Medical professionals have turned to comms channels such as Whatsapp when co-ordinating responses to emergency situations such as the Grenfell Tower blaze and terrorist attacks in London and Manchester.
But using such apps does not come without risks, says the guidance, released this month.
Laws on data protection and privacy need to be considered when people are deciding how and when to use instant messaging safely in acute clinical settings, it states.
People should only use apps and other messaging tools that meet the NHS encryption standard; not allow others to use their device; and disable message notifications to protect patient confidentiality.
Information that relates to patients and their care should be transferred into their medical records.
The guidance does not recommend any specific type of instant messaging, choosing instead to outline the issues to be considered and the standards that need to be met.
It calls for a "proportionate approach" by health professionals who should "balance the benefits and risks of instant messaging depending on the purpose for which they wish to use it."
The guidance warns: "Remember that the law places obligations on organisations to protect patient confidentiality. If you are a clinician, you may also have to defend yourself against regulatory investigation if you have not taken sufficient steps to safeguard confidentiality."
Doctors should "Only use a standalone instant messaging application if your organisation does not provide a suitable alternative."
And apps should be used only if they have security features such as encryption and password protection.
The new guidance has been welcomed by senior doctors.
Dr Helgi Johannsson, a consultant anaesthetist at Imperial College Healthcare NHS Trust, set up a major incident instant messaging group to help co-ordinate his hospital’s response to the Grenfell Tower fire in June 2017 after learning a key lesson from the terrorist attack on Westminster just a few months earlier.
He commented: "From the Westminster attack we learnt it was important not to overload the emergency care co-ordinators with offers of help, so with Grenfell we used instant messaging to help co-ordinate which staff should come in, who was needed where and plan the service for later on that day, which vastly improved the care we were able to provide."
Dr Johannsson added: "These sensible guidelines will make the care of our patients safer through better communication by NHS staff."
Dr Simon Eccles, chief clinical information officer for health and care, said: "Instant messaging services can be a vital part of the NHS toolkit… These new guidelines will help our doctors and nurses to make safe and effective use of technology under the most intense pressure."
Dawn Monaghan, director of the information governance alliance, a government health body, commented: "This guidance has been designed with clinicians to help NHS organisations and their staff take a proportionate approach, considering both the potential risks to privacy and the potential improvements in patient safety."
She added: "I’m hopeful this new guidance will prove a valuable resource to assist NHS organisations in implementing policies that will help their staff decide when it is appropriate to use instant messaging tools and when it isn't."
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