The diameter of a urinary catheter used in a pediatric patient needs to match the diameter of the patient’s urethra.
The diameter of a urinary catheter refers to its external diameter (outer diameter or OD).
1 French = 0.3333 mm
The smallest diameter balloon catheters (5, 6 or 8 French) may be somewhat flimsy. Some people use a feeding catheter instead. Others try to use 8 Fr catheters in infants.
Age in Years
Body Weight in Kilograms
Suggested Size FrenchCatheter
Corresponding OD
infant
< 10
5 or 6
1.67 to 2.0 mm
1 year
10
6 to 8
2 years
12
8
2.67 mm
3 years
14
8 to 10
5 years
18
10
3.3 mm
6 years
21
12
4.0 mm
8 years
27
12
12 years and above
30 or more
14
4.67 mm
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