***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: BACKGROUND Unfractionated heparin and the low molecular weight heparin , dalteparin , are used for prophylaxis against venous thromboembolism in patients undergoing craniotomy . These drugs were compared in a r and omized , prospect i ve pilot study comparing intermittent pneumatic compression devices plus dalteparin to intermittent pneumatic compression devices plus heparin . METHODS One hundred patients undergoing craniotomy were r and omly allocated to receive perioperative prophylaxis with subcutaneous ( SC heparin , 5000 units every 12 hours , or dalteparin , 2,500 units once a day , begun at induction of anesthesia and continued for 7 days or until the patient was ambulating . Entry criteria were age over 18 years , no deep vein thrombosis ( DVT ) preoperatively as judged by lower limb duplex ultrasound and no clinical evidence of pulmonary embolism preoperatively . Patients with hypersensitivity to heparin , penetrating head injury or who refused informed consent were excluded . Patients underwent a duplex study 1 week after surgery and 1 month clinical follow-up . All patients were treated with lower limb intermittent pneumatic compression devices . RESULTS There were no differences between groups in age , gender , and risk factors for venous thromboembolism . There were no differences between groups in intraoperative blood loss , transfusion requirements or postoperative platelet counts . Two patients receiving dalteparin developed DVT ( one symptomatic and one asymptomatic ) . No patient treated with heparin developed DVT and no patient in either group developed pulmonary embolism . There were two hemorrhages that did not require repeat craniotomy in patients receiving dalteparin and one that did require surgical evacuation in a patient treated with heparin . Drug was stopped in two patients treated with dalteparin because of thrombocytopenia . None of these differences were statistically significant . CONCLUSION There was no significant difference in postoperative hemorrhage , venous thromboembolism or thrombocytopenia between heparin and dalteparin . The results suggest that , given the small sample size of this trial , both drugs appear to be safe and the incidence of venous thromboembolism by postoperative screening duplex ultrasound appears to be low when these agents are used in combination with intermittent pneumatic compression devices BACKGROUND Current treatment regimens that are design ed to prevent deep venous thrombosis in patients undergoing orthopaedic procedures rely predominantly on drug prophylaxis alone . The purpose of this r and omized clinical study was to evaluate the effectiveness of a mechanical adjunct to chemoprophylaxis that involves intermittent compression of the legs . METHODS During a twenty-two month period , 1803 patients undergoing a variety of orthopaedic procedures were prospect ively r and omized to receive either chemoprophylaxis alone or a combination of chemoprophylaxis and mechanical prophylaxis .  Nine hundred and two patients were managed with low-molecular-weight heparin alone , and 901 were managed with low-molecular-weight heparin and intermittent pneumatic compression of the calves for varying time periods . Twenty-four percent of the patients underwent total hip or knee joint replacement . Screening for deep venous thrombosis was performed on the day of discharge with duplex-color-coded ultrasound . RESULTS In the chemoprophylaxis-only group , fifteen patients ( 1.7 % ) were diagnosed with a deep venous thrombosis ; three thromboses were symptomatic . In the chemoprophylaxis plus intermittent pneumatic compression group , four patients ( 0.4 % ) were diagnosed with deep venous thrombosis ; one thrombosis was symptomatic . The difference between the groups with regard to the prevalence of deep venous thrombosis was significant ( p = 0.007 ) . In the chemoprophylaxis plus intermittent pneumatic compression group , no deep venous thromboses were found in patients who received more than six hours of intermittent pneumatic compression daily . CONCLUSIONS Venous thrombosis prophylaxis with low-molecular-weight heparin augmented with a device that delivers rapid-inflation intermittent pneumatic compression to the calves was found to be significantly more effective for preventing deep venous thrombosis when compared with a treatment regimen that involved low-molecular-weight heparin alone Background Venous thromboembolism ( VTE ) remains a common problem in critically ill patients . Pharmacologic prophylaxis is currently the st and ard