title: Instant myocardial blood flow monitor: its calibration and assessment of flow capacity of the intracoronary shunt tube.
abstract: BACKGROUND
  We developed a new instant regional myocardial blood flow (RMBF) monitor utilizing the thermal diffusion method in which the RMBF value is presented as the value inversely proportional to the thermocouple voltage output (1/V). The purposes of this study were (1) to validate the accuracy of RMBF measurement by the instant RMBF monitor in comparison with the colored microsphere method for calibration; (2) to investigate influences of it on the RMBF; and (3) to assess changes in RMBF caused by the shunt tube insertion.
  
  
  METHODS
  Twenty pigs were used for this study: 4 for comparison between the instant RMBF meter and the colored microsphere method, 4 for validation of reproducibility, and 6 for measurement of RMBF during shunt tube.
  
  
  RESULTS
  The relation between RMBF values obtained by the colored microsphere method and 1/V values by instant RMBF monitor was colored microsphere = 140,992 (1/V)--231 in epicardial layer (R2 = 0.819) and colored microsphere = 111,381 (1/V)--165 in endocardial layer (R2 = 0.693). The correlation coefficient and R2 values between RMBF values measured by both methods were 0.985 and 0.839 in epicardial layer, and 0.963 and 0.679 in endocardial layer, respectively. The RMBF at each layer did not change after the attachment of the monitor. Fifteen minutes after shunt tube insertion, RMBF measured by the colored microsphere method decreased to 31.1% (p = 0.0001) and 33.7% (p = 0.0001) in epicardium and endocardium, respectively, and no difference was observed from the value measured by the instant RMBF monitor.
  
  
  CONCLUSIONS
  This instant RMBF monitor can provide instantaneous and continuous information of RMBF without requiring tissue examination.
authors.affiliation: Department of General and Cardiothoracic Surgery, Kanazawa University School of Medicine, Takaramachi, Japan. h.kamiya@trition.ocn.ne.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kamiya
authors.forename: Go
authors.initials: G
authors.lastname: Watanabe
authors.forename: Taro
authors.initials: T
authors.lastname: Kanamori
authors.forename: Nobuki
authors.initials: N
authors.lastname: Ishikawa
authors.forename: Takuro
authors.initials: T
authors.lastname: Terada
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kawakami
mesh_terms: D000818:Animals; D001706:Biopsy; D001783:Blood Flow Velocity; D002138:Calibration; D006328:Cardiac Catheterization; D003326:Coronary Circulation; D004699:Endocardium / Q000648:ultrastructure; D004867:Equipment Design; D045268:Flowmeters; D006439:Hemodynamics; D018056:Hemorheology / Q000295:instrumentation*; D008863:Microspheres; D009206:Myocardium / Q000648:ultrastructure; D010496:Pericardium / Q000648:ultrastructure; D015203:Reproducibility of Results; D034421:Sus scrofa; D013814:Thermal Conductivity