***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 
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    ***EXAMPLES*** 
    Input: 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 The effect of incremental increases in external pressure , applied to the leg , on blood volume flow in the femoral vein was studied in dogs . Clinical investigation of external pressure increases was also carried out on nine patients undergoing surgery for varicose veins . An external pressure between 5 and 15 mm . Hg caused a sustained increase in mean femoral vein flow both in a control and in the compressed limb . Above 15 mm . Hg external pressure flow decreased in the compressed limb but was maintained at an increased level in the control limb . If external compression is to be used to prevent and treat deep vein thrombosis its application must be carefully controlled Lower‐limb venous haemodynamics were studied prospect ively in 40 patients ( 24 women , 16 men of median age 52 years ) undergoing laparoscopic cholecystectomy . Patients were r and omized to wear compression stockings during surgery or no stockings . All received subcutaneous heparin prophylaxis . Venous capacitance and outflow were measured non‐invasively before , during and after pneumo‐peritoneum . In the group without compression stockings ( 20 patients ) venous capacitance and outflow decreased during pneumoperitoneum in most patients . In the group wearing stockings ( 20 patients ) the changes were less pronounced or abolished . There was a significant difference between the groups in venous capacitance and outflow ratios at mid‐operation : median ( interquartile range ) 0‐89 ( 0‐56‐1‐16 ) and 0‐89 ( 0‐56‐1‐15 ) respectively in the group without stockings versus 1‐48 ( 1‐09‐2‐19 ) and 1‐71 ( 1‐20‐2‐19 ) respectively in that with stockings ( P < 0.001 ) . Pneumoperitoneum creates a significant resistance to venous return . Compression stockings counteract the changes observed 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 The efficacy of graduated compression stockings in the prevention of deep vein thrombosis ( DVT ) after major gynaecological surgery was investigated in a controlled r and omized prospect i ve trial in 196 patients who were > 35 years of age . The stockings were worn by 104 of the 196 patients throughout their stay in hospital , the other 92 patients  did not wear the stockings ( control group ) . All the patients were scanned for DVT postoperatively with the 125I‐labelled fibrinogen test . None of the 104 patients who wore the stockings  developed a thromboembolism , but four of the 92 control patients who did not wear the stockings had DVT . This difference between the two groups was statistically significant 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 INTRODUCTION Pneumatic compression stocking ( PCS ) devices have been introduced to decrease the incidence of postoperative deep venous thrombosis ( DVT ) . However , their role in the prophylaxis against pulmonary embolism ( PE ) remains unclear . This study was undertaken to compare the prophylactic effectiveness of subcutaneous heparin ( SCH ) alone vs the combined use of PCS and SCH in the prevention of PE following cardiac surgery . METHODS We studied 2,551 consecutive patients who underwent cardiac surgery over a 10-year period . They were r and omly allocated to two groups . Group A included 1,196 patients who were treated with 5,000 U of SCH every 12 h and group B included 1,355 patients treated with a combined prophylactic regimen of PCS and SCH . RESULTS The diagnosis of PE was established in 69 patients by either high-probability ventilation perfusion scan , pulmonary angiogram , or autopsy . The incidence of PE in group A patients was 4 % ( 48/1,196 ) and in group B was 1.5 % ( 21/1,355 ) . The concomitant use of bilateral PCS and SCH reduced the frequency of postoperative PE in 62 % in comparison to the prophylaxis with SCH alone ( p < 0.001 ) . CONCLUSIONS These data suggest that the combined prophylactic method of bilateral PCS and SCH is superior to SCH alone in the prevention of PE after cardiac surgery 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 Background : Patients have been shown to be at greater risk for deep venous thrombosis , particularly proximal thrombosis , after total hip 
    Output:
    
GCS are effective in diminishing the risk of DVT in hospitalised patients .
Data examination also suggests that GCS on a background of another method of prophylaxis is more effective than GCS on its own