The reproducibility of limb blood flow measurements in human volunteers at rest and after exercise by using mercury-in-Silastic strain gauge plethysmography under standardized conditions

Roberts, D.; Tsao, Y; Breckenridge, AM

doi:10.1042/cs0700635

Cited by 69 publications

(56 citation statements)

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“…Plethysmographic measurements of blood flows are precise and reproducible, granting the widespread use of this technique in clinical studies [Norton et al, 1982;Roberts et al, 1986]. The reproducibility of venous occlusion plethysmography has been extensively reported.…”

Section: Measurements Of Regional Blood Flows With Venous Occlusion Pmentioning

confidence: 99%

“…The reproducibility of venous occlusion plethysmography has been extensively reported. The within-subject coefficient of variation for unilateral forearm blood flow (FBF) measurement has been shown to be 10% [Roberts et al, 1986], whereas the bilateral (i.e. flow ratios) within-subject coefficient of variation over 3 sessions one-week apart is about 19% [Petrie et al, 1998].…”

Section: Measurements Of Regional Blood Flows With Venous Occlusion Pmentioning

confidence: 99%

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Sympathetic Vascular Tone in Human Obesity

Agapitov

Sinkey

Dopp

et al. 2004

Journal of Hypertension

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Obesity is associated with increased sympathoactivation that elevates arterial pressure. However, the mechanism linking sympathetic activation to arterial pressure is unclear. Specifically, it has never been demonstrated unequivocally that sympathetically mediated vasoconstriction is increased in obesity. This project tested the hypothesis that sympathetic vascular tone is increased in obese normotensive and hypertensive subjects.The effect of weight loss on sympathetic vascular tone was also assessed.Sympathetic vascular tone was assessed as forearm vasodilatation to intra-arterial phentolamine (α 1/2 -adrenergic receptor antagonist). Pharmacological responses were correlated with skeletal muscle sympathetic nerve activity (mSNA). Obese subjects with and without hypertension had increased mSNA. However, the vasodilatator response to phentolamine was not augmented in obese normotensive and hypertensive subjects versus lean controls. Additionally, weight loss did not alter phentolamine's vasodilatator response, despite reducing mSNA and arterial pressure in obese groups. These results indicate that sympathetic vascular tone is not increased in obesity despite higher mSNA.These studies also assessed forearm resistance vessel function using intra-arterial nitroprusside (nitric oxide donor) and isoproterenol (β 2 -adrenergic receptor agonist). The effects of weight loss on these responses were studied in the obese groups. The response to both vasodilators was blunted, but only in obese hypertensive subjects. Weight loss normalized the response to nitroprusside but not to isoproterenol. This result suggests that obesity-related hypertension is associated with vascular smooth muscle dysfunction, which can be improved by weight loss. Blunted vasodilatation to isoproterenol suggests an abnormality on β 2 -adrenergic receptor-dependent mechanisms that may or may not depend on the endothelium. Also, mental stress-induced forearm vasodilatation was blunted in obese normotensive subjects, which was not normalized by weight loss. 2In conclusion, increased sympathetic nerve activity does not augment forearm sympathetic vascular tone. This dissociation could be due to opposing local factors (e.g. insulin, leptin) or to a different target of limb sympathoactivation (e.g. adipocytes vs. vascular). Sympathetic drive to tissues other than the peripheral circulation may play a more important role in arterial pressure elevation in obesity, either directly or indirectly.Abstract Approved: ____________________________________ Thesis Supervisor ____________________________________

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Section: Measurements Of Regional Blood Flows With Venous Occlusion Pmentioning

confidence: 99%

Section: Measurements Of Regional Blood Flows With Venous Occlusion Pmentioning

confidence: 99%

Sympathetic Vascular Tone in Human Obesity

Agapitov

Sinkey

Dopp

et al. 2004

Journal of Hypertension

View full text Add to dashboard Cite

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“…Reproducibility studies in our laboratory have shown that the coefficient of variation for FBF in six males (aged 18-25 years) measured both over consecutive and alternate days was 10.5%, 18 which is in agreement with previous reports. 19 In this study, FBF was measured as opposed to leg blood flow, despite the use of leg exercise, because higher levels of reproducibility were found for FBF in our laboratory. The measurement of FBF was justified due to the fact that FBF and LBF responses after leg exercise are highly correlated.…”

