Inaccurate body temperature readings can harm the entire health care system

As we head into a flu season where the 2009 H1N1 swine flu is expected to cause increased sickness, hospitalization and deaths across the U.S., something as simple as inaccurate body temperature measurements may lead to social and economic turmoil – and may cause many more deaths.

At the same time that reports estimate that half the U.S. population, or greater than 150 million people, may be affected by the flu this season and the Centers for Disease Control (CDC) recommends that people with influenza remains at home until at least 24 hours after they are free of fever, other reports have shown that approximately 40% of thermometer readings overestimate and 20% underestimate body temperature. The result is a perfect storm with 60% of Americans -- or 90 million people – receiving the wrong temperature readings during the flu season.

The consequences of these errors in temperature readings could have severe results. It can cause people who are sick to be falsely diagnosed as healthy, further spreading the flu virus. At the same time, healthy individuals can be falsely diagnosed as having fever and “forced” to remain at home. This can have a serious detrimental effect on our entire health care system and the economy as companies face shortages of healthy workers and consumer spending is curtailed.

Just sorting out which patients to treat and which to send home, for example, could strain our healthcare system. A recent report from the nonprofit Trust for America’s Health noted that if 33% of the population caught swine flu, 15 states could run out of hospital beds at the peak of the outbreak.

Businesses can be affected in two ways. Overall productivity will be reduced simply because there are fewer workers, and businesses that rely on customers, such as restaurants, movie theaters, malls and the travel industry, will be affected if more people, possibly millions, are not able – or willing, due to false fever readings – to go out. This will cause a ripple effect throughout the economy.

Children are particularly at risk because of their parent’s dependence on the only objective emergency warning sign, which is fever, according to the CDC. The other signs are subjective and difficult to interpret, such as fast breathing, not drinking enough fluids, bluish color or irritability. Therefore, wrong thermometry jeopardizes children in two ways -- lack of detection, which can lead to complications and possibly death; and false fever, which can expose them to the dangers of infections in a medical setting.

In addition, the military could be one of the greatest casualties of incorrect temperature measurements because they live in close quarters where disease can be easily transmitted. This was the case almost 100 years ago when the first wave of what became known as the 1918 flu pandemic appeared in military camps causing an enormous number of deaths.

BETTER TEMPERATURE MONITORING, BETTER CONTAINMENT OF DISEASE

Fever implies increased transmissibility, and a high fever that persists beyond three days is the only measurable flu danger sign and the key determining factor when someone should seek medical care. For people with underlying conditions, it’s important to be seen promptly if they have a high fever. According to CDC, that could make the difference between being severely ill and recovering well.

In a flu pandemic, precise temperature readings and accurate fever information are vital to make the right decisions. A new study from a research group at Yale University released today shows the reliability of temperature measurements from the body’s own natural temperature indicator using the Brain Temperature Tunnel (BTT), which transmits brain temperature to a small area of skin. The study, “Infrared Thermographic Analysis of Temperature on the Face, Forehead, Neck and Supero-medial Orbit,” is being presented today at the 2009 Annual Meeting of the American Society of Anesthesiologists in New Orleans, LA.

“Humans have invaded multiple orifices and penetrated multiple sites in an attempt to overcome the body’s thermal barriers to monitor core temperature,” said Dr. David G. Silverman, Director of Clinical Research and Professor in the Department of Anesthesiology and Critical Care Medicine at Yale University in New Haven, CT. “Our findings indicate that, all along, a tunnel to the organ most sensitive to -- and most responsible for -- body temperature has existed right between our eyes.

“The discovery of the BTT enables clinicians to escape dependence on invasive thermometry and surface measurements across thermal barriers,” he added.

CURRENT THERMOMETRY’S INABILITY TO OVERCOME THERMAL BARRIERS

As shown in this study, because the body’s fat layer provides insulation and prevents adequate thermal emission, the skin surface, such as the forehead and axila, cannot provide accurate thermal measurement. Forehead thermometers are thereby forced to rely on artificial calculations, which can lead to overestimation and underestimation. Ear canal thermometry also relies on artificial estimations, and numerous reports, including reports by the British Government, show the limitations and dangers of the errors caused by ear thermometers.

