Forearm vascular resistance responses to the Valsalva maneuver in healthy young and older adults.
Clin Auton Res
; 31(6): 737-753, 2021 12.
Article
em En
| MEDLINE
| ID: mdl-34014418
ABSTRACT
PURPOSE:
Effective end-organ peripheral vascular resistance responses are critical to blood pressure control while upright, and prevention of syncope (fainting). The Valsalva maneuver (VM) induces blood pressure decreases that evoke baroreflex-mediated vasoconstriction. We characterized beat-to-beat forearm vascular resistance (FVR) responses to the VM in healthy adults, evaluated the impact of age and sex on these responses, and investigated their association with orthostatic tolerance (OT; susceptibility to syncope). We hypothesized that individuals with smaller FVR responses would be more susceptible to syncope.METHODS:
Healthy young (N = 36; 19 women; age 25.4 ± 4.6 years) and older (N = 21; 12 women; age 62.4 ± 9.6 years) adults performed a supine 40 mmHg, 20 s VM. Graded 60° head-up-tilt with combined lower body negative pressure continued to presyncope was used to determine OT. Non-invasive beat-to-beat blood pressure and heart rate (finger plethysmography) were recorded continuously. FVR was calculated as mean arterial pressure (MAP) divided by brachial blood flow velocity (Doppler ultrasound) relative to baseline.RESULTS:
The VM produces a distinctive FVR pattern that peaks (+137.1 ± 11.6%) in phase 2B (17.5 ± 0.3 s) as the baroreflex responds to low-pressure perturbations. This response increased with age overall (p < 0.001) and within male (p = 0.030) and female subgroups (p < 0.001). Maximum FVR during the VM was significantly correlated with maximal tilt FVR (r = 0.364; p = 0.0153) and with OT when expressed relative to the MAP decrease in phase 2A (Max FVR (%)/MAP2A-1; r = 0.337; p = 0.0206).CONCLUSION:
This is the first characterization of FVR responses to the VM. The VM elicits large baroreflex-mediated increases in FVR; small FVR responses to the VM may indicate susceptibility to syncope.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Manobra de Valsalva
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Antebraço
Limite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Clin Auton Res
Assunto da revista:
NEUROLOGIA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Canadá