Inditherm patient warming mattress for the prevention of inadvertent hypothermia

System impact

4.1 Avoidance of inadvertent hypothermia has been demonstrated to reduce the incidence of postoperative infections, with consequent savings in cost to the NHS.

4.2 The Inditherm mattress can be left in place on an operating table throughout a theatre operating list with low running costs. This may allow faster turnaround times for patients compared with the use of forced air warming.

4.3 The Inditherm mattress is a reusable device and no consumables are needed. This limits the need for disposal of consumables and any impact that might have on the environment.

4.4 The Inditherm mattress is silent, has low energy consumption and specifically warms the patient without inadvertently warming the surgical team.

Committee considerations

4.5 The Committee considered that the clinical evidence supported the effectiveness of the Inditherm mattress in maintaining core body temperature and therefore, preventing inadvertent hypothermia. The Committee was advised by clinical experts that it was reasonable to assume that the prevention of inadvertent hypothermia would result in a decrease in surgical site infections, as demonstrated for forced air warming. Direct evidence showing that the use of the Inditherm mattress reduces the incidence of surgical site infections, compared with not warming, was not available. It is unlikely that such research would now be conducted, because the advantages of keeping patients warm are known.

4.6 The Committee considered the claims for practical advantages of the Inditherm mattress compared with forced air warming to be plausible and likely to be realised in clinical practice.

4.7 The Committee recognised that availability of the Inditherm warming mattress would be likely to result in more patients being warmed during surgery than in current practice. It noted that the mattress can be left switched on, so that increased use would not require increased staff or time.

4.8 Mindful of possible transmission of infection, the Committee asked the expert advisers and the manufacturer about cleaning the Inditherm mattress between patients. It was told that the mattress is cleaned in the same way as the normal operating table mattress. The Committee also enquired in detail about the durability of the mattress and the possibility that damage to mattresses might allow fluid ingress. It was sufficiently reassured on all these points.

4.9 The Committee questioned whether warming areas of the body with poor perfusion (for example, warming the legs when arterial perfusion is reduced during vascular procedures) might lead to thermal injury. It was advised that mattresses of different sizes are available which means that warming poorly perfused areas can be avoided. The Committee recognised that clinical judgement is required to select Inditherm mattresses and blankets of appropriate size for individual patients.

4.10 The Committee considered that there was no evidence to suggest that the use of the Inditherm patient warming mattress had caused harm to patients, although it noted expert advice that thermal injury was a theoretical risk (for example, as a result of pooling of surgical antiseptic preparations).

4.11 The Committee considered that the Inditherm mattress offers a practical means of maintaining core body temperature during procedures done under X-ray guidance, including endovascular aneurysm repair. It noted that testing showed that image quality was not significantly affected when the Inditherm mattress was used, and was advised that a potential 15% increase in radiation dose associated with use of the warming blanket was not clinically significant.

4.12 The Committee was advised that the connection rails, sensors and wiring down the sides of the mattress could interfere with imaging if X-rays were used at certain oblique angles.