Intermittent catheterisation in children September 2016 3.3 Charrière The external diameter (size) of catheters is measured in millimetres, and is known as the Charrière scale (CH,Fr or Ch). 1 Ch corresponds to 0.33 mm. Generally most types of catheters are available is sizes from 6 to 20 Ch for intermittent catheterisation (Table 4 ). The size is commonly represented by the international colour coding of the connector at the end of the catheter, and the Charrière is stated on the package. Additionally for small or premature babies/neonates or difficulties with inserting size 6 catheters there are non-coated smaller catheters available a size 4 male length (Vygon) and a size 5 paediatric length ( Wycath). The use of feeding tubes is not recommended due to the incidence of knotting in the bladder. 21 Recommended size by age can be seen table 5. Table 4 Catheter connector colour chart Catheter size 6 8 10 12 14 16 18 20 Colour Diameter 2 2.7 3.3 4 4.7 5.3 6 6.7 Table 5 General overview of recommended Charrière per age category Age Charrière 0-1 years Ch 6-8 1-8 years Ch 8-10 8-12 years Ch 10-12 12 years and older Ch 12-14 As the urethra is able to tolerate large sizes of catheter e.g. a 3yr old boy can tolerate a size 14 catheter clinicians may recommend larger sizes than those in the table above in order to promote more effective emptying, reduce time to empty and minimize infection risks. 3.4 Length A catheter with a length of 20 cm is normally suitable for most boys up to 8 years old. In Charrière sizes 8, 10, and 12 there are catheters available with an ‘in-between’ length of 30 cm (Lofric, Coloplast, Teleflex). When boys become older, they can move on to the ‘adult’ length of 40 cm. There is a male compact version which is available for teenage boys which is graduated from a size 12 to 18 within the same catheter. These catheters should be only used in consultation with the health professionals. For girls, catheter lengths from 7 to 20 cm are available. These lengths can basically be used by children of all ages, with the shortest sizes intended especially for catheterisation when sitting on the toilet. The short catheters are packed in a way to ensure they are easy and discreet to carry. 3.5 Tip design There are a variety of catheters available with different tips Nelaton This is the standard tip. The catheter is straight, and has a rounded tip. Tiemann The tip is slightly curved. This catheter is sometimes recommended in case of an obstruction near the prostate, or after specific surgery (sling), or a high bladder neck. The curved tip should be inserted with the tip pointed upward. Pointed tip The pointed tip has a bendy part, and ends in a ball. It can be recommended in case of obstruction or pain in the sphincter region. Flexible tip This catheter has a tip that is somewhat narrower than the rest of the catheter. It can be recommended in case of a narrow meatus or a stricture.
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