CHAPTER 13. ARTERIAL CANNULATION
Indications112
Contraindications112
Equipment112
National Patient Safety Agency (NPSA) recommendations113
Practical procedure113
Post-procedure investigations116
Complications116
Suggested reading117
The Reverend Stephen Hales (1677–1761), a British veterinarian, cannulated the femoral artery of a horse using a brass tube and published his findings in 1733 in Hemastatiks. He connected the brass tube to a glass tube and recorded the rise of the blood column, thus becoming the first individual to measure blood pressure. This invasive approach was refined by Carl Ludwig in 1847 with his kymograph, which with the use of a quill plotted the waveform undulation of the arterial pulse. Non-invasive measurement followed individual observations and instrumental modifications by Karl Vierordt in 1855, Etienne Jules Mary in 1860, Samuel Von Basch in 1881 and Scipione Riva Rocci in 1896, cumulating into the modern day sphygmomanometer.
INTRODUCTION
Arterial cannulation is an advanced procedure performed on patients who require regular measurements of blood gases or who require continuous monitoring of blood pressure. It is normally performed on patients in a critical care environment. The radial artery is usually the vessel most suitable for cannulation. It is readily palpable and accessible, and the hand usually has an extensive collateral ulnar arterial circulation, thereby minimizing risk of digital ischaemia.
There are various cannulae available for arterial cannulation: some are the same design as venous cannulae whilst others are inserted using a guidewire approach. Note that whichever cannula is used it is unusual to use one larger than 20 G – larger cannulae risk damage to the vessel, whilst smaller cannulae become easily damped, kinked and provide poorer arterial traces. This chapter will concentrate on the insertion of guidewire-placed arterial cannulae using the Seldinger technique.
INDICATIONS
• Regular monitoring of arterial blood gases.
• Continuous or regular monitoring of blood pressure – mandatory if on inotropic support in the critical care setting.
• Patients undergoing major surgery, such as cardiovascular, cardiothoracic or neurosurgical procedures.
CONTRAINDICATIONS
• Negative Allen’s test (see Chapter 12).
• Previous injury – such as from trauma, burns or surgery performed on the arm.
• Previous radial artery harvesting for coronary artery bypass surgery (may only have one vessel remaining for perfusion of the hand).
• Congenital deformities (such as in radial club hand) may result in anomalous vasculature to the extremity.
• A history of diabetes, hypertension, peripheral vascular disease, active infection in the extremity, collagen vascular disorders and blood dyscrasias may affect the decision to place the arterial catheter. All of these conditions have been associated with an increased risk of complications with arterial cannulation.
• Anticoagulant medications such as warfarin, aspirin, heparin and clopidogrel increase the risk of bleeding. This may lead to haematoma formation and a risk of hand ischaemia.
• Lack of consent.
EQUIPMENT
• 10 mL syringe.
• Green needle.
• Orange needle.
• Lidocaine.
• Dressing pack.
• Sterile gloves.
• Chlorhexidine cleaning solution.