Leg Blood Volume Research Articles

The validity and reliability of continuous-wave near-infrared spectroscopy for the assessment of leg blood volume during an orthostatic challenge

Near-infrared spectroscopy (NIRS) can potentially be used to assess the cardiovascular autonomic system by monitoring orthostatic challenge-induced shifts in lower limb blood volume. However, in order to be of clinical utility the test must be valid, reliable, and relatively simple to conduct. PurposeTo induce lower limb blood volume shifts using a 10 min 70° head-up tilt, and: (1) in the soleus, determine the validity of an inexpensive continuous wave (cw)-NIRS device by comparing to a criterion frequency-domain (fd-) NIRS device, (2) determine the between-day reliability of soleus assessments obtained from cw-NIRS and fd-NIRS; and, (3) compare the between-day reliability for fd-NIRS assessments obtained at the soleus (standard) and gastrocnemius (simpler alternative). MethodsFifteen non-smoking healthy adults were tested on 3 different mornings, under standardized conditions, separated by a maximum of 7 days. Total haemoglobin concentration (tHb) was continuously monitored bi-laterally in the medial soleus using cw-NIRS and fd-NIRS. For site comparison, tHb was measured in the medial gastrocnemius using fd-NIRS. Results(1) The area under the curve (AUC) for cw-NIRS and fd-NIRS assessments at the soleus were not significantly different (p = 0.619). (2) The criterion (0.75) intra-class correlation coefficient (ICC) was exceeded for both cw-NIRS and fd-NIRS. (3) The criterion ICC was exceeded for both soleus and gastrocnemius assessments. ConclusionContinuous-wave NIRS can be used to monitor orthostatic stress-induced shifts in lower leg blood volume with acceptable validity and reliability. This orthostatic test may present a relatively simple and inexpensive approach for assessing the cardiovascular autonomic nervous system.

Effect of Hyperhydration on the Cardiovascular Responses to an LBNP Presyncopal Challenge

PURPOSETo determine the effects of hyperhydration on heart rate, blood pressure, leg blood volume and forearm blood flow during a lower body negative challenge to presyncope.METHODSNine subjects (Age = 20.2 ± 1.3 yrs, Weight = 75.3 ± 21.1 kgs) participated in two graded LBNP (Lower Body Negative Pressure) tests to pre‐syncope while forearm blood flow (FBF), heart rate (HR), blood pressure (BP), and leg blood volume were measured. Each subject was tested in a control trial (with no fluid ingestion), and after consumption of a hypervolemia‐inducing beverage (NaCl solution of 4.9g per kg of body weight in 10mL of grape flavored Propel). Treatment order was randomized for all subjects. A cumulative stress index (CSI) was subsequently calculated (minutes completed x box pressure) to assess changes in orthostatic tolerance between the control and fluid ingestion LBNP. For all trials in the LBNP chamber, subjects were tested at LBNP levels of −20 mmHg, −40 mmHg, and −60 mmHg for three minutes at each trial, and then an additional increase of −10 mmHg every three minutes until pre‐syncopal symptoms appeared. Forearm blood flow was measured using venous occlusion plethysmography. Near‐infrared spectroscopy (Portamon, Artinis, Inc.) in the right calf muscle was used to determine lower leg blood volume.RESULTSThere were no significant differences in CSI between the hyperhydration (619.8 ± 55.2mmHg.min) and control conditions (640.0 ± 70.3 mmHg.min). Furthermore, the change in forearm blood flow, lower leg blood volume, and heart rate during the LBNP hyperhydration trial were not different from the control trial.CONCLUSIONIngestion of a hypervolemia‐inducing beverage did not alter orthostatic tolerance or the cardiovascular responses to an orthostatic challenge. This suggests that either a larger volume of fluid or a fluid with a different composition needs to be ingested to improve orthostatic tolerance.

Normal Diaphragmatic and Rib Cage Breathing: Effects on Venous Return Patterns in Monitored Human Subjects

