Peritoneal Dialysis
Kt/V (in the context of peritoneal dialysis) was developed by Michael J. Lysaght in a series of articles on peritoneal dialysis.
The steady-state solution of a simplified mass transfer equation that is used to describe the mass exchange over a semi-permeable membrane and models peritoneal dialysis is
where
- CB is the concentration in the blood
- KD is the clearance
- is the urea mass generation
This can also be written as:
The mass generation (of urea), in steady state, can be expressed as the mass (of urea) in the effluent per time:
where
- CE is the concentration of urea in effluent
- VE is the volume of effluent
- t is the time
Lysaght, motivated by Equations 6b and 6c, defined the value KD:
Lysaght uses "ml/min" for the clearance. In order to convert the above clearance (which is in m³/s) to ml/min one has to multiply by 60 x 1000 x 1000.
Once KD is defined the following equation is used to calculate Kt/V:
where
- V is the volume of distribution. It has to be in litres (l), as the equation is not really non-dimensional.
The 7/3 is used to adjust the Kt/V value so it can be compared to the Kt/V for hemodialysis, which is typically done thrice weekly in the USA.
Read more about this topic: Kt/V