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October 16-20, 2010 San Diego, CA Home Abstract Archive Search Abstracts 2010 Session Grid 2010 Meeting Website Policy Statements ASA Website Feedback 
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A190
October 17, 2009 10:00 AM - 11:30 AM Room Room 356 |
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| Infrared Thermographic Analysis of Temperature on the Face, Forehead, Neck, and Supero-Medial Orbit | ||||||||||||||||
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Ala S. Haddadin, M.D., F.C.C.P., Marc Abreu, M.D., Tyler Silverman, B.S., William Amalu, Ph.D., David G. Silverman, M.D. Anesthesiology, Yale University School of Medicine, New Haven, Connecticut |
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Research (1-3) has noted that a tunnel of infrared radiant energy exists between fat-free (thermally conductive) skin at the supero-medial orbit (SMO) and the cavernous sinus around the hypothalamic thermoregulatory center. A thermal sensor placed on the skin of the SMO, corresponding to the end of the Brain Temperature Tunnel (BTT), enables noninvasive measurement of core and intracranial temperatures (1-3). The purpose of this study was to examine the reliability of temperature measurement on the face, forehead (FH), neck, and BTT using detection of thermal infrared (IR) emission.
Methods: Thermal mapping of IR light emission from the BTT, FH, face, and neck was performed in 5 volunteers using high-resolution isotherm (IsoT) delineation. The images provide a visual display of radiated IR energy over a range of 8°C (darker represent cooler areas while hotter are lighter). Each image contains two colored areas (red and green). These referenced regions are placed on the images using computer processing and represent isotherms. Red IsoT represents the hottest area of face/neck and green IsoT the hottest area of the FH (green has a lower temperature than red). By appointing the highest amount of IR energy radiated as 100 (top of the scale) and the lowest amount of IR energy as 0 (bottom of the scale), we can extrapolate a given percentage of heat energy radiated from any region on the image. The IR images were processed for quantitative analysis and the thermal differences among the regions determined. Results: IR mapping showed a highly defined region of IR emission in the SMO, and the red isotherm (hottest area) was only present in the SMO area. The BTT was the hottest area on the face/neck, the surrounding corona of the BTT was the second hottest, and the third hottest area was the FH, however, the FH showed low IR emission and great variability in size and location of IR emission. In each radiant image, regardless of when the image was taken or what the subjects were exposed to, the area with the highest IR emission corresponded to the BTT. The mean temperature difference of the warmest area of FH scanning compared to the BTT was 1.29°C (3.6% of all forehead areas), the remaining 96.4% had differences between 1.30 and 3.6°C.[table1] Discussion: The data indicate that the BTT has the highest surface temperature on the face/neck and it is the only area that provides a reliable measurement of surface temperature. The face, FH and neck have much lower surface temperature and have great variability of IR emission. The mean difference between FH sites and BTT is consistent with the 1.3°C difference reported between FH scanning and pulmonary artery temperatures (4). The FH offers a non-reliable site for temperature measurement and true FH readings may fail to detect hyperthermia or falsely detect hypothermia. References: 1. Haddadin A, et al: Anesthesiology, 103:A857 ASA Abstract, 2005. 2. Haddadin A, et al: Anesthesiology, 103:A38 ASA Abstract, 2005. 3. Haddadin A, et al: Anesthesiology, 105:A70 ASA Abstract, 2006. 4. Suleman M et al. Insufficiency in a new temporal-artery thermometer for adult and pediatric patients. Anesth Analg 95(1):67-71, 2002. From Proceedings of the 2009 Annual Meeting of the American Society Anesthesiologists. |
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