Objective: To measure the natural prevalence of diaphragmatic (DB) and rib cage breathing (RCB) and their respective effects on venous return in human subjects. Methods: Sixteen subjects (9 men, 4 women, and 3 boys, aged 10 to 83) were monitored for breathing patterns with stretch transducers on the upper chest, the mid chest, and the abdomen at the umbilicus. Monitoring for venous flow patterns was carried out with infrared transducers on the forehead, sampling superior vena cava (SVC) volume, and with leg electrodes, sampling leg blood volume (LBV) by electrical impedance. Recordings were made during 3 minute periods of sitting and standing after knee bending exercise. Results: DB, indicated by inward movement of the mid chest with breathing, accounted for 0 - 46% of breathing activity in all positions (One subject had no DB) this breathing pattern correlated with an overflow of venous volume into the SVC. RCB, consisting of upper chest expansion, mid chest constriction, and inward abdominal movement at the umbilicus - accounted for 9 - 37% of breathing activity. This breathing pattern correlated with extraction of LBV, superimposed on an underlying sinusoidal fluctuation of LBV. Conclusions: DB and RCB are normal, prevalent breathing patterns augmenting venous return to the heart. SVC backflow and rhythmic LBV were observed for the first time.

Effect of Localized Exercise on Blood Volume and Orthostatic Tolerance

Previous studies have documented connections between orthostatic intolerance and changes in whole-body blood volume after exercise. However, few studies have looked at whether localized exercise has a direct influence on blood volume in the exercised limb and how that might influence orthostatic tolerance. PURPOSE: To determine the effects of localized exercise on blood volume within the gastrocnemius muscle and orthostatic tolerance. METHODS: Nine subjects (Age = 20.2 ± 1.3 yrs, Weight = 75.3 ± 21.1 kgs) participated in three graded LBNP (Lower Body Negative Pressure) tests to pre-syncope while forearm blood flow (FBF), heart rate (HR), blood pressure (BP), and leg blood volume were measured. Near-Infrared Spectroscopy (Portamon, Artinis, Inc.) in the right calf muscle was used to determine lower leg blood volume. Near-Infrared Spectroscopy measures continuous changes in blood volume by measuring the change in oxygenated (O2Hb) and deoxygenated (Hhb) hemoglobin concentration to determine total hemoglobin (tHb) concentrations Each subject was tested in a control trial (with no exercise), after exercise in the left leg (contralateral) of the exercise, and in the right leg (ipsilateral) of the exercise in a randomized order. Exercise trials were performed using an isokinetic dynamometer (Cybex Norm, Cybex Inc.) immediately before the LBNP testing. Subjects performed three sets of 30 plantar flexions with a 30 second rest period between sets. Cumulative stress index (CSI) was subsequently calculated (minutes completed x box pressure) to assess changes in orthostatic tolerance between the control and exercise conditions. RESULTS: CSI significantly decreased (p<0.05) after exercise in both the right and left leg trials (Right = 452.9 ± 51.8 mmHg.min; Left = 556.2±58.3mmHg.min) compared to control values (Control = 640.0 ± 70.3 mmHg.min) suggesting reduced orthostatic tolerance with leg exercise. Furthermore, during LBNP blood volume in the right leg (measured) was similar (P<0.05) after right and left leg exercise ( Right 0 = -4.2 ± 2.2, -70 mmHg = -16.0 ± 3.4; Left 0 = -2.7 ± 1.0, -70 mmHg 24.4 ± 4.0) CONCLUSION: Localized exercise in the lower leg significantly reduced orthostatic tolerance. However, it appears as if blood volume in the exercised leg is similar to blood volume in the non-exercised leg, suggesting no direct influence of localized exercise on venous compliance and LBNP tolerance.

Orthostatic leg blood volume changes assessed by near‐infrared spectroscopy

Standing up shifts blood to dependent parts of the body, and blood vessels in the leg become filled. The orthostatic blood volume accumulation in the small vessels is relatively unknown, although these may contribute significantly. We hypothesized that in healthy humans exposed to the upright posture, volume accumulation in small blood vessels contributes significantly to the total fluid volume accumulated in the legs. Considering that near-infrared spectroscopy (NIRS) tracks postural blood volume changes within the small blood vessels of the lower leg, we evaluated the NIRS-determined changes in oxygenated (Δ[O(2)Hb]), deoxygenated (Δ[HHb]) and total haemoglobin tissue concentration (Δ[tHb]) and in total leg volume by strain-gauge plethysmography during 70 deg head-up tilt (HUT; n = 7). In a second experiment, spatial and temporal reproducibility were evaluated with three NIRS probes applied on two separate days (n = 8). In response to HUT, an initially fast increase in [O(2)Hb] was followed by a gradual decline, while [HHb] increased continuously. The increase in [tHb] during HUT was closely related to the increase in total leg volume (r(2) = 0.95 ± 0.03). After tilt back, [O(2)Hb] declined below and [HHb] remained above baseline, whereas all NIRS signals gradually returned to baseline. Spatial heterogeneity was observed, and for two probes [tHb] was highly correlated between days (r(2) = 0.92 ± 0.09 and 0.91 ± 0.12), but less for the third probe (r(2) = 0.44 ± 0.36). The results suggest a non-linear accumulation of blood volume in the small vessels of the leg, with an initial fast phase followed by a more gradual increase at least partly contributing to the relocation of fluid during orthostatic stress.

