Calf exercise in the seated position using a new dynamic biped device increases femoral vein peak velocity up to eight-fold

Background and objective: Lower limb deep venous thrombosis is a common condition with a recognized morbidity and mortality. Hitherto known as a complication in hospitalized patients, anecdotal media reports and scientific trials have raised the profile of the same condition in association with air travel. Although probably multifactorial in aetiology, venous stasis is considered an important and correctable risk factor in the pathogenesis of deep venous thrombosis. The aim of this study was to assess the effectiveness of exercising the calf muscle blood pump in increasing venous blood flow using a new dynamic alternating inflatable biped device (Lymgym™, Lymgym Ltd, UK) which has been designed to be used by air passengers. Methods: Doppler ultrasound was used to assess peak flow velocity in the superficial femoral vein in 30 lower limbs of 15 healthy volunteers with no history of venous disease. Measurements of peak flow velocity were taken at rest in the seated 'coach position' and during calf muscle pump exercises with the device. Results: Peak blood flow velocity was eight-fold higher ( P < 0.0001, Wilcoxon signed rank test) during exercise with the device than at rest. Conclusions: These results show that use of the dynamic alternating biped device (Lymgym™) effectively reduces venous stasis when used in the seated position as defined by measurements of peak venous blood flow. These results provide the scientific justification for further studies assessing the value of this device in reducing the risk of travel-related thrombosis.