A senior physician has praised staff at Carlisle’s Cumberland Infirmary for their quick action over saline tampering.

A police probe has been launched after it was discovered that an undisclosed number of saline bags were damaged.

Hospital bosses believe they were tampered with, but stress that as far as they are aware no patients have been affected.

Andrew Goddard, registrar at the Royal College of Physicians, said this is largely due to the quick actions of staff.

“Patients can be reassured. The fact this has been highlighted shows that the system works. Well done to the staff in Carlisle for spotting it and for raising the alarm,” he told the News & Star .

Although North Cumbria Hospitals NHS Trust has yet to release details of the incident, Dr Goddard stressed it is highly uncommon.

“It’s really rare. The big case that was relatively recently was Stepping Hill at Stockport. That was a single individual injecting insulin into saline bags so that patients would come to harm,” he said.

“We do not know the details about what has happened in Carlisle. All we know is that the bags were found to have been tampered with.

“Generally when we talk about tampering we mean people trying to inject something into the bag.”

Dr Goddard said saline is commonly given via intravenous drip to treat dehydration or to replace fluids in patients who can’t eat, such as those in intensive care. It is also used to administer drugs with.

“The bags come in different sizes – 150ml, 250ml or one litre. We do not know what sizes these bags were. If they are smaller they are generally used for drugs, if it’s larger it’s to replace fluids.

“Saline bags come in sealed box. You open that and there are lots of individual bags which are themselves wrapped in clear plastic. It therefore becomes fairly easy and fairly quick to see if a bag has been tampered with.

“Staff know about Stepping Hill so they do watch out for it. There are lots of safety checks,” he said.

He explained that the seal acts like a vacuum, so if the bags are pierced staff will be able to tell something is wrong. And he stressed that it didn’t necessarily happen at the hospital and believes the investigation will be looking at this.

“It could have been tampered with at the manufacturing end, through the route of delivery right through to going on to wards. We do not know the details of that,” said Dr Goddard.

He stressed it is difficult to mitigate for those intent on doing patients harm, citing serial-killing doctor Harold Shipman or child-murdering nurse Beverley Allitt as “maleficent” examples, because they are so devious. But he stressed these cases stick with NHS staff and have made them all the more wary.

And he said that the fact that, despite high-profile winter pressures in hospitals across the country, staff spotted the tampering and urgent action was taken was good news.

“I can reassure people that the NHS does put patients first. There are lots of safety checks. Yes the NHS is in crisis but staff within it are still looking out for patients and should be praised,” he added.

The alarm was raised on Wednesday last week. The trust said it immediately implemented serious incident procedures. It was made public on Tuesday after initial investigations.

The trust said early indications show that no patients have been adversely affected .

If patients have concerns, they can call 01228 814247.