Procedure

• Patient or donor is best placed lying on a couch with the chosen arm placed comfortably on a supporting pillow.

• A large gauge needle attached to a collection pack containing anticoagulant is inserted in an antecubital vein or forearm vein after application of a sphygmomanometer cuff to the upper arm (inflated to diastolic pressure) and sterilisation of the skin. It is widespread practice to infiltrate the skin over the chosen vein with local anaesthetic (1% lidocaine (lignocaine)) prior to insertion of the large bore needle.

• Inflation of the sphygmomanometer cuff is maintained until the desired volume of blood is collected.

• The patient may assist the flow of blood by squeezing a soft ball or similar object in the hand of the arm from which the blood is drawn.

• Blood is allowed to drain into the collection pack until the desired volume has been obtained (usually 500mL).

• The volume collected may be monitored by suspension of the pack from a simple spring measuring device.

• The positioning of the collection pack below the patient's (or donor's) level facilitates blood flow into the bag.

• Once the desired volume has been collected the cuff is deflated, the line should be clamped and the needle removed and a dry cotton wool ball used to apply pressure to the venesection site.

• Direct firm pressure should be applied for 5 minutes and the site inspected for haemostasis prior to application of a firm bandage.

566 • The patient should slowly adopt the erect posture and should remain seated for several minutes if symptoms of lightheadedness occur.

• Patients should not be permitted to drive after venesection.

• The collected blood from a therapeutic venesection should be disposed of by incineration.

Note: for patients with PPP/PRV isovolaemic venesection is recommended to minimise volume depletion whilst still reducing Hct.

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