A life-threatening risk associated with accessing a patient's bloodstream via haemodialysis central venous catheters has been highlighted by the Healthcare Safety Investigation Branch (HSIB).
A new HSIB investigation report emphasises that if the catheter is left 'uncapped and unclamped' without attaching a syringe when used to access a patient's blood supply, then the patient can be put at risk of an air embolism, leading to the possibility of catastrophic right-sided heart failure and cardiac arrest.
Almost 30,000 people in the UK are on dialysis, and there are over one million treatments a year using dialysis catheters in the UK. Haemodialysis catheters have a wide bore (internal diameter) compared to other types of central line, to allow a high volume of blood to flow through, which increases the risk of a large air embolus, compared with narrower catheters.
Statistics from one national reporting database showed there had been 14 air embolus incidents between 2017 and 2022, all of which related to uncapped and unclamped lines, and three of which were for haemodialysis catheters. In the same period, another national database showed that there had been 70 occurrences where central lines had been found uncapped and unclamped.
The HSIB launched a national investigation after it was notified of the safety risks associated with haemodialysis catheters by the Department of Health and Social Care, following a Prevention of Future Deaths report by the coroner following a fatal patient safety incident. The case involved Joan, a 75-year-old woman, who was on long-term haemodialysis for end-stage renal failure.
Joan had a cardiac arrest caused by an air embolus after her haemodialysis catheter was uncapped, unclamped, and left open to air. This took place during a procedure to take blood culture samples to test for a possible line infection.
The analysis of Joan's case pinpointed the safety risks and challenges at a national level. In her case, HSIB identified that the that blood cultures were taken from a haemodialysis catheter in an inappropriate location, without the required equipment available, by staff without the required specific competencies.
Improvements Needed to Address Risks
Key findings from the HSIB investigation include:
- There are currently no long-term haemodialysis catheters on the UK market, or being developed, that have integrated 'safety-valves'
- Manual clamps on haemodialysis catheters rely on people ensuring that the clamp is on before accessing the haemodialysis catheter ports and do not mitigate against design-induced error
- There is currently no recognised national training or national training guidelines regarding the safe access of haemodialysis catheters
- There is a general lack of literature on, and knowledge of, catheter-related air embolism in relation to access when the catheter is in situ, rather than during insertion or removal of the catheter
- Incidents appear to be under-reported to the Medicines and Healthcare products Regulatory Agency (MHRA), due to misconceptions about 'human error' being the cause, rather than the design of the equipment
The HSIB stated in their safety observations that it may be beneficial for manufacturers of haemodialysis catheters to develop an engineering solution to maintain a sealed system, thereby reducing the risk of an air embolism.
The recommendations in relation to administrative controls focus on helping medical students to handle uncertainty in clinical settings, making it clear in GMC practical skills guidance that newly qualified doctors should only be taking blood from a peripheral site (usually arms or hands), and ensuring that the safety risk of an air embolus is reflected in MHRA's dialysis guidance (updated in 2022).
'Devastating Example' of Safety Failures
Helen Jones, HSIB national investigator, said: "Our investigation highlighted that improvements to address this particular safety risk sit across different parts of industry and the healthcare sector. In the report, we have covered everything from the design and manufacture of haemodialysis catheters to the regulatory environment and the culture surrounding medical student competencies."
She added: "Joan's case is a devastating example of what can happen when there isn't barriers in place to mitigate this risk."
Paul Cockwell, a consultant nephrologist in Birmingham and President of the UK Kidney Association said: "On behalf of kidney healthcare professionals, we are distressed to hear of Joan's death and offer our deepest condolences to her family and friends. We are grateful for the work of Helen Jones and the HSIB team and will support renal services and healthcare professionals to institute the recommendations in the report.
"Haemodialysis catheters are used for in excess of a million treatments a year for thousands of patients with kidney failure and it is crucial that patients are confident that safeguards are in place to minimise the risk of air embolus and other complications associated with their use."