Temperature monitoring and mentoring Recent updates in perioperative thermoregulation

Abstract

In 2008, the national institute for health and care excellence (NICE) in the UK developed guidelines for the management of inadvertent peri-operative hypothermia. In these guidelines, hypothermia is defined as a patient core temperature below 36.0°C. Adult surgical patients are at risk of developing hypothermia at any stage of the perioperative pathway. In the guidelines, the perioperative pathway is divided into three phases: the preoperative phase is defined as the 1 hour before induction of anaesthesia (when the patient is prepared for surgery on the ward or in the emergency department), the intraoperative phase is defined as total anaesthesia time, and the postoperative phase is defined as the 24 hours after entry into the recovery area in the theatre suite (which will include transfer to and time spent on the ward). The phrase 'comfortably warm' is used in recommendations relating to both the preoperative and postoperative phases, and refers to the expected normal temperature range of adult patients (between 36.5°C and 37.5°C).

It is important to prevent inadvertent perioperative hypothermia. Although there are several different types of patient warming devices available that can be used for prevention, the evidence for many of these was too limited for recommendations to be made, and further research in this area is required. The key priorities for implementation in these guidelines provide strong direction for healthcare professionals in helping to prevent perioperative hypothermia in patients undergoing surgery. Perioperative care

 Patients (and their families and carers) should be informed that:

• staying warm before surgery will lower the risk of postoperative complications. • they should tell staff if they feel cold at any time during their hospital stay.

 When using any device to measure patient temperature, healthcare professionals should: 1. be aware of, and carry out, any adjustments that need to be made in order to obtain an estimate of core temperature from that recorded at the site of measurement. 2. be aware of any such adjustments that are made automatically by the device used.

Preoperative phase

Each patient should be assessed for their risk of inadvertent perioperative hypothermia and potential adverse consequences before transfer to the theatre suite. Patients should be managed as higher risk if any two of the following apply: 1. ASA grade II to V (the higher the grade, the greater the risk) 2. preoperative temperature below 36.0°C (and preoperative warming is not possible because of clinical urgency) 3. undergoing combined general and regional anaesthesia 4. undergoing major or intermediate surgery 5. at risk of cardiovascular complications.

 If the patient's temperature is below 36.0°C:

• forced air warming should be started preoperatively on the ward or in the emergency department (unless there is a need to expedite surgery because of clinical urgency, for example bleeding or critical limb ischaemia) • forced air warming should be maintained throughout the intraoperative phase.