Editing Peritoneal dialysis (section)

==Method==
Best practices for peritoneal dialysis state that before peritoneal dialysis should be implemented, the person's understanding of the process and support systems should be assessed, with education on how to care for the catheter and to address any gaps in understanding that may exist.  The person should receive ongoing monitoring to ensure adequate dialysis, and be regularly assessed for complications. Finally, they should be educated on the importance of infection control and an appropriate medical regimen established with their cooperation.<ref>{{cite web | url = http://www.cannt.ca/en//files/CANNT_Nursing_Standards_2008.pdf | title = Nephrology Nursing Standards and Practice Recommendations | publisher = Canadian Association of Nephrology Nurses and Technologists | access-date = 2010-09-08 | date = 2008-08-01 | vauthors = Wood M, etal | collaboration = CANNT Nursing Standards Working Group | url-status = dead | archive-url = https://web.archive.org/web/20100331050104/http://www.cannt.ca/en/files/CANNT_Nursing_Standards_2008.pdf | archive-date = 2010-03-31 }}</ref>

<gallery caption="Dialysis process" widths="80px" perrow="5">
File:DP branchement.svg|Hookup
File:DP infusion.svg|Infusion
File:DP stase.svg|Diffusion (fresh)
File:DP fin stase.svg|Diffusion (waste)
File:DP drainage.svg|Drainage
</gallery>

[[File:Blausen 0160 CAPD.png|thumb|right|Continuous Ambulatory Peritoneal Dialysis (CAPD)]]
The abdomen is cleaned in preparation for surgery and a [[catheter]] is surgically inserted with one end in the abdomen and the other protruding from the skin.<ref name="pmid16769289">{{cite journal | vauthors = Harissis HV, Katsios CS, Koliousi EL, Ikonomou MG, Siamopoulos KC, Fatouros M, Kappas AM | title = A new simplified one port laparoscopic technique of peritoneal dialysis catheter placement with intra-abdominal fixation | journal = American Journal of Surgery | volume = 192 | issue = 1 | pages = 125–9 | date = July 2006 | pmid = 16769289 | doi = 10.1016/j.amjsurg.2006.01.033 }}</ref> Catheters can also be inserted without a general anaesthetic by a physician using a needle, known as a medical insertion. Both methods have similar safety profiles.<ref>{{Cite journal |last1=Fotheringham |first1=James |last2=Solis-Trapala |first2=Ivonne |last3=Briggs |first3=Victoria |last4=Lambie |first4=Mark |last5=McCullough |first5=Keith |last6=Dunn |first6=Louese |last7=Rawdin |first7=Andrew |last8=Hill |first8=Harry |last9=Wailloo |first9=Allan |last10=Davies |first10=Simon |last11=Wilkie |first11=Martin |date=2023-12-01 |title=Catheter Event Rates in Medical Compared to Surgical Peritoneal Dialysis Catheter Insertion |url=https://doi.org/10.1016/j.ekir.2023.09.015 |journal=Kidney International Reports |volume=8 |issue=12 |pages=2635–45 |doi=10.1016/j.ekir.2023.09.015 |pmc=10719604 |pmid=38106573}}</ref><ref>{{Cite journal |date=9 April 2024 |title=Kidney failure: medical insertion of catheters for peritoneal dialysis is as safe as surgery |url=https://evidence.nihr.ac.uk/alert/kidney-failure-medical-insertion-of-catheters-for-peritoneal-dialysis-is-as-safe-as-surgery/ |journal=NIHR Evidence|doi=10.3310/nihrevidence_62664 |url-access=subscription }}</ref> Before each infusion the catheter must be cleaned, and flow into and out of the abdomen tested.  2-3 liters of dialysis fluid is introduced into the abdomen over the next ten to fifteen minutes.<ref name = Nursing/>  The total volume is referred to as a ''dwell''<ref name = Crowley2009/> while the fluid itself is referred to as dialysate.  The dwell can be as much as 3 liters, and medication can also be added to the fluid immediately before infusion.<ref name = Nursing>{{cite book | vauthors = Munden J |title=Best practices : evidence-based nursing procedures. |date=2007 |publisher=Lippincott Williams & Wilkins |location=Philadelphia |isbn=978-1-58255-532-4 |edition=2nd | url = https://archive.org/details/bestpracticesevi0000unse}}</ref> The dwell remains in the abdomen and waste products diffuse across the peritoneum from the underlying blood vessels.  After a variable period of time depending on the treatment (usually 4–6 hours<ref name = Nursing/> ), the fluid is removed and replaced with fresh fluid.  This can occur automatically while the patient is sleeping (automated peritoneal dialysis, APD), or during the day by keeping two litres of fluid in the abdomen at all times, exchanging the fluids four to six times per day (continuous ambulatory peritoneal dialysis, CAPD).<ref name=Crowley2009>{{cite book | vauthors = Crowley LV | year = 2009 | publisher = Jones & Bartlett | isbn = 978-0-7637-6591-0 | title = An Introduction to Human Disease: Pathology and Pathophysiology Correlations | url = https://books.google.com/books?id=TEiuWP4z_QIC&pg=PA507 | pages = 507–9 | url-status = live | archive-url = https://web.archive.org/web/20130618122928/http://books.google.com/books?id=TEiuWP4z_QIC&pg=PA507 | archive-date = 2013-06-18 }}</ref><ref name = McPhee2007>{{cite book | vauthors = McPhee SJ, Tierney LM, Papadakis MA |chapter=Dialysis | title = Current medical diagnosis and treatment | year = 2007 | isbn = 978-0-07-147247-0 | publisher = [[McGraw-Hill]] | pages = 934–5 }}</ref>

