Overview
Definition:
Dialysis catheter tunneling is a surgical technique used to create a subcutaneous path for a central venous catheter, directing the exit site away from the venous insertion site
This reduces the risk of infection and improves cosmetic outcomes
Proper tip positioning within the appropriate central vein is critical for effective dialysis and minimizing complications.
Epidemiology:
Millions of patients worldwide require chronic dialysis, necessitating reliable vascular access
Central venous catheters are a common temporary or bridging solution
The incidence of catheter-related bloodstream infections (CRBSIs) varies but remains a significant morbidity and mortality factor, often linked to suboptimal tunneling and tip placement.
Clinical Significance:
Effective dialysis requires adequate blood flow rates, which are directly dependent on proper catheter tip placement in a high-flow central vein (e.g., superior vena cava)
Poor tunneling increases infection risk by creating a direct conduit from the skin to the bloodstream
Mastering these techniques is crucial for surgical residents to ensure patient safety, treatment efficacy, and reduce healthcare costs associated with complications.
Surgical Indications
Indications:
Placement of central venous catheters for hemodialysis when peripheral arteriovenous access is not feasible or as a temporary measure
Patients requiring long-term dialysis awaiting fistula maturation or transplant
Acute kidney injury requiring urgent dialysis
Certain peritoneal dialysis catheter placements may also involve tunneling.
Contraindications:
Active infection at the insertion site or tunnel pathway
Known central venous thrombosis
Uncorrected coagulopathy
Patient refusal.
Procedure Steps
Preoperative Preparation:
Informed consent obtained
Patient assessment including coagulation profile and relevant comorbidities
Imaging (e.g., ultrasound) to identify appropriate venous anatomy and rule out thrombosis
Preoperative antibiotics administered according to institutional protocols.
Venous Access And Cannulation:
Typically performed under local anesthesia with sedation
Seldinger technique is commonly used
Ultrasound guidance is preferred for common femoral or internal jugular vein cannulation
A small skin incision is made over the chosen insertion site.
Tunneling Technique:
A separate skin incision is made at a predetermined distance from the venous access site (typically 5-10 cm away, ipsilateral to the vein)
A tunneling device (e.g., Trocath) is used to create a subcutaneous tunnel connecting the two incisions
The catheter is then threaded through this tunnel from the distal skin incision to the venous lumen.
Catheter Insertion And Securing:
The catheter is advanced into the central vein until the tip is optimally positioned
Securing the catheter at the exit site and insertion site with sutures or specialized devices prevents dislodgement
Dressing applied according to sterile technique.
Tip Positioning Guidelines:
The catheter tip should ideally be positioned in the superior vena cava (SVC), near its junction with the right atrium, to facilitate adequate blood inflow and outflow and minimize recirculation
For femoral vein access, the tip should be in the inferior vena cava (IVC), above the diaphragm.
Tip Positioning And Confirmation
Ideal Tip Location:
Superior Vena Cava (SVC) at its cavoatrial junction
This position ensures maximum blood flow and minimizes the risk of catheter-related recirculation and thrombosis.
Imaging Confirmation:
Post-procedure chest X-ray is mandatory to confirm tip position and rule out pneumothorax
Ideally, the tip should be located 3-4 cm above the carina for right IJ or subclavian insertion
Fluoroscopy during placement can also confirm position.
Troubleshooting Malposition:
If tip is too high (e.g., brachiocephalic vein), it may cause recirculation or venous stenosis
If too low (e.g., right atrium), it can cause arrhythmias or cardiac perforation
Malpositioned catheters may require repositioning or removal and reinsertion.
Complications
Early Complications:
Bleeding at insertion or tunnel site
Hematoma formation
Arterial puncture
Pneumothorax or hemothorax
Arrhythmias during cannulation
Air embolism
Nerve injury
Catheter malposition
Wound infection.
Late Complications:
Catheter-related bloodstream infections (CRBSIs)
Catheter occlusion (thrombosis or fibrin sheath)
Catheter migration
Venous stenosis or thrombosis
Exit site infection and erosion
Tunnel infection
Seroma formation.
Prevention Strategies:
Strict aseptic technique during insertion and dressing changes
Appropriate tunneling to create distance between exit and insertion sites
Secure catheter fixation
Use of antibiotic-locked solutions
Prompt removal of catheters when no longer needed
Regular patient education on exit site care.
Postoperative Care And Monitoring
Immediate Postoperative:
Monitor vital signs, bleeding, and pain
Chest X-ray to confirm tip position and rule out pneumothorax
Apply sterile dressing.
Monitoring For Infection:
Regular assessment of exit site for erythema, swelling, pain, or discharge
Monitor for signs and symptoms of systemic infection (fever, chills, elevated WBC count).
Monitoring For Functionality:
Assess blood flow rates during dialysis sessions
Monitor for signs of recirculation (e.g., increased venous pressure, decreased arterial pressure)
Ensure adequate dialysis delivery.
Patient Education:
Instruct patients on proper exit site care, daily inspection, hand hygiene, and signs/symptoms of infection or malfunction
Advise on activity restrictions and signs to report immediately.
Key Points
Exam Focus:
Optimal tip position in SVC for inflow/outflow efficiency and minimal recirculation
Understanding the rationale behind tunneling for infection prevention
Differentiating early vs
late complications.
Clinical Pearls:
Always use ultrasound for venous access
The distance of the tunnel is crucial for preventing infection
A post-procedure CXR is non-negotiable
Lumbar pain can be a sign of malpositioned femoral dialysis catheter in the IVC.
Common Mistakes:
Inadequate tunneling distance
Placing the tip too low in the SVC or too high
Failure to confirm tip position with imaging
Poor aseptic technique
Delayed catheter removal leading to infection or thrombosis.