title: Validation of a new transit time ultrasound flowmeter in man.
abstract: OBJECTIVE
  To validate the new CardioMed CM 4000 transit time ultrasound apparatus for intraoperative measurement of volume blood flow in vivo in man.
  
  
  METHODS
  Open, prospective series.
  
  
  METHODS
  Thirteen patients undergoing in situ saphenous vein grafting for chronic critical leg ischaemia and 12 patients subjected to myocardial revascularisation with the internal thoracic artery as coronary bypass.
  
  
  METHODS
  During operations, volume blood flows were measured simultaneously by exsanguination from the cut distal end of the in situ saphenous vein graft or the internal thoracic artery and by the transit time flowmeter equipment. In addition, the feasibility to detect arteriovenous fistula during in situ saphenous vein grafting was examined.
  
  
  RESULTS
  Within the examined blood flow range, the volume blood flow determined by the transit time method corresponded to the directly measured blood flow. For in situ saphenous vein grafts: y = -2.4 + 0.95.x (r = 0.99; 35 measurements in 13 patients), and for internal thoracic artery grafts: y = -9.6 + 1.1.x (r = 0.99; 21 measurements in 12 patients), where y is blood flow determined by transit time, and x is directly measured blood flow by exsanguination (r = correlation coefficient) as calculated by the least squares regression method. Fistula detection was easy and swift.
  
  
  CONCLUSIONS
  The transit time apparatus was simple to use during intraoperative settings and gave fast, precise measurements of volume blood flow.
authors.affiliation: Department of Cardiothoracic and Vascular Surgery T, Aarhus University Hospital, Skejby Sygehus, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Laustsen
authors.forename: E M
authors.initials: EM
authors.lastname: Pedersen
authors.forename: K
authors.initials: K
authors.lastname: Terp
authors.forename: D
authors.initials: D
authors.lastname: Steinbrüchel
authors.forename: H H
authors.initials: HH
authors.lastname: Kure
authors.forename: P K
authors.initials: PK
authors.lastname: Paulsen
authors.forename: H
authors.initials: H
authors.lastname: Jørgensen
authors.forename: W P
authors.initials: WP
authors.lastname: Paaske
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001164:Arteriovenous Fistula / Q000175:diagnosis; D001783:Blood Flow Velocity; D001810:Blood Volume; D001026:Coronary Artery Bypass; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D018056:Hemorheology / Q000295:instrumentation*; D006801:Humans; D007511:Ischemia / Q000601:surgery; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012212:Rheology / Q000295:instrumentation*; D012501:Saphenous Vein / Q000637:transplantation; D013895:Thoracic Arteries / Q000637:transplantation; D014463:Ultrasonography / Q000295:instrumentation*