Effects of respiratory muscle unloading on leg muscle oxygenation and blood volume during high-intensity exercise in chronic heart failure

Blood flow requirements of the respiratory muscles (RM) increase markedly during exercise in chronic heart failure (CHF). We reasoned that if the RM could subtract a fraction of the limited cardiac output (QT) from the peripheral muscles, RM unloading would improve locomotor muscle perfusion. Nine patients with CHF (left ventricle ejection fraction = 26 +/- 7%) undertook constant-work rate tests (70-80% peak) receiving proportional assisted ventilation (PAV) or sham ventilation. Relative changes (Delta%) in deoxy-hemoglobyn, oxi-Hb ([O2Hb]), tissue oxygenation index, and total Hb ([HbTOT], an index of local blood volume) in the vastus lateralis were measured by near infrared spectroscopy. In addition, QT was monitored by impedance cardiography and arterial O2 saturation by pulse oximetry (SpO2). There were significant improvements in exercise tolerance (Tlim) with PAV. Blood lactate, leg effort/Tlim and dyspnea/Tlim were lower with PAV compared with sham ventilation (P < 0.05). There were no significant effects of RM unloading on systemic O2 delivery as QT and SpO2 at submaximal exercise and at Tlim did not differ between PAV and sham ventilation (P > 0.05). Unloaded breathing, however, was related to enhanced leg muscle oxygenation and local blood volume compared with sham, i.e., higher Delta[O2Hb]% and Delta[HbTOT]%, respectively (P < 0.05). We conclude that RM unloading had beneficial effects on the oxygenation status and blood volume of the exercising muscles at similar systemic O2 delivery in patients with advanced CHF. These data suggest that blood flow was redistributed from respiratory to locomotor muscles during unloaded breathing.

The role of muscle pump in the development of cardiovascular drift

This study examined the role of muscle pump in the development of cardiovascular drift (CVdrift) during cycling. Twelve healthy males (23.4 +/- 0.5 years, mean +/- SE) exercised for 90 min with 40 and 80 pedal revolutions per minute (rpm) at the same oxygen consumption, in two separate days. CVdrift was developed in both conditions as indicated by the drop in stroke volume (SV) and the rise in heart rate (HR) from the 20th min onwards (Delta SV = -16.2 +/- 2.0 and -17.1 +/- 1.0 ml beat(-1); Delta HR = 18.3 +/- 2.0 and 17.5 +/- 3.0 beats min(-1) for 40 and 80 rpm, respectively, P < 0.05) but without difference between conditions. Mean cardiac output (CO2 rebreathing) was 14.7 +/- 0.3 l min(-1) and 15.0 +/- 0.3 l min(-1), and mean arterial pressure was 100.0 +/- 1.0 mmHg and 96.7 +/- 0.8 mmHg for 40 and 80 rpm, respectively, without significant changes over time, and without difference between conditions. Electromyographic activity (iEMG) was lower throughout exercise with 80 rpm (35.6 +/- 1.2% and 11.0 +/- 1.0% for 40 and 80 rpm, respectively). Similarly, total hemoglobin, determined with near-infrared spectroscopy (NIRS) was 58.0 +/- 0.8 (AU) for 40 rpm and 53.0 +/- 1.4 (arbitrary units) for 80 rpm, from 30th min onwards (P < 0.05), an indication of lower leg blood volume during the faster pedal rate condition. Thermal status (rectal and mean skin temperature), blood and plasma volume changes, blood lactate concentration, muscle oxygenation (NIRS signal) and the rate of perceived exertion were similar in the two trials. It seems that muscle pump is not an important factor for the development of CVdrift during cycling, at least under the present experimental conditions.

