Bma Illustrated Medical Dictionary

dialysisA filtering technique used to
remove waste products from the blood
and excess fluid from the body as a
treatment for kidney failure. The kidneys
normally filter about 1,500 litres of blood
daily. They maintain the fluid and elec-
trolytebalance of the body and excrete
wastes in the urine. Important elements,
such as sodium, potassium, calcium,
amino acids, glucose, and water are re-
absorbed. Urea, excess minerals, toxins,
and drugs are excreted. Dialysis is used
to perform this function in people whose
kidneys have been damaged due to
acute kidney failure or chronic kidney
failure. Without dialysis, wastes accu-
mulate in the blood. In chronic kidney
failure, patients may need to have dialy-
sis several times a week for the rest of
their lives or until they can be given a
kidney transplant. In acute kidney failure,
dialysis is carried out more intensively
until the kidneys are working normally.
There are 2 methods of dialysis: haemo-
dialysis and peritoneal dialysis. In both
methods, excess water and wastes in the
blood pass across a membrane into a
solution (dialysate), which is then discard-
ed. Haemodialysis filters out wastes by

passing blood through an artificial kid-

ney machine. The process takes 2–6 hours.

Peritoneal dialysis makes use of the

peritoneum(the membrane that lines

the abdomen) as a filter. The procedure

is often carried out overnight or contin-

uously during the day and night. Both

types of dialysis carry the risk of upset-

ting body chemistry and fluid balance.

There is also a risk of infection within

the peritoneum in peritoneal dialysis.

diamorphineA synthetic, opioid anal-

gesic drugsimilar to morphine; it is

another name for heroin. Diamorphine

is used to relieve severe pain and also

to relieve distress in acute heart failure.

It carries the risk of dependence so is

prescribed with caution. The drug may

also cause nausea, vomiting, and con-

stipation. (See also heroin abuse.)

diaphragm, contraceptiveA female

barrier method of contraception in the

form of a hemispherical dome of thin

rubber with a metal spring in the rim.

(See also contraception, barrier methods.)

diaphragm muscleThe dome-shaped

sheet of muscle that separates the chest

from the abdomen. It is attached to the

spine, ribs, and sternum (breastbone)

DIALYSIS DIAPHRAGM MUSCLE

D

Fresh
dialysate

Blood pump

Blood

tubing

Dialysate

tubing

Bag of used
dialysate

Saline solution

DIALYSIS

PERITONEAL DIALYSIS HAEMODIALYSIS

Blood

filter

Monitor

Connection

to vein

Dialysate

tubing

Fresh dialysate

fluid