Always select the smallest gauge peripheral catheter that will accommodate the prescribed therapy and patient need. Peripheral catheters larger than 20G are more likely to cause phlebitis. Do not use peripheral veins for continuous infusions of vesicants, parenteral nutrition or infusates with an osmolarity of 900 mOsm/L.1 External catheter diameters, length and water flow rates are variable among each brand of catheter, with the dimensions and flow rates listed below being approximate. Fluid flow rates in actual patient use, are influenced by the type and viscosity of fluid, fluid temperature, height of the container and the use of needleless connectors.2 There are numerous factors that could also affect fluid flow rates, once the catheter is inserted into a patient.
Peripheral IV Catheter Chart
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Orange |
14G |
2.1 mm |
45 mm |
~240 mL/min |
Trauma, Rapid blood transfusion, Surgery1 |

Gray |
16G |
1.8 mm |
45 mm |
~180 mL/min |
Rapid fluid replacement, Trauma, Rapid blood transfusion1 |

Green |
18G |
1.3 mm |
32 mm |
~90 mL/min |
Rapid fluid replacement, Trauma, Rapid blood transfusion1 |

Pink |
20G |
1.1 mm |
32 mm |
~60 mL/min |
Most infusions, Rapid fluid replacement, Trauma, Routine blood transfusion1 |

Blue |
22G |
0.9 mm |
25 mm |
~36 mL/min |
Most infusions, Neonate, Pediatric, Older adults, Routine blood transfusion1 |

Yellow |
24G |
0.7 mm |
19 mm |
~20 mL/min |
Most infusions, Neonate, Pediatric, Older adults, Routine blood transfusion, Neonate or Pediatric blood transfusion1 |

Purple |
26G |
0.6 mm |
19 mm |
~13 mL/min |
Pediatrics, Neonate1 |
References: Infusion Therapy Standards of Practice Jan/Feb 20161
https://www.bd.com/infusion/products/ivcatheters/iagbc/videos/pdfs/iagbc_wp3.pdf 2
*varies by specific catheter and manufacturer