Alterations in forearm position and environmental temperature influences the segmental volume expansion during venous occlusion plethysmography – special attention on hand circulation

Abstract

The volume expansion rate in a particular segment is dependent not only on arterial inflow. Segmental differences in capacity for venous expansion results in redistribution of blood to and from a segment, thus influencing the results obtained.

Differential effects of age on large artery stiffness and minimal vascular resistance in normotensive and mildly hypertensive individuals

“…This methodology has been shown to result in maximal vasodilation and hyperaemic flow (Conway, ; Takeshita & Mark, ) and corresponds to approximately 15‐fold increase from resting flow. Also, the exclusion of the hand circulation is essential to avoid arterio‐venous shunts (Vedung et al ., ). The blood flow and R min values reported in our study are in line with those from other investigations performed with similar protocols (Ridout et al ., ; Mathiassen et al ., ).…”

“…However, this approach does not completely abolish vascular tone as maximal vasodilatation is only obtained following at least 10 min of ischaemia (Takeshita & Mark, ; Lauer et al ., ) with a further reduction in vascular tone induced by skin heating (Johnson et al ., ). Also, the circulation of the hand must be excluded to avoid the disturbance from arterio‐venous shunts (Lenders et al ., ; Vedung et al ., ). Taking these important considerations into account, peripheral minimum vascular resistance has never been compared to PWV.…”

Measurement of peripheral blood flow in patients with peripheral artery disease: Methods and considerations

“…Highest segmental volume expansion rates occur with the strain gauge placed on limb at the location of maximal circumference. 8,62 The strain gauge should be placed on the investigated limb over the area of maximal circumference. For pre-post testing, measure the distance between the location of maximal circumference of the calf or forearm and an anatomical landmark such as the olecranon process and lateral malleolus, respectively.…”

“…Calf and forearm blood flow increases as room temperature increases from 13°C to 20°C and 20°C to 38°C, independent of limb position. 8,62 Perform VOP measurement in a thermoneutral room setting (20°C to 25°C).…”

“…This represents the rate and/or rate of change of volume expansion for the area under the strain gauge, which is collectively referred to in the literature as blood flow values. 62 Blood flow values are determined by calculating the slope between beat complexes ( Figure 1B). Assuming proper measurement, the predominant source of error during analysis is the number of beat complexes selected to calculate slope.…”