Studies of autonomic response patterns: Rationale and methods

This report briefly summarizes the results of eighteen years of research on the measurement of autonomic functions in human subjects during rest, and presents a discussion of hypotheses and methodology for the study of autonomic response patterns. Most of the report is devoted to a discussion of instrumentation and methods of measurement employed in current investigations. The following variables are measured: electrical resistance of palmar skin; respiration rate; finger, face, and axillary temperatures; heart rate, potentials and rhythms; changes in finger and leg blood volume; systolic and diastolic blood pressures; stroke volume of the heart; pupillary diameter; stomach and lower bowel motility; salivary output; and selected muscle action potentials. Most responses are amplified and recorded continuously and simultaneously by means of chopper type Offner amplifiers. Pupillary diameter and systolic and diastolic blood pressure are time sampled; the former by means of a Bolex motion picture camera, the latter by means of a Gilson automatic blood pressure recorder. Stomach motility is recorded continuously by means of a new method—a magnetometer which remotely detects the movements of a small ingested magnet. Lower bowel motility is recorded by a bipolar electrode.

Related Trends in Locomotor and Respiratory Muscle Oxygenation during Exercise

We investigated the potential effect of respiratory muscle work on leg muscle oxygenation without artificial intervention in non-endurance-trained young subjects and searched for the range of intensity when this effect could occur. We simultaneously monitored accessory respiratory and leg muscle oxygenation patterns with near-infrared spectroscopy (NIRS) in 15 healthy young men performing maximal incremental exercise on a cycle ergometer. Pulmonary gas exchange was measured. The respiratory compensation point (RCP) was determined. Oxygenation (RMO2) and blood volume (RMBV) of the serratus anterior (accessory respiratory muscle) and of the vastus lateralis (LegO2 and LegBV) were monitored with NIRS. The breakdown point of accessory respiratory muscle oxygenation (BPRMO2) and the accelerated (BP1LegO2) and attenuated fall (BP2LegO2) in leg muscle oxygenation were detected. BPRMO2 occurred at approximately 85% .VO2max and was related to RCP (r = 0.88, P < 0.001). BP2LegO2 appeared at approximately 83% .VO2max and was related to RCP (r = 0.57, P < 0.05) and with BPRMO2 (r = 0.64, P = 0.01). From BP2LegO2 to maximal exercise, LegBV was significantly reduced (P < 0.05). In active subjects exercising at heavy exercise intensities, we observed that the appearance of the accelerated drop in accessory respiratory muscle oxygenation-associated with high ventilatory level-was related with the attenuated fall in leg muscle oxygenation detected with near-infrared spectroscopy. This suggests that the high oxygen requirement of respiratory muscle leads to limited oxygen use by locomotor muscles as demonstrated in endurance-trained subjects. The phenomenon observed was associated with reduced leg blood volume, supporting the occurrence of leg vasoconstriction. These events appeared not only at maximal exercise but onward above the respiratory compensation point.

Splanchnic hyperemia and hypervolemia during Valsalva maneuver in postural tachycardia syndrome

Prior work demonstrated dependence of the change in blood pressure during the Valsalva maneuver (VM) on the extent of thoracic hypovolemia and splanchnic hypervolemia. Thoracic hypovolemia and splanchnic hypervolemia characterize certain patients with postural tachycardia syndrome (POTS) during orthostatic stress. These patients also experience abnormal phase II hypotension and phase IV hypertension during VM. We hypothesize that reduced splanchnic arterial resistance explains aberrant VM results in these patients. We studied 17 POTS patients aged 15-23 yr with normal resting peripheral blood flow by strain gauge plethysmography and 10 comparably aged healthy volunteers. All had normal blood volumes by dye dilution. We assessed changes in estimated thoracic, splanchnic, pelvic-thigh, and lower leg blood volume and blood flow by impedance plethysmography throughout VM performed in the supine position. Baseline splanchnic blood flow was increased and calculated arterial resistance was decreased in POTS compared with control subjects. Splanchnic resistance decreased and flow increased in POTS subjects, whereas splanchnic resistance increased and flow decreased in control subjects during stage II of VM. This was associated with increased splanchnic blood volume, decreased thoracic blood volume, increased heart rate, and decreased blood pressure in POTS. Pelvic and leg resistances were increased above control and remained so during stage IV of VM, accounting for the increased blood pressure overshoot in POTS. Thus splanchnic hyperemia and hypervolemia are related to excessive phase II blood pressure reduction in POTS despite intense peripheral vasoconstriction. Factors other than autonomic dysfunction may play a role in POTS.

Reciprocal splanchnic-thoracic blood volume changes during the Valsalva maneuver.

