Percutaneous Nephrostomy Periprocedural Care

Preprocedural evaluation

The following steps are included the preprocedural evaluation for percutaneous nephrostomy (note that the list is not all-inclusive and may differ from the preprocedural preparation performed):

• Informed consent is obtained from the patient, next of kin, or healthcare proxy

• Appropriate laboratory studies are reviewed or ordered if not available, including prothrombin time, activated partial thromboplastin time, platelet count, blood urea nitrogen and creatinine levels, hematocrit and hemoglobin levels, white blood cell count, and urinalysis and urine culture

• Pertinent images (eg, sonograms, computed tomography (CT) scans, intravenous (IV) urograms, or radionuclide scintigrams) are reviewed to assess the location of the colon, liver, and spleen and help determine the optimal approach. Scintigrams may assist with decision making process for the procedure

• IV access is established, and the patient is adequately hydrated

• Prophylactic antibiotics are administered 60 minutes before the procedure, especially if pyonephrosis is suspected or if the obstruction is caused by a renal calculus

• The patient receives nothing by mouth for 4-8 hours before the procedure

The use of antibiotics is somewhat controversial; however, in patients with a known urinary tract obstruction, antibiotics should be administered before the procedure (preferably 1 hour before puncture) and should be continued for at least 24 hours after the procedure. Antibiotics should be chosen on the basis of urine culture results, if available. If culture results are not available, use of a broad-spectrum antibiotic is recommended.

Some have advocated placing percutaneous nephrostomy tubes without performing preprocedural coagulation studies; however, the authors disagree with this approach unless the situation is an absolute emergency. Because the kidney is highly vascular, needle puncture and tract dilation in a patient with a coagulopathy could result in massive hemorrhage.

Guidance and selection of access system

After the preprocedural evaluation, an appropriate approach and modality for guidance is chosen. In most cases, guidance involves ultrasonography, ^[10] though either conventional fluoroscopy or CT (e.g. CT fluoroscopy) may also be used. ^[11]

Once the guidance method is determined, the access system is selected. Currently available systems include the micropuncture set (Cook, Bloomington, IN), the AccuStick introduction system (Boston Scientific, Natick, MA), and the Hawkins needle. The first 2 systems are 21- and 22-gauge needle systems, whereas the third is an 18-gauge system. Because of the smaller needles, the first 2 systems are often more difficult to visualize on ultrasonography than the Hawkins needle; however, they are associated with a significantly lower bleeding risk.

Currently, most interventionalists use the following 2 main types of nephrostomy tubes, both of which have an end that is secured in the renal pelvis by locking the distal portion of the tube (see the image below):

• Pigtail (locking-loop or Cope-loop) catheter - The locking loop of the catheter is formed within the renal pelvis by tugging gently on the internal suture and locking the catheter in place

• Malecot (tulip-shaped) catheter - The catheter tip retracts slightly so that the tulip portion is larger than the tube diameter; these catheters are mainly used when the renal pelvis is small (because the patient is small) or when a large staghorn calculus is present

  Percutaneous nephrostomy. Shown are two types of nephrostomy tubes: the Malecot (top) tube, and the pigtail catheter (bottom).

  View Media Gallery

In a study comparing catheters with and without locking strings, Chuang et al found no significant difference in complication rate between the 2 types after 90 days. ^[12]

The patient is commonly placed in a prone or prone-oblique position with the target side elevated. The expected region of the percutaneous nephrostomy should be evaluated by means of ultrasonography, CT, or fluoroscopy, and the puncture site marked. This region should then be prepared (eg, cleansed with povidone-iodine solution) and draped in the usual manner.

After proper positioning, the patient is given an appropriate medication for conscious sedation (eg, fentanyl and midazolam), along with a local anesthetic (usually 1% lidocaine) to anesthetize the skin.

Postprocedural management and follow-up may include the following:

• Bed rest for 4 hours

• Resumption of the preprocedural diet

• Checking of vital signs every 30 minutes for 4 hours and then every shift

• Antibiotic therapy, if infection is identified or suspected

• Catheter flushing with 5 mL of bacteriostatic isotonic sodium chloride solution and then aspiration every 6-12 hours

• Monitoring of urine output