Case of the month: December 2019 - pass the baton

About this case study

Each month JAG publishes a case of the month highlighting a real life clinical scenario which has impacted patient safety. Case studies are contributed by JAG leads and endoscopy services across the UK and are designed to provide an opportunity for discussion and to share learning. 


Download the PDF version hereand share this for discussion with your team.

Case synopsis

A 57-year-old patient was seen in the gastroenterology clinic having been referred for an episode of jaundice. An ultrasound scan found a dilated common bile duct and a 16mm stone lodged in the distal end of the duct. 

The patient’s jaundice recurred and an urgent ERCP was performed under conscious sedation. The main bile duct was found to be grossly dilated but no stone was seen. A sphincterotomy (cut into the bile duct) was performed, with plan to conduct a balloon trawl. A larger balloon (18mm) was required to make sure small stones were captured. 

An 18mm balloon can be inflated to two measurements 15mm or 18mm. The volume of an 18mm balloon is almost twice that of the 15mm balloon (3050mm3 vs 1700mm3). There is a ‘mark’ on the air syringe attached to the balloon, up to which the endoscopy assistant pushes the plunger to achieve 15mm inflation. 

The endoscopist placed the balloon in a narrower part of the bile duct (intra-hepatic portion) and asked the endoscopy assistant, who had just swapped into the procedure due to the arrangement of breaks, to inflate it ‘to the mark’. The balloon was inflated all the way so that it reached 18mm in diameter. 

There was an immediate suspicion that damage may have been done to the bile duct, and indeed injection of contrast revealed a biloma, or leak.

A stent was inserted to encourage bile to drain down through the liver. A CT scan was performed on the same day and appeared to confirm a bile duct injury. Intravenous antibiotics were given for several days.

The patient was informed of the incident on the day of the ERCP, an apology was given, and the incident was notified through an incident-reporting system (DATIX). The patient recovered and was discharged 4 days later. A repeat ERCP was performed 3 weeks later and the bile duct injury was completely healed.

JAG analysis

What are the learning points you took away from this case?
How could things have been improved?

The following patient safety incidents were identified by JAG. They have been categorised for severity (mild, moderate and severe) based on the actual or potential impact to the patient and adherence to clinical guidance, as well as by theme [2]:

1. Oxygen monitoring
2. Distractors and time management 
3. Non-technical skills and training
4. Documentation and reporting errors
5. Technical skills and equipment 
6. Sedation intravenous access and monitoring
7. Drug errors
8. Consent 
9. Histology and sampling errors
10. Administrative error

Patient safety incident



Assistant changeover at technically complex stage with possible ineffective handover

 3. 4Moderate
Imparement of situational awareness of team members after a change in the team3Mild

Over-inflation of balloon beyond the desired diameter


Did you identify any other patient safety incidents?


1. An endoscopy assistant’s focus on the precise stage of the procedure can be impaired by swapping into procedures or handing over while it is in process. Ideally, staff should not swap during advanced, therapeutic endoscopic procedures. If it is necessary, the endoscopist should be warned at an appropriate moment, and asked to confirm that he/she is happy for this to go ahead. If a swap does occur, it should not happen during a challenging phase of the procedure. The incoming assistant must have time to be briefed on the stage of the procedure and what the therapeutic intention is.

2. The new assistant may not have understood the instruction to inflate to the desired limit as a result of ineffective handover and/or familiarity with equipment. It is good practice for the endoscopy assistant to repeat instructions back to the endoscopist for confirmation. This reflects the concept of ‘closed-loop communication’ where the ‘sender’ of messages ensures that they are conveyed and understood by ‘recipients’. This could be improved through simulated role play and didactic updates on best practice.

3. It is apparent that two-stage balloons may carry an inherent risk. Services should make enquiries into ordering balloons with fixed diameter syringes so that accidental over-inflation cannot occur.

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This case is informed by real-life events and the narrative has been adapted to enhance educational benefit. No identifiable information has been provided.

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