Prevention and Management of Complications Related to Catheterization

1. Urethral Mucosal Injury

(1) Causes

1. The male urethra is long and has physiological curvatures and narrow segments, with considerable individual variation, making it difficult to accurately determine the appropriate catheter insertion depth.
2. The operator lacks sufficient knowledge of catheterization techniques and of male urethral anatomy under pathological conditions.
3. Negative psychological factors such as embarrassment, worry, anxiety, and fear may cause the patient to become highly tense; during catheter insertion this can lead to urethral sphincter spasm.
4. When there are lesions of the lower urinary tract, the urethral anatomy may be altered. For example, in benign prostatic hyperplasia, uneven enlargement of the prostatic lobes can cause narrowing, distortion, and deformation of the prostatic urethra, increasing the risk of urethral injury during catheter insertion.
5. The patient may be unable to tolerate bladder and urethral irritation caused by the catheter and may pull on the catheter or even forcibly remove it, resulting in injury.

6. Use of an inappropriate catheter size or stiff rubber catheters can easily damage the urethral mucosa during insertion. Repeated catheterization may further cause urethral mucosal edema, injury, and bleeding.
7. When using a balloon catheter, the catheter tip has not yet entered the bladder or has only just entered it, and water is injected into the balloon at this time. Although urine may flow out through the catheter, the balloon portion is still located in the posterior urethra, and inflation of the balloon compresses the posterior urethra.

(II) Clinical manifestations

Bleeding from the urethral meatus, sometimes accompanied by blood clots; pain within the urethra that is aggravated during urination and may be associated with localized tenderness; some cases present with dysuria or even urinary retention. In severe injuries, perineal hematoma, urinary extravasation, or even rectourethral fistula may occur. When complicated by infection, purulent urethral discharge or periurethral abscess may be observed.

(III) Prevention and management

To prevent urethral mucosal injury, in addition to being familiar with the anatomical characteristics of the male urethra and strictly following standard operating procedures, the operator should also pay attention to the following points:

1. Adequate lubrication before insertion: Routinely lubricate the catheter to reduce friction. Use gentle techniques with slow insertion; never force the catheter, and avoid repeated in-and-out movements or repeated catheterization.
2. For patients with incomplete lower urinary tract obstruction: Before catheterization, prepare lubricating anesthetic gel. Apply a small amount to the catheter tip and urethral meatus, then gently insert the nozzle into the urethra and press firmly once with the thumb to deliver the gel into the urethra up to the membranous portion. After withdrawing the nozzle, compress the urethral meatus with the thumb, index, and middle fingers of the left hand for 1–2 minutes. Alternatively, inject lubricant into the urethral meatus using a syringe without a needle, or connect a lubricant syringe to the proximal end of the catheter and inject lubricant during insertion, which often improves success.
3. For patients with benign prostatic hyperplasia: If resistance is encountered during insertion, rapidly inject 5–10 mL of sterile liquid paraffin oil (preloaded in a syringe) through the distal end of the catheter. The operator lifts the penis with the left hand to form a 60° angle with the abdominal wall, while the right hand injects the paraffin oil with slight force, using its lubricating effect to advance the catheter smoothly past the enlarged segment.
4. Select an appropriate catheter: Choose a catheter of suitable diameter and soft material.
5. When using a balloon (Foley) catheter: Insert the catheter further; after urine appears, advance it an additional ≥5 cm before inflating the balloon. Then gently withdraw until resistance is felt (usually 2–3 cm). This helps prevent balloon inflation outside the bladder, which could compress and injure the posterior urethra.
6. Psychological support: Explain the procedure patiently. If the patient is excessively anxious, administer prescribed intramuscular sedatives (e.g., diazepam) or anticholinergics (e.g., atropine) before catheterization, and proceed once the patient is calm.
7. Management of catheter-related mucosal injury: Mild injuries usually require no specific treatment or resolve with symptomatic measures such as hemostasis and analgesia. In rare cases of severe injury, surgical interventions such as urinary diversion or urethral repair may be necessary.
8. Urinary Tract Infection (UTI)

(I) Causes

1. Failure to comply with aseptic techniques by the operator, allowing bacteria to ascend retrogradely into the urethra and bladder.
2. Catheterization is an invasive procedure and may cause urethral mucosal injury, disrupting the protective barrier function of the urethral mucosa.
3. Use of an inappropriate catheter size or a catheter made of overly rigid material.
4. Lack of technical proficiency, resulting in difficult insertion and repeated catheterization attempts.
5. With increasing age, men often develop benign prostatic hyperplasia, which predisposes to urinary retention and increases the risk of infection.
6. Bacterial contamination of the catheter used.

(II) Clinical manifestations

The main symptoms include urinary frequency, urgency, and dysuria. When the infection involves the upper urinary tract, chills and fever may occur. Purulent discharge may be seen at the urethral meatus. Urinalysis may show red blood cells and white blood cells, and urine culture may yield positive results.

(III) Prevention and management

1. All equipment must be strictly sterilized. Aseptic technique should be strictly followed during catheter insertion, with gentle manipulation and careful perineal disinfection. Before catheterization, 3–5 mL of 2% povidone-iodine solution may be instilled into the urethral meatus to disinfect the distal urethra and provide a lubricating effect.
2. Avoid indwelling catheterization whenever possible. For patients with urinary incontinence, absorbent perineal pads or condom catheters may be used instead.
3. Use silicone or latex catheters instead of traditional rubber catheters. Lubricating the catheter with sterile cotton soaked in 0.1% hexestrol can reduce urinary tract irritation. Applying salicylic acid to the catheter surface can inhibit Gram-negative bacteria and prevent bacterial and yeast adhesion to silicone catheters, thereby reducing the risk of urinary tract infection.
4. Once a urinary tract infection occurs, the catheter should be removed whenever possible, and appropriate antimicrobial therapy should be administered according to the patient’s condition.

1. Urethral Bleeding

(I) Causes

Various causes of urethral mucosal injury can lead to urethral bleeding when severe.

Coagulation disorders.

Medications that cause urethral mucosal congestion and edema, making the urethra susceptible to mechanical injury.

In patients with severe urinary retention leading to elevated intravesical pressure, rapid drainage of large volumes of urine causes sudden decompression of the bladder, resulting in severe mucosal congestion and bleeding, leading to hematuria.

(II) Clinical Manifestations

The appearance of gross hematuria or microscopic hematuria after catheterization, while excluding hematuria originating from the upper urinary tract, suggests injury from catheterization.

(III) Prevention and Management

1. Urethral bleeding from catheterization almost always occurs on the basis of urethral mucosal injury; therefore, all measures to prevent urethral mucosal damage are applicable to preventing urethral bleeding.
2. In patients with severe coagulation disorders, correction should be attempted as much as possible before catheterization.
3. For patients with urethral mucosal congestion and edema, select a catheter with a smaller diameter whenever possible, ensure adequate lubrication before insertion, operate gently, and avoid injury as much as possible.
4. After catheter insertion, urine drainage should not be too rapid; the first drainage should not exceed 1000ml.
5. Microscopic hematuria generally requires no special treatment; if hematuria is severe, hemostatic agents may be used appropriately.

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