The Valsalva maneuver is frequently used to test autonomic function. Previous work demonstrated that the blood pressure decrease during the Valsalva maneuver relates to thoracic hypovolemia, which may preclude pressure recovery during phase II, even with normal resting peripheral vasoconstriction. We hypothesized that increased regional blood volume, specifically splanchnic hypervolemia, accounts for the degree of thoracic hypovolemia during the Valsalva maneuver. We studied 17 healthy volunteers aged 15-22 yr. All had normal blood volumes by dye dilution. Subjects also had normal vascular resistance while supine as well as normal vasoconstrictor responses during 35 degrees upright tilt. We assessed changes in estimated splanchnic, pelvic-thigh, and lower leg blood volume, along with thoracic blood volume shifts, by impedance plethysmography before and during the Valsalva maneuver performed in the supine position. Early increases in splanchnic blood volume dominated the regional vascular changes during the Valsalva maneuver. The increase in splanchnic blood volume correlated well (r2 = 0.65, P < 0.00001) with the decrease in thoracic blood volume, there was less correlation of the increase in pelvic blood volume (r2 = 0.21, P < 0.03), and there was no correlation of the increase in leg blood volume (r2 = 0.001, P = 0.9). There was no relation of thoracic hypovolemia with blood volume or peripheral resistance in supine or upright positions. Thoracic hypovolemia during the Valsalva maneuver is closely related to splanchnic hyperemia and weakly related to regional changes in blood volume elsewhere. Changes in baseline splanchnic vascular properties may account for variability in thoracic blood volume changes during the Valsalva maneuver.

Redistribution of regional and organ blood volume and effect on cardiac function in relation to upright exercise intensity in healthy human subjects.

To determine the effect of relative exercise intensity on organ blood volume and its relation to cardiac function, changes in relative blood volume and cardiac function were monitored with radionuclide techniques in 14 healthy volunteers. After labeling the subject's red cells with technetium 99m, we acquired data at rest, zero-load cycling, and at 50%, 75%, and 100% of maximal oxygen uptake. From rest to zero-load cycling, leg blood volume decreased 32 +/- 2% (mean +/- SEM), whereas relative end-diastolic blood volume increased 9.6 +/- 1.2%, and lung blood volume increased 18 +/- 2%, suggesting that the lungs may act as a blood volume buffer during periods of acutely increased venous return. With relative increasing exercise, leg blood volume stabilized, and then the blood volume in the abdominal organs decreased, further augmenting cardiopulmonary blood volume; leg blood volume and abdominal blood volume decreased by 23 +/- 2% and 19 +/- 2% from baseline, respectively, whereas thoracic blood volume increased 38 +/- 4%. In the abdomen, large decreases in blood volume were observed in the spleen (46 +/- 2%), kidney (24 +/- 4%), and liver (18 +/- 4%). In contrast, lung blood volume increased 50 +/- 4%, with the upper lung fields increasing more than the lower. Blood sampling revealed an increase in the hematocrit level by 4.3 +/- 0.4 units at peak exercise that paralleled the decrease in splenic blood volume (r2 = -0.64, p less than 0.001), suggesting a role for the spleen in augmenting cardiovascular performance by the release of concentrated red blood cells into general circulation. We conclude that upright exercise results in marked blood volume shifts from the legs and abdominal organs to the heart and lungs in a dynamic process correlating closely with oxygen consumption.

Plasma volume changes with upright tilt: studies in hypertension and in syncope.

