The Times and Daily Mail have reported that almost 50,000 NHS patients are to be warned that they might have contracted a serious Mycobacterium infection from contaminated heater-cooler units, used during heart surgery.

Heater-cooler units have been linked to bacterial infections with non-tuberculous mycobacteria (NTM). The devices are used in hospitals to heat and cool patients' blood temperature during heart surgery.

Serious infections of the heart and sepsis have been linked to LivaNova PLC (formerly Sorin Group Deutschland GmbH) heater-cooler units and Marquet heater-cooler units.

It can take months and even years following exposure during surgery before a patient develops symptoms. Symptoms include high temperature, chills, muscle pain and an elevated heart rate.

In an update on 20 January 2017 Public Health England (PHE) has stated that there have been 26 reported cases with 15 fatalities, with an on-going investigation in to the use of the devices being conducted in the UK.

The risk of infection was first identified in around 2014 following reports of NTM infections in the USA, Switzerland, the Netherlands and Germany in patients following heart surgery. Public Health England (PHE) published an investigation into the risks in the UK in 2015.

According to the Daily Mail, NHS England and Public Health England has issued a joint statement stating: "It is important to remember that the risk of contracting this infection remains low. A balance needs to be struck between deriving benefit from notifying patients to that of causing undue alarm. We have been guided by the best clinical advice, as international knowledge and evidence about this infection has grown."

Rami Sommerstein, of Bern University Hospital in Switzerland and a lead author of a November 2016 study of infections caused by heater-cooler devices said that: 'Now that we know [heater-cooler devices] are the source, individual action from the different players (healthcare institutions, manufacturers, etc.) is needed to contain the ongoing patient risk. The most important action a hospital can take is to remove contaminated [heater-cooler devices] from the operating room and other critical areas. That is the only way to ensure that patients are protected from this infection moving forward.'

Chris Haan, an associate solicitor in Leigh Day's product liability team, said: "Patients should be able to expect that heater-cooler devices used during heart surgery are safe and that appropriate steps are taken to reduce the risk of infection. I am pleased that the NHS is now informing heart patients that they might have been exposed to this dangerous bacteria during surgery."

If you have undergone heart surgery and have been experiencing the symptoms of an infection you should contact your hospital or surgeon for clinical advice as a matter of urgency.