Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Mechanisms of Peritoneal Water and Solute transport - Computational Modelling and Clinical Implications

Helman, Jakob LU orcid (2026) In Lund University, Faculty of Medicine Doctoral Dissertation Series
Abstract
Peritoneal dialysis is a widely used, cost-effective and accessible renal replacement therapy. The
primary aim of this thesis is to study and measure the mechanisms that govern fluid and electrolyte
transport in peritoneal dialysis by combining theoretical models with experiments on rats and analysis
of clinical datasets. Despite the apparent simplicity of the treatment, the physiological mechanisms that
govern the transport of solutes and water are highly complex.

In study 1, we investigate the effects of very high ultrafiltration rates on blood plasma volume.
Experimental peritoneal dialysis was performed on rats using dialysis fluid with a very high glucose
content, and plasma volumes were measured using... (More)
Peritoneal dialysis is a widely used, cost-effective and accessible renal replacement therapy. The
primary aim of this thesis is to study and measure the mechanisms that govern fluid and electrolyte
transport in peritoneal dialysis by combining theoretical models with experiments on rats and analysis
of clinical datasets. Despite the apparent simplicity of the treatment, the physiological mechanisms that
govern the transport of solutes and water are highly complex.

In study 1, we investigate the effects of very high ultrafiltration rates on blood plasma volume.
Experimental peritoneal dialysis was performed on rats using dialysis fluid with a very high glucose
content, and plasma volumes were measured using albumin with a radioactive tracer technique.
Plasma volumes appeared unchanged despite high ultrafiltration rates.

The aim of study 2 was to validate and test a new mathematical model for estimating ultrafiltration rate
in peritoneal dialysis from the phenomenon known as the sodium dip. The model was tested
experimentally on rats, by estimating ultrafiltration rates during peritoneal dialysis using the new model
and a reference method. Then, the same analysis was performed on a cohort of patient data. Results
showed excellent agreement between ultrafiltration estimates obtained with the new method and the
reference method in experimental data, and moderate agreement in clinical data. The same was true
for osmotic conductance to glucose in clinical data.

Finally, in study 3, the well-established three-pore model for peritoneal transport was modified by using
the Nernst-Planck equation to describe electrolyte transport. The model was fitted to experimental data
from peritoneal dialysis performed on rats, by using the kinetics of sodium to estimate hydraulic
conductance and area-to-diffusion length ratio. After incorporating the parameters, the model
independently predicted the transport of water and solute species other than sodium. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Docent Heimbürger, Olof, Karolinska Institutet, Stockholm
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Peritoneal dialysis, Mathematical model, Ultrafiltration, Peritonealdialys, Dialys, Matematisk modell, Ultrafiltration
in
Lund University, Faculty of Medicine Doctoral Dissertation Series
issue
2026:38
pages
67 pages
publisher
Lund University, Faculty of Medicine
defense location
Föreläsningssalen, Avdelningen för njurmedicin, Barngatan 2, Skånes Universitetssjukhus i Lund. Join by Zoom: https://lu-se.zoom.us/j/61904953119?pwd=aFaGj6xJTtUzTADI2Jro8wjU5XrKV1.1
defense date
2026-03-20 13:00:00
ISSN
1652-8220
ISBN
978-91-8021-836-8
project
Mechanisms of peritoneal water and solute transport - Computational modeling and clinical implications
language
English
LU publication?
yes
id
b9d07cea-10d2-45d1-a11e-a445efa36a46
date added to LUP
2026-02-19 09:37:25
date last changed
2026-02-24 09:18:57
@phdthesis{b9d07cea-10d2-45d1-a11e-a445efa36a46,
  abstract     = {{Peritoneal dialysis is a widely used, cost-effective and accessible renal replacement therapy. The<br/>primary aim of this thesis is to study and measure the mechanisms that govern fluid and electrolyte<br/>transport in peritoneal dialysis by combining theoretical models with experiments on rats and analysis<br/>of clinical datasets. Despite the apparent simplicity of the treatment, the physiological mechanisms that<br/>govern the transport of solutes and water are highly complex.<br/><br/>In study 1, we investigate the effects of very high ultrafiltration rates on blood plasma volume.<br/>Experimental peritoneal dialysis was performed on rats using dialysis fluid with a very high glucose<br/>content, and plasma volumes were measured using albumin with a radioactive tracer technique.<br/>Plasma volumes appeared unchanged despite high ultrafiltration rates.<br/><br/>The aim of study 2 was to validate and test a new mathematical model for estimating ultrafiltration rate<br/>in peritoneal dialysis from the phenomenon known as the sodium dip. The model was tested<br/>experimentally on rats, by estimating ultrafiltration rates during peritoneal dialysis using the new model<br/>and a reference method. Then, the same analysis was performed on a cohort of patient data. Results<br/>showed excellent agreement between ultrafiltration estimates obtained with the new method and the<br/>reference method in experimental data, and moderate agreement in clinical data. The same was true<br/>for osmotic conductance to glucose in clinical data.<br/><br/>Finally, in study 3, the well-established three-pore model for peritoneal transport was modified by using<br/>the Nernst-Planck equation to describe electrolyte transport. The model was fitted to experimental data<br/>from peritoneal dialysis performed on rats, by using the kinetics of sodium to estimate hydraulic<br/>conductance and area-to-diffusion length ratio. After incorporating the parameters, the model<br/>independently predicted the transport of water and solute species other than sodium.}},
  author       = {{Helman, Jakob}},
  isbn         = {{978-91-8021-836-8}},
  issn         = {{1652-8220}},
  keywords     = {{Peritoneal dialysis; Mathematical model; Ultrafiltration; Peritonealdialys; Dialys; Matematisk modell; Ultrafiltration}},
  language     = {{eng}},
  number       = {{2026:38}},
  publisher    = {{Lund University, Faculty of Medicine}},
  school       = {{Lund University}},
  series       = {{Lund University, Faculty of Medicine Doctoral Dissertation Series}},
  title        = {{Mechanisms of Peritoneal Water and Solute transport - Computational Modelling and Clinical Implications}},
  url          = {{https://lup.lub.lu.se/search/files/242722982/Online_Jakob.pdf}},
  year         = {{2026}},
}