Continuous kidney replacement therapy circuit represented pumps and sites of entry of dialysate and predilution and postdilution substitution fluid

Q_s (pre): substitution fluid rate infused prefilter; Q_b: blood flow rate; Q_d: dialysate flow rate; Q_ef: effluent flow rate (equivalent to Q_uf in slow continuous ultrafiltration and continuous venovenous hemofiltration, Q_d in continuous venovenous hemodialysis, and Q_uf + Q_d in continuous venovenous hemodiafiltration); Q_uf: ultrafiltration rate; Q_s (post): substitution fluid rate infused postfilter.