NEW YORK, March 11 (Reuters) -- Doubt as to the accuracy of ear, or 'tympanic,' thermometers is heating up debate within the medical community as to whether or not they are safe for everyday use.
"We need to stop looking at (tympanic temperature) as a substitute for rectal temperature," asserted Dr. Robert Yetman, who has conducted studies comparing tympanic temperatures against rectal and axillary (armpit) readings. "In one study," according to an article in Pediatric News, "almost two thirds of 234 children had a 0.3 degree Celsius or greater difference between tympanic and rectal temperatures."
Unlike traditional glass rectal and oral thermometers, tympanic thermometers are battery-powered and resemble a small glue gun. They are inserted into the ear, near the ear-drum, measuring body temperature within seconds.
Seeking to avoid the risk of breakage that comes with traditional glass thermometers, hospitals and homes are increasingly using tympanic models for everyday use.
But one doctor already blames the use of the ear-thermometer for one 'false' outbreak of childhood bacterial blood infection, or sepsis. "We had an 'epidemic' of febrile newborns having work-ups (testing) for sepsis," explained Dr. Jan Fitzgerald-Soapes; a Lawrenceville, Georgia, pediatrician. She said that when high readings gleaned from tympanic thermometers were rechecked using a rectal thermometer, most of the previously-diagnosed 'feverish' babies were found to have normal temperatures.
Yetman isn't surprised. "The significant degree of variance" would misclassify many feverish children as normal, and normal youngsters as feverish, he says.
Not everyone agrees. Lauren Key, product manager for Thermoscan, a tympanic thermometer manufacturer, says ear-sourced readings are most accurate, since they come very close to the hypothalamus -- that portion of the brain which is credited as being the body's 'thermostat.' She says tympanic thermometers could be catching the very beginnings of fever -- "(it) could be picking up the spike of a fever."
And many people were simply "using it wrong," said Jennifer Trombley, also a Thermoscan spokesperson. Older Thermoscan models had 'offset' buttons, which automatically converted unfamiliar tympanic readings to traditional rectal or oral temperatures. Many people got confused, leading to beliefs that the tympanic reading was 'wrong.' Newer, home-usage models will cut down on the confusion by issuing readouts on the tympanic scale alone, Trombley says.
But Yetman stands by his assertion that parents stick to their old thermometers. And he believes hospitals should double-check their tympanic readings against those from other sources.
SOURCE: Pediatric News (February, 1997; pg. 46)
