Haemodialysis vs Peritoneal Dialysis

Introduction 

Renal replacement therapy (RRT) refers to life-supporting treatments for severe acute kidney injury (AKI) or end-stage kidney disease.¹ Types of RRT include haemodialysis, peritoneal dialysis, hemofiltration, haemodiafiltration, and kidney transplant.

This article will cover the similarities and differences between haemodialysis (HD) and peritoneal dialysis (PD). Further information on each can be found in their individual articles.

It should be noted that they are not the only types of RRT. For more details, refer to our articles on chronic kidney disease (CKD) and renal transplantation.

Indications for RRT

Acute RRT

Important indications can be remembered using the mnemonic AEIOU:^2,3,4

• Acidosis: severe metabolic acidosis, pH <7.2
• Electrolyte disturbance: severe, refractory hyperkalaemia, >7.0
• Ingested toxins: BLAST (barbiturates, lithium, alcohol, salicylate, theophylline)
• Refractory pulmonary oedema
• Uraemia: manifesting as pericarditis/encephalopathy

Chronic RRT

NICE recommends the initiation of chronic RRT when there is the presence of:¹

• Symptomatic uraemia (pericarditis/encephalopathy)
• Biochemical measures (electrolyte or acid-base disturbances that are refractory to medical therapy) or uncontrollable fluid overload
• Asymptomatic with an eGFR of 5-7 ml/min/1.73m²

Other indications outlined by Kidney Disease Improving Global Outcomes (KDIGO) include:⁴

• Anorexia
• Reduced energy level
• Weight loss with no other potential explanation
• Progressive deterioration in nutritional status that is refractory to interventions

Choice of dialysis modalities

All patients who are likely to require RRT should be offered a choice of RRT or conservative management (which involves supportive management and controlling symptoms but without RRT).^1,4

NICE does not provide a straightforward recommendation in the initial choice of dialysis modality, apart from recommending PD as the first choice in patients two years or younger.¹

The selection of dialysis modality should reflect shared decision-making between the clinician and patient after all available options are presented and explained to them.

Haemodialysis

Access

In HD, access refers to a connection between the patient’s circulatory system and the dialysis machine. The two broad options for access are:

• Arteriovenous (AV) access: most commonly through the formation of an AV fistula^4,5 
• Central venous catheter (CVC) access: generally either through a temporary dialysis catheter or a tunnelled haemodialysis catheter^5,6 

AV access

The most common form of AV access is an AV fistula:^4,5 

• An artery is directly connected to a vein
• Takes six to eight weeks to mature
• Common fistula sites are radio-cephalic, brachio-cephalic and brachio-basilic
• Precautions must be taken to prevent damage to the fistula: venepuncture, intravenous cannulation, and blood pressure measurement at the site of the fistula should be avoided
• The preferred option if life expectancy is more than 1 year

CVC access

Temporary dialysis catheters:^5,6 

• Allow immediate use when emergency dialysis is needed in AKI
• Common sites of insertion are the internal jugular, subclavian and femoral veins
• High risk of infection, so should only be in situ for two weeks

Tunnelled haemodialysis catheters:^5,6

• Involve subcutaneous tunnelling of a large, double-lumen venous catheter inserted into a central vein
• Often used while waiting for an AV fistula to mature
• Lower risk of infection compared to temporary catheters
• The preferred option if life expectancy is less than 1 year

Principles

The most common regimen for patients receiving HD is three sessions per week, for 12 hours total (i.e. four hours per session).⁷

The HD circuit consists of:⁵

• A pump that removes blood from the patient
• Anticoagulation of the blood with heparin
• Pumping blood through the dialyser, where filtration takes place 
• Dialysate: a solution of water, electrolytes, dextrose and a buffer
• Filtered blood is returned to the patient, and dialysate discarded

Filtration occurs via passive diffusion across a semi-permeable membrane. The dialysate is continuously replaced to maintain the concentration gradient.

Blood cells and proteins are not lost; only water and low-molecular-weight solutes can pass through the membrane. However, this means it is not as efficient at removing larger solutes.

Contraindications

The only absolute contraindications to long-term HD are:⁴

• Absence of AV access
• Haemodynamic instability

Complications

Complications of HD can be divided into intra-dialysis complications and long-term complications. A more comprehensive discussion of the complications can be found in the HD article.

