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Victoria Elizabeth Claydon - One of the best experts on this subject based on the ideXlab platform.
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Intermittent Calf Compression Delays the Onset of Presyncope in Young Healthy Individuals
Frontiers in Physiology, 2020Co-Authors: Brooke C.d. Hockin, Victoria Elizabeth ClaydonAbstract:Orthostatic fluid shifts reduce the effective circulating volume and thus contribute to syncope susceptibility. Recurrent syncope has a devastating impact on quality of life and is challenging to manage effectively. To blunt orthostatic fluid shifts, static calf compression garments are often prescribed to patients with syncope, but have questionable efficacy. Intermittent calf compression, which mimics the skeletal muscle pump to minimize pooling and filtration, holds promise for the management of syncope. We aimed to evaluate the effectiveness of intermittent calf compression for increasing orthostatic tolerance (OT; time to Presyncope). We conducted a randomized single-blind crossover study, in which participants (n=21) underwent three graded, 60° head-up-tilt tests to Presyncope with combined lower body negative pressure on separate days. Low frequency intermittent calf compression (ICLF; 4s on and 11s off) at 0-30mmHg and 0-60mmHg was applied during two tests and compared to a placebo condition where the garment was fitted, but no compression applied. We measured continuous leg circumference changes (strain gauge plethysmography), cardiovascular responses (finger plethysmography; Finometer Pro), end tidal gases (nasal cannula), and cerebral blood flow velocity (CBFv, transcranial Doppler). The 0-60mmHg ICLF increased OT (33±2.2min) compared to both placebo (26±2.4min; p
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are compression stockings an effective treatment for orthostatic Presyncope
PLOS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:Background: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance. Methodology/Principal Findings: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.062.3 min) and calf (29.362.4 min) or ankle (27.663.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject’s calf circumference and shoe size (r=0.780, p=0.004). Conclusions/Significance: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.
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Are compression stockings an effective treatment for orthostatic Presyncope?
PLoS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:BACKGROUND: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance.\n\nMETHODOLOGY/PRINCIPAL FINDINGS: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.0±2.3 min) and calf (29.3±2.4 min) or ankle (27.6±3.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject's calf circumference and shoe size (r = 0.780, p = 0.004).\n\nCONCLUSIONS/SIGNIFICANCE: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.
Clare Louise Protheroe - One of the best experts on this subject based on the ideXlab platform.
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are compression stockings an effective treatment for orthostatic Presyncope
PLOS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:Background: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance. Methodology/Principal Findings: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.062.3 min) and calf (29.362.4 min) or ankle (27.663.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject’s calf circumference and shoe size (r=0.780, p=0.004). Conclusions/Significance: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.
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Are compression stockings an effective treatment for orthostatic Presyncope?
PLoS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:BACKGROUND: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance.\n\nMETHODOLOGY/PRINCIPAL FINDINGS: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.0±2.3 min) and calf (29.3±2.4 min) or ankle (27.6±3.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject's calf circumference and shoe size (r = 0.780, p = 0.004).\n\nCONCLUSIONS/SIGNIFICANCE: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.
Kenichi Iwasaki - One of the best experts on this subject based on the ideXlab platform.
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blunted cutaneous vasoconstriction and increased frequency of Presyncope during an orthostatic challenge under moderate heat stress in the morning
European Journal of Applied Physiology, 2014Co-Authors: Ken Aoki, Yojiro Ogawa, Kenichi IwasakiAbstract:Purpose In normothermia, the tolerance time to Presyncope during an orthostatic challenge is shortened during the early morning. Heat stress reduces tolerance to Presyncope and the degree of cutaneous vasoconstriction prior to Presyncope. However, whether these changes show diurnal variations remains unknown. Therefore, we examined diurnal changes in orthostatic tolerance and cutaneous vascular conductance (CVC) during an orthostatic challenge under moderate heat stress.
