***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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    Input: BACKGROUND Venous stasis caused by immobility is an important risk factor for deep vein thrombosis following surgery and lower limb trauma , in bed-ridden medical patients , and in high-risk long distance air travelers . A safe and convenient method for reducing venous stasis would be useful in patients while in hospital and after discharge during their rehabilitation . SUBJECTS AND METHODS 49 healthy subjects aged 51 - 76 were seated for 4 hours during which they received mild electrical stimulation of the calf , or sole of the foot ( plantar muscles ) .  Popliteal and femoral venous blood flow velocities were measured via doppler ultrasound . The non-stimulated lower extremity served as the simultaneous control . Subjects completed a question naire regarding their acceptance and tolerance of the electrical stimulation . RESULTS There was a significant increase in venous femoral and popliteal blood flow for both calf ( p < 0.035 , p < 0.003 ) , and plantar muscles ( p < 0.0001 , p < 0.009 ) on the stimulated side compared to the unstimulated side . The magnitude of the effect was similar for calf and plantar muscle stimulation . Subjects did not find the experience uncomfortable , and would use an electrical stimulator if told by their physician that they were at risk for developing blood clots . CONCLUSIONS Mild electrical stimulation of the feet , as well as the calf , is a safe effective and convenient method for counteracting venous stasis and therefore has the potential to reduce the risk of deep vein thrombosis and pulmonary embolism for subjects who are immobilized In a prospect i ve trial of preventing deep vein thrombosis  electrical stimulation of the calf muscles of one leg was used in 110 patients undergoing major surgery .  Deep vein thrombosis was detected by means of the 125I-fibrinogen uptake test in nine of the stimulated legs and in 23 of the unstimulated legs . It is suggested that this technique , which is both simple and effective , should be used on all patients undergoing major surgery Bed rest poses an increased risk factor for a potentially fatal venous thromboembolism ( VTE ) . Lack of activation of the calf muscle pump during this resting period gives rise to venous stasis which may lead to deep vein thrombosis ( DVT ) development . Our aim was to investigate the effects that 4h of bed rest have on the lower limb hemodynamics of healthy subjects and to what extent electrically elicited contractions of the calf muscles can alleviate these effects . Outcome variables included popliteal vein blood flow and heart rate . Primary results indicated that the resting group experienced a significant decline in popliteal venous blood flow of approximately 47 % with approximately 13 % decrease in heart rate . The stimulated groups maintained a significantly higher venous blood flow and heart rate . Volume flow in the contralateral limb remained constant throughout the study and was comparable to that of the stimulated limb 's recovery flow . The results suggest that even short periods of bed rest can significantly reduce lower limb blood flow which could have implication s for DVT development . Electrically elicited calf muscle contractions significantly improve lower limb blood flow and can alleviate some debilitating effects of bed rest This week , a series of four articles considers the place of the r and omised controlled trial as we approach the second century of experience with the concept . Its basic principle is genuine uncertainty as to which treatment arm of the trial it would be in a patient 's best interests to enter . This is not necessarily an easy concept to transmit , The purpose of this study was to determine whether 2,500-Hz sine-wave electrical stimulation modulated at 50 bursts per second producing grade d muscular responses affects blood flow .  Healthy volunteer subjects were assigned r and omly to an Experimental group ( n = 14 ) that received bursts of electrical stimulation to the gastrocnemius muscle or to a  Control group ( n = 14 ) that received no treatment .  