PD Catheters and Exchange Technique

PD Catheters and Exchange Technique

Quick Answer: The Tenckhoff (or similar) peritoneal catheter is the lifeline of PD therapy. CDN candidates must know catheter placement timing, exit-site orientation, aseptic exchange technique, the flush-before-fill method, and recommended antiseptics (povidone-iodine or chlorhexidine—not alcohol or hydrogen peroxide). Early malfunction is most often caused by fibrin clot or omentum wrap.

PD Catheter Types and Placement

The standard PD catheter is a soft silicone or polyurethane tube with cuffs that anchor in subcutaneous tissue and the deep fascia, reducing migration and bacterial tracking. The intraperitoneal segment contains side holes (often with a curled tip) to minimize occlusion against bowel or omentum. The exit site should point downward to discourage fluid pooling and skin maceration.

Catheters are placed surgically (open, laparoscopic, or percutaneous) or by interventional radiology. A break-in period of approximately 2 weeks (sometimes longer if healing is delayed) allows the tunnel to mature before full-volume exchanges begin. Starting PD too early risks leak, infection, and catheter displacement—an exam scenario may ask which finding during week one requires holding exchanges.

Initial fill volumes for a typical adult are 1.0–1.5 L (up to 2.0 L for larger patients), gradually increased to target volumes of 2.0–2.5 L as tolerated. Ramping volumes reduces pain, leak risk, and respiratory discomfort.

Exit-Site Care and Prophylaxis

Daily exit-site care prevents infection that can seed the peritoneum. Recommended cleansing agents include povidone-iodine or chlorhexidine. Hydrogen peroxide and alcohol are discouraged because they damage tissue and delay epithelialization—classic CDN distractors.

Mupirocin ointment at the exit site reduces Staphylococcus aureus colonization and is widely used for prophylaxis. The catheter must be secured to prevent traction trauma, which can enlarge the exit wound and invite organisms. Patients should avoid swimming in non-chlorinated water and should cover the site during showers per program policy.

Dry crusting at the exit site can be normal; purulent drainage with erythema and tenderness signals infection (covered in the next section). Nurses document exit-site appearance using a standardized scale (e.g., redness, swelling, crust, drainage) at every clinic visit.

Aseptic Exchange Technique (CAPD Focus)

Touch contamination during exchanges is the leading preventable cause of peritonitis. NNCC emphasizes the full aseptic sequence:

1. Hand hygiene (soap and water or alcohol-based rub) before gathering supplies.
2. Mask over nose and mouth to reduce droplet contamination.
3. Close doors/windows and minimize airflow over the exchange area.
4. Drape a clean surface; arrange drain bag, fill bag, transfer set, and cap.
5. Inspect dialysate for clarity and expiration; warm bags only per manufacturer instructions (never microwave).
6. Flush-before-fill: Connect the fill line and allow a small volume of fresh dialysate to flush the line before connecting to the patient—this clears air and potential contaminants from the tubing.
7. Drain completely before fill unless a tidal prescription specifies otherwise.
8. Cap and secure the transfer set; document volumes.

The flush-before-fill technique specifically reduces peritonitis risk by displacing stagnant or contaminated fluid in the connection pathway before it enters the peritoneum—a direct CDN test point.

Worked Scenario: Exchange Error

A patient reports skipping the mask during a hurried exchange and notes the fill bag was below waist level, increasing contamination risk. The nurse's immediate teaching reinforces mask use, hand hygiene, and keeping bags elevated. If the patient develops cloudy effluent within 24 hours, effluent goes for cell count and culture before antibiotics are adjusted.

Heparin and Fibrin Management

Fibrin clot or omentum wrapping is the most common cause of catheter malfunction in the first month. Cloudy strands in effluent may indicate fibrin. Low-dose heparin added to dialysate (per prescription) can prevent fibrin accumulation. Persistent poor outflow despite good inflow suggests malposition against bowel wall or omentum, kinking, or clot—notify the nephrology team; imaging or repositioning may be needed.

Constipation displaces catheter tip position and impairs drainage; prompt laxatives or stool softeners are first-line nursing management when a PD patient is constipated.

Patient Environment and Training Checklist

Home PD training spans multiple sessions covering:

• Room setup and supply storage
• Recognition of cloudy effluent, abdominal pain, fever
• Daily weight and blood pressure logs
• When to call the on-call nurse (leak, inability to drain, exit-site pus)
• Emergency manual exchange if cycler fails (APD patients)

CDN Exam Traps

1. Antiseptics: Povidone-iodine or chlorhexidine—not hydrogen peroxide or alcohol for routine exit-site care.
2. Flush-before-fill reduces infection risk; know its purpose.
3. Early poor drainage with good inflow = mechanical issue (fibrin, omentum, malposition), not inadequate prescription alone.
4. Catheter break-in requires weeks of healing before full exchanges—do not rush.