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Blunted cutaneous vasoconstriction and increased frequency of Presyncope during an orthostatic challenge under moderate heat stress in the morning
European Journal of Applied Physiology, 2014Co-Authors: Ken Aoki, Yojiro Ogawa, Kenichi IwasakiAbstract:Purpose In normothermia, the tolerance time to Presyncope during an orthostatic challenge is shortened during the early morning. Heat stress reduces tolerance to Presyncope and the degree of cutaneous vasoconstriction prior to Presyncope. However, whether these changes show diurnal variations remains unknown. Therefore, we examined diurnal changes in orthostatic tolerance and cutaneous vascular conductance (CVC) during an orthostatic challenge under moderate heat stress. Methods Each lower body negative pressure (LBNP) under normothermia and whole body heat stress was applied for 7 min or until the appearance of presyncopal symptoms in 16 males at both 08:00 (a.m.) and 17:00 hours (p.m.). Measurements included internal and skin temperatures, forearm skin blood flow, arterial pressure, and heart rate. CVC was calculated as skin blood flow/mean arterial pressure, normalized to CVC prior to LBNP and expressed as %CVC. Results The average tolerance time in eight subjects exhibiting presyncopal symptoms due to LBNP and moderate heat stress was significantly shorter in the a.m. than in the p.m. (3.7 ± 0.8 versus 6.7 ± 0.3 min, respectively; P = 0.005). Neither %CVC during LBNP in these subjects under moderate heat stress nor normothermia were significantly decreased in the a.m. ( P > 0.05, respectively). Conclusions These findings indicate an orthostatic challenge even during moderate heat stress that led to an increase in the frequency of Presyncope, especially in the morning. The reduction in tolerance was accompanied by blunted cutaneous vasoconstriction prior to Presyncope. Hence, diurnal changes in cutaneous vascular responses during combined orthostatic and heat stresses should contribute, at least partly, to heat-induced orthostatic intolerance in the morning.
Anastasia Dikareva - One of the best experts on this subject based on the ideXlab platform.
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are compression stockings an effective treatment for orthostatic Presyncope
PLOS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:Background: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance. Methodology/Principal Findings: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.062.3 min) and calf (29.362.4 min) or ankle (27.663.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject’s calf circumference and shoe size (r=0.780, p=0.004). Conclusions/Significance: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.
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Are compression stockings an effective treatment for orthostatic Presyncope?
PLoS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:BACKGROUND: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance.\n\nMETHODOLOGY/PRINCIPAL FINDINGS: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.0±2.3 min) and calf (29.3±2.4 min) or ankle (27.6±3.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject's calf circumference and shoe size (r = 0.780, p = 0.004).\n\nCONCLUSIONS/SIGNIFICANCE: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.
Carlo Menon - One of the best experts on this subject based on the ideXlab platform.
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are compression stockings an effective treatment for orthostatic Presyncope
PLOS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:Background: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance. Methodology/Principal Findings: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.062.3 min) and calf (29.362.4 min) or ankle (27.663.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject’s calf circumference and shoe size (r=0.780, p=0.004). Conclusions/Significance: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.
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Are compression stockings an effective treatment for orthostatic Presyncope?
PLoS ONE, 2011Co-Authors: Clare Louise Protheroe, Anastasia Dikareva, Carlo Menon, Victoria Elizabeth ClaydonAbstract:BACKGROUND: Syncope, or fainting, affects approximately 6.2% of the population, and is associated with significant comorbidity. Many syncopal events occur secondary to excessive venous pooling and capillary filtration in the lower limbs when upright. As such, a common approach to the management of syncope is the use of compression stockings. However, research confirming their efficacy is lacking. We aimed to investigate the effect of graded calf compression stockings on orthostatic tolerance.\n\nMETHODOLOGY/PRINCIPAL FINDINGS: We evaluated orthostatic tolerance (OT) and haemodynamic control in 15 healthy volunteers wearing graded calf compression stockings compared to two placebo stockings in a randomized, cross-over, double-blind fashion. OT (time to Presyncope, min) was determined using combined head-upright tilting and lower body negative pressure applied until Presyncope. Throughout testing we continuously monitored beat-to-beat blood pressures, heart rate, stroke volume and cardiac output (finger plethysmography), cerebral and forearm blood flow velocities (Doppler ultrasound) and breath-by-breath end tidal gases. There were no significant differences in OT between compression stocking (26.0±2.3 min) and calf (29.3±2.4 min) or ankle (27.6±3.1 min) placebo conditions. Cardiovascular, cerebral and respiratory responses were similar in all conditions. The efficacy of compression stockings was related to anthropometric parameters, and could be predicted by a model based on the subject's calf circumference and shoe size (r = 0.780, p = 0.004).\n\nCONCLUSIONS/SIGNIFICANCE: These data question the use of calf compression stockings for orthostatic intolerance and highlight the need for individualised therapy accounting for anthropometric variables when considering treatment with compression stockings.