Using a Doppler device , pulsatility index ( PI ) values were determined for multivariate statistical analysis . Electrical stimulation grade d to simulate isometric torques equivalent to 10 % and then 30 % of the subjects ' isometric maximum voluntary contraction result ed in respective mean increases in PI values of 20.5 % and 19.6 % over prestimulation PI values . We found no significant difference in PI values between the two levels of torque . No significant change in PI values was found among the Control group subjects . Our results indicate that electrical stimulation , as used in this study , can alter the blood flow to the muscle being stimulated BACKGROUND Compression devices have been shown to prevent thromboembolic disease . However , the pressures generated may not be the same as the ones recommended by the manufacturer . The purpose of this study is to investigate a new sequential compression device with feedback to maintain optimal therapy , and to determine whether therapy is improved with this new device . PATIENTS AND METHOD A series of 50 patients undergoing elective total hip arthroplasty at a major tertiary-care hospital with a special interest in joint replacement were enrolled prospect ively . In addition to pharmacological prophylaxis for thromboembolic disease , all patients received compression from a modified device .  Maximum pressures generated and the rate of pressure rise in each of the 3 compartments within the device sleeves were measured and the results compared with data from historical controls . RESULTS We considered therapy to be ideal when in a particular compression cycle all chambers of both right and left sleeves reach within 10 % of their target pressures at within 10 % of their target pressure rise rates . The average patient received this ideal therapy 88 % of the time that the new trial sequential compression device was operating . This represents a dramatic improvement over previous devices . CONCLUSIONS The new device allows dramatically improved pressures within the device because of a feedback loop that allows dynamic control of each chamber 's pressure . Improved consistency of delivery should make it easier to accurately assess the true benefits of mechanical prophylaxis with a sequential compression device Background Patients post total hip arthroplasty ( THA ) remain at high risk of developing Deep Vein Thrombosis ( DVT ) during the recovery period following surgery despite the availability of effective pharmacological and mechanical prophylactic methods . The use of calf muscle neuromuscular electrical stimulation ( NMES ) during the hospitalised recovery period on this patient group may be effective at preventing DVT . However , the haemodynamic effectiveness and comfort characteristics of NMES in post-THA patients immediately following surgery have yet to be established . Methods The popliteal veins of 11 patients , who had undergone unilateral total hip replacement surgery on the day previous to the study , were measured using Doppler ultrasound during a 4 hour neuromuscular electrical stimulation ( NMES ) session of the calf muscles . The effect of calf muscle NMES on peak venous velocity , mean venous velocity and volume flow were compared to resting values . Comfort was assessed using a 100 mm non-hatched visual analogue scale taken before application of NMES , once NMES was initiated and before NMES was withdrawn . Results In the operated limb NMES produced increases in peak venous velocity of 99 % compared to resting . Mean velocity increased by 178 % compared to resting and volume flow increased by 159 % compared to resting . In the un-operated limb , peak venous velocity increased by 288 % , mean velocity increased by 354 % and volume flow increased by 614 % compared to basal flow ( p<0.05 in all cases ) . There were no significant differences observed between the VAS scores taken before the application of NMES , once NMES was initiated and before NMES was withdrawn ( p=.211 ) . Conclusions NMES produces a beneficial hemodynamic response in patients in the early post-operative period following orthopaedic surgery . This patient group found extended periods of calf-muscle NMES tolerable . Trial registration Clinical Trials.gov BACKGROUND Current methods of posttraumatic thromboprophylaxis ( heparins and sequential compression devices ) are inadequate . New methods should be tested . Muscle electrostimulation ( MEST ) has been used over the years with mixed-but predominantly encouraging- results for a variety of conditions , including prevention of deep venous thrombosis ( DVT ) . It has not been tested in multiple trauma patients . METHODS Trauma patients with Injury Severity Score higher than 9 who were admitted to the intensive care unit and had a contraindication for prophylactic heparinization were r and omized to groups MEST and control .  