Peripheral venous cannulation animated demonstration

Equipment needed

  • Gloves (and consider a plastic gown and protective eyewear in high-risk patients)

  • Antiseptic wipes (2% chlorhexidine gluconate in 70% alcohol)

  • Tourniquet (ideally disposable)

  • Intravenous cannula of a suitable gauge

  • Cannula dressing pack (usually transparent dressings)

  • Syringe and 0.9% sodium chloride flush

  • Needle-free connector (optional)

  • Cotton wool swabs or gauze swabs

  • Sharps bin.


Do not perform intravenous cannulation when there is no immediate need or predicted imminent need for intravenous access. Not every patient in hospital will require a cannula, although any acute admission necessitates early establishment of intravenous access in case of emergency.

Sites to avoid when performing cannulation include:

  • Anatomical snuffbox

  • Arms where there are arteriovenous fistulas (e.g., in dialysis patients)

  • Areas where lymphatic drainage has been affected (e.g., the arm following axillary surgery)

  • Areas of cellulitis or burns

  • Small veins in the lower limbs and feet, especially in diabetic patients

  • Areas of peripheral vascular disease, varicose veins, venous hypertension, or oedema

  • Joint surfaces.


Intravenous cannulas are used for bolus injections or prolonged infusion of fluids and drugs. In the initial assessment of a critically ill patient, intravenous cannulation specifically forms part of the ABCDE algorithm. After checking airway (A) and breathing (B), examination of the circulation (C) should be completed with the establishment of at least one site of intravenous access. This normally requires two large-bore cannulas (14-gauge to 16-gauge), one in each antecubital fossa.


  • Bruising/haematoma: relatively common, particularly after failed or vigorous cannulation attempts

  • Infection of the cannulation site: cellulitis may arise around the insertion site, which in some patients may progress to systemic sepsis

  • Displacement (tissueing): the cannula may become dislodged from the vein; if so, remove it and site a new cannula

  • Extravasation: if the cannula has not been properly sited, injected fluids or drugs may pool under the skin, which may be irritating to the patient and in some cases cause tissue necrosis

  • Thrombophlebitis: irritation and clotting of the vein at the cannula site requires removal of the cannula

  • Blockage: clots or collections of infusion products may occlude the cannula. In some cases this can be resolved by flushing the cannula with normal saline but it may be necessary to remove the cannula

  • Arterial puncture: detected by pulsatile blood flow into the cannula chamber and from the end of the cannula after the needle is removed. Arterial puncture may be intensely painful and lead to distal limb ischaemia. If this occurs you should remove the cannula immediately, remove the tourniquet, and apply firm pressure to the site

  • Peripheral nerve injury: this is rare. Remove the cannula immediately if the patient develops paraesthesia or numbness near the cannula site.


Unless cannulation proceeds smoothly and without resistance to the needle, sheath, or flush, the cannula may be sited incorrectly. Discard the cannula and always use a new cannula in another attempt. Applying pressure over the site of a failed cannulation will minimise bruising and bleeding. Once a cannula has been successfully sited, connect it to a giving set or intravenous infusion as required.

Cellulitis may arise around the insertion site. Check intravenous cannulation sites regularly for signs of infection such as redness or weeping. Most cannulation dressing packs use transparent materials to aid this.

Previous infection-control policies suggested that peripheral cannulas should not be left in situ for more than 72 hours. However, a Cochrane review in 2015 showed there was no evidence that routinely replacing cannulas every 72 to 96 hours had any difference in catheter-related bloodstream infection or phlebitis rates compared with removing them when clinically indicated (e.g., inflammation, infiltration, or blockage).[87]

If infection of the cannula site occurs, remove the cannula, take swabs of the site and blood cultures before promptly starting antibiotics.