A foley catheter is a flexible tube that is inserted to the urinary meatus to be indwelled in the urinary bladder in order to drain urine. Catheters are sized in units called French, wherein one French is equal to 0.33 millimeter. Sizes vary to cater pediatric and adult sizes of urinary passages. A very large diameter of a foley catheter may post a trauma when inserted to a small urethral passage while a very thin catheter may have leaks and may have inaccurate urine output measurement for patients requiring intake and output measurements. Catheter sizes vary from French 9 (smallest diameter) to French 48 (largest diameter). Continue reading →