title: Effects of respiration on pulmonary venous flow and its clinical applications by Doppler echocardiography.
abstract: OBJECTIVE
  This study was aimed to explore respiratory variations of pulmonary venous flow and its clinical applications and the potential mechanism.
  
  
  METHODS
  Pulsed-wave Doppler waveforms of right-upper pulmonary vein were recorded with Siemens Sequoia 512 in 20 healthy young subjects. Electrocardiogram and respiratory tracing were recorded simultaneously. The inspiratory and expiratory pulmonary venous peak flow velocities of S- and D-waves and their velocity-time integrals (VTIs) were acquired and averaged for five consecutive respiratory cycles, respectively. The ratios of velocities and the VTIs of S- to D-waves (S/D, VTIs/VTId) during inspiration and expiration were calculated.
  
  
  RESULTS
  The velocity and VTI of S-wave did not vary significantly between inspiration and expiration (58.31 cm/sec +/- 9.22 cm/sec, 58.96 cm/sec +/- 7.79 cm/sec, P = 0.221; 16.29 cm +/- 2.59 cm, 16.54 cm +/- 2.18 cm, P = 0.090), while the velocity and VTI of D-wave increased significantly from inspiration to expiration (48.23 cm/sec +/- 8.32 cm/sec, 51.82 cm/sec +/- 8.72 cm/sec, P < 0.0001; 10.84 cm +/- 1.65 cm, 11.66 cm +/- 1.53 cm, P < 0.0001), resulting in significantly decreased ratios of the velocity and the VTI of S- to D-waves from inspiration to expiration (1.23 +/- 0.22, 1.17 +/- 0.27, P < 0.0001; 1.53 +/- 0.31, 1.43 +/- 0.22, P < 0.0001).
  
  
  CONCLUSIONS
  Respiration has significant influence on pulmonary venous flow, which should be taken into account in evaluating left ventricular diastolic function when adopting pulmonary venous flow waveform, especially in diseased settings. The different anatomical positions of left and right heart relative to the thoracic cavity may account for the respiratory variations of pulmonary venous flow.
authors.affiliation: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Yuan
authors.forename: Tie-Sheng
authors.initials: TS
authors.lastname: Cao
authors.forename: Yun-You
authors.initials: YY
authors.lastname: Duan
authors.forename: Hua-Ping
authors.initials: HP
authors.lastname: Jia
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods / Q000706:statistics & numerical data; D011667:Pulmonary Veins / Q000000981:diagnostic imaging* / Q000502:physiology*; D012016:Reference Values; D015656:Respiratory Mechanics / Q000502:physiology*; D055815:Young Adult