The fluid used typically contains [[sodium chloride]], [[Lactic acid|lactate]] or [[bicarbonate]] and a high percentage of [[glucose]] to ensure [[osmolarity|hyperosmolarity]].  The amount of dialysis that occurs depends on the volume of the dwell, the regularity of the exchange and the concentration of the fluid. APD cycles between 3 and 10 dwells per night, while CAPD involves four dwells per day of 2-3 liters per dwell, with each remaining in the abdomen for 4–8 hours.  The viscera accounts for roughly four-fifths of the total surface area of the membrane, but the parietal peritoneum is the most important of the two portions for PD.  Two complementary models explain dialysis across the membrane — the three-pore model (in which molecules are exchanged across membranes which sieve molecules, either [[protein]]s, electrolytes or water, based on the size of the pores) and the distributed model (which emphasizes the role of [[capillary|capillaries]] and the solution's ability to increase the number of active capillaries involved in PD).  The high concentration of glucose drives the filtration of fluid by osmosis (osmotic UF) from the peritoneal capillaries to the peritoneal cavity. Glucose diffuses rather rapidly from the dialysate to the blood (capillaries). After 4-6 h of the dwell, the glucose osmotic gradient usually becomes too low to allow for further osmotic UF. Therefore, the dialysate will now be reabsorbed from the peritoneal cavity to the capillaries by means of the plasma colloid osmotic pressure, which exceeds the colloid osmotic pressure in the peritoneum by approximately 18-20 mmHg (cf. the Starling mechanism).<ref name="pmid15104333">{{cite journal | vauthors = Rippe B, Venturoli D, Simonsen O, de Arteaga J | title = Fluid and electrolyte transport across the peritoneal membrane during CAPD according to the three-pore model | journal = Peritoneal Dialysis International | volume = 24 | issue = 1 | pages = 10–27 | date = 2004 | pmid = 15104333 | doi = 10.1177/089686080402400102 | s2cid = 25034246 }}</ref> Lymphatic absorption will also to some extent contribute to the reabsorption of fluid from the peritoneal cavity to the plasma. Patients with a high water permeability (UF-coefficient) of the peritoneal membrane can have an increased reabsorption rate of fluid from the peritoneum by the end of the dwell. The ability to exchange small solutes and fluid in-between the peritoneum and the plasma can be classified as high (fast), low (slow) or intermediate.  High transporters tend to diffuse substances well (easily exchanging small molecules between blood and the dialysis fluid, with somewhat improved results with frequent, short-duration dwells such as with APD), while low transporters have a higher UF (due to the slower reabsorption of glucose from the peritoneal cavity, which results in somewhat better results with long-term, high-volume dwells), though in practice either type of transporter can generally be managed through the appropriate use of either APD or CAPD.<ref name=Daugirdas2006>{{cite book | vauthors = Daugirdas JT, Blake PG, Ing TS | year = 2006 | title = Handbook of dialysis | publisher = Lippincott Williams & Wilkins | chapter-url = https://books.google.com/books?id=IGV4boOFjZYC&pg=PA323 | page = 323 | chapter = Physiology of Peritoneal Dialysis | isbn = 978-0-7817-5253-4 | url-status = live | archive-url = https://web.archive.org/web/20130618180548/http://books.google.com/books?id=IGV4boOFjZYC&pg=PA323 | archive-date = 2013-06-18 }}</ref>

Though there are several different shapes and sizes of catheters that can be used, different insertion sites, number of cuffs in the catheter and immobilization, there is no evidence to show any advantages in terms of morbidity, mortality or number of infections, though the quality of information is not yet sufficient to allow for firm conclusions.<ref>{{cite journal | vauthors = Htay H, Johnson DW, Craig JC, Schena FP, Strippoli GF, Tong A, Cho Y | title = Catheter type, placement and insertion techniques for preventing catheter-related infections in chronic peritoneal dialysis patients | journal = The Cochrane Database of Systematic Reviews | volume = 2019 | pages = CD004680 | date = May 2019 | issue = 5 | pmid = 31149735 | pmc = 6543877 | doi = 10.1002/14651858.CD004680.pub3 }}</ref>

A [[peritoneal equilibration test]] may be done to assess a person for peritoneal dialysis by determining the characteristics of the peritoneal membrane mass transport characteristics.

=== Improvised dialysis ===
Peritoneal dialysis can be improvised in conditions such as combat surgery or disaster relief using surgical catheters and dialysate made from routinely available medical solutions to provide temporary renal replacement for people with no other options.<ref>{{cite journal | vauthors = Pina JS, Moghadam S, Cushner HM, Beilman GJ, McAlister VC | title = In-theater peritoneal dialysis for combat-related renal failure | journal = The Journal of Trauma | volume = 68 | issue = 5 | pages = 1253–56 | date = May 2010 | pmid = 20453775 | doi = 10.1097/TA.0b013e3181d99089 | s2cid = 24251777 | url = https://works.bepress.com/cgi/viewcontent.cgi?article=1043&context=vivianmcalister }}</ref>