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 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.
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.
| Original language | English |
|---|---|
| Qualification | Doctor |
| Awarding Institution |
|
| Supervisors/Advisors |
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| Award date | 2026 Mar 20 |
| Place of Publication | Lund |
| Publisher | |
| ISBN (Print) | 978-91-8021-836-8 |
| Publication status | Published - 2026 |
Bibliographical note
Defence detailsDate: 2026-03-20
Time: 13:00
Place: Föreläsningssalen, Avdelningen för njurmedicin, Barngatan 2, Skånes Universitetssjukhus i Lund. Join by Zoom: https://lu-se.zoom.us/j/61904953119?pwd=aFaGj6xJTtUzTADI2Jro8wjU5XrKV1.1
External reviewer(s)
Name: Heimbürger, Olof
Title: Docent
Affiliation: Karolinska Institutet, Stockholm
Subject classification (UKÄ)
- Medical Biotechnology
- Medical Modelling and Simulation
Free keywords
- Peritoneal dialysis
- Mathematical model
- Ultrafiltration
Fingerprint
Dive into the research topics of 'Mechanisms of Peritoneal Water and Solute transport - Computational Modelling and Clinical Implications'. Together they form a unique fingerprint.Research output
- 2 Article
-
Quantifying Ultrafiltration in Peritoneal Dialysis Using the Sodium Dip
Helman, J., Wahlgren, H., Andersson, L., Morelle, J. & Öberg, C. M., 2024, In: Kidney360. 5, 2, p. 195-204Research output: Contribution to journal › Article › peer-review
Open Access -
High versus low ultrafiltration rates during experimental peritoneal dialysis in rats: Acute effects on plasma volume and systemic haemodynamics
Helman, J. & M Öberg, C., 2023, In: Peritoneal Dialysis International. 43, 1, p. 84-91Research output: Contribution to journal › Article › peer-review
Open Access
Projects
- 1 Finished
-
Mechanisms of peritoneal water and solute transport - Computational modeling and clinical implications
Helman, J. (Research student), Öberg, C. (Supervisor) & Christensson, A. (Assistant supervisor)
2021/10/01 → 2026/03/20
Project: Dissertation
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