Modulation of pulmonary arterial input impedance during transition from inspiration to expiration

P. Castiglioni, R. Tommasini, M. Morpurgo, M. Di Rienzo

Research output: Contribution to journalArticle


We investigated whether respiration influences pulmonary arterial input impedance during transition from inspiration to expiration in five anesthetized, spontaneously breathing dogs. Impedance (Z) was separately assessed for heart beats occurring in inspiration, in expiration, and during the transition from inspiration to expiration (transitional beat). Transitional beats were scored by the ratio between the fraction of beat falling in expiration and the total beat duration [expiratory fraction (E(fr))] to quantify their position within the transition. In transitional beats, input resistance linearly increased with E(fr); Z modulus at the heart-rate frequency (f(HR)) decreased up to -50% for F(fr) = 50%. Z phase at f(HR) was greater than in inspiration for E(fr) 50%. Unlike blood flow velocity, mean value and first harmonic of pulmonary arterial pressure were correlated to E(fr) and paralleled the changes of input resistance and Z at f(HR). This indicates that respiration influences Z through modifications in arterial pressure. The evidence of important respiratory influences on Z function may help the pathophysiological interpretation of dysfunctions of the right heart pumping action, such as the so-called cor pulmonale.

Original languageEnglish
Pages (from-to)2123-2130
Number of pages8
JournalJournal of Applied Physiology
Issue number6
Publication statusPublished - Dec 1997



  • Intrapleural pressure
  • Pulmonary blood flow
  • Pulmonary blood pressure
  • Pulmonary circulation

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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