Which of the following catheter materials is most suited for long term is used

Ans. is 'b' i.e., Silicone "Catheters made of silicone are, in general better tolerated over the long-term than those made of materials like latex and polyurathane." - Cambell, 8/e Also remember Catheter size is usually measured in French (fr) it refers to the outside circumference of the catheter, not the luminal diameter. (Thus a 20 fr catheter may have different luminal size for urinary drainage, depending on the type of material used for construction and the number of lumens within the catheter). 1 Fr = 0.33 nun in diameter thus 3 Fr = 1 mm in diameter (thus a 21 Fr catheter would be 7 mm in diameter)