Ultrasound studies of the deep venous system of the leg in pregnancy

• Main Author: Macklon, Nicholas Stephen
• Published: University of Edinburgh 1997
• Subjects: 616.2
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654355

The physiology of venous flow in the proximal deep veins of the leg was studied. A pulsed Doppler ultrasound study of flow phasicity showed respiratory phasicity to be present in 95% of subjects. In the supine position during pregnancy and the puerperium, venous flow velocity was maximal on inspiration but on standing upright it was maximal during expiration indicating that intra-abdominal pressure may influence venous return. The effect of posture was further considered in a longitudinal study of gestational changes in vessel diameter, flow velocity and respiratory fluctuation in flow. In the supine position, vessel diameter increased and flow velocity decreased with advancing gestation. These changes were most marked in the common femoral vein. No significant gestational changes in respiratory flow fluctuation were observed. Flow velocity was significantly slower in the left compared to the right common femoral and popliteal veins, in keeping with the observed increased incidence of left ileofemoral DVT in pregnancy. Adoption of the left lateral position increased flow velocity in both legs throughout pregnancy and postnatally. These novel findings re-evaluate the role of the gravid uterus in determining venous return from the lower limbs. The deep venous system of the leg was studied with duplex Doppler ultrasound in the early and late puerperium. Flow velocity was reduced in the left leg and changes in vessel diameter and flow velocity were observed between the 4<SUP>th</SUP> and 42nd postnatal day. Although flow velocity was significantly lower in the common femoral vein after caesarean section compared to vaginal delivery, no other differences were observed. Duplex Doppler ultrasound was used to study the effects of three types of stocking on venous diameter, flow velocity and respiratory fluctuation in the supine, left lateral and upright positions in non-pregnant women. Graduated stockings reduced vessel diameter at the popliteal vein, but no other effects were observed.