What You Need to Know about IV Cannula

hsn_er/icu_nurse.

The intravenous cannula is used by medical personnel to access the vein of patient, either for injecting medicine or withdrawing blood. This is commonly known as an IV. It is made in different gauge sizes. The smaller the gauge number, the bigger the needle will be. As a new nurse, you may find it difficult to spot its’ differences. Luckily, most manufacturers color code their IV needles. Here’s a little rhyme you can use to help you remember what colors correspond to what sized gauge: 22 is blue and 18 is green, pink is the one in the middle. However, there are other IV gauge sizes besides these.

      Gauge sizes, Color code and Recommended uses

Color	Gauge Size	External Diameter (mm)	Length (mm)	Water Flow Rate(mL/min)	Recommended Uses
Orange	14G	2.1 mm	45 mm	~240 mL/min	Trauma, Rapid blood transfusion, Surgery
Gray	16G	1.8 mm	45 mm	~180 mL/min	Rapid fluid replacement, Trauma, Rapid blood transfusion
Green	18G	1.3 mm	32 mm	~90 mL/min	Rapid fluid replacement, Trauma, Rapid blood transfusion
Pink	20G	1.1 mm	32 mm	~60 mL/min	Most infusions, Rapid fluid replacement, Trauma, Routine blood transfusion
Blue	22G	0.9 mm	25 mm	~36 mL/min	Most infusions, Neonate, Pediatric, Older adults, Routine blood transfusion
Yellow	24G	0.7 mm	19 mm	~20 mL/min	Most infusions, Neonate, Pediatric, Older adults, Routine blood transfusion, Neonate or Pediatric blood transfusion
Purple	26G	0.6 mm	19 mm	~13 mL/min	Pediatrics, neonate

References:  Infusion Therapy Standards of Practice Jan/Feb 2016
https://www.bd.com/infusion/products/ivcatheters/iagbc/videos/pdfs/iagbc_wp3.pdf 2
*varies by specific catheter and manufacturer