title: Multi-channel electrical bioimpedance: a new noninvasive method to simultaneously measure cardiac and peripheral blood flow.
abstract: OBJECTIVE
  We sought to assess the ability of a new multi-channel electrical bioimpedance (MEB) methodology to accurately measure both cardiac blood flow and peripheral limb blood flow.
  
  
  BACKGROUND
  Cardiac output is the primary determinant of peripheral blood flow; however, optimal regional tissue perfusion is ultimately dependent on the patency of the arterial conduits that transport that flow. A complete understanding of regional tissue perfusion requires knowledge of both cardiac and peripheral blood flow. Existing noninvasive devices do not simultaneously assess the cardiac and peripheral circulations.
  
  
  METHODS
  Cardiac blood flow (cardiac output) was measured by MEB in 30 healthy volunteers and was compared to a 2D-Echo Doppler cardiac output. Peripheral blood flow (regional ankle and arm flow) was measured by MEB in 15 healthy volunteers. The MEB ankle/arm flow ratio (AAI index) was then compared to a conventional ankle/brachial pressure ratio (ABI index).
  
  
  RESULTS
  There was good correlation between the mean cardiac index by MEB (3.08 l/min/m2) and by Echo Doppler (3.13 l/min/m2) and bias and precision was 0.051 (1.6%) and +/-0.52 l/min/m2 (+/-17%), respectively. The close correlation was maintained for each measurement over a wide range of cardiac indices. There was good correlation between AAI and ABI measurements (p < 0.05) with a sensitivity of 100% and specificity of 100%.
  
  
  CONCLUSIONS
  MEB methodology can precisely measure cardiac output and peripheral limb flow in healthy volunteers.
authors.affiliation: Kemp-Carraway Heart Institute, Birmingham, AL, USA.
authors.forename: Alfred W H
authors.initials: AW
authors.lastname: Stanley
authors.forename: Jeffery W
authors.initials: JW
authors.lastname: Herald
authors.forename: Constantine L
authors.initials: CL
authors.lastname: Athanasuleas
authors.forename: Saji C
authors.initials: SC
authors.lastname: Jacob
authors.forename: Scott W
authors.initials: SW
authors.lastname: Sims
authors.forename: Alfred A
authors.initials: AA
authors.lastname: Bartolucci
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Tsoglin
mesh_terms: D000328:Adult; D000842:Ankle / Q000098:blood supply / Q000502:physiology; D001132:Arm / Q000098:blood supply / Q000502:physiology; D015982:Bias; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002302:Cardiac Output / Q000502:physiology*; D015150:Echocardiography, Doppler; D017097:Electric Impedance; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D012039:Regional Blood Flow / Q000502:physiology*; D015203:Reproducibility of Results; D012107:Research Design; D012680:Sensitivity and Specificity