What factors can cause the differences between the prescribed and delivered Kt/V?
The factors that can cause a discrepancy between the prescribed and delivered dose of dialysis can be categorized into factors resulting from compromised urea clearance and factors resulting from a decrease in the effective dialysis session length.
Reasons for Compromised Urea Clearance
Modified from Parker, T. F. (1992). Trends and concepts in the prescription and delivery of dialysis in the United States. Seminars in Nephrology, 12, 267–275.
|PATIENT-RELATED REASONS||STAFF-RELATED REASONS||MECHANICAL PROBLEMS|
|Decreased effective time on dialysis• Decreased BFR• Access clotting• Use of intravenous catheters (instead of arteriovenous graft or fistula)• Inadequate flow through vascular accessRecirculation• Use of catheters• Inadequate access for prescribed BFR• Stenosis, clotting of access||Decreased effective timeDecreased BFR• Less than prescribed• Difficult cannulationDecreased dialysate flow rate• Less than prescribed• Inappropriately setDialyzer• Inadequate quality control of “reuse”||Dialyzer clotting during reuse• Blood pump calibration errorDialysate pump calibration errorInaccurate estimation of dialyzer performance by the manufacturerVariability in blood tubing|
BFR, Blood flow rate.