title: Application of ultrasound dilution technology for cardiac output measurement: Cerebral and systemic hemodynamic consequences in a juvenile animal model.
abstract: OBJECTIVE
  Analysis of cerebral and systemic hemodynamic consequences of ultrasound dilution cardiac output measurements.
  
  
  METHODS
  : Prospective, experimental piglet study.
  
  
  METHODS
  Animal laboratory.
  
  
  METHODS
  Nine piglets.
  
  
  METHODS
  Ultrasound dilution cardiac output measurements were performed in ventilated, anesthetized piglets. Interventions that are required for ultrasound dilution cardiac output measurement were evaluated for its effect on cerebral and systemic circulation and oxygenation.
  
  
  RESULTS
  DeltacHbD and DeltactHb, representing changes in cerebral blood flow and cerebral blood volume, respectively, were measured with near infrared spectrophotometry. Pulmonary artery (Q) and left carotid artery (Q) blood flow were assessed with transit time flow probes. Starting and/or stopping blood flowing through the arteriovenous loop did not cause relevant hemodynamic changes. Fast injection of isotonic saline caused a biphasic change in DeltacHbD and DeltactHb. After injection of 0.5 mL/kg, the mean (sd) increase in DeltacHbD and DeltactHb was 0.175 (0.213) micromol/L and 0.122 (0.148) micromol/L, respectively, with a subsequent mean decrease of -0.191 (0.299) micromol/L and -0.312 (0.266) micromol/L. Injection of 1.0 mL/kg caused a mean increase in DeltacHbD and DeltactHb of 0.237 (0.203) micromol/L and 0.179 (0.162) followed by a mean decrease of -0.334 (0.407) micromol/L and -0.523 (0.335) micromol/L, respectively. Q and Q changed shortly with a mean increase of 5.9 (3.0) mL/kg/min and 0.23 (0.10) mL/kg/min after injection of 0.5 mL/kg and with 12.0 (4.2) mL/kg/min and 0.44 (0.18) mL/kg/min after injection of 1.0 mL/kg, respectively. The observed changes were more profound after an injection volume of 1.0 mL/kg compared with 0.5 mL/kg for DeltacHbD (p = .06), DeltactHb (p = .09), Q, and Q (p < .01). No relevant changes in mean arterial blood pressure or heart rate were detected in response to the indicator injection.
  
  
  CONCLUSIONS
  Cardiac output measurement by ultrasound dilution does not cause clinically relevant changes in cerebral and systemic circulation and oxygenation in a piglet model.
authors.affiliation: Department of Neonatology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. W.deBoode@cukz.umcn.nl
authors.forename: Willem P
authors.initials: WP
authors.lastname: de Boode
authors.forename: Arno F J
authors.initials: AF
authors.lastname: van Heijst
authors.forename: Jeroen C W
authors.initials: JC
authors.lastname: Hopman
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Tanke
authors.forename: Hans G
authors.initials: HG
authors.lastname: van der Hoeven
authors.forename: K Djien
authors.initials: KD
authors.lastname: Liem
mesh_terms: D000818:Animals; D000833:Animals, Suckling; D001794:Blood Pressure; D001810:Blood Volume; D002302:Cardiac Output; D002339:Carotid Arteries / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D004195:Disease Models, Animal; D006339:Heart Rate; D006439:Hemodynamics; D007201:Indicator Dilution Techniques; D007552:Isotonic Solutions; D009996:Osmotic Fragility; D011651:Pulmonary Artery / Q000503:physiopathology; D012039:Regional Blood Flow; D019265:Spectroscopy, Near-Infrared; D013552:Swine; D014463:Ultrasonography / Q000379:methods
chemical_list: D007552:Isotonic Solutions