When the catheter reaches the junction of the penile shaft and the perineum, it may help to position the penis more vertically, as shown in Figure 130.31B The catheter should be passed into the bladder all the way to the Y-connection; this is important because urine may begin to flow while the catheter is in the proximal urethra, and inflation of the balloon in the urethra may lead to complications Figure 130.31C shows withdrawal of the catheter after inflation of the balloon When the balloon strikes the wall, a “clunking” sensation is appreciated; this indicates that the balloon is resting on the trigone The catheter should then be secured to the child’s inner leg, leaving a lax portion to prevent injury to the trigone if the catheter is accidentally pulled Female In the female, the principles of catheterization are similar to those in the male Have an assistant carefully spread the labia or use your nondominant hand to so, as shown in Figure 130.31D , if it is difficult to visualize the urethra Then, introduce a well-lubricated, pretested Foley catheter into the bladder Again, advance the catheter its entire length before inflating the balloon After withdrawing the catheter until a “clunking” sensation is appreciated, secure it with a securement device to the child’s leg SUPRAPUBIC BLADDER ASPIRATION Indications To obtain a sterile urine specimen for culture in infants and children younger than years of age or children who are incontinent or when anatomic abnormalities, such as fused labia, are encountered In general, urethral catheterization has become the preferred technique Complications Hematuria—microscopic hematuria virtually always occurs Gross hematuria is uncommon Intestinal perforation Infection of the abdominal wall Procedure Use ultrasound to confirm the presence of urine in the bladder If ultrasound is unavailable, it is wise to wait at least to hours before performing this procedure if the infant has recently voided Position the infant supine Holding the legs in the frog-leg position as shown in Figure 130.32A , restrain the child