Section: Cardiovascular Datamentioning

confidence: 99%

Impact of moderate overweight and body composition on postexercise hemodynamic responses in healthy men

Hamer

Boutcher

2006

J Hum Hypertens

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Postexercise hypotension (PEH) is a well-established phenomenon that may contribute to the antihypertensive mechanisms of exercise. The purpose of this study was to examine the impact of moderate overweight on postexercise hemodynamic responses in a group of healthy nonobese men (n ¼ 16, aged 20.471.8 years) with apparently normal cardiovascular function at rest. Forearm blood flow, using strain gauge plethysmography, blood pressure, using a Finapres device, and cardiac output (CO), using impedance cardiography, were measured on a control day and on a separate day following a bout of moderate intensity exercise (20 min at 75% heart rate reserve). Linear regression analysis, adjusted for exercise intensity, revealed that body mass index (BMI) was associated with specific postexercise hemodynamic responses. Higher BMI was associated with greater reductions in CO and stroke volume, but lower reductions in total peripheral resistance. These findings suggest body composition impacts on mechanisms of PEH and should therefore be considered as an important confounding variable in future studies.

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“…Increase in circumference when the venous cuff was inflated is reflected by a change in electrical resistance of the strain gauge. 25 Baseline FBF was then determined by averaging six blood flow measurements. The blood flow wave was collected and analysed through customised data acquisition software (BP Monitor, The University of New South Wales).…”

Section: Subjectsmentioning

confidence: 99%

Acute effect of a single bout of aerobic exercise on vascular and baroreflex function of young males with a family history of hypertension

2010

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The effect of one single bout of aerobic exercise on the vascular and baroreceptor function of individuals with a family history of hypertension was investigated. Forty young males, mean age 21 years, comprising offspring with (FH þ ; n ¼ 20) and without (FH À ; n ¼ 20) a family history of hypertension participated in this study. Acute exercise was performed on a stationary bike for 20 min at 60% of maximal oxygen uptake. Peak forearm blood flow (FBF) was assessed using plethysmography and was determined as the highest blood flow after 5 min of reactive hyperaemia. Cardiopulmonary baroreceptor (CPBR) sensitivity was measured using lowerbody negative pressure (LBNP) for 5 min at À20 mm Hg. CPBR was determined by calculating change of stroke volume and forearm vascular resistance (FVR) at baseline and during LBNP. Carotid baroreceptor (CBR) sensitivity was assessed using neck suction at À20, À40, À60 and À80 mm Hg pressures and was determined from RR interval divided by systolic blood pressure. Augmentation index (AIx), a measure of wave reflection, was assessed using applanation tonometry, and was calculated as the ratio of augmented pressure and pulse pressure. The peak FBF at preexercise was lower in FH þ than in FH À subjects. Twenty minutes of acute cycle exercise resulted in significantly increased peak FBF by 22% in FH þ and by 11% in FH À subjects, whereas peak FVR of both groups decreased by 17% and 11%, respectively. No change occurred in CPBR, CBR or AIx. It is concluded that 20 min of acute cycle exercise normalised baseline FBF and forearm vasodilation during hyperaemia in FH þ subjects.

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The reproducibility of limb blood flow measurements in human volunteers at rest and after exercise by using mercury-in-Silastic strain gauge plethysmography under standardized conditions

Cited by 69 publications

References 0 publications

Sympathetic Vascular Tone in Human Obesity

Sympathetic Vascular Tone in Human Obesity

Impact of moderate overweight and body composition on postexercise hemodynamic responses in healthy men

Acute effect of a single bout of aerobic exercise on vascular and baroreflex function of young males with a family history of hypertension

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