Biomedical Engineering Reference
In-Depth Information
Chapter 15
A
LBUMIN
-B
OUND
T
OXIN
R
EMOVAL IN
L
IVER
S
UPPORT
D
EVICES
: C
ASE
S
TUDY OF
B
ILIRUBIN
A
DSORPTION AND
D
IALYSIS
M. Cristina Annesini, Vincenzo Piemonte and Luca Turchetti
Department of Chemical Engineering Materials & Environment
University of Rome
“La Sapienza” via Eudossiana 18, 00184 Roma (Italy)
Abstract
Dialysis and adsorption units are commonly used in liver support devices for the re-
moval of albumin-bound toxins such as bilirubin. In this chapter, an engineering ap-
proach to the analysis of a liver support device implementing these units is presented.
Starting from the physico-chemical description of the basic phenomena involved in
the detoxification process, a mathematical model of a recirculating albumin dialysis
liver support device was built and used to calculate bilirubin clearances obtained by
the device with different operating conditions.
The results highlight the possible existence of an optimum dialysate albumin con-
centration; furthermore, the overall bilirubin clearances obtained in the simulations
did not exceed 4% of the blood flow-rate fed to the device, this poor performance be-
ing limited by the slow bilirubin mass transfer across the membrane. The information
presented in this chapter can be helpful for the optimization of existing liver support
devices and for the design of new ones; nevertheless, for a complete assessment of the
device performance, a similar analysis should be extended to the clearance of other
toxins and some of the model parameters should be also checked against clinical data.
1.
Introduction
The liver is a vital organ that performs a wide range of life-important functions, among
which is blood detoxification. Therefore, liver failure is associated with high plasmatic lev-
els of different types of toxins, some of which are involved in the aethiology of secondary
life-threatening multi-organ pathologies. For this reason, if not correctly and timely man-
aged, liver failure can lead to a sudden worsening of the clinical state of the patient, and
easily result in a fatal outcome.
