National Institute for Health and Clinical Excellence (NICE)
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NICE guidance aims to prevent hypothermia in patients undergoing surgery

The National Institute for Health and Clinical Excellence (NICE) and the National Collaborating Centre for Nursing and Supportive Care (NCC NSC) have today (23 April) issued guidance to the NHS in England and Wales on preventing hypothermia in patients before, during and up to 24 hours after surgery (known as perioperative hypothermia).

Hypothermia – defined as a core body temperature of less than 36°C - is a recognised and common occurrence during surgery, with estimates suggesting that up to 70% of unwarmed patients may be hypothermic on admission to the recovery room. Patients who develop perioperative hypothermia can experience a number of complications, including a greater chance of heart problems, higher rates of infection and increased blood loss. Patients experiencing perioperative hypothermia may need a longer stay in hospital.

Important recommendations in the guideline include:

Before surgery (the hour before anaesthesia is given, during which the patient is prepared for surgery)

•Patients should be considered at an increased risk of hypothermia or its complications if any two of the following apply:

−They have a condition that affects their general health, such as high blood pressure, asthma, diabetes or angina

−Their temperature is already below 36°C (and it is not possible to warm them up before surgery because they need to be operated on urgently)

−The patient is undergoing a combined general and regional (such as an epidural) anesthetic

−The patient is undergoing major or intermediate surgery

−The patient is at risk of heart complications.

•Healthcare professionals should ensure that patients are kept comfortably warm while waiting for surgery by giving them at least one cotton sheet plus two blankets, or a duvet.

If the patient’s temperature is below 36.0°C:

•They should be warmed using a technique called ’forced air warming‘ where hot air is blown in to a specially designed blanket

•This treatment should be started preoperatively on the ward or in the emergency department (unless this is not possible because they need to be operated on urgently).

•Forced air warming should be maintained throughout surgery.

During surgery (from when anaesthetic is first given through to patient transfer to the recovery area)

•Patients should not be given an anaesthetic until their temperature is 36.0°C or above (unless this is not possible because they need to be operated on urgently).

•Intravenous fluids (500 ml or more) and blood products should be warmed to 37°C using a fluid warming device.

•If the patient’s operation lasts longer than 30 minutes, or if their operation is shorter than this but they are at higher risk of hypothermia or its complications, they should be kept warm throughout the operation using forced air warming (and their temperature measured throughout surgery).

After surgery (defined as the 24 hours after the patient has entered the recovery area)

•The patient’s temperature should be measured and documented on admission to the recovery room and then every 15 minutes.

•The patient should not be transferred to the ward unless their temperature is 36.0°C or above.

•If the patient’s temperature is below 36.0°C, they should be actively warmed using forced air warming until they are discharged from the recovery room or until they are comfortably warm.

•If the patient’s temperature falls below 36.0°C while on the ward they should be warmed using forced air warming until they are comfortably warm and their temperature should be measured and documented at least every 30 minutes during warming.

Andrew Dillon, NICE Chief Executive, said:
“There is a great deal of misunderstanding about the risks associated with perioperative hypothermia but equally there is a huge amount that can be done to prevent hypothermia happening. Prevention begins with simple measures, such as providing sufficient bedding to keep patients comfortably warm before surgery. More active interventions to warm patients should be used during surgery when patients are at most risk of becoming hypothermic. Providing patients with the right information is also very important – an issue that this guideline seeks to address. Implementation of this guideline is likely to have significant benefits for patients and the NHS, including a reduction in rates of surgical site infection and shorter hospital stays.”

Dr Ratan Alexander, Consultant Anaesthetist and Chair of the Guideline Development Group, said:
As a clinician with a particular interest in the issue of perioperative hypothermia I was extremely pleased that NICE was asked to look at this topic as part of its clinical guidelines work programme. My concern has been that some colleagues may not always fully appreciate the rationale for avoiding perioperative hypothermia, and therefore may not consider the issue seriously enough – to the potential detriment of their patients. However, the evidence base that informs this guideline points to very clear benefits to patients by ensuring they are kept properly warm during the perioperative phase and the recommendations we have been able to make in the guideline fully reflect that evidence. Anyone who has woken up shivering after an operation would be the first to acknowledge that warming of patients during the perioperative phase should be an integral part of the anaesthetic process.”

Dr Mark Harper, Consultant Anaesthetist and member of the Guideline Development Group, said: “Unfortunately it is too often the case that patchy implementation of perioperative warming is due to inadequate resources. Hopefully the leverage provided by this guideline, and the importance it places on interventions that are both clinically and cost effective, will bring about a significant improvement in this situation. I am also very happy to see the research recommendations made in the guideline as there are a number of other technologies – for example, the new generation of electric warming mattresses – that have the potential to drive down the cost without compromising care. “

Jane Bovey, an Anaesthetics and Recovery Nurse and member of the Guideline Development Group, said:
"This guideline will be instrumental in empowering nurses to set standards, working in partnership with their surgical and anaesthetic colleagues, of temperature management in the perioperative setting, as well as offering nurses an important opportunity to champion ‘evidence into practice’ in order to improve patient outcomes. “

Notes to Editors

1.The guideline is available at

About NICE

2.The National Institute for Health and Clinical Excellence (NICE) is the independent organisation responsible for providing national guidance on the promotion of good health and the prevention and treatment of ill health.

3.NICE produces guidance in three areas of health:

public health – guidance on the promotion of good health and the prevention of ill health for those working in the NHS, local authorities and the wider public and voluntary sector

health technologies – guidance on the use of new and existing medicines, treatments and procedures within the NHS

clinical practice – guidance on the appropriate treatment and care of people with specific diseases and conditions within the NHS.

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