Peritoneal dialysis

# Overview
Peritonial dialysis is a procedure to remove waste and excess fluid e.g. urea and potassium from blood when kidneys are no longer capable of doing so, such as in cases of renal failure. Peritonial dialysis is a type of renal dialysis and therefore also referred to as renal replacement therapy. It follows the process of diffusion, wherein peritoneal membrane surrounding the abdominal viscera serves a semipermeable membrane and can, in the presence of specifically formulated dialysis fluid, help dialysis. Another process involves osmosis wherein excessive fluid can be removed by altering the concentration of glucose in the dialysis fluid. The fluid used for dialysis is instilled via a catheter. The most common dialysis catheter is Tenckhoff Catheter. It is placed in the patient's peritoneum and runs to the skin surface near the umbilicus. These catheters may also be tunneled subcutaneously and exit various locations such as near the rib margin or close to sternum (presternal catheter) or even higher  near the clavicle. The procedure involves a small surgery and choice of exit site is influenced by multiple factors viz patient's or surgeon's preference, anatomical variations, and/or ability to maintain good hygiene. Peritoneal dialysis can be done anywhere; at home or at workplace and all it requires is a clean area, a way to elevate the fluid bag, and means to warm the fluid. As one may imagine, there is, however, a predilection for infection e.g. peritonitis. Hence the importance of taking hygienic precautions cannot be over emphasized.

# Types
There are three types of peritoneal dialysis: 
- Continuous ambulatory peritoneal dialysis (CAPD), the most common type, needs no machine and can be done at home. Exchanges of fluid are done throughout the day, usually four exchanges a day.
- Continuous cyclic peritoneal dialysis (CCPD) uses a machine and is usually performed at night when the person is sleeping.
- Intermittent peritoneal dialysis (IPD) uses the same type of machine as CCPD - if done overnight is called Nocturnal intermittent peritoneal dialysis (NIPD).

# Indications
Indications of peritoneal dialysis include:
- Uremia
- Metabolic derangements
- Heart failure
For details on indications of dialysis click here

# Advantages and disadvantages of Peritoneal dialysis

## Advantages
The following are the advantages:
- Can be done at home.
- Relatively easy to learn.
- Easy to travel with, bags of solution are easy to take on holiday.

## Disadvantages
- Requires a degree of motivation and attention to cleanliness while performing exchanges.
- Possible complications (see below)

# Complications
Following are the complications associated with Peritoneal Dialysis:
- Infection
- Peritonitis
- Hernias
- Accumulation of fibrin in the PD effluent
- Damage to peritoneal membrane
- Diabetes because of the glucose levels that are in the 'bags'
- Fluid leaks into surrounding soft tissue, often the scrotum in males

# CAPD exchange

## Precautions:
- A disposable surgical mask
- Antibacterial soap
- IV stand or other elevated location, such as a coat hook.

### Materials needed:
- A dialysis fluid bag: contains glucose and electrolytes dissolved in water.
- Two bags: one empty and one with the fluid, connected via flexible tubing to a Y-shaped fitting.
- Once connected to the system, the patient clamps the tubing connected to the full bag of dialysis fluid and then releases the twist valve located in the tip of their catheter; this permits fluid to flow into or out of the peritoneal cavity. Because the full bag of fluid is clamped off but the empty bag is not, the effluent (used dialysis fluid) from within the peritoneum can drain out of the catheter and into the lower, waste bag. Emptying the abdomen of fluid takes approximately fifteen minutes.
- When the abdomen has drained, the lower drain-bag is clamped off. The twist valve in the catheter is also closed. The clamp is then removed from the upper tubing, permitting dialysis fluid to drain out into the abdomen. The clamp to the drain bag is briefly opened and some fluid is drained directly from the upper bag into the lower bag. This clears the line of air and other impurities. The drain line is then clamped off and the twist valve on the catheter end is opened. This permits fluid to enter the peritoneum. Filling the abdomen with fresh fluid takes about fifteen minutes, and the patient enjoys the same freedoms as while draining.
- Once the entire bag of fluid (an amount varying primarily based on body size, ranging from 1500 to 3000 mL) has been introduced to the abdomen, the patient then cleans their hands again (typically using an antiseptic alcohol-based cleanser) and puts the surgical mask on. The Y-connector is detached from the catheter tip and a protective cap is placed on the end of the catheter.
- The effluent is inspected after a dialysis exchange is complete; a cloudy effluent indicates probable peritoneal infection. The effluent is drained into a toilet, and the various dialysis supplies are discarded with normal garbage.