Background: On-line monitoring systems of spent dialysate, used to estimate dialysis dose, have been developed with different instrumentation during the last two decades. The routine use of an on-line monitoring system has been suggested to provide an adequate dialysis dose to the haemodialysis (HD) patient. The aim of this study was to show that monitoring the spent dialysate using UV-absorbance might bring new information about the clearance process.
Methods: 108 HD treatments distributed among 16 clinical stable patients were monitored on-line using ultra violet (UV) absorbance. For the measurement of UV-absorbance a spectrophotometer was connected to the fluid outlet of the dialysis machine with all spent dialysate passing through a flow cuvette. The UV-absorbance curves were examined in combination with the recorded observations of events that occurred during the studied treatments.
Results: The study demonstrates that UV-absorbance visualizes different kinds of events such as hypotension, conductivity alarms and restricted flow in artery needle blood pump stops that often occur during dialysis treatment.
Conclusion: An on-line UV-monitoring system with a high sampling rate makes it possible to identify variations in dialysis clearance of different origin and gives feedback after performing interventions during a dialysis session.