A reassessment of mercury in silastic strain gauge plethysmography for microvascular permeability assessment in man.

Gamble, J.; Gartside, I B; Christ, F.

doi:10.1113/jphysiol.1993.sp019642

Cited by 130 publications

(254 citation statements)

References 19 publications

Supporting

Mentioning

231

Contrasting

Unclassified

Order By: Relevance

“…However, differences in sympathetic activation (e.g., high as opposed to low LBNP, or differences in peripheral resistance) do not seem to affect CFC in the leg during LBNP (Fig. 4) (26), and when CFC is studied with local techniques only, similar values as in the present study have been found, indicating only minor importance of the sympa- (2,11,33). The increased capillary filtration in women may be due to higher levels of estrogen and its effect on the microcirculation (45,54,55).…”

Section: Discussionsupporting

confidence: 79%

Sex-related effects on venous compliance and capillary filtration in the lower limb

Lindenberger

Länne²

2007

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

Recent studies in humans have suggested sex differences in venous compliance of the lower limb, with lower compliance in women. Capillary fluid filtration could, however, be a confounder in the evaluation of venous compliance. The venous capacitance and capillary filtration response in the calves of 12 women (23.2 Ϯ 0.5 years) and 16 men (22.9 Ϯ 0.5 years) were studied during 8 min lower body negative pressure (LBNP) of 11, 22, and 44 mmHg. Calf venous compliance is dependent on pressure and was determined using the first derivative of a quadratic regression equation that described the capacitance-pressure relationship [compliance ϭ ␤ 1 ϩ (2 ⅐ ␤2 ⅐ transmural pressure)]. We found a lower venous compliance in women at low transmural pressures, and the venous capacitance in men was increased (P Ͻ 0.05). However, the difference in compliance between sexes was reduced and not seen at higher transmural pressures. Net capillary fluid filtration and capillary filtration coefficient (CFC) were greater in women than in men during LBNP (P Ͻ 0.05). Furthermore, calf volume increase (capacitance response ϩ total capillary filtration) during LBNP was equivalent in both sexes. When total capillary filtration was not subtracted from the calf capacitance response in the calculation of venous compliance, the sex differences disappeared, emphasizing that venous compliance measurement should be corrected for the contribution of CFC. lower body negative pressure; capillary filtration coefficient; venous capacitance THE VENOUS SECTION OF THE cardiovascular system can be looked upon as a voluminous blood reservoir (70% of total blood volume), designed to preserve a proper inflow of blood into the heart during various cardiovascular adjustments. Thus central venous pressure and filling of the heart may be maintained at a fairly stable level, despite variations in venous blood volume (49). During upright posture, however, the pooling of blood in the veins of the lower part of the body decreases central blood volume and venous return (4, 5, 16). The venous compartment in the legs, rather than the pelvic or abdominal region, seems to have a hemodynamic impact during lower body negative pressure (LBNP) (16), and in studies on men, a greater calf venous compliance has been linked to an increased venous capacitance response with a concomitant reduction in central blood volume (44,56). This, in turn, elicits an increased sympathetic response with higher peripheral resistance and increased heart rate (4, 5, 10, 16, 44, 58). Thus venous compliance of the lower limb may have an impact on cardiovascular responses to orthostatic stress and orthostatic tolerance, although there might be differences between sexes confounding such a link (4).Women are more susceptible to orthostatic stress than men (4,10,13,40,51,58), and in accordance with some findings in the arterial tree, it may be hypothesized that women have greater venous compliance in the lower limbs predisposing to orthostatic intolerance (52). This seems to be refuted however, by recent fi...

show abstract

Section: Discussionsupporting

confidence: 79%

Sex-related effects on venous compliance and capillary filtration in the lower limb

Lindenberger

Länne²

2007

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

show abstract

“…They concluded that the volume increase after this time was due to net capillary fluid filtration in accordance with findings by Schnizer et al (43). The time for completion of the capacitance response gradually diminishes when lower increases in pressures are applied and the time for completion of the capacitance has been found to be well below 2 min, when an increase in transmural pressure of 10 mmHg is applied (13). Furthermore, the duration of the capacitance response is shorter when tissue pressure is reduced compared with methods of venous stasis (23).…”

Section: Methodsmentioning

confidence: 94%

Decreased capillary filtration but maintained venous compliance in the lower limb of aging women

