Accuracy of parents in measuring body temperature with a tympanic thermometer

Robinson, Joan L; Jou, Hsing; Spady, Donald W

The chief limitation of this study is that readings obtained by a nurse from the hospital tympanic thermometer must be reliable for the results of this study to be accurate. Some studies have concluded that tympanic thermometers do not give an accurate measurement of body temperature [7, 9, 10] . However, the reference standard in these studies (axillary or rectal temperature) may not be ideal. Studies have shown that when used by a skilled operator on a cooperative patient with rapidly changing body temperature, the readings from models of tympanic thermometers commonly used in hospitals more closely approximate pulmonary artery or esophageal temperature than do rectal or axillary temperatures [2, 3] . Therefore, a tympanic temperature measured with a hospital tympanic thermometer was considered the best available reference standard for this study. However, if the nurses used incorrect technique, this would affect the results of the study. Falsely high readings with a properly calibrated tympanic thermometer should only occur if the thermometer itself has been stored above room temperature, so the fact that in 25 of the 60 cases the parent obtained a higher reading than did the nurse suggests the possibility that the nurses were not using ideal technique. Another limitation is that we could not blind the nurses for comparing their own two temperature readings. There is some evidence that falsely low readings can be obtained if tympanic readings are obtained in rapid succession as placement of the thermometer results in local cooling, so it is possible that readings would have been more comparable had we waited at least 2 minutes between readings [11] It is possible that parents would have performed better had they leisurely read the instructions in their own home rather than doing so in a hospital-based setting, or had they had time to practice. However, it is also possible that they performed better than they would have in the home, as they knew evaluation of their performance was occurring. It is also possible that parents who would choose to buy a tympanic thermometer will differ from our study population. It is not clear what advice to give to parents about purchasing a thermometer. The ability of parents from the inner city to correctly use and read a mercury glass thermometer was poor in previous studies [12, 13] . An electronic thermometer is easier to read and is now relatively inexpensive, but may not be as accurate as a mercury thermometer [14] . The results of the current study suggest that readings obtained by parents with a tympanic thermometer often differ by a clinically significant amount from readings obtained by nurse. Despite their ease of use, there are reports of parents inserting tympanic thermometers in the rectum [15] . It is not clear if parents could more accurately use an infrared temporal artery thermometer. A study showed that using the highest of three temporal artery temperature obtained by a parent or nurse, a reading of ≥ 37.8 °C was 97% sensitive and 84% specific for detecting a rectal temperature of ≥ 38.5 °C, and that the limits of agreement for temperatures Scatter plot of the difference between temperature measured by a parent and that measured by a nurse using a thermometer designed for home use Figure 2 Scatter plot of the difference between temperature measured by a parent and that measured by a nurse using a thermometer designed for home use obtained by parents versus nurses using this thermome