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Bladder
catheterization:
Bladder catheterization is used to obtain urine for examination, measure residual urine volume, relieve urinary retention or incontinence, deliver radiopaque contrast or drugs directly to the bladder, and irrigate the bladder. Catheters vary by caliber, tip configuration, number of ports, balloon size, type of material, and length.
Caliber is standardized in French (F) units—also known as Charrière (Ch) units. Each unit is 0.33 mm, so a 14-F catheter is 4.6 mm in diameter. Sizes range from 14 to 24 F for adults and 8 to 12 F for children. Smaller catheters are usually sufficient for uncomplicated urinary drainage and useful for urethral strictures and bladder neck obstruction; bigger catheters are indicated for bladder irrigation and some cases of hemorrhage (eg, postoperatively or in hemorrhagic cystitis) and pyuria, because clots could obstruct smaller caliber catheters.
Straight-tipped catheters (eg, Robinson, whistle-tip) can be used for intermittent urethral catheterization (ie, catheter is removed immediately after bladder drainage). Foley catheters have a straight tip and an inflatable balloon for self-retention. Other self-retaining catheters may have an expanded tip shaped like a mushroom (de Pezzer catheter) or a 4-winged perforated mushroom (Malecot catheter); they are used in suprapubic catheterization or nephrostomy. Elbowed (coudé) catheters, which may have balloons for self-retention, have a bent tip to ease catheterization through strictures or obstructions.
All catheters have ports for urinary drainage and may have ports for balloon inflation and irrigation (eg, 3-way Foley).
Balloons on self-retaining catheters have different volumes, from 2.5 to 5 mL in children's and 10 to 30 mL in adult's catheters. Larger balloons and catheters are generally used to manage bleeding; traction on the catheter pulls the balloon against the base of the bladder and puts pressure on vessels, while the larger caliber facilitates clearance of blood clots.
Choice of catheter material depends on use: plastic, latex, or polyvinyl chloride for intermittent use; or latex with silicone, hydrogel, or polymer (to diminish bacterial colonization) for continuous use. Silicone catheters are used in patients with latex allergy.
Stylets are flexible metal guides inserted through the catheter to give it stiffness and to facilitate insertion through strictures or obstructions.
Catheterization may be urethral or suprapubic. Urethral catheters can be inserted by any health care practitioner and sometimes by patients themselves. No patient preparation is necessary. Relative contraindications are urethral strictures and current UTI. After careful cleaning of the urethral meatus with an antibacterial solution, the catheter is lubricated with sterile gel and gently advanced through the urethra into the bladder. Complications include urethral or bladder trauma with bleeding, creation of false passages, scarring and strictures, UTI, and bladder perforation.
Suprapubic catheterization via percutaneous cystostomy is performed by a urologist or other experienced physician. No patient preparation is necessary. Indications include drainage after urethral reconstruction or bladder surgery, repair after trauma, and long-term bladder drainage. Contraindications include prior lower abdominal surgery. After the abdomen above the pubic area is numbed with a local anesthetic, a spinal needle in inserted into the bladder. A catheter is then placed through a special trocar or over a guide wire threaded through the spinal needle. Complications include UTI, intestinal injury, and bleeding.
Cystoscopy:
Cystoscopy is insertion of a rigid or flexible fiberoptic instrument into the bladder. It is used to help diagnose urologic disorders (eg, bladder tumors or calculi), to manage urethral strictures, and to access the bladder for ureteral x-rays or placement of JJ stents (stents with coiled ends placed in the renal pelvis and bladder). The main contraindication is active UTI. Cystoscopy is usually performed in an outpatient setting with local anesthesia or, when necessary, conscious sedation or general anesthesia. Prophylactic antibiotics are required. Complications include UTI, bleeding, and bladder and urethral trauma.
Biopsy:
Biopsy requires a trained specialist (nephrologist, urologist, or interventional radiologist).
For renal biopsy, relative contraindications include bleeding diatheses, a solitary kidney, and an uncooperative patient. Mild preoperative sedation with opioids and atropine may be needed. Complications include severe renal bleeding requiring transfusion or even surgical intervention.
For bladder biopsy, contraindications include bleeding diathesis and acute tuberculous cystitis. Preoperative antibiotics are only necessary if active UTI is present. The biopsy instrument is inserted into the bladder through a cystoscope; rigid or flexible instruments can be used. The biopsy site is cauterized to prevent bleeding, and a drainage catheter is left in place to facilitate healing and drainage of clots. Complications include excessive bleeding, UTI, and bladder perforation.
For prostate biopsy, contraindications include bleeding diathesis, acute prostatitis, and UTIs. Patient preparation includes stopping maintenance aspirin a week before biopsy, preoperative antibiotics (usually a fluoroquinolone), and an enema to clear the rectum. With the patient in a lateral position, the prostate is located by palpation or ultrasonography. Overlying structures (perineum or rectum) are anesthetized, a spring-loaded biopsy needle is inserted into the prostate, and 6 to 12 tissue cores are obtained from various sites. Complications include urosepsis, hemorrhage, urinary retention, hematuria, and hematospermia (often for 3 to 6 mo after biopsy).
Urethral
dilation:
Urethral dilation is used to manage urethral strictures, urethral (urgency-frequency) syndrome, and meatal stenosis. In cases of stricture, a fine filiform probe is passed through, then followers (dilators) of progressively larger diameter are attached to the distal end of the filiform probe and passed behind the probe to dilate the stricture until urine stream becomes adequate; the procedure is usually performed over several sessions.
Last full review/revision November 2005
Content last modified November 2005
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