Continuous analysis in extracorporeally circulating blood--a rat model applying flow-through ion-selective electrodes for the measurement of Ca2+, K+, Na+ and pH.
A rat model is introduced which enables investigations in anticoagulated blood with continuous measurements by a flow-through electrode system. In the present study, a potentiometric ion-selective electrode (ISE)-system was used for measuring Ca2+, K+, Na+ and pH in rats. The setup was adjusted to an extracorporeal blood-volume of 0.750 ml. This permits indirect measurements of the analytes via a dialysis membrane, with electrical separation of the ISE's and the animal. The flow-rates of blood and dialysis-solution were adjusted in such a way that water diffusing from the aqueous dialysis solution into the blood, across the dialysis membrane, does not alter the haematocrit. Polyethyleneglycol-hirudin was used for anticoagulation, since it was superior to heparin. The assembly enables continuous measurements in the living anaesthetized rat over a time period of at least 3 hours.
Heidrich
J P
JP
Institut für Klinische Chemie, Medizinische Universität zu Lübeck, Germany.
Niemeier
A
A
Seyfarth
M
M
D000818:Animals; D002118:Calcium / Q000097:blood*; D002412:Cations; D004566:Electrodes; D005112:Extracorporeal Circulation; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D011188:Potassium / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D012964:Sodium / Q000097:blood*
D002412:Cations; D012964:Sodium; D011188:Potassium; D002118:Calcium