Indications
- • Continuous BP monitoring (vasopressors, unstable)
- • Frequent ABGs
- • Cardiac output monitoring
Contraindications
- ⚠ Inadequate collateral (modified Allen's)
- ⚠ Local infection
- ⚠ Severe peripheral vascular disease
- ⚠ Raynaud's, Buerger's
Equipment
- • 20G arterial cannula or Seldinger kit
- • Pressurised flush set with transducer
- • USS (optional but recommended)
- • Chlorhexidine, suture, dressing
Technique
- • Wrist extended over rolled towel, slight dorsiflexion
- • Palpate / USS radial artery 1–2 cm proximal to wrist crease
- • Sterilise, infiltrate local anaesthetic
- • Insert cannula at 30–45° towards pulsation — flash of arterial blood
- • Lower angle, advance cannula over needle (or pass guidewire if Seldinger)
- • Connect to transducer at phlebostatic axis, zero
- • Suture and apply dressing
Complications
- ⚠ Thrombosis, distal ischaemia
- ⚠ Haematoma, bleeding
- ⚠ Infection
- ⚠ Accidental drug injection — never administer drugs into arterial line
Aftercare
- • Check distal perfusion hourly
- • Zero transducer per shift
- • Remove ASAP; manual pressure ≥5 min after removal
Clinical pearls
- • Sharp upstroke + dicrotic notch on waveform confirms position
- • Damped trace: kink, clot, air, low pressure bag — flush and check
Perform under supervision until competent. Follow local SOPs and consent policy.
