Healthcare and Medicine Reference
Figure 20.6 Step-by-step guide: insertion of arterial cannula. (a) The
patient positioned with the wrist dorsifl exed. (b) Sterilising the wrist with
2% chlorhexidine in 70% isopropyl alcohol solution. (c) Palpating the
radial artery to identify the point of maximal pulsation. (d) Infi ltrating local
anaesthetic (0.5-1 mL 1% lidocaine) subcutaneously. (e) Puncturing the skin
at an angle of 30-40°. (f) Advancing the needle until a fl ashback of blood is
seen in the hub of the needle. (g) Advancing the cannula off the needle up
the lumen of the artery. (h) Dressed cannula with sterile dressing.
Advance the needle until the artery is punctured giving a free
pulsating fl ow of blood.
Pass the guidewire through the needle and up the artery so that
majority of the guidewire is in the artery lumen (Figure 20.8a).
Withdraw the needle completely whilst maintaining the position
of the guidewire in the artery. Place the cannula over the guide-
wire whilst holding the guidewire at the level of the skin and
advance the cannula towards your fi ngers (Figure 20.8b). Feed the
wire back through the cannula until it protrudes from the hub
of the cannula and then, taking care to maintain a hold on the
guidewire, advance the cannula over the guidewire into the lumen
of the artery. A rotational motion helps advance the cannula.
Remove the guidewire and cap the end of the cannula to prevent
Advance cannula up
blood loss (Figure 20.8c).
The cannula can then be secured, with sutures if required, and
covered with a semipermeable sterile dressing that allows visual
inspection (Figure 20.6h).
Figure 20.7 Transfi xing technique. As the cannula is withdrawn a secondary
fl ashback is seen.