Lindenberger¹,

Länne²

2007

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

There are sex-related differences in venous compliance and capillary filtration in the lower limbs, which to some extent can explain the susceptibility to orthostatic intolerance in young women. With age, venous compliance and capacitance are reduced in men. This study was designed to evaluate age-related changes in venous compliance and capillary filtration in the lower limbs of healthy women. Included in this study were 22 young and 12 elderly women (23.1 Ϯ 0.4 and 66.4 Ϯ 1.4 yr). Lower body negative pressure (LBNP) of 11, 22, and 44 mmHg created defined transmural pressure gradients in the lower limbs. A plethysmographic technique was used on the calf to assess venous capacitance and net capillary filtration. Venous compliance was calculated with the aid of a quadratic regression equation. No age-related differences in venous compliance and capacitance were found. Net capillary filtration and capillary filtration coefficient (CFC) were lower in elderly women at a LBNP of 11 and 22 mmHg (0.0032 vs. 0.0044 and 0.0030 vs. 0.0041 ml ⅐ 100 ml Ϫ1 ⅐ min Ϫ1 ⅐ mmHg Ϫ1 , P Ͻ 0.001). At higher transmural pressure (LBNP, 44 mmHg), CFC increased by ϳ1/3 (0.010 ml ⅐ 100 ml Ϫ1 ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ) in the elderly (P Ͻ 0.001) but remained unchanged in the young women. In conclusion, no age-related decrease in venous compliance and capacitance was seen in women. However, a decreased CFC was found with age, implying reduced capillary function. Increasing transmural pressure increased CFC in the elderly women, indicating an increased capillary susceptibility to transmural pressure load in dependent regions. These findings differ from earlier studies on age-related effects in men, indicating sex-specific vascular aging both in the venous section and microcirculation. capillary filtration coefficient; lower body negative pressure; age A TRANSITION FROM the supine to standing posture leads to a progressive pooling of blood in the compliant veins in the lower part of the body, which produces an immediate circulatory challenge due to the concomitant decrease in thoracic blood volume (5,6,39). Subjects with increased limb venous compliance have been shown to have greater orthostatic intolerance, probably due to an increased venous capacitance (24,36,46), although this relationship has recently been challenged by Hernandez and Franke (18). Venous compliance in the lower limbs decreases with age in men (33,38,39,49), but there is no reason to believe that venous compliance and capacitance are similar in men and women, since a sex difference has been established in young adults (26,30,34). Furthermore, age-related changes might be sex specific, in accordance with age-related changes of arteries, with women having a slower decrease in arterial compliance with age compared with men, an effect probably attributed to estrogen (9, 48). Estrogen has been shown to affect cellular transcription of elastin and collagen, and estrogen-receptors are known to exist in vascular smooth muscle cells (21,22,32).There is a marked capillary fluid filtratio...

show abstract

“…We also measured calf size change and calf blood flow during HUT. Methods were adapted from the work of Gamble et al (15,16) and are summarized in Figure 1. Occlusion cuffs were first placed around the upper limb approximately 10 cm above a strain gauge of appropriate size attached to a Whitney-type strain gauge plethysmograph (Hokanson, Inc, Bellevue, WA, U.S.A.).…”

Section: Methodsmentioning

confidence: 99%

Inappropriate Early Hypotension in Adolescents: A Form of Chronic Orthostatic Intolerance with Defective Dependent Vasoconstriction

Stewart

Weldon

2001

Pediatr Res

View full text Add to dashboard Cite

Instantaneous orthostatic hypotension (INOH) has been reported in children and adolescents as a new entity of orthostatic intolerance in children who underwent rapid standing as an orthostatic stress test. Children with INOH were discovered among patients presenting with symptoms of chronic orthostatic intolerance, which is often related to orthostatic tachycardia. We used head-up tilt table testing at 70°to investigate children presenting with symptoms of chronic orthostatic intolerance. We compared 24 patients aged 12-17 y, with chronic orthostatic intolerance and symptoms for Ն3 mo, with 13 healthy normal control patients. We recorded continuous heart rate, blood pressure, and respiratory rate and used venous occlusion strain gauge plethysmography to measure calf and forearm blood flow while supine and calf blood flow during head-up tilt. Patients with chronic orthostatic intolerance fulfilled criteria for the postural orthostatic tachycardia syndrome. Postural orthostatic tachycardia syndrome patients were divided into two groups by the occurrence of INOH. Supine forearm and calf arterial resistance was decreased in patients with INOH (n ϭ 8) compared with postural orthostatic tachycardia syndrome patients without INOH (n ϭ 16) and compared with control (n ϭ 13). Resting calf venous pressure was elevated, suggesting excess venous filling because of vasodilation. During early head-up tilt, calf blood flow increased markedly in INOH, less in No-INOH, postural orthostatic tachycardia syndrome patients and least in control patients. Flow was temporally related to calf swelling and negatively correlated to hypotension. The data suggest that INOH occurs in patients with chronic orthostatic intolerance and orthostatic tachycardia and is related to rapid caudal blood flow when upright because of a vasoconstrictor defect. INOH has recently been reported as a new entity of orthostatic intolerance in children and adolescents who underwent rapid standing as an orthostatic stress test (1, 2). Data from that original study suggested that some patients developed systolic hypotension whereas others did not. Upright tachycardia was a common feature of all patients. Orthostatic tachycardia with COI has been described at least since 1940 (3) and more recently by investigators designating the syndrome POTS (for postural orthostatic tachycardia syndrome) (4 -6) or COI (7,8) in adults. We and others have described the syndrome in children and adolescents (6, 9 -12), often in the context of the chronic fatigue syndrome (12). We suspect that vascular resistance is lower than healthy control subjects in many COI-POTS patients. We hypothesized that abnormally increased blood flow to the lower extremities in COI-POTS patients during orthostatic challenge related to reduced lower limb resistance causes a precipitous early fall in blood pressureergo INOH. To investigate this hypothesis we used venous occlusion plethysmography to study blood flow supine and during HUT, comparing 24 patients with COI-POTS with 13 healthy control patients....

show abstract

A reassessment of mercury in silastic strain gauge plethysmography for microvascular permeability assessment in man.

Cited by 130 publications

References 19 publications

Sex-related effects on venous compliance and capillary filtration in the lower limb

Sex-related effects on venous compliance and capillary filtration in the lower limb

Decreased capillary filtration but maintained venous compliance in the lower limb of aging women

Inappropriate Early Hypotension in Adolescents: A Form of Chronic Orthostatic Intolerance with Defective Dependent Vasoconstriction

Contact Info

Product

Resources

About