The Healthcare Safety Investigation Branch (HSIB) was notified by an Acute Trust of an incident that took place in June 2017 relating to a wrong site intervention.

After a preliminary investigation, HSIB have decided to launch a full investigation as it feels that there are significant national learning opportunities. The notification raised concerns of checking processes in place - right through from the point the patient is referred to the completion of invasive procedures. 

HSIB's investigation centred on how the reference event error occurred and what recommendations could be made to reduce the risk of a similar event happening again. The investigation considered the contributory factors to the patient receiving the anaesthetic nerve block to the wrong leg including a review of the Stop Before You Block (SBYB) process and its efficacy in reducing the risk of a wrong site block. The investigation team observed similar anaesthetic procedures in several NHS Trusts and witnessed variations in practice and compliance with the national and local guidance.   

The report makes two safety recommendations to the Royal College of Anaesthetists and one safety observation.


  • The Royal College of Anaesthetists establishes a specialist working group to evaluate the current practices used to reduce wrong site block incidents. This group should consider how safety initiatives to reduce wrong site blocks can be standardised in anaesthesia training and practice. It is recommended that the specialist working group consider the impact of: the patient’s state of consciousness, changes in a patient’s position and the prevalence of wrong site block incidents compared to the number of blocks administered.
  • The Royal College of Anaesthetists ensures any further work identified by the specialist working group to reduce wrong site block incidents is subject to human factors-based testing and evaluation.

Safety observation 

The development of patient safety initiatives should incorporate human factors and safety science specialism. This can help ensure that appropriate planning, testing, and evaluation take place to ensure a strong evidential basis for patient safety initiatives.

Find the link to the media statement here