title: Pulsed-wave Doppler ultrasonographic evaluation of hepatic veins during variable hemodynamic states in healthy anesthetized dogs.
abstract: OBJECTIVE
  To quantify direction and velocity of blood flow in hepatic veins in dogs under different hemodynamic conditions by use of pulsed-wave Doppler ultrasonography.
  
  
  METHODS
  10 healthy dogs.
  
  
  METHODS
  Dogs were anesthetized, and venous flow velocities in the quadrate lobe were measured. Arterial blood pressure, right atrial pressure, pulmonary artery pressure, and cardiac output were measured simultaneously. The timing of each waveform during the cardiac cycle was used to identify velocity profiles. Peak waveform velocities were measured during conditions of light anesthesia with isoflurane (baseline; period 1), cardiovascular depression following administration of high-dose isoflurane and esmolol i.v. (period 2), cardiovascular depression with crystalloid volume expansion (period 3), and high cardiac output induced with dobutamine (period 4). Hemodynamic measurements and maximum waveform velocities were compared among the 4 periods by use of an ANOVA and univariate and multivariate linear regression.
  
  
  RESULTS
  During each study period, 4 distinct, low-velocity waves were identified. Mean velocities recorded during period 1 were as follows: retrograde atrial contraction a-wave, 7.3 cm/s; antegrade systolic S-wave, 15.0 cm/s; retrograde venous return v-wave, 2.7 cm/s; and antegrade diastolic D-wave, 11.4 cm/s. Mean S:D ratio was 1.27. During periods 3 and 4, S-wave velocity increased; D-wave velocity was highest during period 4.
  
  
  CONCLUSIONS
  Consistent hepatic venous velocity profiles were observed in healthy dogs under different hemodynamic conditions. These findings provide baseline values that may be useful in evaluating clinical cases, but further study involving healthy, awake dogs and dogs with cardiac and hepatic diseases is required.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Bryan Todd
authors.initials: BT
authors.lastname: Smithenson
authors.forename: John S
authors.initials: JS
authors.lastname: Mattoon
authors.forename: John D
authors.initials: JD
authors.lastname: Bonagura
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Abrahamsen
authors.forename: William Tod
authors.initials: WT
authors.lastname: Drost
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure; D004285:Dogs / Q000502:physiology*; D006339:Heart Rate; D006503:Hepatic Veins / Q000000981:diagnostic imaging* / Q000502:physiology*; D007530:Isoflurane; D012039:Regional Blood Flow / Q000502:physiology; D013318:Stroke Volume; D018617:Ultrasonography, Doppler, Pulsed
chemical_list: D007530:Isoflurane