{'fraction_non_alphanumeric': 0.03026634382566586, 'fraction_numerical': 0.005447941888619854, 'mean_word_length': 4.924731182795699, 'pattern_counts': {'":': 0, '<': 2, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The Physiological Effect of Graded Compression Stockings on Blood Flow in the Lower Limb: An Assessment with Colour Doppler Ultrasound

Objectives: To assess the physiological effect of low-pressure graded compression stockings (GCS) on the blood flow of the lower limb with the use of colour Doppler. Design: A randomised controlled study. Setting: X-ray Department in a teaching hospital. Patients: Forty-five healthy, adult, voluntary subjects. Method: Subjects were randomised into three groups to either wear thigh- or knee-length GCS of the same type or no stockings. The diameter and cross-sectional area of the femoral and popliteal veins and the peak venous velocities were measured with colour Doppler before the application of GCS and after 20 min bed rest with the stockings in situ. Results: Measurements showed a significant increase of the peak velocity in the femoral vein with thigh-length GCS (p<0.002). There was a significant decrease of the popliteal vein diameter and cross-sectional area with thigh-length GCS (p<0.05). There was no significant change in the knee-length GCS group and the control group, in which patients did not wear stockings. A paired t-test was used to determine the significance of the changes. Conclusions: Thigh-length GCS have an effect of increasing venous peak velocity in the femoral vein, hence decreasing venous stasis. Furthermore, they decrease the dilatation of the popliteal vein, which may reduce the risk of intimal tears occurring, which may contribute to venous thrombogenesis. Other methods can given more information in assessing the effect of various lengths of stocking on venous stasis.