of care based on high-level evidence from r and omized controlled trials . However , limited evidence exists regarding the effectiveness of intermittent pneumatic compression ( IPC ) devices . The Pneumatic compREssion for preventing VENous Thromboembolism ( PREVENT trial ) aims to determine whether the adjunct use of IPC with pharmacologic prophylaxis compared to pharmacologic prophylaxis alone in critically ill patients reduces the risk of VTE . Methods / Design The PREVENT trial is a multicenter r and omized controlled trial , which will recruit 2000 critically ill patients from over 20 hospitals in three countries . The primary outcome is the incidence of proximal lower extremity deep vein thrombosis ( DVT ) within 28 days after r and omization . Radiologists interpreting the scans are blinded to intervention allocation , whereas the patients and caregivers are unblinded . The trial has 80 % power to detect a 3 % absolute risk reduction in proximal DVT from 7 to 4 % . Discussion The first patient was enrolled in July 2014 . As of May 2015 , a total of 650 patients have been enrolled from 13 centers in Saudi Arabia , Canada and Australia . The first interim analysis is anticipated in July 2016 . We expect to complete recruitment by 2018.Trial registration Clinical trials.gov : NCT02040103 ( registered on 3 November 2013).Current controlled trials : IS RCT N44653506 ( registered on 30 October 2013 ) OBJECTIVE Prophylactic therapies have demonstrated efficacy in reducing the incidence of deep venous thrombosis ( DVT ) in neurosurgical patients . Retrospective analysis of patients undergoing neurosurgical procedures at the University of Michigan demonstrated a high incidence ( 14 % ) of postoperative DVT among patients with intracranial neoplasms treated with sequential compression device ( SCD ) prophylaxis alone . Therefore , we investigated the efficacy and safety of the low-molecular weight heparin enoxaparin in preventing DVT in patients with brain tumors . The goal of the study was to compare SCD , enoxaparin , and combined SCD/enoxaparin prophylaxis among patients requiring surgery for treatment of intracranial neoplasms . METHODS Eligible patients were r and omized to SCD , enoxaparin , or combined therapy .  Treatment was initiated before the induction of anesthesia and was continued throughout the hospital stay . Patients were screened for DVT , using duplex imaging , on four occasions in the first 1 month after surgery . The incidences of DVT and serious adverse events were compared between groups using analysis of variance and the Dunnet two-sided t test . RESULTS Sixty-eight patients completed the study .  Postoperative DVT occurred in 3 of 22 ( 13.6 % ) SCD-treated patients , 1 of 23 ( 4.3 % ) enoxaparin-treated patients , and 4 of 23 ( 17.4 % ) SCD/enoxaparin-treated patients . Differences were not statistically significant . Postoperative intracranial hemorrhage did not occur in patients in the SCD-treated group , whereas 5 of 46 patients receiving low-molecular weight heparin suffered clinical ly significant intracranial hemorrhage . The study was terminated because of the increased incidence of adverse events in the enoxaparin-treated groups . CONCLUSION Enoxaparin therapy initiated at the time of anesthesia induction increases postoperative intracranial hemorrhage BACKGROUND The benefit of combined mechanical and pharmacologic methods for venous thromboembolism prevention after abdominal surgery has not been clearly established . OBJECTIVES To compare the efficacy and safety of fondaparinux in conjunction with intermittent pneumatic compression vs. intermittent pneumatic compression alone in this context . PATIENTS AND METHODS This was a r and omized , double-blind , placebo-controlled superiority trial . Patients aged at least 40 years undergoing abdominal surgery were r and omized to receive either fondaparinux 2.5 mg or placebo  s.c . for 5 - 9 days , starting 6 - 8 h postoperatively . All patients received intermittent pneumatic compression . The primary efficacy outcome was venous thromboembolism up to day 10 . The main safety outcomes were major bleeding and all-cause mortality . Follow-up lasted 32 days . RESULTS Of the 1309 patients r and omized , 842 ( 64.3 % ) were evaluable for efficacy . The venous thromboembolism rate was 1.7 % ( 7/424 ) in the fondaparinux-treated patients and 5.3 % ( 22/418 ) in the placebo-treated patients ( odds ratio reduction 69.8 % ; 95 % confidence interval 27.9 - 87.3 ; P = 0.004 ) . Fondaparinux significantly reduced the proximal deep vein thrombosis rate from 1.7 % ( 7/417 ) to 0.2 % ( 1/424 ; P = 0.037 ) . Major bleeds occurred in 1.6 % ( 10/635 ) and 0.2 % ( 1/650 ) of fondaparinux-treated and placebo-treated patients , respectively ( P = 0.006 ) , none being fatal or involving a critical organ . By day 32 , eight patients ( 1.3 % ) receiving fondaparinux and five ( 0.8 % ) receiving placebo had died . CONCLUSIONS In patients undergoing abdominal surgery and receiving intermittent pneumatic compression , fondaparinux 2.5 mg reduced the venous thromboembolism rate by 69.8 % as compared to pneumatic compression alone , with a low bleeding risk as compared to placebo Deep-vein thrombosis ( DVT ) and pulmonary embolism ( PE ) represent life-threatening postoperative complications frequently responsible for in-hospital mortality following total knee arthroplasty ( TKA ) . Mechanical prophylaxis in the form of a foot pump offers an alternative to pharmacological and physical therapy . The aim of this prospect i ve and r and omised study was to examine the clinical efficacy of the A-V Impulse ( AVI ) system in reduction of soft-tissue swelling of the lower limb following a TKA . A total of 80 patients undergoing cemented TKA between September 2005 and December 2006 were r and omised into two groups of 40 patients ( n¹ = 40 , n² = 40 ) during the 16-month study period . All patients received a subcutaneous dose of low molecular weight heparin ( LMWH ) ( Enoxaparin/Clexane ® 40 mg ) once daily beginning 24 hours prior to the operation . The mean age for the groups n¹ and n² were 68.93 and 68.15 years , respectively .  The reduction of soft-tissue swelling in the n¹ group was significantly higher ( p < 0.05 ) compared with n² . Evaluation of body mass index ( BMI ) with regard to the average reduction of soft-tissue swelling showed no significant influence ( p < 0.05 ) . The better function of the operated knee in group AVI was a significant predictor for improved agility and mobility ( p < 0.01 ) . No complications were reported for the application of the AVI . No ultrasonographic evidence of DVT or PE was found in any of the 80 patients during the investigative time period of eight days . After three months , there was no evidence of a symptomatic DVT BACKGROUND Anticoagulation , the use of sequential compression devices on the lower extremities perioperatively , and early ambulation are thought to reduce the incidence of venous thromboembolism ( VTE ) postoperatively and are recommended to reduce VTE risk . However , the evidence on which this recommendation has been based is not particularly strong . We have demonstrated that even a large , multicenter cohort with carefully collected prospect i ve data is inadequate to provide sufficient evidence to support , or refute , this recommendation . METHODS Longitudinal Assessment of Bariatric Surgery participants from 10 centers in the United States who underwent their first bariatric surgery between March 2005 and December 2007 constituted the study group . We examined the ability to address the question of whether anticoagulation therapy , in addition to sequential compression , reduces the 30-day incidence of VTE or death sufficiently to recommend the use of prophylactic anticoagulation , a therapy that is not without risk . RESULTS Of 4416 patients , 396 ( 9.0 % ) received sequential compression alone , and 4020 also received anticoagulation therapy . The incidence of VTE within 30 days of surgery was low ( .25 % among those receiving sequential compression alone and .47 % when anticoagulation therapy was added ) , and the 30-day incidence of death was also low ( .25 % versus .34 % , respectively , P = .76 , for sequential compression alone versus sequential compression plus anticoagulation therapy ) . Estimates of the number of cases required to address 
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Moderate quality evidence suggests that combining IPC and pharmacological prophylaxis , compared with IPC or pharmacological prophylaxis alone , decreases the incidence of DVT when compared to compression , and incidence of PE when compared to anticoagulation .
Moderate quality evidence suggests that there is no difference between combined and single modalities in the incidence of PE when compared with compression alone and DVT when compared with anticoagulation alone .
Moderate quality evidence suggests the addition of pharmacological prophylaxis to IPC , increased the risk of bleeding compared to IPC alone , a side effect not observed for IPC when added to pharmacological prophylaxis ( very low quality evidence ) , as expected for a physical method of thromboprophylaxis .