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Calf venous compliance measured by venous occlusion plethysmography: methodological aspects.
Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.ORCID-id: 0000-0002-4507-8392
Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US. Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin.
Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för kardiovaskulär medicin. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Hjärt- och Medicincentrum, Kardiologiska kliniken US.
Ekman Biomed Data AB, Gothenburg, Sweden.
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2015 (Engelska)Ingår i: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 115, nr 2, s. 245-56Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

PURPOSE: Calf venous compliance (C calf) is commonly evaluated with venous occlusion plethysmography (VOP) during a standard cuff deflation protocol. However, the technique relies on two not previously validated assumptions concerning thigh cuff pressure (P cuff) transmission and the impact of net fluid filtration (F filt) on C calf. The aim was to validate VOP in the lower limb and to develop a model to correct for F filt during VOP.

METHODS: Strain-gauge technique was used to study calf volume changes in 15 women and 10 age-matched men. A thigh cuff was inflated to 60 mmHg for 4 and 8 min with a subsequent decrease of 1 mmHg s(-1). Intravenous pressure (P iv) was measured simultaneously. C calf was determined with the commonly used equation [Compliance = β 1 + 2β 2 × P cuff] describing the pressure-compliance relationship. A model was developed to identify and correct for F filt.

RESULTS: Transmission of P cuff to P iv was 100 %. The decrease in P cuff correlated well with P iv reduction (r = 0.99, P < 0.001). Overall, our model showed that C calf was underestimated when F filt was not accounted for (all P < 0.01). F filt was higher in women (P < 0.01) and showed a more pronounced effect on C calf compared to men (P < 0.05). The impact of F filt was similar during 4- and 8-min VOP.

CONCLUSIONS: P cuff is an adequate substitute for P iv in the lower limb. F filt is associated with an underestimation of C calf and differences in the effect of F filt during VOP can be accounted for with the correction model. Thus, our model seems to be a valuable tool in future studies of venous wall function.

Ort, förlag, år, upplaga, sidor
2015. Vol. 115, nr 2, s. 245-56
Nationell ämneskategori
Klinisk medicin
Identifikatorer
URN: urn:nbn:se:liu:diva-113393DOI: 10.1007/s00421-014-3009-4ISI: 000347725800003PubMedID: 25272971OAI: oai:DiVA.org:liu-113393DiVA, id: diva2:781611
Tillgänglig från: 2015-01-17 Skapad: 2015-01-17 Senast uppdaterad: 2023-12-28
Ingår i avhandling
1. Cardiovascular regulation in women with vasovagal syncope: With special reference to the venous system
Öppna denna publikation i ny flik eller fönster >>Cardiovascular regulation in women with vasovagal syncope: With special reference to the venous system
2016 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Although vasovagal syncope (VVS) is a common clinical condition the mechanisms behind VVS remain elusive. Upright posture is the major trigger of VVS and lower limb blood pooling affecting cardiac output has been proposed as a major determinant. The overall aim of this thesis was twofold. First, to develop new methodology for calculating limb venous compliance. Second, to study lower limb venous volume load and cardiovascular responses during hypovolemic circulatory stress caused by lower body negative pressure (LBNP) in healthy women and women with VVS, emphasizing compensatory mechanisms to maintain central blood volume.

Net fluid filtration was associated with an underestimation ofvenous compliance. This could be accounted for with a correctionmodel. Further, a new venous wall model made it possible to adopt thevenous pressure-volume curve through the entire pressure range andthus provide a valid characterization of venous compliance.

Calf blood pooling was similar between the groups and was not associated with tolerance to hypovolemic circulatory stress. Venous compliance was reduced at low venous pressures in VVS and correlated with decreased tolerance to circulatory stress. VVS women displayed attenuated sympathetic vasoconstrictor responses during graded circulatory stress, and mobilization of arm capacitance blood as well as capillary fluid absorption from extra- to intravascular space were reduced. Accordingly, more pronounced reductions in cardiac output were found in VVS. Thus, reduced compensatory mechanisms to maintain cardiac output could contribute to the pathogenesis oforthostatic VVS.

In healthy women, rapid pooling in the lower limb was associated with higher tolerance to circulatory stress and more efficient cardiovascular responses, in part due to speed-dependent baroreflex-mediated sympathetic activation. In VVS however, rapid lower limb blood pooling was associated with lower tolerance and deficient cardiovascular responses. No speed-dependent baroreflexmediated sympathetic activation was found in VVS, indicating welldefined differences in cardiovascular regulation already in the initial responses to orthostatic stress.

Ort, förlag, år, upplaga, sidor
Linköping: Linköping University Electronic Press, 2016. s. 86
Serie
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1519
Nationell ämneskategori
Fysiologi Anestesi och intensivvård Annan klinisk medicin Kardiologi
Identifikatorer
urn:nbn:se:liu:diva-126942 (URN)10.3384/diss.diva-126942 (DOI)978-91-7685-793-9 (ISBN)
Disputation
2016-05-13, Berzeliussalen, ingång 65, Campus US, Linköping, 13:00 (Svenska)
Opponent
Handledare
Forskningsfinansiär
Futurum - Akademin för hälsa och vård, Jönköpings län Forskningsrådet i Sydöstra Sverige, FORSSRegion ÖstergötlandHjärt-Lungfonden
Tillgänglig från: 2016-04-08 Skapad: 2016-04-08 Senast uppdaterad: 2023-12-28Bibliografiskt granskad

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Skoog, JohanZachrisson, HeleneLindenberger, MarcusLänne, Toste

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Avdelningen för kardiovaskulär medicinHälsouniversitetetFysiologiska kliniken USCentrum för medicinsk bildvetenskap och visualisering, CMIVMedicinska fakultetenKardiologiska kliniken USThorax-kärlkliniken i Östergötland
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