Intra-dialysis complications^8-10

• Dialysis disequilibrium syndrome: acute cerebral oedema secondary to the rapid shifting of urea from the blood
• Dialyser reactions: reaction between blood components and the semi-permeable membrane of the dialysis machine, may present with anaphylaxis-like symptoms
• Acute intravascular haemolysis: can be from reactions to contaminants in the dialysate or from mechanical forces
• Air embolism
• Haemorrhage: from vascular access
• Hypotension
• Non-specific symptoms: headache, back pain, pruritis and muscle cramps are common¹¹

Long-term complications^8-10 

• Cardiovascular disease (the leading cause of death)^5,12-14
• Bleeding: due to platelet dysfunction resulting from CKD and/or platelet contact with the dialysis membrane
• Electrolyte disturbances: commonly hyperkalaemia, hyponatraemia, hypocalcaemia and hyperphosphataemia
• Mineral bone disorders: associated with CKD
• Loss of venous access: due to thrombosis 
• Catheter-related bacteraemia
• Dialysis access-associated steal syndrome: limb ischaemia due to AV access shunting blood away from the limb

Peritoneal dialysis

Access

In PD, access involves the placement of a catheter into the peritoneal cavity to allow the flow of dialysate solution.

The most commonly used catheter is the Tenckhoff catheter and this can be implanted surgically (open or laparoscopic) or via a percutaneous procedure.^{15, 16,17}

It is recommended to create access around two weeks before starting dialysis to prevent leakage.¹ 

Principles

The two most common regimes for PD patients are:

• Continuous ambulatory peritoneal dialysis (CAPD)
• Automated peritoneal dialysis (APD)

Both can be carried out at home, and patients require PD daily. Patients cannot remain on PD indefinitely and will usually need to change to HD at some point unless they receive a kidney transplant.¹⁸

In PD the patient’s peritoneal membrane acts as the interface between the blood and dialysate. It acts as a semi-permeable membrane which solutes can diffuse across down their concentration gradients. Excess water is also removed from the blood through the creation of a net positive osmotic gradient.

CAPD^9,15

• Dialysate is infused into the peritoneal cavity
• The patient is disconnected from the system and can carry out normal activities
• Dialysate remains in the peritoneal cavity for four to six hours and filtration occurs
• The patient is reconnected to the system to drain the used dialysate
• This is repeated around four times a day

APD^9,19

• Dialysate is infused into the peritoneal cavity via a dialysis machine
• The patient remains connected to the machine, often while sleeping
• Dialysis remains in the peritoneal cavity and filtration occurs
• The dialysate is drained and replaced automatically by the machine
• The machine completes this cycle three to five times a night and takes around eight to ten hours total

Contraindications

Absolute contraindications to PD are when catheter access or use of the peritoneal membrane is not feasible:^4,16,20

• Inflammatory abdominal diseases: Crohn’s disease, ulcerative colitis, current clostridium difficile infection
• End-stage liver disease with ascites
• Unrepaired hernias
• Presence of stomas or feeding tubes
• Presence of abdominal adhesions
• Non-functional peritoneal membrane

Complications

The complications of PD can be divided into four main groups. A more comprehensive discussion of these can be found in the PD article.

Catheter-related complications¹⁷

• Catheter obstruction
• Catheter mispositioning
• Bowel perforation
• Infection: which may progress to bacterial peritonitis
• Peritoneal leak

Membrane-related complications

• Peritonitis: generally secondary to contamination with skin commensal bacteria during exchange or a catheter-related infection, requires prompt assessment and management with intra-peritoneal antibiotics^21,22, the leading cause of needing to transfer to HD²³
• Peritoneal fibrosis: occurs with long-term PD and can cause membrane failure, a common cause of needing to transfer to HD²⁴
• Sclerosing encapsulating peritonitis (SEP): recurrent episodes of small bowel obstruction due to adhesions and strictures²⁵

Metabolic complications

• Cardiovascular disease^26,27
• Fluid overload^26,27
• Hyperglycaemia and insulin resistance: due to high glucose concentrations in dialysate⁵
• Hypokalaemia²⁶

Fluid dwelling-related complications

• Hernias: due to chronically raised intra-abdominal pressure²¹
• Abdominal pain²¹

Summary table

Table 1. Table summarising haemodialysis and peritoneal dialysis.

