The rapid infusion catheter (RIC)

The CICM  question relating to this device (Question 22.3from the first paper of 2010) had nothing to ask about the device itself, but rather was interested in the physics of fluid movement: " What are the major determinants of fluid flow through this device?" The Poiseuille relationship is discussed elsewhere. Fortunately, LITFL have a good overview.

Flow rate through tubes

Poiseuilles formula is:

Flow = (π × pressure gradient × radius⁴) / ( 8 × viscosity × length of tubing)

Thus, for every doubling of the radius, the flow rate increases by the fourth power, or by sixteen times. 

The Rapid Infusion Catheter itself

The actual device itself is sufficiently interesting to merit some discussion.

Firstly, it is a rather beautiful device.

Secondly, and in briefest summary, its operative features are:

• 8.5 Fr diameter, 6.5cm long infusion catheter (thus, short and fat, as per Poiseuille)
• Seldinger insertion technique, to permit the guidewire-assisted exchange of a 20G peripheral cannula for this RIC.

Its safety features include:

• Latex-free inert plastic
• Non-pyrogenic components

• Single use disposable product, sterilised with ethylene oxide
• Secure eyelet for skin fixation with sutures
• Secure ribbed hub for additional sutures
• Luer lock connector to fit standard giving sets

The Arrow propaganda booklet contains all the relevant information for this device.

It does not contain the most important part, however, which is the rate of flow though it.

Fortunately, some clever Canadian has gone so far as to test this catheter and a whole bunch of other catheters to determine their maximal flow rates with normal saline. The RIC performed best, delivering a torrential flow rate of 600ml/min (603 +/- 21ml, to be precise; and without a spring-loaded cannula hub).