MEST patients received 30-minute MEST sessions twice daily for 7 to 14 days . Venous flow velocity and venous diameter were measured by duplex venous scan . Venography-or , if not available , duplex-was used to evaluate the presence of proximal and peripheral DVT between days 7 and 15 . RESULTS After exclusions , 26 MEST and 21 control patients completed the study and received outcome evaluation by venography ( 25 ) or duplex ( 22 ) . Three patients in each group developed proximal DVT ( 11.5 % vs 14 % , P = .79 ) , and an additional 4 ( 15 % ) MEST group and 3 ( 14 % ) control group patients developed peripheral DVT ( P = .96 ) . There was no difference in venous flow velocity or venous diameter between the groups . CONCLUSIONS MEST was not effective in decreasing DVT rates in major trauma patients Neuromuscular electrical stimulation ( NMES ) refers to the application of current pulses , through surface or implanted electrodes to trigger generation of a neural action potential train to produce artificial muscle contraction in the associated muscle . In surface NMES pre-gelled electrodes are placed on the skin surface over the motor point of the muscle of interest , and is a completely non-invasive technique . Graduated compression stockings ( GCS ) and b and aging facilitate venous return initiated by a physiological calf-muscle contraction . We hypothesised that an NMES-elicited artificial calf muscle contraction would augment venous return from the lower limbs and that the use of NMES in conjunction with a GCS would result in increased augmentation . The aims of this study were Background : The venous stasis of soleal vein during surgery may be an important factor in the development of deep vein thrombosis ( DVT ) . The stimulation of calf muscle during surgery may help in preventing DVT . The present study is conducted to evaluate the role of peroperative calf muscle electrostimulation in prevention of DVT in patients undergoing surgeries around the hip joint . Material s and Methods : The study comprised 200 patients undergoing surgeries around the hip joint . The patients having risk factors ( such as previous myocardial infa rct ion , malignancies , paraplegia or lower limb monoplegia , previous history of DVT or varicose veins , etc . ) for the development of DVT were excluded . They were r and omized into two groups : 100 cases were given peroperative calf muscle electrostimulation for DVT prophylaxis ( Group A ) and the remaining 100 patients were taken as controls without any prophylaxis ( Group B ) . The color Doppler ultrasound was performed to exclude pre-existing DVT and on 7th day postoperative to find out the incidence of DVT in both the groups . Results : Two patients among Group A and six patients among Group B demonstrated DVT on ultrasonography , but the difference was not found to be statistically significant ( P=0.279 ) . None of the patients had any clinical evidence of DVT . Conclusion : The role of peroperative calf muscle electrostimulation for DVT prophylaxis remains controversial . The risk of developing DVT in patients undergoing surgeries around the hip joint is very less in patients analysed in our series Summary This study compares the safety and effectiveness of two methods for the prophylaxis of  post-operative thromboembolism in neurosurgical patients : A : low-dose heparin ( 5,000 IU × 2 s.c . ) started preoperatively and continued daily for one week post-operatively , and B : per-operative electrical calf muscle stimulation with groups of impulses plus post-operative dextran infusions every other day for one week . Neurosurgical patients aged 40 years or more with normal laboratory coagulation values and operated under general anaesthesia were included . The 125:I-fibrinogen uptake test ( FUT ) was used for screening and phlebography for verification of deep venous thrombosis ( DVT ) . 122 patients entered the study and 104 completed the prophylactic protocol , 58 in group A and 46 in group B. The two groups were comparable according to pre-operative data and distribution of diagnoses.89 patients completed screening for post-operative DVT . We found an overall incidence of 5/49 ( 10 percent ) DVT in group A and 5/40 ( 13 percent ) in group B , compared to a frequency of 32–50 percent for controls without prophylaxis reported in the literature 6 , 16 , 18 . In spite of prophylaxis our patients with intracranial neoplasms and intracranial vascular disease showed a relatively higher incidence of DVT , 4/23 ( 17 percent ) and 4/14 ( 29 percent ) respectively , compared to patients with spinal diagnoses 2/25 ( 8 percent ) . In combination with cranial diagnoses paretic lower limbs meant an apparent risk factor , 4/7 ( 57 percent ) . However , paretic limbs appearing in cases with spinal disorders did not predetermine an unsuccessful prophylaxis , 2/14 ( 14 percent).Blood loss , transfusion requirements and post-operative complications did not differ significantly between the two prophylactic groups . It is concluded that both methods reduce the 
    Output:
    
Review of these articles showed that neuromuscular electrical stimulation increases venous blood flow and is generally associated with an acceptable tolerability , potentially leading to good patient compliance .
Conclusion Neuromuscular electrical stimulation increases venous blood flow and is well tolerated , but current evidence does not support a role for neuromuscular electrical stimulation in thromboprophylaxis .