Reviewer

Dr Roberta Callus

Consultant Nephrologist

Editor

Dr Jess Speller

References

1. National Institute for Health and Care Excellence (NICE). Renal replacement therapy and conservative management (Clinical guideline [NG107]). NICE 2018. Published 2018 Oct. Available from: [LINK]
2. Malhotra A. Acute Kidney Injury (AKI). Geriatric Trauma and Acute Care Surgery 2017 Jul;367-380
3. Baker JB, Navarro Y, Sisroe TA, Everett C. Indications for Urgent and Emergent Hemodialysis. Annals of Vascular Surgery 2024 Jan;98:39-40.
4. Chan CT, et al. Dialysis initiation, modality choice, access, and prescription: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference. Kidney International 2019 Jul;96(1):37-47.
5. Steddon, S. et al. Chapter 4 Dialysis. Oxford Handbook of Nephrology and Hypertension. Oxford: Oxford University Press, 2018
6. Hemodialysis Catheters: How to Keep Yours Working Well. National Kidney Foundation. 2018. Available from: [LINK] 
7. Pauly RP. Survival comparison between intensive hemodialysis and transplantation in the context of the existing literature surrounding nocturnal and short-daily hemodialysis. Nephrology Dialysis Transplantation 2013 Jan;28(1):44-7.
8. Murdeshwar HN, Anjum F. Hemodialysis. Treasure Island (FL): StatPearls Publishing 2024 Jan [Internet]. Updated: 2023 Apr. Available from: [LINK]
9. NHS. Dialysis. Last reviewed: 2021 Sep. Available from: [LINK] 
10. Krause RS. Dialysis Complications of Chronic Renal Failure. Medscape. Last updated: 2023 Nov. Available from: [LINK]
11. Headache attributed to disorder of homeostasis. The International Classification of Headache Disorders 3^rd Available from: [LINK]
12. Survival and Cause of Death in Adult Patients Receiving Renal Replacement Therapy. The Renal Association UK Renal Registry. Available from: [LINK]
13. Bhandari SK, et al. Causes of Death in End-Stage Kidney Disease: Comparison between the United States Renal Data System and a Large Integrated Health Care System. American Journal of Nephrology 2022 Mar;53(1):32-40.
14. Saravanan P, Davidson NC. Risk Assessment for Sudden Cardiac Death in Dialysis Patients. Circulation: Arrhythmia and Electrophysiology 2010 Oct;3(5):553-559.
15. Andreoli MCC, Totoli C. Peritoneal Dialysis. Revista da Associação Médica Brasileira 2020; 66(1):37-44.
16. Sachdeva B, Zulfiqar H, Aeddula NR. Peritoneal Dialysis. Treasure Island (FL): StatPearls Publishing 2024 Jan [Internet]. Updated: 2023 Aug. Available from: [LINK]
17. Peppelenbosch A, et al. Peritoneal dialysis catheter placement technique and complications. NDT Plus 2008 Oct;1(4):23-28.
18. Floege J, Johnson RJ, Feehally J. Comprehensive Clinical Nephrology, 4th edition. London: Elsevier Saunders 2010.
19. Peritoneal dialysis (PD). Kidney Care UK. Available from: [LINK]
20. Al-Natour M, Thompson D. Peritoneal Dialysis. Seminars in Interventional Radiology 2016 Mar;33(1):3-5.
21. Teitelbaum I, Burkart J. Peritoneal dialysis. American Journal of Kidney Diseases 2003 Nov;42(5):1082-1096.
22. Li PKT, et al. ISPD peritonitis guideline recommendations: 2022 update on prevention and treatment. Sage Journals 2022 Mar;42(2).
23. Boissinot L, et al. Is Transition Between Peritoneal Dialysis and Haemodialysis Really a Gradual Process? Journal of the International Society for Peritoneal Dialysis 2013 Jul-Aug;33(4):391-397.
24. Terri M, et al. Mechanisms of Peritoneal Fibrosis: Focus on Immune Cells-Peritoneal Stoma Interactions. Frontiers in Immunology 2021 Mar;12:607204.
25. Machado NO. Sclerosing Encapsulating Peritonitis. Sultan Qaboos University Medical Journal 2016 May;16(2):142-151.
26. Mehrotra R. Chapter 32 Metabolic Complications of Peritoneal Dialysis. Handbook of Dialysis Therapy, 6^th Elsevier 2023.
27. Krediet RT, Balafa O. Cardiovascular risk in the peritoneal dialysis patient. Nature Reviews Nephrology 2010 Jun;6:451-460.