title: Reproducibility of the blood flow index as noninvasive, bedside estimation of cerebral blood flow.
abstract: OBJECTIVE
  To investigate the feasibility and reproducibility of the blood flow index (BFI) method for measuring cerebral blood flow.
  
  
  METHODS
  Prospective functional study in pediatric intensive care.
  
  
  METHODS
  14 consecutive patients with median age of 2 months (range 1 days-11 years) requiring artificial ventilation, invasive arterial blood pressure monitoring, and central venous access.
  
  
  METHODS
  The first passage of an intravenous indocyanine green (ICG) bolus through the cerebral vasculature was monitored by noninvasive near-infrared spectroscopy. BFI was calculated by dividing maximal ICG absorption change by rise time. Reproducibility was evaluated by six ICG injections at 5-min intervals.
  
  
  RESULTS
  Of all ICG injections 6% were canceled, and 4% were eliminated due to injection failures. Median BFI of 17 reproducibility determinations was 71 (range 12-213) and median coefficient of variation (CV) of BFI was 10% (4.9-18.5). The quantity of ICG bolus did not affect the CV (0.1 vs. 0.3 mg ICG/kg). Eight reproducibility tests in patients after cardiac surgery had smaller CV than the others, and the eight in newborns had higher CV than in older children. Patient parameters such as arterial blood pressure, endtidal CO(2), and percutaneous oxygen saturation were stable and showed CV below 2% during reproducibility determination.
  
  
  CONCLUSIONS
  The BFI method allows rapid and repeated measurements of CBF with good feasibility and reproducibility. As a relative but not absolute measure of CBF, BFI seems to be suited for clinical evaluation of intraindividual CBF changes during determination of cerebrovascular reactivities or during therapeutic interventions.
authors.affiliation: Pediatric Intensive Care, Department of Pediatrics, Inselspital, University of Berne, 3010, Berne, Switzerland. wagner@insel.ch
authors.forename: Bendicht P
authors.initials: BP
authors.lastname: Wagner
authors.forename: Susanne
authors.initials: S
authors.lastname: Gertsch
authors.forename: Roland A
authors.initials: RA
authors.lastname: Ammann
authors.forename: Juerg
authors.initials: J
authors.lastname: Pfenninger
mesh_terms: D001776:Blood Circulation Time / Q000379:methods*; D001783:Blood Flow Velocity; D001927:Brain Diseases / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D001930:Brain Injuries / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D002493:Central Nervous System Diseases / Q000150:complications; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D003422:Critical Care / Q000379:methods; D005240:Feasibility Studies; D006330:Heart Defects, Congenital / Q000150:complications / Q000601:surgery; D006801:Humans; D007208:Indocyanine Green; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008471:Meconium Aspiration Syndrome / Q000150:complications; D008991:Monitoring, Physiologic / Q000379:methods*; D018579:Patient Selection; D019095:Point-of-Care Systems / Q000592:standards; D011446:Prospective Studies; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013997:Time Factors
chemical_list: D007208:Indocyanine Green