We have started an investigation looking at the risks to patients when intravenous (IV) drugs are retained in cannulae and extension lines.

Some drugs, such as those used in anaesthesia and pain management, can cause patients to stop breathing. After administration these drugs should be flushed through cannulae and extension lines to make sure no residual quantities of the drugs are left.

Despite the issuing of multiple safety alerts over the past ten years, residual drugs in cannulae and extension line events continue to happen. When these events involve drugs that cause the patient to stop breathing, there is a risk of hypoxic brain injury (where the brain is damaged after a period where it does not get enough oxygen) or death.

A cannula is a plastic tube that is inserted into a patient’s vein to administer medicines. Cannulae are available in a range of sizes and design types which vary between hospital departments and wards. Extension lines may be connected to the cannula to increase the number of access points to allow multiple medicines to be given at the same time. Cannulae are subject to careful infection prevention and control oversight as these devices can be a route through which infection is caused.

Reference event

The investigation was launched after concerns were reported to HSIB by a consultant anaesthetist at a district general hospital where a patient had stopped breathing several hours after undergoing an anaesthetic.

It’s thought that a quantity of the drug Suxamethonium - a muscle relaxant - was retained in their cannula after the procedure. The cannula containing the drug was flushed on the ward by a nurse preparing to administer intravenous paracetamol around three hours after the patient had returned from his procedure.

The event was witnessed by a doctor who immediately started manual ventilation. The patient began to breathe spontaneously a few minutes later and suffered no physical harm. However, they have been left with a significant psychological impact following their experience of being awake but unable to move or breathe.

Investigation summary

This investigation will:

  • Explore the design, procurement and change management of intravenous consumables, such as cannulae and extension lines.
  • Observe how checklists are used in the theatre and non-theatre setting to ensure that cannula flushing is undertaken.
  • Examine medicines safety, management and governance arrangements. This may include prescribing arrangements, record keeping, medicines dosage and presentations, and reporting of incidents.
  • Seek to develop safety recommendations.

Safety recommendations

As part of our final investigation report we will make safety recommendations to the appropriate national bodies in order to improve patient safety.

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