Maintaining catheter patency is one of the most persistent challenges in vascular access management. While device innovation has introduced valved catheters designed to reduce reflux and occlusion, real-world experience continues to show that occlusion remains a significant and costly complication across all device types.
This raises an important question for clinical practice: how can we more effectively prevent occlusion while balancing clinical outcomes with cost efficiency?
The Ongoing Challenge of Occlusion
Catheter occlusion is not an isolated or rare event. It is a common complication that affects both short and long-term vascular access devices and continues to drive avoidable clinical and financial burden.
Occlusion typically develops progressively and is closely linked to:
- Blood reflux into the catheter lumen
- Fibrin deposition along the internal or external catheter surface
- Fibrin sheath formation, which can begin within 24 hours of insertion
- Thrombotic build-up leading to partial or complete blockage
A key early indicator is withdrawal occlusion, where infusion remains possible, but blood cannot be aspirated. This is frequently observed across both valved and non-valved devices.
Importantly, valved catheters do not eliminate this risk. Despite their design intent, reports show that blockages and withdrawal occlusion still occur in valved systems, demonstrating that device design alone cannot prevent the occlusion pathway.
The Clinical and Financial Impact
When occlusion occurs, the consequences extend beyond device function:
- Delays to treatment and therapy interruption
- Increased use of thrombolytic agents
- Additional nursing time and resource utilisation
- Potential catheter replacement procedures
- Increased infection risk due to repeated manipulation
These complications come at a cost. The cumulative financial impact includes:
- Drug costs for declotting agents
- Staff time for troubleshooting and intervention
- Procedure costs for line replacement
- Extended patient stays or delayed discharge
At a system level, occlusion represents a significant and recurring cost burden, particularly when it leads to escalation of care.
Valved vs Open-Ended Catheters: Cost Without Clear Benefit
Valved catheters are often perceived as a solution to reflux and occlusion. However, in practice:
- Occlusion still occurs, including withdrawal occlusion and thrombotic blockage
- Effectiveness is highly dependent on correct handling and maintenance
- There is no clear, consistent clinical evidence demonstrating superiority in preventing occlusion compared to open-ended devices
Crucially, valved catheters are significantly more expensive than open-ended alternatives. When the higher acquisition cost is combined with similar rates of occlusion-related complications, the value proposition becomes difficult to justify.
This places greater importance on maintenance strategy, rather than relying solely on device design.
TKO: A Practical and Preventative Approach
“TKO” or “to keep open” remains a simple, effective and widely understood method of maintaining catheter patency, particularly for devices not in continuous use.
Its value lies in preventing the conditions that lead to occlusion, rather than reacting after it occurs.
TKO supports patency through:
- Continuous low-rate flow or routine flushing
- Reduction of blood reflux into the catheter
- Prevention of fibrin accumulation within the lumen
A key advantage of TKO-based approaches, particularly when used with appropriate systems, is regular set replacement.
Why TKO Can Be More Effective Than Valved Systems
One of the most important advantages of TKO is that associated systems are typically changed every 7 days. This has a direct impact on occlusion prevention:
- Reduces the duration for fibrin and residue build-up
- Minimises the risk of biofilm formation
- Prevents long-term accumulation that contributes to blockage
- Supports consistent, controlled maintenance
In contrast, catheters with integrated valves remain in situ for extended periods, where build-up can develop over time despite the presence of a valve mechanism.
As a result, TKO offers a more proactive and cyclical approach to patency management, rather than relying on the passive function of a valve.
Shifting the Focus: Prevention Over Design
The evidence and clinical experience increasingly point to a clear conclusion:
Occlusion is driven more by maintenance practices than by catheter design alone.
Focusing on prevention requires:
- Consistent flushing protocols
- Minimising blood reflux
- Routine system changes
- Early recognition of withdrawal occlusion
- Standardised approaches to line care
TKO aligns closely with these principles by embedding regular intervention into everyday practice.
A More Cost-Effective Strategy
When comparing approaches, TKO combined with open-ended catheters can offer:
- Lower upfront device costs
- Reduced reliance on expensive valved technology
- Fewer severe occlusion events requiring escalation
- Predictable and controlled maintenance cycles
This creates a more cost-effective and clinically reliable solution, particularly in high-volume settings.
Improving Patient Experience and Outcomes
From a patient perspective, preventing occlusion is critical. It avoids:
- Treatment disruption
- Additional procedures
- Repeated interventions
- Increased anxiety
By maintaining a functional catheter through proactive care, TKO supports:
- Reliable therapy delivery
- Reduced complications
- Greater confidence in long-term vascular access
Key Takeaway
Catheter occlusion remains a common and costly complication, affecting both valved and non-valved devices. While valved catheters were introduced to address reflux, real-world use shows they do not eliminate blockage or withdrawal occlusion yet come at a significantly higher cost.
TKO provides a practical and preventative alternative. Through regular flow and routine system changes every 7 days, it reduces the risk of fibrin build-up, maintains patency and supports consistent catheter function.
Ultimately, focusing on maintenance over mechanism offers a more effective path to reducing occlusion, improving patient outcomes and managing cost across vascular access services.
