Peritoneal Dialysis

Form of renal replacement therapy that involves introducing dialysate into the abdominal cavity, relying on the semi-permeable peritoneal membrane to filter solute and adjust volume state. Peritoneal dialysis is:

Peritoneal dialysis is used less commonly for AKI due to the wide availability of venovenous options, but remains the mainstay of therapy in the developing world.

Performed via an intra-abdominal catheter
Classically a Tenckhoff.
Generally divided into:
- Continuous Ambulatory Peritoneal Dialysis
  - Dialysate solution is periodically drained into, and then out of, the abdomen under gravity
  - Exchanges usually occur 3-4×/day, and once in the evenings
- Automated Peritoneal Dialysis
  - Dialysate “cycler” changes dialysate during the night, usually whilst asleep
  - Requires 8-10 hours of continuous connection
Occasionally performed urgently

Indications

Standard dialysis indications are covered under Continuous Renal Replacement.

In addition to standard indications, PD has been used for:

Volume control in NYHA IV heart failure
Hyperthermia
Necro-haemorrhagic pancreatitis

Contraindications

Abdominal injury
- Abdominal adhesions
- Peritoneal fibrosis
- Recent abdominal surgery
Uncontrolled uraemia
Due to ↓ solute clearance.
Emergent situations
Less effective than haemodialysis, although still successful.

The ↓ urea clearance is particularly relevant in hypercatabolic patients.

Principles

Peritoneal dialysis relies on:

Solute clearance via dialysis
Urea clearance is used as a surrogate marker for clearance of small solutes, and therefore the determinant of dialysate dose.
Fluid removal via ultrafiltration
Adjusting the concentration of the dialysate affects the degree of volume removal.

Practice

Considerations for Peritoneal Dialysis
Advantages	Disadvantages
Technical simplicity Haemodynamic tolerance No bleeding risk No requirement for anticoagulation	Requires intact peritoneum Infection risk ↓ Solute clearance Obligate protein losses 0.5-4g/L of dialysate. Risk of hyperglycaemia Impaired respiratory mechanics

Prescription should specify dialysate:

Note that these solutions aren’t pure dextrose; they are all hypertonic solutions that contain a variety of other electrolytes. E.g., The DIANEAL PD-2 2.5% dextrose solution contains:

Dextrose: 2.5%
Sodium: 132mEq/L
Chloride: 96mEq/L
Magnesium: 0.5mEq/L
Calcium: 3.5mEq/L
Lactate: 40mEq/L
Total osmolarity: 396mmol/L

Volume
- Generally 30-40mL/kg
- Smaller volumes used when commencing
Composition
Constituents include:
- Osmotic agents
  Facilitate fluid removal. Options include:
  - Dextrose
    Rapidly absorbed, necessitating short dwell times. Comes in:
    - 1.5% dextrose
    - 2.5% dextrose
    - 4.25% dextrose
  - Icodextrin
  - Polypeptides
- Buffers
  - Lactate
  - Acetate
  - Bicarbonate
- Electrolytes
Dwell time
- ↑ Dwell time results in reabsorption of fluid and fluid overload
- ↓ Dwell time ↓ ultrafiltration and may ↓ efficacy of dialysis
- Patients may need shorter or longer dwell times based on individual speed of their peritoneal membrane
Number of exchanges per day

Chronic hyperglycaemia ↓ the osmotic pressure between blood and dialysate, leading to fluid retention.

Complications

Key Studies

References

Ponce Gabriel D, Nascimento GVR, Teixeira Caramori J, Cuadrado Martim L, Barretti P, Luís Balbi A. Peritoneal Dialysis in Acute Renal Failure. Renal Failure. 2006;28(6):451-456. doi:10.1080/08860220600781245
Roseman DA, Schechter-Perkins EM, Bhatia JS. Treatment of life-threatening hyperkalemia with peritoneal dialysis in the ED. The American Journal of Emergency Medicine. 2015;33(3):473.e3-473.e5. doi:10.1016/j.ajem.2014.08.041
Ilabaca-Avendaño MB, Yarza-Solorzáno G, Rodriguez-Valenzuela J, et al. Automated peritoneal dialysis as a lifesaving therapy in an emergency room: Report of four cases. Kidney International. 2008;73:S173-S176. doi:10.1038/sj.ki.5002620