Objective evaluation for venous leg ulcer-related nociceptive pain using thermography

Abstract

Correspondence: hiromi sanada 7-3-1 hongo, Bunkyo-ku, Tokyo 113-0033, Japan Tel +81 3 5841 3419 Fax +81 3 5841 3419 email hsanada-tky@umin.ac.jp Purpose: We aimed to identify distinguishing characteristics in thermographic images of venous leg ulcer (VLU), for objective evaluation of VLU-related nociceptive pain. Patients and methods: Secondary analysis was performed, using existing data obtained from April to November 2010, for patients with VLU. Thermographic images of wounds and their surrounding area were classified according to the periwound temperature pattern as "normal temperature" or "high temperature". These results were compared with the self-reported pain intensity assessed by the short-form McGill Pain Questionnaire. Cohen's kappa coefficients were used to evaluate the interrater reliability for temperature assessment, and Wilcoxon rank sum test was used to compare pain intensities between the two groups. Results: Among 39 thermographic examinations in eight patients, 22 were classified into the high-temperature group and 17 into the normal-temperature group. Kappa coefficients for the temperature classification were 0.90 between the wound, ostomy, and continence nurse and a wound care specialist, and 0.90 between the wound, ostomy, and continence nurse and a graduate student. The pain rating index (Z=−2.981, P=0.003), sensory pain (Z=−3.083, P=0.002), affective pain (Z=−2.764, P=0.006), and present pain intensity (Z=−2.639, P=0.006) ratings were significantly higher in the high-temperature group than in the normal-temperature group, but the visual analog scale (Z=−0.632, P=0.527) was not significantly different between the two groups. Conclusion: Thermographic pattern may reflect VLU-related nociceptive pain due to inflammation and has the possibility of being an easy and rapid tool for objective pain evaluation.

Lower temperature at the wound edge detected by thermography predicts undermining development in pressure ulcers: a pilot study

“…periwound skin > wound edge > wound bed). This pattern is observed in almost all cases that heal normally . In some cases that differ from the pattern mentioned above, the temperature is lower at the wound edge than at the periwound skin and wound bed (periwound skin and wound bed > wound edge) (Figure ).…”

“…Our previous study using thermography focused on the mechanism underlying the relative temperature increase caused by increased blood flow via significant vasodilation due to the inflammatory response . On the other hand, this study is a new investigation focusing on a relative temperature decrease based on deficient blood flow in the devitalised tissue at the wound edge.…”

“…Classification of the thermal images of the wounds was performed according to the concepts in previous studies . The highest temperature is usually observed in the periwound skin, defined as the normal skin surrounding the wound, followed in order by the temperature at wound edge, defined as the outline of the wound itself, and the wound bed (i.e.…”

“…To address these challenges, we focused on thermography, which offers the great advantage of real‐time 2D temperature measurement on the skin surface. We have reported that the relative temperature differences at measurement points on the wound and periwound skin detected by thermography can indicate inflammation without clinical manifestations in calluses of patients with diabetic neuropathy, PUs and venous leg ulcers . These studies were performed based on the idea that vasodilation and tissue metabolism induced by the inflammatory response can produce a thermal change at the inflammatory site.…”

Can Wound Exudate from Venous Leg Ulcers Measure Wound Pain Status?: A Pilot Study

“…We previously reported that a high temperature specifically at the periwound area on thermography may well be an indicator of a painful wound [14]. However, thermography cannot be used to assess neuropathic pain that is not accompanied by a temperature elevation.…”