Age‐dependent effects of thoracic and capillary blood volume distribution on pulmonary artery pressure and lung diffusing capacity

Aging is associated with pulmonary vascular remodeling and reduced distensibility. We investigated the influence of aging on changes in cardiac output (Q), mean pulmonary artery pressure (mPAP), and lung diffusing capacity in response to alterations in thoracic blood volume. The role of pulmonary sm...

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Published inPhysiological reports Vol. 6; no. 17; pp. e13834 - n/a
Main Authors Coffman, Kirsten E., Boeker, Matthew G., Carlson, Alex R., Johnson, Bruce D.
Format Journal Article
LanguageEnglish
Published United States John Wiley & Sons, Inc 01.09.2018
John Wiley and Sons Inc
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Summary:Aging is associated with pulmonary vascular remodeling and reduced distensibility. We investigated the influence of aging on changes in cardiac output (Q), mean pulmonary artery pressure (mPAP), and lung diffusing capacity in response to alterations in thoracic blood volume. The role of pulmonary smooth muscle tone was also interrogated via pulmonary vasodilation. Nine younger (27 ± 4 years) and nine older (71 ± 4 years) healthy adults reached steady‐state in a Supine (0°), Upright (+20°), or Head‐down (−20°) position in order to alter thoracic blood volume. In each position, echocardiography was performed to calculate mPAP and Q, and lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO) was assessed. Next, 100 mg sildenafil was administered to reduce pulmonary smooth muscle tone, after which the protocol was repeated. mPAP (P ≤ 0.029) and Q (P ≤ 0.032) were lower in the Upright versus Supine and Head‐down positions, and mPAP was reduced following sildenafil administration (P = 0.019), in older adults only. SV was lower in the Upright versus Supine and Head‐down positions in both younger (P ≤ 0.008) and older (P ≤ 0.003) adults. DLCO and DLNO were not greatly altered by position changes or sildenafil administration. However, the DLNO/DLCO ratio was lower in the Supine and/or Head‐down positions (P ≤ 0.05), but higher following sildenafil administration (P ≤ 0.007), in both younger and older adults. In conclusion, older adults experience greater cardiopulmonary alterations following thoracic blood volume changes, and pulmonary smooth muscle tone plays a role in resting mPAP in older adults only. Furthermore, mPAP is an important determinant of pulmonary capillary blood volume distribution (DLNO/DLCO), regardless of age. We investigated the influence of aging on changes in cardiac output (Q), mean pulmonary artery pressure (mPAP), and lung diffusing capacity in response to alterations in thoracic blood volume as well as pulmonary vasodilation via sildenafil. We found that older adults experience greater cardiopulmonary alterations following thoracic blood volume changes, and pulmonary smooth muscle tone plays a role in resting mPAP in older adults only. Furthermore, mPAP is an important determinant of pulmonary capillary blood volume distribution (DLNO/DLCO), regardless of age.
Bibliography:KEC was supported by Mayo Clinic Graduate School of Biomedical Sciences and NIH grant F31HL131076. This study was funded by NIH grant HL71478. Access to the Clinical Research and Trials Unit (CRTU) was available through Mayo Clinic's Center for Clinical and Translational Science (CCaTS). CCaTS is funded by the National Institute of Health's (NIH) Clinical and Translational Science Awards (CTSA) program, grant number UL1TR000135, from the National Center for Advancing Translational Sciences (NCATS).
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ISSN:2051-817X
DOI:10.14814/phy2.13834