On-line monitoring of the intravascular volume during haemodialysis by continuous refractometry.
The control of intravascular volume (IVV) by continuous on-line measurement of protein concentration would optimise the patients' specific rate of ultrafiltration. To prove the accuracy of a refractometric device, plasma was continuously drawn by haemofiltration during 10 haemodialysis treatments of male patients. Refractometry reflects highly significant changes in the concentrations of filtrate proteins (r = 0.862, p < 0.001) and blood proteins (rtotal = 0.593, ptotal < 0.001). In vitro, the refractometric device detected a change of protein concentration of 0.041 g/L through a refraction increase of 0.1 mV. The power of discrimination was 0.067% of IVV However, in vivo, the accuracy of IVV refractometric monitoring is reduced by interference factors such as sodium (0. 141 mV/mmol/L), glucose (0.034 mV/mg/dl) and triglycerides (-0.040 mV/mg/dl). Adjustment of the refraction data using sodium and glucose electrodes and plasma filters with a cut-off below the size of chylomicrons is recommended.
Kuhlmann
U
U
Department of Nephrology, Philipps University of Marburg, Germany.
van Buuren
F
F
Aziz
O
O
Lange
H
H
D001798:Blood Proteins / Q000032:analysis; D006440:Hemofiltration; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D009862:Online Systems; D012031:Refractometry / Q000379:methods*; D006435:Renal Dialysis / Q000379:methods*; D014462:Ultrafiltration / Q000379:methods
D001798:Blood Proteins