The colour coding of of 20G IV cannula is
**Core Concept**
The colour coding of IV cannulas is a standardized system used to prevent accidental arterial puncture. This system is based on the International Organization for Standardization (ISO) 80369-7 standard, which specifies the colour coding for different sizes of IV cannulas.
**Why the Correct Answer is Right**
The correct answer is based on the ISO 80369-7 standard, which states that a 20G IV cannula should be colour-coded blue. This is because the gauge (G) of the cannula is inversely related to its outer diameter, and a 20G cannula has a larger outer diameter than a 22G or 24G cannula. The blue colour coding serves as a visual reminder to healthcare professionals to use caution when inserting the cannula, as it may be more likely to cause arterial puncture.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the colour coding of IV cannulas is not based on the gauge number, but rather on the outer diameter and ISO standard.
* **Option B:** This option is incorrect because a 22G IV cannula is typically colour-coded yellow, not the correct answer.
* **Option C:** This option is incorrect because a 24G IV cannula is typically colour-coded green, not the correct answer.
**Clinical Pearl / High-Yield Fact**
To remember the colour coding of IV cannulas, use the mnemonic "BYG" for blue (20G), yellow (22G), and green (24G).
**Correct Answer:** C. Green