To the Editor:—

We thank Gali et al.  for their description of what they consider to be a pressure/burn injury following the use of the Allon thermoregulation system. 1Management of patient body temperature and successful maintenance of normothermia in such a procedure is challenging and, as noted by the authors themselves, the patient maintained normothermia and her temperature at the end of the procedure was 36.3°C.

The incidence of pressure ulcers during surgery is well documented in the literature. Overall incidence is around 8%, depending on type of surgical procedure and length of surgery. The incidence rate is positively correlated to the length of the procedure and exceed 13% in procedures lasting longer than 7 h. 2–5 

As Gali et al.  state, this patient had numerous risk factors that predisposed her to pressure-related injury during the operative procedure, including prolonged surgery (6.5 h), advanced age, severe muscle wasting, poor nutritional status, end-stage liver disease, and intraoperative hypotension. We therefore beg to differ with the authors’ favoring the injury as being primarily due to a burn. This interpretation is based on the surgeon’s impression and on the patient’s postoperative complaint of a burning sensation in the affected area.

It is nearly impossible to differentiate by observation alone whether a skin lesion is due to pressure or a burn, whereas a burning sensation is certainly not specific to burns and can be caused by different kinds of lesions. Moreover, water temperature in the garment is limited to maximum of 40.8°C, so a contact burn due to overheating is virtually impossible. 6–7The Allon system itself was checked and found to be functioning properly.

In anticipated long-duration procedures and in chronically ill, high-risk patients, the usual precautions of meticulous attention to adequate relief of pressure points should be followed. MTRE’s user’s manual and leaflet guidelines specifically recommend the use of protective means for pressure sores between the operating table and the ThermoWrap. Furthermore, using ThermoWrap reduces the risk of developing such skin lesions because the Allon system is equipped with a unique pressure relief algorithm, the purpose of which is to address the known phenomena of intraoperative pressure ulcers.

MTRE’s main goal is to provide normothermia in anesthetized patients with maximal patient safety. Despite our excellent track record (< 0.5% reported skin injury out of ≥ 10,000 procedures), MTRE is continuously looking into new concepts, materials, and wraps that will improve patient safety even more.

Gali B, Findlay JY, Plevak DJ: Skin injury with the use of a water warming device. A nesthesiology 2003; 98: 1509–10
Aronovitch SA: Intraoperatively acquired pressure ulcer prevalence: A national study. Adv Wound Care 1998; 11: 8–9
Aronovitch SA: Intraoperatively acquired pressure ulcer prevalence: A national study. J Wound Ostomy Continence Nursing 1999; 26: 130–6
Kemp MG, Keithley JK, Smith DW, Morreale B: Factors that contribute to pressure sores in surgical patients. Res Nurs Health 1990; 13: 293–301
Schultz A: Etiology and incidence of pressure ulcers in surgical patients. AORN J 1999; 70: 434–49
Stewart TP: When a burn is not a burn. Int J Dermatol 1998; 37: 729–32
Stewart TP, Magnano SJ: Burns or pressure ulcers in the surgical patient? Decubitus 1988; 1: 36–40