Noninvasive, quantitative determination of muscle blood flow in man by a combination of venous-occlusion plethysmography and computed tomography

Abstract

Because of the lack of non-invasive methods for measuring muscle blood flow, quantitative investigations of blood flow in the skeletal muscle of hypertensive subjects are rare. We therefore developed a new method for the determination of muscle blood flow noninvasively and quantitatively by a combination of computed tomography and venous occlusion plethysmography (strain-gauge method). At two sites on one forearm (p = site of the largest diameter, d = 1 cm proximal to the epicondyle lat.) the volumes of tissues [Vt = total volume, VM = muscle volume, VSk = bone volume, VR = residual volume = Vt - (VM + VSk)] were determined by computed tomograms and total forearm blood flow (Fp and Fd, respectively in ml/100 ml tissue x min) measured by strain-gauge plethysmography. After correcting for the bone volume at the different sites, Fp and Fd were transformed into the absolute influx rates of blood volume (Qp and Qd). From Qp and Qd and the different tissue volumes, the muscle blood flow (FM in ml/100 ml muscle x min) could be calculated: (formula; see text) Results thus derived were compared with data from the literature Cooper et al. (17). At rest there was neither a significant difference in Fp (own results: 3.62 +/- 1.67, Cooper: 3.25 +/- 1.42 ml/100 ml tissue x min, means +/- S.D.) nor in FM (4.08 +/- 2.07 and 3.66 +/- 1.57 ml/100 ml muscle x min, respectively), however, Fp and FM were significantly different (p less than 0.05). In the mean, FM was 13% greater than Fp, range: -40 to +38% (Cooper 15%, range: -17 to +43%). The individual difference could not be predicted by any of the parameters. Testing the procedure by means of a pharmacological agent (clonidine) with known effects on muscle blood flow (no change) and skin blood flow (decrease) revealed the correct reproduction of this hemodynamic pattern with our method. The usual identification of total with muscle blood flow would have led to false conclusions.

Physiologically based pharmacokinetic modeling of arterial – antecubital vein concentration difference

“…al. [56]measured human forearm muscle blood flow using 133 Xe washout and found values of 1.6 to 1.8 ml/min/100 gm, similar to the PKQuest PBPK value of 2.2. Weber et.…”

Resting peripheral blood flow in normal pregnancy and in pre-eclampsia

“…The technique is based on the principles put forward by Whitney [13], and has been described in detail elsewhere [14]. Plethysmography, which is well established as a non-invasive means of assessing limb blood flow, has been used on non-pregnant subjects [13,14], women with normal pregnancy [15] and patients with essential hypertension [16]. It has also been used to study endothelial-dependent vascular responses to pharmacological agents [11].…”

Veränderungen der Flüssigkeitsfiltrationskapazität und des Blutflusses nach Tourniquet bei Knieoperationen in Spinalanästhesie

“…Hiatts et al zeigten, daß die Meßmethode mit einem Variationskoeffizient von 8-9% ähnlich reproduzierbare Ergebnisse liefert wie Doppler Flußmessungen. In der Literatur werden arterielle Ruheblutflußwerte in der Extremität von 2,3 [35], 2,4 [20], 3,6 ml min −1 100 ml Gewebe −1 [44] angegeben. Die etwas höheren Ausgangsblutflußwerte des Beins mit Tourniquet können unserer Meinung nach auf das zugrunde liegende Knietrauma und die damit verbunden Schmerzen zurückgeführt werden.…”

“…Die Volumenänderungen der Extremität werden lediglich auf Höhe des Dehnungsmeß-streifens erfaßt, wobei zwischen Haut, subkutanem Gewebe und Skelettmuskel nicht unterschieden werden kann. Bei Berücksichtigung der Volumenverteilung am Unterschenkel konnten Weber et al zeigen, daß der Skelettmuskelblutfluß durchschnittlich um 13% unterschätzt wird, wobei eine große interindividuelle Variabilität von −40% bis 38% bestand [44].…”