Rapid digital oral and rectal thermometry frequently rely on estimation techniques as well, leading to further inaccuracies. In addition, oral thermometry requires at least a 30-minute wait after food or liquid is consumed, otherwise the measurements will provide an erroneous reading. This is particularly problematic when consistent fluid intake, as recommended by the CDC, is vitally important for those recovering from the flu and to avoid complications. On the other hand, the BTT is not affected by food or liquid and the skin over the BTT is, surprisingly, fat free.

IMMEDIATE BENEFITS -- FEVER DETECTION AND MONITORING

“The resultant ability to achieve heretofore unavailable noninvasive one-time or continuous measurement of core temperature offers the immediate benefits of detection of fever and enables individual and population-wide monitoring of the prodromal, symptomatic and recovery phases for myriad disorders,” said Dr. Silverman.

“Wrong thermometry can cause social and economic turbulence during a pandemic,” said Dr. Marc Abreu, who originally identified the BTT and is one of the authors on the infrared emission study. “Nothing like these has affected the U.S. to this scale before. However, there is hope because we are all equipped by nature with a way to accurately read body temperature and fever -- in nature the threat, in nature the solution.

“We cannot succeed in the battle against swine flu or any other infectious disease unless we use the best of biology,” he added. “This is what the study we are presenting today shows. We are all equipped with a natural indicator of temperature, a tool -- a tunnel of infrared light -- that provides a reliable measurement of body temperature, with much less variability than the face, forehead and neck. It can be an important weapon in our battle against the swine flu pandemic. It could help save many lives while avoiding crippling our economy due to healthy people unnecessarily being absent from work or not going out shopping because of a false fever.”

For those who do become sick or hospitalized, besides monitoring during surgery, Dr. Abreu, explained that the BTT could offer continuous noninvasive temperature monitoring -- without the need for nurse intervention -- to detect infection early, thereby enabling the timely administration of therapy and preventing complications. Dr. Abreu, who is also Clinical Faculty in the Department of Anesthesiology and Critical Care Medicine at the Yale University School of Medicine, noted that hospital infections alone kill 100,000 patients annually in the U.S.

DETECTION OF INFRARED EMISSION

The research presented at ASA noted that a tunnel of infrared radiant energy exists between the 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, which corresponds to the end of the BTT, enables the noninvasive measurement of core and intracranial temperatures.

The purpose of the study was to examine the reliability of temperature measurement on the face, forehead, neck and BTT using detection of thermal infrared (IR) emission. The forehead showed low IR emission and great variability in size and location of IR. 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 and surface temperature corresponded to the BTT. The BTT also had the least variability of IR emission.

“The identification of an intracranial pathway that is insulated for heat retention and whose distal end is uniquely designed for energy transfer allows a surface sensor to view and virtually ‘sit’ on a beam of infrared light coming from the hypothalamic region of the brain,” said Dr. Silverman.

In addition to Dr. Silverman and Dr. Abreu, other authors on the study included Ala S. Haddadin, M.D., F.C.C.P., Tyler Silverman, B.S., and William Amalu, Ph.D.

Under the leadership of Dr. Silverman, the team of Dr. Abreu, Dr. Haddadin and Mr. Silverman have presented three other studies on the BTT in the past three years. The Yale research group is in the process of submitting to a major scientific journal a multi-center investigation, which includes Dr. Ricardo L. Smith, Professor and Chairman, Department of Anatomy, School of Medicine of the Federal University of Sao Paulo, Sao Paulo, Brazil; Dr. Airdem Assis and Dr. Marcos Hott of Embrapa, National Cattle Research Center of the Brazilian Ministry of Agriculture and Livestock; Dr. Claudio Campi Castro, Chief, Magnetic Resonance Imaging Section, Heart Institute, University of Sao Paulo Medical School, Sao Paulo, Brazil; Roger Titone of Brain Tunnelgenix Technologies Corp., Tiffin, IA; and Dr. Michael F. Bergeron, Director, National Institute for Athletic Health & Performance, Sanford USD Medical Center, Sioux Falls, SD.

Additionally, BTT research has been carried out in collaboration with Dr. Robert Gochman and Dr. Alexander Arroyo, Department of Pediatrics and Emergency Medicine, Long Island Jewish Medical Center and Albert Einstein College of Medicine, New Hyde Park, NY, and Dr. Joseph McIsaac, Department of Anesthesiology, University of Connecticut School of Medicine, Hartford, CT.