR 0.48 ( 95 % confidence interval 0.26 to 0.89 ) , p = 0.019 ) , whereas the safety profile was similar , based on length of stay , rate of readmission , return to theatre , deep infection , stroke , gastrointestinal bleeding , myocardial infa rct ion , pneumonia , deep-vein thrombosis and pulmonary embolism . The financial benefit of OTA is £ 2.04 for a 70 kg patient ; this is amplified when the cost saving associated with significantly fewer blood transfusions is considered . Although the number of patients in the study is modest , this work supports the use of OTA , and we recommend that a r and omised trial be undertaken to compare the different methods of administering tranexamic acid Background Dexamethasone and tranexamic acid are used to decrease post-rhinoplasty periorbital edema and ecchymosis . We compared the impact of each medication separately or in combination in this regard . Methods A prospect i ve , r and omized triple-blinded study was undertaken on 60 patients who underwent primary open rhinoplasty . They were divided into four groups : Group D ( n = 15 ) received 8 mg dexamethasone , group T ( n = 15 ) received 10 mg/kg tranexamic acid , group DT ( n = 15 ) received both 8 mg dexamethasone and 10 mg/kg tranexamic acid , and group P ( n = 15 ) received neither medication and served as the placebo control group . The medications were given intravenously ( IV ) 1 h before and three doses every 8 h postoperatively . Digital photographs were taken on the first , third and seventh postoperative days . One expert examiner blinded to the study evaluated the periorbital edema and ecchymosis on a scale of 0–4 . Periorbital edema and ecchymosis were examined in all groups . Results In group D , group T and group DT , periorbital edema and ecchymosis ratings were significantly lower compared with the control group ( p < 0.01 ) . No statistically significant difference was seen in preventing or decreasing both periorbital edema and ecchymosis among group D , group T and group DT . Conclusion Tranexamic acid and dexamethasone , separately or in combination , had similar effects in reducing periorbital edema and ecchymosis in open rhinoplasty . Combined application did not show a significantly higher beneficial effect in this regard . Level of Evidence IIIThis journal requires that authors assign a level of evidence to each article . For a full description of these Evidence -Based Medicine ratings , please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 Background : One of the major problems in surgery is intraoperative bleeding which reduces visibility in the operative field . An important task for an anesthetist during head and neck surgery is to improve intraoperative visibility . Objectives : The purpose of this study was to compare the amount of bleeding using different doses of oral metoprolol during three common types of nasal operation ; rhinoplasty , septoplasty and functional endoscopic sinus surgery , as this is one of the complications during head and neck surgery . Patients and Methods : In a r and omized , controlled , open clinical trial , 88 patients who were c and i date s for nasal operations were studied . Patients entering the study were divided into four groups and r and omly assigned to receive 50 mg metoprolol a night before the operation , 50 mg metoprolol on the day of operation , 50 mg metoprolol on the night and on the day of operation , or a placebo . Following the patient ’s preparation on the operating table and after intubation , systolic and diastolic blood pressures were measured in a non-invasive oscillometric way , and their pulse rate was recorded simultaneously . All the data were recorded during the surgery as well . Bleeding was measured by the quality scale proposed by Formme and Boezaart . Results : There was a statistical significance between using metoprolol and the amount of intraoperative bleeding . All patients who received metoprolol the night before surgery and on the day of surgery had slight bleeding during the surgery . In addition , there was a statistical significance between patients ’ agitation levels and the time they received metoprolol . Conclusions : Decreases in both systolic blood pressure and heart rate to less than 60 beats per minute reduces intraoperative bleeding . These rates can be achieved by using beta-blocker drugs . In this study , using a double-dose of metoprolol significantly reduced intraoperative bleeding and improved the quality of the operative field . It also reduced patients ’ agitation in the recovery room Background : Perioperative bleeding is a common side effect of rhinoplasty which may impose the blood transfusion to the patients . As a result of risks and cost of blood transfusion , this study is planned to reduce blood loss in these surgeries . Since tranexamic acid ( TXA ) has been reported to reduce bleeding and subsequent possible need for blood transfusion , the purpose of this study was to evaluate the efficacy of oral TXA on blood loss during rhinoplasty . Methods and Material s : In this double-blind , r and omized , placebo-controlled clinical trial , 50 participants underwent rhinoplastic surgery .  