Evaluation of mean skin temperature formulas by infrared thermography

Abstract

To study the reliability of formulas for calculating mean skin temperature (Tsk), values were computed by 18 different techniques and were compared with the mean of 10,841 skin temperatures measured by infrared thermography. One hundred whole-body infrared thermograms were scanned in ten resting males while changing the air temperature from 40 degrees C to 4 degrees C. Local, regional average and mean skin temperatures were obtained using an image processing system. The agreement frequency, defined as the percentage of the calculated Tsk values which agreed with the corresponding infrared thermographic Tsk within +/- 0.2 degree C, ranged for with the various formulas from 7% to 80%. In many sites, the local skin temperature did not coincide with the regional average skin temperature. When the local skin temperatures which showed the highest percentage similarity to the regional average skin temperature within +/- 0.4 degree C were applied to the formula, the agreement frequency was markedly improved for all formulas. However, the agreement frequency was not affected by changing the weighting factors from specific constants to individually measured values of regional surface area. By applying the physiologically reliable accuracy range of +/- 0.2 degree C in the moderate and +/- 0.4 degree C in the cool condition, agreement frequencies of at least 95% were observed in formulas involving seven or more skin temperature measurement sites, including the hand and foot. We conclude that calculation of a reliable mean skin temperature must involve more than seven skin temperature measurement sites regardless of ambient temperature. Optimal sites for skin temperature measurement are proposed for various formulas.

Broiler surface temperature distribution of 42 day old chickens

“…Cangar et al (2008) found that the comb had the highest temperature gradient while the wing had the lowest. The head and neck regions and perhaps some areas around the abdomen are poorly feathered, hence insulation is quite poor in these areas, and consequently the sensible heat flow is improved (Li and Yamamoto, 1991;Choi et al, 1997).…”

Time required to stabilize thermographic images at rest

“…Roy and collaborators [16] performed a study in which thermography was used to analyze the time necessary for the temperature in the region of the spine to stabilize and suggested a minimum time of 8 min and maximum of 16 min for reliable measurements [16]. The recommended acclimatization time varies between studies of skin thermometry, with periods of 10 min [14,17], 15 min [8] and 20 min [4] suggested for the subject to remain at rest in a room with controlled temperature and humidity. This variation may be influenced by environmental conditions, especially by the temperature outside the test room.…”

“…This lack of consensus [4,8,[14][15][16][17] makes it difficult to determine the optimal acclimatization protocol because each study recommends a different acclimatization period to achieve a stable T SK to ensure the homogeneity of results and allow consistent interpretation and comparison of results between studies. Consequently, the objective of this study was to identify the time required to achieve a stable T SK at rest in a group of young men and women.…”

Use of infrared thermography as a tool to monitor skin temperature along the recovery process of an anterior cruciate ligament surgery

“…Roy and collaborators (2006) performed a study in which thermography was used to analyze the time necessary for the temperature in the region of the spine to stabilize and suggested a minimum time of 8 minutes and maximum of 16 minutes for reliable measurements (Roy et al, 2006). The recommended acclimatization time varies between studies of skin thermometry, with periods of 10 minutes (Choi et al, 1997;Ferreira et al, 2008) 15 minutes (Zontak et al, 1998) and 20 minutes (Merla et al, 2010) suggested for the subject to remain at rest in a room with controlled temperature and humidity. This variation may be influenced by environmental conditions, especially by the temperature outside the test room.…”

“…This variation may be influenced by environmental conditions, especially by the temperature outside the test room. This lack of consensus (Choi et al, 1997;Ferreira et al, 2008;Merla et al, 2010;Ring & Ammer, 2000;Zontak et al, 1998) makes it difficult to determine the optimal Introduction １６ acclimatization protocol because each study recommends a different acclimatization period to achieve a stable T sk to ensure the homogeneity of results and allow consistent interpretation and comparison of results between studies. A recent study by Bouzas Marins and collaborators has directly analysed the optimal acclimatisation time for IRT evaluation in humans.…”