Should a port always have blood return, especially in patients with a history of cancer or chronic conditions?

Should a Port Always Have Blood Return?

No, a port does not always need to have blood return to be functional, but absence of blood return warrants immediate assessment and should never be ignored, as it may indicate serious complications including catheter malposition, thrombosis, or occlusion that could lead to treatment delays, infection risk, or life-threatening complications.

Understanding Blood Return in Ports

While blood return is generally expected with a properly functioning port, its absence does not automatically mean the device is non-functional or requires removal. However, this finding demands systematic evaluation:

• Absence of blood return can occur even with patent catheters due to catheter tip position against the vessel wall, fibrin sheath formation, or patient positioning 1
• The ability to infuse fluids without blood return does NOT confirm proper catheter function and should never be used as the sole criterion for port use 2

Immediate Assessment Algorithm

When blood return is absent, follow this systematic approach:

Step 1: Rule Out Simple Mechanical Causes

• Check for external kinks in the catheter or tubing 2
• Reposition the patient - have them raise arms, turn head, cough, or change body position 1
• Verify needle placement in the port septum (for implanted ports) 2
• Ensure proper flushing technique using 10mL or larger syringe to avoid excessive pressure 1, 2

Step 2: Attempt Gentle Aspiration

• Use gentle back-and-forth motion to promote catheter patency 2
• Flush with 10mL normal saline using turbulent push-pause technique 1
• Never force flush if significant resistance is encountered, as this risks catheter rupture 2

Step 3: Consider Thrombolytic Therapy

• If mechanical causes are ruled out and resistance persists, consider alteplase (Cathflo Activase) 3
• Dosing: 2mg/2mL instilled into the catheter lumen for patients ≥30kg 3
• Assess function at 30 minutes and 120 minutes after instillation 3
• Up to 85% of occluded catheters achieve restored function after up to two doses 3

Step 4: Radiologic Evaluation

• If function is not restored after two doses of alteplase, obtain radiographic assessment 2
• Evaluate for catheter tip malposition - tips in the upper or middle SVC are associated with higher complication rates 1
• Assess for thrombosis, which occurs in 4-8% of cases with central venous access devices 1
• Look for fibrin sheath formation or catheter fracture 4

Critical Red Flags Requiring Immediate Intervention

Do NOT use the port if any of the following are present:

• Pain, swelling, or redness at the insertion site - suggests thrombosis or infection 1
• Resistance during flushing with inability to aspirate blood - indicates partial or complete occlusion 1
• Systemic symptoms including shortness of breath, chest pain, or palpitations during flushing 1
• Signs of infection including fever, chills, or purulent drainage 5

When Port Removal is Indicated

Remove the port immediately in the following circumstances:

• Severe sepsis or bloodstream infection persisting despite 48-72 hours of appropriate antibiotics 5
• Tunnel infection, port pocket infection, or abscess 5
• Infections with S. aureus, fungi, or mycobacteria 5
• Suppurative thrombophlebitis or endocarditis 5
• Mechanical complications that cannot be resolved (catheter fracture with migration, irreversible occlusion) 4

Maintenance to Prevent Loss of Blood Return

Proper maintenance significantly reduces the risk of catheter dysfunction:

• For subcutaneous ports not in active use, flush every 4 weeks with normal saline 6
• Normal saline is equally effective as heparin for routine flushing 1, 7
• Use proper flushing technique with 10mL or larger syringes and turbulent push-pause method 1
• Maintain strict aseptic technique during all port manipulations 1

Common Pitfalls to Avoid

• Never use syringes smaller than 5mL as they generate excessive pressure that can damage the catheter 2
• Do not assume the port is functional simply because fluids infuse easily - this can occur even with malpositioned or partially occluded catheters 2
• Avoid excessive force during flushing attempts as this risks catheter rupture 2
• Do not delay evaluation - early intervention prevents progression to complete occlusion or thrombosis 1, 2

Clinical Context Matters

In oncology patients specifically:

• Ports have the lowest infection rates (0.8-7.5%) compared to other central venous access devices 6, 8
• Cancer patients have higher infection risk (16-31%) compared to general population 9
• Thrombosis risk is elevated in patients receiving chemotherapy, particularly with certain malignancies 6
• Early detection and treatment of catheter dysfunction prevents treatment delays that could impact cancer outcomes 6

The absence of blood return should trigger systematic evaluation rather than automatic port removal, but it must never be dismissed as inconsequential.