Материал: Oxford American Handbook of Urology ( PDFDrive )

98 CHAPTER 3 Bladder outlet obstruction

Indications for and technique of suprapubic catheterization

Indications

Suprapubic catheterization is indicated if there is failed urethral catheterization in urinary retention; it is the preferred site for long-term catheters.

Long-term urethral catheters commonly lead to acquired hypospadias in males (ventral splitting of glans penis) and patulous urethra in females (leading to frequent balloon expulsion and bypassing of urine around the catheter). Hence, a suprapubic site is preferred for long-term catheters.

Contraindications

Suprapubic catheterization is best avoided in the following:

•Patients with clot retention, the cause of which may be an underlying bladder cancer (the cancer could be spread along the catheter track to involve the skin)

•Patients with lower midline incisions (bowel may be stuck to the deep aspect of the scar, leading to the potential for bowel perforation)

•Pelvic fractures, where the catheter may inadvertently enter the large pelvic hematoma that always accompanies severe pelvic fracture. This can lead to infection of the hematoma, 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 urethrography) and is an indication for formal open, suprapubic cystotomy.

Technique

Prior to insertion of the trocar, be sure to confirm the diagnosis by

•Abdominal examination (palpate and percuss the lower abdomen to confirm bladder is distended),

•Ultrasound (in practice, usually not available), and

•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 catheterization 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 2–3 fingerbreadths above the pubis symphysis. Placement too close to the symphysis will result in a difficult trocar insertion (the trocar will hit the symphysis).

Instill a few mL of local anesthetic into the skin of the intended puncture site and down to the rectus sheath. Confirm location of the bladder by drawing back on the needle to aspirate urine from the bladder. This helps guide the angle of trocar insertion.

SUPRAPUBIC CATHETERIZATION 99

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 as that in which you previously aspirated urine.

As soon as urine passes 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.

100 CHAPTER 3 Bladder outlet obstruction

Management of nocturia and nocturnal polyuria

Nocturia can be particularly resistant to treatment.

First, establish whether the patient is polyuric (>3 L of urine/24 hr) by having the patient complete a frequency–volume chart. If polyuric, this may account for the daytime and nighttime voiding frequency. Establish whether the patient has a solute or water diuresis and the causes thereof (see Box 3.3).

If nonpolyuric (<3 L urine output/24 hr), determine the distribution of urine output over the 24-hour period. If >1/3 of urine output is between the hours of midnight and 8 a.m., then the patient has nocturnal polyuria (NP).

Nonpolyuric nocturia

BPH medical therapy

The impact of A-blockers, 5A-reductase inhibitors, and anticholinergics on nocturia is modest.

TURP

Nocturia persists in 20–40% of men after TURP.

Medtronic InterStim therapy for nocturia

Patients preselected on the basis of a favorable symptomatic response to a test stimulation can experience a reduction in nocturia,1 but not all patients respond to the test stimulation. The treatment is expensive and not yet widely available in all countries.

Treatment for nocturnal polyuria

The evidence base for NP treatments is limited (very few randomized, placebo-controlled trials).2

Fluid restriction

Many patients have reduced their afternoon and evening fluid intake in an attempt to reduce their nighttime diuresis.

Diuretics

Diuretics, taken several hours before bedtime, reduce nocturnal voiding frequency in some patients.3

DDAVP

DDAVP is a synthetic analogue of arginine vasopressin (endogenous ADH), which, if taken at night, can reduce urine flow by its antidiuretic action. It has been suggested that NP may be caused by a lack of endogenous production of ADH in elderly people.

However, adults both with and without NP have no rise in ADH at night (i.e., ADH secretion remains remarkably constant throughout the day in adults with and without NP). Furthermore, the diuresis in adults with NP is a solute diuresis due to a nocturnal natriuresis.4

Thus, lack of ADH secretion at night is not the cause of the diuresis in nocturnal polyuric adults, and thus from a theoretical perspective, there

MANAGEMENT OF NOCTURIA AND NOCTURNAL POLYURIA 101

is no logical basis for using DDAVP in NP.5 There is limited evidence that it reduces nighttime voiding frequency (at least in responder enrichment studies) and increases sleep duration in a proportion of patients with NP.6

Side effects include hyponatremia (Na <130 mmol/L) in 5% of patients. Measure serum Na 3 days after starting DDAVP and stop its use if hyponatremia develops.

Nocturia and sleep apnea

Obstructive sleep apnea (OSA) is highly prevalent in those over 65 years of age. It is often manifested by snoring. There is a strong association between OSA symptoms and nocturia.7

Large negative intrathoracic pressure swings may trigger a cardiac-medi- ated natriuresis and hence cause NP.

Box 3.3 Investigation of the polyruic patient (urine output of >3 L/24 hr)

Urine osmolality?

•>250mosm/kg = solute diuresis

•<250mosm/kg = water diuresis

Solute diuresis

•Poorly controlled diabetes mellitus; saline loading (e.g., postoperative diuresis); diuresis following relief of high-pressure chronic retention

Water diuresis

•Primary polydipsia; diabetes insipidus (nephrogenic—e.g., lithium therapy, central—ADH deficiency)

1 Spinelli M (2003). New sacral neuromodulation lead for percutaneous implantation using local anesthesia: description and first experience. J Urol 170:1905–1907.

2 Kujubu DA, Aboseif SR (2008). An overview of nocturia and the syndrome of nocturnal polyuria in the elderly. Nat Clin Pract Nephrol 4(8):426–435.

3 Reynard JM, Cannon A, Yang Q, Abrams P (1998). A novel therapy for nocturnal polyuria: a double-blind randomized trial of frusemide against placebo. Br J Urol 81:215–218.

4 Matthiesen TB, Rittig S, Norgaard JP, Pedersen EB, Djurhuus JD (1996). Nocturnal polyuria and natriuresis in male patients with nocturia and lower urinary tract symptoms. J Urol 81:215–218.

5 McKeigue P, Reynard J (2000). Relation of nocturnal polyuria of the elderly to essential hypertension. Lancet 355:486–488.

6 Mattiasson A (2002). Efficacy of desmopressin in the treatment of nocturia: a double-blind place- bo-controlled study in men. Br J Urol 89:855–862.

7 Umlauf M (1999). Nocturia and sleep apnea symptoms in older patients: clinical interview. Sleep 22:S127.