How does peritoneal dialysis work?

The lining of your abdomen (the peritoneum) does the filtering. Dialysis fluid is run into the abdominal cavity through a soft tube, draws waste and excess fluid out of the blood across the lining, and is then drained away. The filtering happens inside your body, with no external blood circuit.

The PD cycle: fluid is run in (fill), left to sit in the abdomen (dwell), then drained out (drain), carrying waste and excess fluid with it. The fluid contains glucose to draw off water. You do several exchanges over a day or overnight.

What is the difference between CAPD and APD?

CAPD uses manual exchanges done by hand several times a day, needing no machine. APD uses a machine (a cycler) to do exchanges automatically overnight while you sleep, freeing up your day. Your team helps you choose, and some people switch between them.

What is the most important warning sign in PD?

Peritonitis. The classic sign is cloudy drained fluid, usually with tummy pain and sometimes fever. A single cloudy bag is enough to act on: contact your PD unit immediately and keep the cloudy bag to show them. It is treatable but needs prompt attention.

Why is clean technique so important in PD?

Because careful hand washing, a clean space, a mask if instructed, and careful handling of connections are your main defence against introducing infection into the abdomen, which causes peritonitis. Clean technique at every exchange and every exit-site care is essential.

Peritoneal Dialysis (PD): What to Expect

Written & reviewed by the BestDoctors.sg editorial team · Last updated 28 Aug 2026 · General information, not medical advice

Peritoneal dialysis, or PD, is a home dialysis treatment that uses the lining of your own abdomen as a natural filter, rather than a machine and blood circuit. It offers flexibility and independence, and after training you or a carer do it yourself. Knowing how it works, and above all the one warning sign to act on quickly, makes PD much less daunting. This guide explains what to expect, with the key safety point front and centre.

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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

This is general information and does not replace your renal team’s training. The most important thing to know: cloudy drained PD fluid, with or without tummy pain or fever, can mean peritonitis, an infection of the abdominal lining. Contact your PD unit immediately, and keep the cloudy bag to show them. Keep clean technique at every exchange.

How PD works

In peritoneal dialysis, the lining of your abdomen, called the peritoneum, does the filtering. It is a natural membrane richly supplied with tiny blood vessels. Dialysis fluid is run into the abdominal cavity through a soft tube, where it draws waste products and excess fluid out of the blood across the peritoneum, and is then drained away. Because the filtering happens inside your body, there is no external blood circuit and no needles into a fistula for each treatment. This is one reason some people prefer it, and it can make PD gentler on the heart and blood pressure than centre haemodialysis for certain people.

The catheter and exit site

PD is done through a soft, flexible tube called a PD catheter, placed by a small operation into the abdomen, usually near the navel, with one end coming out through the skin at a point called the exit site. The catheter usually needs a few weeks to heal and settle before regular use. Looking after the exit site, keeping it clean and watching for early signs of infection, is a daily part of PD, taught by your PD nurse.

The exchange

The basic cycle of PD is called an exchange, and it has three steps: fluid is run in (fill), left to sit in the abdomen for a set time (dwell), and then drained out (drain), carrying the waste and excess fluid with it. The fluid contains glucose, which draws off excess water, and your team advises which strength of fluid to use depending on how much fluid you need to remove. You do several exchanges over a day or overnight.

CAPD and APD

There are two main ways to do PD. CAPD (continuous ambulatory peritoneal dialysis) uses manual exchanges done by hand, typically several times a day, each taking a short while, with fluid dwelling in between; it needs no machine or electricity. APD (automated peritoneal dialysis) uses a machine, sometimes called a cycler, to do the exchanges automatically overnight while you sleep, freeing up your day. Your team helps you choose the option that fits your life, and some people switch between them at different stages of their treatment.

A home therapy and clean technique

PD is a home therapy that you or a trained carer carry out after a training course from the PD unit, which is why it offers independence and can fit around work, study and family. The single most important habit is clean, careful technique at every exchange and every time you handle the exit site: washing your hands, using a clean space, wearing a mask if instructed, and handling the connections carefully. This is your main defence against introducing infection.

Peritonitis, the key sign

The one complication every PD patient must know is peritonitis, an infection of the peritoneum. The classic sign is cloudy drained fluid, usually with tummy pain, and sometimes fever, nausea or feeling generally unwell. A single cloudy bag is enough to act on. Peritonitis is treatable, often with antibiotics added into the PD fluid, but it needs prompt attention, so contact your PD unit immediately, do not wait to see whether it clears, and keep the cloudy bag to show them. Repeated episodes can damage the membrane over time, so catching each episode early and treating it promptly is what protects your ability to keep using PD.

Daily life and getting help

Day to day, PD becomes a routine of exchanges, exit-site care, checking your weight and fluid balance, and keeping your supplies stocked. Report an exit-site infection (redness, tenderness, swelling, crusting or discharge, especially with fever) to your unit promptly, as it can lead to peritonitis if untreated, and report drainage problems or feeling unwell. In Singapore, your hospital PD team is your first contact, and 995 is for emergencies such as severe pain, collapse or being seriously unwell. Over time, most people find that peritoneal dialysis fits into their normal daily life far more easily and naturally than they had first expected when they started out.

Sources

NHS – Dialysis: nhs.uk
Kidney Care UK – Peritoneal dialysis: kidneycareuk.org
NIDDK (NIH) – Peritoneal dialysis: niddk.nih.gov
NHS – Peritonitis: nhs.uk

General information only. This guide supports, but does not replace, the advice of your kidney (renal) team, who set your dialysis, diet, fluid limits and medicines. Never miss or shorten a dialysis session without contacting your unit, and protect your fistula arm (no blood-pressure cuffs, blood tests or tight clothing on it). Contact your dialysis unit at once if your drained peritoneal-dialysis fluid looks cloudy or you have tummy pain and fever (a possible peritonitis), or for a hot, red, painful or leaking access site. Call 995 for bleeding from your access that will not stop with firm pressure, or for severe breathlessness (a possible dangerous fluid overload). If you are struggling emotionally, you are not alone: the Samaritans of Singapore (SOS) are on 1767 and mindline.sg on 1771.

Peritoneal Dialysis: What to Expect (Singapore)