Limits...
Are the orthostatic fluid shifts to the calves augmented in autonomic failure?

Thijs RD, Kamper AM, van Dijk AD, van Dijk JG - Clin. Auton. Res. (2009)

Bottom Line: Multiple regression analysis was used to examine the effect of AF on orthostatic fluid shifts after adjustment for potential confounders.Patients did not differ from controls with respect to the increase of calf volume after 5 min HUT.No correlation was found between the degree of orthostatic hypotension and the orthostatic calf volume change in AF.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, Postal Zone J3-R, PO Box 9600, 2300 RC, Leiden, The Netherlands. r.d.thijs@lumc.nl

ABSTRACT

Background: In autonomic failure (AF), blood pressure (BP) falls upon standing which is commonly ascribed to defective vasoconstriction and excessive pooling. Observations on the amount of pooling in AF are contradictory.

Methods: We evaluated pooling using strain-gauge plethysmography (SGP) during head-up tilt (HUT) with a parachute harness fixed to the tilt table to avoid muscle tension in the lower limbs and thus to maximise pooling. 23 healthy subjects and 12 patients with AF were tilted for 5 min. BP and calf volume changes, as measured by SGP, were measured continuously. Multiple regression analysis was used to examine the effect of AF on orthostatic fluid shifts after adjustment for potential confounders.

Results: Patients did not differ from controls with respect to the increase of calf volume after 5 min HUT. The acute (0-1 min) and the prolonged (1-5 min) phases of calf volume responses to HUT were also similar between patients and controls. No correlation was found between the degree of orthostatic hypotension and the orthostatic calf volume change in AF. In one patient an additional measurement was made before rising from bed in the early morning demonstrating a greater albeit small increase of calf volume upon HUT.

Conclusion: Orthostatic fluid shifts at the level of the calf in AF are not augmented during the course of the day despite marked hypotension. However, a small increase of pooling may be expected when the patient first gets out of bed in the morning probably due to the absence of oedema.

Show MeSH

Related in: MedlinePlus

Time course of calf volume changes in patients (black line) and controls (grey line) as measured by strain-gauge plethysmography during head-up tilt with a parachute harness. Because of a significant influence of sex on calf volume changes, males (left panel) and females (right panel) are depicted separately. Data are presented as mean ± SEM
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2821504&req=5

Fig1: Time course of calf volume changes in patients (black line) and controls (grey line) as measured by strain-gauge plethysmography during head-up tilt with a parachute harness. Because of a significant influence of sex on calf volume changes, males (left panel) and females (right panel) are depicted separately. Data are presented as mean ± SEM

Mentions: As shown in Table 1, patients were significantly older, weighed more and had a greater BMI than controls. Patients and controls were similar with respect to length, baseline calf circumference and supine and tilted heart rate. As expected, BP was significantly lower in the HUT position (Table 1). However, patients did not differ from controls with respect to calf volume changes after 5 min HUT both before and after adjustment for age, sex, weight and BMI (crude 95% CI for the effect of AF: −0.2 to 1.1%, p = 0.2; adjusted 95% CI: −0.8 to 0.7%, p = 0.9; Fig. 1). Calf volume change in the acute (0–1 min) and the prolonged (1–5 min) phase of tilting were also similar between patients and controls both before and after adjustment for age, sex, weight and BMI (Table 2). No correlation was found between the degree of orthostatic hypotension and the orthostatic calf volume change in the patients with AF (r = 0.14, p = 0.7; Fig. 2).Table 1


Are the orthostatic fluid shifts to the calves augmented in autonomic failure?

Thijs RD, Kamper AM, van Dijk AD, van Dijk JG - Clin. Auton. Res. (2009)

Time course of calf volume changes in patients (black line) and controls (grey line) as measured by strain-gauge plethysmography during head-up tilt with a parachute harness. Because of a significant influence of sex on calf volume changes, males (left panel) and females (right panel) are depicted separately. Data are presented as mean ± SEM
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2821504&req=5

Fig1: Time course of calf volume changes in patients (black line) and controls (grey line) as measured by strain-gauge plethysmography during head-up tilt with a parachute harness. Because of a significant influence of sex on calf volume changes, males (left panel) and females (right panel) are depicted separately. Data are presented as mean ± SEM
Mentions: As shown in Table 1, patients were significantly older, weighed more and had a greater BMI than controls. Patients and controls were similar with respect to length, baseline calf circumference and supine and tilted heart rate. As expected, BP was significantly lower in the HUT position (Table 1). However, patients did not differ from controls with respect to calf volume changes after 5 min HUT both before and after adjustment for age, sex, weight and BMI (crude 95% CI for the effect of AF: −0.2 to 1.1%, p = 0.2; adjusted 95% CI: −0.8 to 0.7%, p = 0.9; Fig. 1). Calf volume change in the acute (0–1 min) and the prolonged (1–5 min) phase of tilting were also similar between patients and controls both before and after adjustment for age, sex, weight and BMI (Table 2). No correlation was found between the degree of orthostatic hypotension and the orthostatic calf volume change in the patients with AF (r = 0.14, p = 0.7; Fig. 2).Table 1

Bottom Line: Multiple regression analysis was used to examine the effect of AF on orthostatic fluid shifts after adjustment for potential confounders.Patients did not differ from controls with respect to the increase of calf volume after 5 min HUT.No correlation was found between the degree of orthostatic hypotension and the orthostatic calf volume change in AF.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, Postal Zone J3-R, PO Box 9600, 2300 RC, Leiden, The Netherlands. r.d.thijs@lumc.nl

ABSTRACT

Background: In autonomic failure (AF), blood pressure (BP) falls upon standing which is commonly ascribed to defective vasoconstriction and excessive pooling. Observations on the amount of pooling in AF are contradictory.

Methods: We evaluated pooling using strain-gauge plethysmography (SGP) during head-up tilt (HUT) with a parachute harness fixed to the tilt table to avoid muscle tension in the lower limbs and thus to maximise pooling. 23 healthy subjects and 12 patients with AF were tilted for 5 min. BP and calf volume changes, as measured by SGP, were measured continuously. Multiple regression analysis was used to examine the effect of AF on orthostatic fluid shifts after adjustment for potential confounders.

Results: Patients did not differ from controls with respect to the increase of calf volume after 5 min HUT. The acute (0-1 min) and the prolonged (1-5 min) phases of calf volume responses to HUT were also similar between patients and controls. No correlation was found between the degree of orthostatic hypotension and the orthostatic calf volume change in AF. In one patient an additional measurement was made before rising from bed in the early morning demonstrating a greater albeit small increase of calf volume upon HUT.

Conclusion: Orthostatic fluid shifts at the level of the calf in AF are not augmented during the course of the day despite marked hypotension. However, a small increase of pooling may be expected when the patient first gets out of bed in the morning probably due to the absence of oedema.

Show MeSH
Related in: MedlinePlus