These participants were divided into 2 groups ; 25 were r and omly assigned to each 1 . The patients in the first group received 1 g ( 2 × 500 mg ) tranexamic acid tablets , and the patients in the second group received placebo 2 hours before starting the surgery . All patients were operated by the same surgical team and the same anesthetic techniques were used during the surgery . Gender , age , BMI , duration of operation , the amount of blood loss , and surgeon 's satisfaction rate were the variables studied . Results : The first group ( TXA group ) consisted of 11 males ( 44 % ) and 14 females ( 56 % ) and the second group consisted of 13 males ( 52 % ) and 12 females ( 48 % ) . There was no statistical difference in the distribution of the variables between the 2 groups , except for the blood loss , duration of operation , and surgeon 's satisfaction . The mean total blood loss was 144.6 ± 60.28 mL in “ group 1 ” and 199.6 ± 73.05 mL in “ group 2 ” ( P < 0.05 ) . Duration of operation in the first group was less than the second group ( 2.60 ± 0.53 hours vs. 2.99 ± 0.59 hours ) ( P = 0.017 ) . The surgeon was more satisfied with the quality of surgical field and visualization in “ group 1 ” ( 3.76 ± 0.72 ) than “ group 2 ” ( 2.16 ± 0.50 ) ( P = 0.001 ) . Conclusion : The preoperative administration of 1 g oral tranexamic acid significantly decreased the blood loss in patients undergoing rhinoplastic surgery without any significant adverse effects . Iranian registry no : I RCT 201312271674N10 ( www.i rct .ir ) Background There is a rich blood flow to the mucosa in the nasal region . In rhinoplasty , surgical procedures are performed in a narrow and confined space . So bleeding during surgery reduces visibility which can complicate the procedure . This study investigated the effects of the patient position on amount of intraoperative bleeding during surgical procedures . Patients and Methods This r and omized controlled trial was conducted on 71 patients who underwent elective rhinoplasty .  The patients were operated on in three groups . Group 1 consisted of 23 patients who were operated on in the  supine position ;  Group 2 included 28 patients who were operated on using a 15 ° angle reverse Trendelenburg position ;  Group 3 consisted of 20 patients who were operated on  at a 20 ° angle reverse Trendelenburg position . Results There were statistically significant differences between the groups in regard to surgeon satisfaction and the amount of intraoperative bleeding . The amount of intraoperative bleeding in Group 1 was significantly higher than those of Groups 2 and 3 , and surgeon satisfaction was lower . Conclusions Reverse Trendelenburg position reduces intraoperative bleeding in rhinoplasty patients while facilitating the procedure compared to the supine position . Surgery at a 15 ° angle reverse Trendelenburg position provides the optimum working conditions by both significantly reducing intraoperative bleeding and allowing for comfortable conditions for the surgeon . Level of Evidence IThis journal requires that authors assign a level of evidence to each article . For a full description of these Evidence -Based Medicine ratings , please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 Background This r and omized , double-blind study was design ed to assess the effect of perioperative remifentanil with controlled hypotension on intraoperative bleeding , postoperative edema , and ecchymosis . Methods Fifty-two patients undergoing rhinoplasty were divided into 2 groups . The remifentanil group received 1 µg · kg−1 intravenously as a bolus before induction of anesthesia , 0.5 to 1 µg · kg−1 · h−1 by continuous intravenous infusion during the operation . After anesthesia induction with propofol ( 2–3 mg · kg−1 ) and fentanyl ( 1–15 µg · kg−1 ) , muscle relaxation was achieved with rocuronium ( 0.45–0.90 mg · kg−1 ) . Mean arterial pressure was maintained at 50 to 60 mm Hg in controlled hypotensive anesthesia achieved using remifentanil infusion . Perioperative hemodynamics and bleeding ; early postoperative pain and agitation scale ; postoperative first , third , and seventh day edema ; and ecchymosis were evaluated . Edema and ecchymosis were evaluated using grade d scale from 0 to 4 .  Results Remifentanil  reduced mean arterial pressure during the entire operative period and the first 30 minutes postoperatively ( P < 0.05 for these comparisons ) . Intraoperative bleeding also decreased ( P < 0.001 ) . There was a significant decrease in edema in both upper and lower eyelid edema on the first and third days in the remifentanil group , although this difference was not detected on the seventh day ( P1upper = 0.000 , P1lower = 0.000 , P3upper = 0.008 , and P3lower = 0.002 ) . Ecchymosis decreased significantly in both upper and lower eyelids on the first , third , and seventh days in the remifentanil group ( P1upper = 0.000 , P3upper = 0.000 , P3upper = 0.002 , P3lower =  
    Output:
    
Conclusions and Relevance Current available evidence suggests that preoperative administration of tranexamic acid is safe and may reduce intraoperative bleeding as well as postoperative eyelid edema and ecchymosis in patients undergoing rhinoplasty