***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: A prospect i ve r and omized trial evaluated grade d-compression antiembolism stockings for prevention of leg vein thrombosis as assessed by Doppler ultrasound , in patients undergoing total hip replacement . The study was terminated after the evaluation of 18 patients revealed a significantly greater  incidence of deep vein thrombosis  , documented by  phlebography  , in patients without stockings ( 5 of 10 ) compared to those with stockings ( none of 8 , p less than 0.03 ) . Three of the patients with thrombosis developed pulmonary emboli . Although the sample size of this study is small , the implication that grade d-compression stockings reduce the incidence of leg vein thrombosis is strong and is supported by the results of other recent trials . These findings are at variance with earlier studies which failed to document efficacy of elastic stockings , which involved products which did not provide grade d limb compression We studied 80 patients who were older than 50 years of age to determine if grade d elastic compression stockings reduced the frequency of postoperative thrombosis in patients undergoing dextran 70 prophylaxis . All of the patients received a total of 2,000 mL of dextran 70 during three days ; according to a r and om table , each of the patients had one leg encased in a grade d compression stocking for one week . Thrombosis development was screened with the fibrinogen I 125 test . Eight patients manifested thrombosis-one in the thigh and seven in the calf -- localized to the unstockinged leg , a frequency significantly greater than the zero frequency in the stockinged leg . No untoward effects of this combination prophylaxis were noted A study of 95 patients determined the incidence of postoperative venous thrombosis  and the effectiveness of simple prophylactic measures . In addition , the accuracy of the radioactive fibrinogen technique for the detection of thrombosis was compared to venography .  Deep venous thrombosis was detected in six of 44 ( 14 % ) control patients . However , only two of 51 ( 4 % ) patients on whom prophylactic measures were applied developed thrombosis . The  ages of the patients with thrombosis occurring postoperatively were significantly higher than the ages of the other patients in this study . There was an excellent correlation of the results obtained by the radioactive method with those of venography . Laboratory tests indicated a deficient endogenous fibrinolytic activity in those patients who developed thrombosis In a prospect i ve , r and omized study on 114 patients undergoing major abdominal surgery , the prophylactic effect of dihydroergotamine ( DHE ) combined with low-dose heparin ( LDH ) against postoperative deep vein thrombosis ( DVT ) was compared with that of peroperative intermittent pneumatic calf compression ( IPCC ) . The additive effect of graduated pressure stockings was also studied , by r and omizing a stocking to the right or left leg in each patient . The  125I-fibrinogen test was used to diagnose DVT . The incidence of postoperative DVT was significantly lower in the DHE-LDH than in the IPCC group ( 4 % v. 19 % ) . In the IPCC group the incidence of postoperative DVT was equal in legs with and without stocking . The study thus indicated that DHE-LDH is more effective than peroperative IPCC in preventing DVT after major abdominal surgery , and that graduated pressure stockings do not enhance the prophylactic effect of peroperative IPCC Totally , 150 patients , subjected to total hip arthroplasty , were r and omly allocated into three prophylactic groups with either conventional dextran alone or with additional grade d compression stockings or with additional preoperative administration of dextran . The overall frequency of deep venous thrombosis ( DVT ) , as studied by radioactive fibrinogen uptake test and ascending phlebography of the operated on thigh was in the conventional dextran group 46 percent , the additional stockinged group 30 percent , and in the additional preoperative dextran group 52 percent . In the stockinged group , there was a lower frequency of DVT in the nonoperated on leg as well as , on an average , about 350 mL less peroperative bleeding as compared with the other two groups . No adverse reaction occurred from dextran administration . Increased and prolonged postoperative administration of dextran decrease the number of femoral DVTs Seventy-eight patients having elective total hip replacement were r and omised into 3 groups A ) control ; B ) low molecular weight heparin : ( enoxaparin 40 mg once daily ) and C ) enoxaparin ( 40 mg once daily ) plus graduated elastic compression ( TEDR stockings ) for 8 - 12 days . All patients had a preoperative perfusion lung scan and chest X-Ray and a postoperative perfusion/ventilation scan together with bilateral ascending venography on days 8 - 12 . A blood sample was taken preoperatively , on the 1st , 3rd and 5th postoperative day and at the end of the study . The control group received placebo injections . The venograms and V/Q scans were reported blindly by an independent panel of three and one radiologists respectively . An independent panel of assessors stopped entry in the control group when a total of 45 patients were admitted according to Ethics Committee directives . The study continued with groups B and C. The incidence of DVT ( including isolated asymptomatic calf thrombi ) was as follows : Group A ( n = 14 ) 93 % ; Group B ( n = 32 ) 38 % ; Group C ( n = 32 ) 25 % ( chi 2 ; p < 0.001 for group A versus B or C ) . The incidence of proximal DVT was : Group A 57 % ; group B 28 % ; group C 13 % ( chi 2 ; p = 0.057 for group A versus B and p < 0.005 for group A versus C ) . The incidence of silent pulmonary embolism ( PE ) ( new defect on V/Q scan ) was 28 % ( 8 out of 29 ) in patients with and 5 % ( 2 out of 43 ) in patients without DVT ( chi 2 ; p < 0.02 ) . The combination of high TAT and low anti-Xa activity on the 1st postoperative day identified a high risk group of patients who had a 56 % incidence of proximal DVT on the 8th to 12th postoperative day . Further studies are needed to confirm the suggested increased efficacy in prophylaxis by the combination of LMWH and GEC as compared with LMWH alone Little is known about the efficacy of graduated compression stockings in preventing venous thromboembolism  after hip surgery . We conducted a prospect i ve , r and omised single-blind study to determine whether the addition of compression stockings to fondaparinux conferred any additional benefit . The study included 874 patients , of whom 795 could be evaluated ( 400 in the fondaparinux group and 395 in the fondaparinux plus compression stocking group ) .  Fondaparinux was given post-operatively for five to nine days , either alone or combined with wearing stockings , which were worn for a mean 42 days ( 35 to 49 ) . The study outcomes were venous thromboembolism , or sudden death before day 42 . Duplex ultrasonography was scheduled within a week of day 42 . Safety outcomes were bleeding and death from venous thromboembolism . The prevalence of deep-vein thrombosis was similar in the two groups 5.5 % ( 22 of 400 ) in the fondaparinux group and 4.8 ( 19 of 395 ) in the fondaparinux plus stocking group ( odds ratio 0.88 , 95 % confidence interval 0.46 to 1.65 , p = 0.69 ) . Major bleeding occurred in only one patient . The addition of graduated compression stockings to fondaparinux appears to offer no additional benefit over the use of fondaparinux alone Background Nurses on an Acute Care Evidence Based Practice Committee , creating a policy to increase patient compliance with  thromboembolic deterrent stockings ( TEDS ) and sequential compression devices ( SCDs ) for deep vein thrombosis prophylaxis , found limited literature on patient preference and response to this treatment . Study Aim The study purpose was to determine whether knee-length or thigh-length TEDS and /or SCDs were more comfortable , correctly applied , and worn by patients , and to assess patient reasons for noncompliance . Method A patient survey and observational data tool was design ed . Six surveyors collected data ( interrater reliability = 93 % ) from 137 r and omly selected patients with orders for TEDS and /or SCDs admitted to acute care medical or surgical nursing units . Results Most patients wore thigh-length SCDs and TEDS . However , only 29.2 % ( n = 40 ) had SCDs on them at the time of survey , and 62.8 % ( n = 86 ) were compliant with TEDS . The most common reasons given for noncompliance with SCDs were that the devices were not reapplied after bathing or ambulating , or were removed because they were hot or itchy . Complaints of discomfort were highest among patients wearing thigh-length SCDs and TEDS .  