An arteriovenous fistula is a surgically created anastomosis between an artery and a vein. Its main use is to dilate a vein for easier access in patients requiring regular haemodialysis.
Examining an AV fistula
Type of fistula
Radiocephalic AV fistula (most): radial artery to cephalic vein at wrist
Brachiocephalic AV fistula = brachial artery to cephalic vein in antecubital fossa
Brachiobasilic transposition AV fistula = brachial artery to transposed basilic vein in upper arm
Signs of inflammation: rash, erythema, swelling
Arm elevation test (for outflow obstruction): fistula should collapse on arm elevation
Presence of collateral veins (suggest venous stenosis)
Hands – compare to other side
Signs of ischaemia (Steal syndrome = vascular insufficiency secondary to AV fistula)
Thrill: a thrill is normal but it shouldn’t be pulsatile
Consistency: should be soft and easily compressible
Augmentation test (for anastomotic stenosis): occlude vein 1-2 cm above anastomosis. If arterial pressure is adequately conducted (i.e. there is no anastomotic stenosis), a pulsation in the vein will be seen. NB: if vein is pulsatile anyway, there is venous outflow stenosis.
Bruit: should be a soft machinery–like rumbling sound (high-pitched = stenosis)
Why is a fistula needed?
How long does it take for an AV fistula becomes patent?
How is an AV fistula used?
What are the complications of an AV fistula?
What special instructions should be given to a patient with a new AV fistula?
What are the advantages of an AV fistula over a central venous catheter?