Venous pressure in the saphenous vein near the ankle during changes in posture and exercise at different ambient temperatures

Abstract

The venous pressure in the saphenous vein at the ankle was measured in ten healthy subjects (5 men, 5 women) aged 19-33 years during supine posture, orthostasis and cycle ergometer exercise (50 W, 50 rpm). Measurements were made at 20, 28 and 36 degrees C at 50% relative humidity. A custom-built setup consisting of two pressure transducers and a differential amplifier was used to compensate for the hydrostatic effects, temperature influences and movement artefacts that disturbed the pressure measurements. Pressure was lowest in the supine position and varied only slightly with the ambient temperature. The mean pressures were 7 (SEM 1) mmHg [0.9 (SEM 0.13) kPa], 7 (SEM 1) mmHg [0.9 (SEM 0.13) kPa], 4 (SEM 1) mmHg [0.5 (SEM 0.13) kPa] at 20, 28 and 36 degrees C. The venous pressure increased when the subjects were passively tilted from a supine to an upright posture. The rate of the increase was smaller at 20 degrees C than at 28 degrees and 36 degrees C. The final level the pressure reached during motionless standing differed slightly. The mean pressures were 76 (SEM 2) mmHg [10.1 (SEM 0.27) kPa], 79 (SEM 7) mmHg [10.5 (SEM 0.93) kPa] and 75 (SEM 3) mmHg [10.0 (SEM 0.40)] at the three temperatures. When starting exercising, venous pressure decreased within the 1st min to a level which remained virtually constant until the end of exercise. However, this level was found to be temperature dependent. It was lowest at 20 degrees C (26 (SEM 3) mmHg [3.5 (SEM 0.40) kPa]) and increased with temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Response of the human triceps surae muscle to electrical stimulation during varying levels of blood flow restriction

“…For comparative purposes, therefore, the test was performed with venous occlusion only. Based on a supine venous pressure in the saphenous vein of 0.93 kPa (7 mmHg, Stick et al 1993) and estimation of the hydrostatic eects when seated giving rise to pressure in the femoral vein of 4±4.7 kPa (30±35 mmHg), it is likely that an externally applied cu pressure of 6.7 kPa was sucient to induce complete venous occlusion. While this did not in¯uence the ABPI measurements, it is clear that there was an eect on force production during the test, since the ®nal force was 50% less potentiated than in the unoccluded state.…”

Pressure-Induced Upregulation of Preproendothelin-1 and Endothelin B Receptor Expression in Rabbit Jugular Vein In Situ

“…18 -20 In contrast to the situation in the rabbit and human jugular veins, the distal portions of the saphenous vein routinely used for aortocoronary bypass grafting experience much greater changes in blood pressure between 5 and 10 mm Hg in the recumbent position and between 75 and 80 mm Hg on quiet standing (ie, without activation of the muscle pump and at ambient temperature). 22 However, this hemodynamic pressure load (averaging 40 to 50 mm Hg over 24 hours) 23 is by no means as constant as after grafting of the saphenous vein into the coronary circulation, where, in addition to the mean arterial blood pressure of 90 to 100 mm Hg, the anastomosed segments are additionally subjected to a significant outflow resistance, owing to the fact that their lumen is usually much wider than that of the bypassed coronary arteries. Thus, the range of intraluminal pressures to which the isolated perfused rabbit jugular veins were subjected in the present study can be regarded as principally similar to the situation in aortocoronary venous bypass grafts.…”

Rapid prototyped sutureless anastomosis device from self‐curing silk bio‐ink

“…At the lower vessel compression (approximately 25%), the failure occurred due to slippage of the coupler past the seat, whereas at 50% compression and above, the mechanism of failure was tearing of the seat of the external clip. Although all compression settings failed at pressures greater than average physiologically relevant pressure, the 25% compression fitting demonstrated the potential to fail at reported peak physiological pressures . A minimum wall compression greater than 25%, such as 50%, would be recommended to confidently support peak pressures as well as resist failure due to longitudinal strains physiologically relevant to a mobile animal.…”

“…Although all compression settings failed at pressures greater than average physiologically relevant pressure, the 25% compression fitting demonstrated the potential to fail at reported peak physiological pressures. 17,18 A minimum wall compression greater than 25%, such as 50%, would be recommended to confidently support peak pressures as well as resist failure due to longitudinal strains physiologically relevant to a mobile animal.…”