Problems with fit were 50 % higher in those who wore thigh-length TEDS , and involved stockings that created restricting b and s. Most patients understood the purpose of treatment , and older patients were more compliant than younger patients . Implication s for Practice Knee-length TEDS and SCDs are more comfortable for patients , encourage higher levels of compliance with treatment , do not pose a risk for venous stasis to patients by creating restricting b and s , and are less expensive . Patients need ongoing education to resume wearing TEDS and SCDs after activities of daily living , and knee-length stockings and devices would be easier to reapply . The policy in our institution was changed for the use of knee-length compression stockings and SCDs The mechanisms by which graduated compression stockings prevent deep venous thrombosis are not completely understood . In the current study the physiologic effect of low-pressure graduated compression stockings on the venous blood flow in the lower limb and the practical aspects of their use were assessed . Patients having elective orthopaedic surgery at a university orthopaedic department were r and omized into five groups to wear two different types of graduated compression stockings in thigh and knee lengths . Patients in the fifth control group did not wear graduated compression stockings . Venous occlusion strain gauge plethysmography was used to measure venous flow . After 20-minutes bed rest there was a highly significant increase in venous capacitance and venous outflow in patients in all of the four groups wearing stockings . There was no difference in the mean of the percentage change of venous capacitance in patients in the four groups wearing stockings . The knee length Brevet stockings were less efficient in increasing the venous outflow . There was no significant change in the venous capacitance and venous outflow in patients in the control group . Visual assessment of the fit and use of stockings was done , and patients ’ subjective opinion of comfort was sought . The knee length graduated compression stockings  wrinkled significantly less , and significantly fewer patients reported discomfort with them . All stockings were reported to be difficult to use . Thigh and knee length stockings have a significant effect on decreasing venous stasis of the lower limb . Knee length graduated compression stockings are similarly efficient in decreasing venous stasis , but they are more comfortable to wear , and they wrinkle less The frequency of deep venous thrombosis ( DVT )  was studied in 98 patients undergoing major abdominal surgery . All the patients received low dose heparin prophylaxis 5000 i.u . every 12 h for 5–7 days . In each patient , a graduated compression stocking was also worn and r and omly allocated to one of the legs and the other leg served as a control . DVT was diagnosed by the 125I‐fibrinogen method . Four patients developed bilateral DVT and 8 patients unilateral DVT , all of whom developed it in the control leg . The difference in unilateral DVT between stockinged and control legs was significant ( P < 0·004 ) . It is concluded that a combination of low dose heparin and graduated compression stockings is more effective than low dose heparin alone in reducing the frequency of postoperative DVT . It is suggested that this combination of prophylaxis might be of value in high risk patients This was a r and omized clinical trial to determine the efficacy and safety of a ‘ blanket ’ protocol of low molecular weight heparin ( LMWH ) and the best length of antiembolism stocking , for every patient requiring surgery under general anaesthesia OBJECTIVE To compare knee-length with thigh-length graduated compression stockings for correct application and rate of compliance when they are prescribed for the prevention of deep-vein thrombosis in surgical patients . METHODOLOGY Patients who were prescribed graduated compression stockings were prospect ively studied in three surgical units at Groote Schuur Hospital from February to June 1997 .  Knee-length stockings were prescribed in the colorectal unit , while the thigh-length variety were prescribed in the hepatobiliary and trauma units . Patients were observed for the correct application and size of stockings , and the presence of compression b and s. A total of 72 patients were studied . RESULTS One patient in the knee-length group and 7 patients in the thigh-length group were not wearing their stockings . Twenty-one of 30 patients ( 70 % ) in the knee-length group and 15 of 42 ( 35.7 % ) in the thigh-length group had correctly applied stockings ( P = 0.009 ) . CONCLUSIONS Knee-length are more likely to be correctly applied than thigh-length stockings . Knee-length should replace thigh-length stockings in general surgical patients Two hundred and 
    Output:
    
CONCLUSIONS Thigh length stockings may be more effective than knee length stockings , but results did not reach statistical significance and the evidence base is weak .
While thigh length stockings appear to have superior efficacy , practical issues such as patient acceptability may prevent their wide use in clinical practice .