Indications are failed urethral catheterisation in urinary retention; preferred site for long-term catheters.
Long-term urethral catheters commonly lead to acquired hypospadias in males (ventral splitting of glans penis) and a patulous urethra in females (leading to frequent balloon expulsion and bypassing of urine around the catheter). Hence, the suprapubic site is preferred for long-term catheters.
Suprapubic catheterisation is best avoided in (1) patients with clot retention, the cause of which may be an underlying bladder cancer (the cancer could be spread along the catheter track to
IO. COMMON EMERGENCY UROLOGICAL PROCEDURES I69
involve the skin); (2) patients with lower midline incisions (bowel may be 'stuck' to the deep aspect of the scar, leading to the potential for bowel perforation); and (3) pelvic fractures, where the catheter may inadvertently enter the large pelvic haematoma, which always accompanies severe pelvic fracture. This can lead to infection of the haematoma, and the resulting sepsis can be fatal! Failure to pass a urethral catheter in a patient with a pelvic fracture usually indicates a urethral rupture (confirmed by ure-thrography) and is an indication for formal open, suprapubic cystotomy.
Prior to insertion of the trocar, be sure to confirm the diagnosis by (a) abdominal examination (palpate and percuss lower abdomen to confirm bladder is distended), (b) ultrasound (in practice usually not available), and (c) aspiration of urine (using a green needle). Patients with lower abdominal scars may have bowel interposed between the abdominal wall and bladder and this can be perforated if the trocar is inserted near the scar and without prior aspiration of urine! In such cases, ultrasound-guided catheterisation may be sensible.
Use a wide-bore trocar if you anticipate that the catheter will be in place for more than 24 hours (small-bore catheters will block within a few days). Aim to place the catheter about two to three fingerbreadths above the pubis symphysis. Placement too close to the symphysis will result in difficult trocar insertion (the trocar will hit the symphysis). Instill a few millilitres of local anaesthetic into the skin of the intended puncture site and down to the rectus sheath. Confirm the location of bladder by drawing back on the needle to aspirate urine from the bladder. This helps guide the angle of trocar insertion. Make a 1-cm incision with a sharp blade through the skin. Hold the trocar handle in your right hand, and steady the needle end with your left hand (this hand helps prevent insertion too deeply). Push the trocar in the same direction in which you previously aspirated urine. As soon as urine issues from the trocar, withdraw the latter, holding the attached sheath in place. Push the catheter in as far as it will go. Inflate the balloon. Peel away the side of the sheath and remove it.