Blood Flow Rate
Blood Flow Rate
Qb
• The rate of blood flow from the patient towards the filter
• Blood flow rates are typically slower than in intermittent dialysis, ranging from 150-200mL/min
Ultrafiltrate Rate
Ultrafiltrate Rate
Quf
• The rate at which ultrafiltrate is produced by hydrostatic pressure across the membrane during convective therapies
• It is influenced by the blood flow rate and the filtration fraction
Dialysate Flow Rate
Dialysate Flow Rate
Qd
• The flow rate of dialysis fluid in dialytic therapies
• Standard flow rates range from 8-50 mL/min
Effluent Rate
(Dose)
Effluent Rate
(Dose)
Qef
• The effluent flow rate is the equivalent to ultrafiltration rate Quf in continuous haemofiltration, Qd in continuous haemodialysis, and both Quf & Qd in continuous hemodiafiltration
• It is analogous to the ‘dose’ in continuous therapies
• Dosing is weight-based and is typically prescribed at a dose ranging from 20 mL/kg/hr to 35 mL/kg/hr
Substitution Fluid Rate
Substitution Fluid Rate
Qs
• Techniques in which produce a volume of ultrafiltrate require replacement of this fluid with a substitute fluid to prevent significant loss of volume.
• The rate of substitution fluid describes the rate at which this replacement fluid is added to the plasma
Net Ultrafiltrate Rate
Net Ultrafiltrate Rate
Qnet
• Represents the overall rate of fluid removal
• It is the difference between the total effluent removed (Qef) minus the volume of replacement therapy
• The fluid removal rate can be tailored by the machine to meet the total removal goal of the patient