title: Effect of supine posture on airway blood flow and pulmonary function in stable heart failure.
abstract: BACKGROUND
  The aim of this study was to determine the relationship between body position, pulmonary function (PF) and bronchial blood flow (Q(aw)) in a group of heart failure (HF) and control subjects.
  
  
  METHODS
  Thirty-six subjects were studied: 24 stable, ambulatory HF patients (HF: LVEF=27±6%, age=65±9 yr) and 12 age- and sex-matched controls (CTRL: LVEF=60±7%, age=62±8 yr). Measures of Q˙(aw) (soluble gas method) and PF were collected upright and following 30min in the supine position.
  
  
  RESULTS
  Q˙(aw) was similar between groups and remained unchanged with body position. Declines in forced vital capacity (FVC) and forced expiratory volume in 1s (FEV1) with the supine position were observed in both groups; declines in forced expiratory flow 25-75% (FEF(25-75)) and FEF 75% (FEF75) with the supine position were observed in the HF group only. Changes in Q˙(aw) were related to changes in PF only in the HF patient groups (ΔFVC, % predicted, r = -0.45, p<0.04, ΔFEV1 r = -0.61, p<0.01, ΔFEV1% predicted, r = -0.45, p<0.04).
  
  
  CONCLUSIONS
  These data demonstrate that relationships between postural changes in Q˙(aw) and PF exist only in the HF population and that the bronchial circulation may contribute to postural PF decline in HF.
authors: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA.
authors: Maile L
authors: ML
authors: Ceridon
authors: Norman R
authors: NR
authors: Morris
authors: Thomas P
authors: TP
authors: Olson
authors: Sophie
authors: S
authors: Lalande
authors: Bruce D
authors: BD
authors: Johnson
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008168:Lung / Q000098:blood supply* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011652:Pulmonary Circulation / Q000502:physiology*; D012129:Respiratory Function Tests / Q000379:methods; D016683:Supine Position / Q000502:physiology