ArticlePlasma volume changes with upright tilt: studies in hypertension and in syncope.R C Tarazi, H J Melsher, H P Dustan, and E D FrohlichR C Tarazi, H J Melsher, H P Dustan, and E D FrohlichPublished Online:01 Feb 1970https://doi.org/10.1152/jappl.1970.28.2.121MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByClinical Use of Impedance Cardiography for Hemodynamic Assessment of Early Cardiovascular Disease and Management of Hypertension28 April 2020 | High Blood Pressure & Cardiovascular Prevention, Vol. 27, No. 3The Effect of Electrical Stimulation of the Calf Muscle on Leg Fluid Accumulation over a Long Period of Sitting20 July 2017 | Scientific Reports, Vol. 7, No. 1Orthostatic leg blood volume changes assessed by near-infrared spectroscopy28 March 2012 | Experimental Physiology, Vol. 97, No. 3Using impedance cardiography with postural change to stratify patients with hypertension28 April 2011 | Therapeutic Advances in Cardiovascular Disease, Vol. 5, No. 3A definition of normovolaemia and consequences for cardiovascular control during orthostatic and environmental stress7 January 2010 | European Journal of Applied Physiology, Vol. 109, No. 2Using Impedance Cardiography to Detect Subclinical Cardiovascular Disease in Women With Multiple Risk Factors: A Pilot StudyPreventive Cardiology, Vol. 12, No. 2A Systematic Review of the Prothrombotic Effects of an Acute Change in PostureChest, Vol. 132, No. 4A New Approach for Low-Cost Noninvasive Detection of Asymptomatic Heart Disease at RestPreventive Cardiology, Vol. 10, No. 1Using Impedance Cardiography to Assess Left Ventricular Systolic Function via Postural Change in Patients With Heart Failure3 August 2009 | Progress in Cardiovascular Nursing, Vol. 20, No. 4Dobutamine-inducible left ventricular obstruction: head-up tilt and autonomic balanceInternational Journal of Cardiology, Vol. 87, No. 2-3Edward D. Frohlich, MD A Conversation About Hypertension: From Bedside to Bench and ReturnCongestive Heart Failure, Vol. 8, No. 6Forearm vascular responses during orthostatic stress in control subjects and patients with posturally related syncopeClinical Autonomic Research, Vol. 10, No. 2Assessment of capillary fluid shifts during orthostatic stress in normal subjects and subjects with orthostatic intoleranceClinical Autonomic Research, Vol. 9, No. 2Is Absolute Hypovolemia a Risk Factor for Vasovagal Response to Head-Up Tilt?Pacing and Clinical Electrophysiology, Vol. 16, No. 4Vascular adjustment and fluid reabsorption in the human forearm during elevationEuropean Journal of Applied Physiology and Occupational Physiology, Vol. 66, No. 5Cardiovascular and Catecholamine Responses to Head-Up Tilt in the Diagnosis of Recurrent Unexplained Syncope in Elderly Patients27 April 2015 | Journal of the American Geriatrics Society, Vol. 39, No. 7Changes in the impedance cardiogram occurring with change in posture in patients with heart diseaseInternational Journal of Cardiology, Vol. 20, No. 3Effect of hydration on some orthostatic and haematological responses to head-up tiltEuropean Journal of Applied Physiology and Occupational Physiology, Vol. 55, No. 2Plasma volumes, noradrenaline levels and renin activity during posture changes in end-stage renal failureClinical Physiology, Vol. 4, No. 2Cardio-respiratory effects of change of body positionCanadian Anaesthetists’ Society Journal, Vol. 30, No. 4The pharmacokinetics of furazlocillin in healthy humans1 February 1983 | Journal of Pharmacokinetics and Biopharmaceutics, Vol. 11, No. 1Mechanisms governing the postural response and baroreceptor abnormalities in chronic congestive heart failure: effects of acute and long-term converting-enzyme inhibition.Circulation, Vol. 66, No. 1Acute effects of hemodialysis on echographic-determined cardiac performance: Improved contractility resulting from serum increased calcium with reduced potassium despite hypovolemic-reduced cardiac outputAmerican Heart Journal, Vol. 103, No. 3Total circulatory capacity in the rat. Effects of epinephrine and vasopressin on compliance and unstressed volume.Circulation Research, Vol. 49, No. 4Effect of hemodialysis on blood volume distribution and cardiac output.Hypertension, Vol. 3, No. 3Blood pressure response to hemodialysis.Hypertension, Vol. 3, No. 3Pathogenesis of Essential Hypertension2 July 2016 | Angiology, Vol. 30, No. 2Travail féminin et orthostatismeSozial- und Präventivmedizin SPM, Vol. 19, No. 4Plasma volume changes with long-term beta-adrenergic blockadeAmerican Heart Journal, Vol. 82, No. 6Changes in blood and plasma volumes during growthThe Journal of Pediatrics, Vol. 78, No. 2Increased Cardiac Output as a Contributory Factor in Experimental Renal Hypertension in DogsCirculation Research, Vol. 27, No. 5 More from this issue > Volume 28Issue 2February 1970Pages 121-6 https://doi.org/10.1152/jappl.1970.28.2.121PubMed5413296History Published online 1 February 1970 Published in print 1 February 1970 Metrics

The Volume and Distribution of Blood in Patients with Varicose Veins

The total blood volume, total hemoglobin, and the blood volume in the legs, both in horizontal and vertical position, were measured by chromium51-labelled red cells. Non-varicose controls and patients with varicose veins were examined before and after operation.Patients with varicose veins had a larger total blood volume and more hemoglobin than the controls. After radical operation this difference decreased.The leg blood volume was large in patients with varicose veins and was normalized after operationThe implications of the disadvantageous distribution of blood in the varicose veins are discussed with emphasis on the central hemodynamics and the physical work capacity.