Hannan et al used bio-impedance analysis (BIA) to estimated body water in surgical patients. The authors are from Western General Hospital and Royal Infirmary of Edinburgh in Scotland.
Patient selection: surgical patient
Method of analysis: BIA
Parameters:
(1) height in centimeters
(2) R50 (resistance at 50 Hz) in Ohms
(3) X50 (reactance at 50 Hz) in Ohms
(4) weight in kilograms
(5) R5 (resistance at 5 Hz) in Ohms
extracellular water in liters =
= (0.123 * ((height)^2) / R50) + (0.0119*((height)^2) / X50) + 6.15
extracellular water in liters =
= (0.165 * ((height)^2) / R5) + (0.01 * ((height)^2) / X50) + 5.75
where:
• Equation 1: r=0.932, SEE=1.72 liters. coefficient of variation 9.5%.
• Equation 2: r=0.933, SEE=1.73 liters. coefficient of variation 9.6%.
