Arterial pressure oscillations are not associated with muscle sympathetic nerve activity in individuals exposed to central hypovolaemia.
J Physiol
; 589(Pt 21): 5311-22, 2011 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-21930599
ABSTRACT
The spectral power of low frequency oscillations of systolic arterial pressure (SAP(LF)) has been used as a non-invasive surrogate of muscle sympathetic nerve activity (MSNA) in both experimental and clinical situations. For SAP(LF) to be used in this way, a relationship must exist between SAP(LF) and MSNA within individuals during sympathetic activation. Using progressive central hypovolaemia to induce sympathetic activation, we hypothesised that SAP(LF) would correlate with MSNA in all subjects. ECG, beat-by-beat arterial pressure and MSNA were recorded in humans (n = 20) during a progressive lower body negative pressure (LBNP) protocol designed to cause presyncope in all subjects. Arterial pressure oscillations were assessed in the low frequency (LF; 0.04-0.15 Hz) domain using a Fourier transform. For the entire group, SAP(LF), MSNA burst frequency, and total MSNA increased during LBNP. Values for coefficients of determination (r(2)) describing the linear associations of SAP(LF) with MSNA burst frequency and total MSNA were 0.73 and 0.84, but rose to 0.89 and 0.98 when curvilinear fits were used, indicating that the relationship is curvilinear rather than linear. Associations between SAP(LF) and MSNA within each individual subject, however, varied widely for both MSNA burst frequency and total MSNA, whether derived by linear (r(2) range, 1.7 × 10(-6) to 0.99) or polynomial (r(2) range, 0.09 to 1.0) regression analysis. Similar results were obtained when relationships between low frequency oscillations in diastolic arterial pressure and MSNA were evaluated. These results do not support the use of low frequency oscillations in arterial pressure as a non-invasive measure of sympathetic outflow for individual subjects during sympathetic activation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sistema Nervoso Simpático
/
Pressão Sanguínea
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Hipovolemia
Tipo de estudo:
Guideline
/
Risk_factors_studies
Limite:
Adult
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Female
/
Humans
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Male
Idioma:
En
Revista:
J Physiol
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos