Ear Thermometer Research Articles

Using an ear thermometer.

Richard L. Pullen, Jr., is a professor of nursing at Amarillo (Tex.) College. Each month, this department illustrates key clinical points for a common nursing procedure. Because of space constraints, it's not comprehensive.

Differential release of matrix metalloproteinase-9 and nitric oxide following infusion of endotoxin to human volunteers.

Roughly 400.000 cases of sepsis occur every year in the United States only and this is associated with a very high mortality. Bacterial lipopolysaccharide (LPS) triggers systemic inflammatory reactions in sepsis. However, down-stream cellular cascade initiated by LPS is still being elucidated. Nitric oxide (NO) and matrix metalloproteinases-2 and -9 (MMP-2 and MMP-9) are known to be induced by LPS. We have investigated the release of NO, MMP-2 and MMP-9 following infusion of LPS to volunteers. IPS (2 ng kg-1) was infused to 10 healthy volunteers. Before the experiments were started the subjects had an intravenous catheters placed. An electrocardiogram was also placed and monitored constantly. Body temperature was measured by ear thermometer every 10 min Venous blood was collected and cell-free plasma assayed for the presence of MMP-2 and MMP-9 using zymography and NO using HPLC assay for NO metabolites, nitrite and nitrate. The administration of LPS resulted in increased body temperature and tachycardia. Time-dependent release of MMP-9(30 fold increase from the baseline) peaking at 2 h following infusion of LPS was observed. LPS did not significantly modify the activity of MMP-2 (P > 0.05). Infusion of LPS did not significantly change the levels of nitrite and nitrate (from 60 +/- 11 to 67 +/- 10 micro m, P > 0.05). The release of MMP-9, but not MMP-2 or NO, is a sensitive index of endotoxaemia in humans. MMP-9 release may contribute to the pathogenesis of sepsis via its pro-inflammatory effects on the vasculature.

A Comparative Study of Three Warming Interventions to Determine the Most Effective in Maintaining Perioperative Normothermia

A Comparative Study of Three Warming Interventions to Determine the Most Effective in Maintaining Perioperative Normothermia

Infrared ear thermometry compared with rectal thermometry in children: a systematic review

Infrared ear thermometry is frequently used in children, because this is a quick method of taking temperature and the ear is easily accessible. Our aim was to evaluate agreement between temperature measured at the rectum and ear in children. We did a systematic review of studies comparing temperature measured at the rectum (the reference site) using mercury, electronic, or indwelling probe thermometers, with temperature measured at the ear (the test site) using infrared ear thermometers. Heterogeneity between studies was investigated by exploring subgroups according to the mode of the infrared ear thermometer. 44 studies containing 58 comparisons (5935 children) were eligible for inclusion in this review. Outcome data were available in reports from 12 comparisons (2312 [39%] children), and data on individual patients were obtained for a further 19 comparisons (2129 [36%] children). 31 comparisons (4441 [75%] children) were therefore included in the meta-analysis. The pooled mean temperature difference (rectal minus ear) was 0.29 degrees C (95% limits of agreement -0.74 to 1.32). We pooled data by ear device mode and the mean temperature differences were rectal mode 0.15 degrees C (-0.95 to 1.25), actual 0.70 degrees C (-0.20 to 1.60), core 0.25 degrees C (-0.78 to 1.27), oral 0.34 degrees C (-0.86 to 1.54), tympanic 0.62 degrees C (-0.40 to 1.64) and mode not stated 0.32 degrees C (-0.57 to 1.21). There was significant residual heterogeneity in both mean differences and sample SDs within the groups of ear device mode. Although the mean differences between rectal and ear temperature measurements were small, the wide limits of agreement mean that ear temperature is not a good approximation of rectal temperature, even when the ear thermometer is used in rectal mode. Our finding suggests that infrared ear thermometry does not show sufficient agreement with an established method of temperature measurement to be used in situations where body temperature needs to be measured with precision.

Ear temperature measurements in healthy children using the arterial heat balance method.

This study was undertaken to determine the upper limit of normal ear temperatures, defined as the 95th percentile for infants, children, and adolescents, using the arterial heat balance method for measuring ear temperatures. Ear temperatures were measured in 62 infants, 0-2 months of age; 346 children, 3-47 months; 226 children, 48-119 months; and 172 adolescents, 120-227 months using the LighTouch Pedi-Q (Exergen Corp, Watertown, MA) ear thermometer. The 95th percentiles for the four age groups were 100.1 degrees F (37.8 degrees C), 100.3 degrees F (37.9 degrees C), 99.8 degrees F (37.7 degrees C), and 99.8 degrees F (37.7 degrees C), respectively. Temperatures above 100.0 degrees F (37.8 degrees C) using the LighTouch Pedi-Q ear thermometer should be considered elevated.

Application criteria for infrared ear thermometers in pediatric surgery

Fever is an important and sensitive indicator of infectious diseases in children. For the past decades, measurement of body temperature in routine medical practice was limited to oral, rectal and axillary sites. In infants and children, however, temperature measurements are further limited to the rectal and axillary sites due to technical and clinical considerations. In the field of pediatric surgery, pathological and surgical conditions of the ano-rectal area often further restrict the application of conventional rectal temperature measurements. The application of tympanic temperature measurements in such pediatric surgical pathologies provides a reliable alternative to conventional rectal temperature measurements. The pediatric surgical clinico-pathological states where ear temperature measurements are the only mode of accurate temperature determination have been identified. Tympanic thermometry is well tolerated by children and predicts temperature with relative accuracy within a few seconds.

Comparison of ear to rectal temperature measurements in infants and toddlers.

The purpose of this study was to compare arterial heat balance ear temperature measurements to rectal temperatures in infants and children and to determine the ability of the ear thermometer being tested to detect fever. From 12/95 to 2/96, 1,175 pairs of ear and rectal temperature measurements were prospectively obtained from 140 infants and toddlers. The mean rectal temperature was 37.58 degrees C (sd = 0.68) and the mean ear temperature was 37.60 degrees C (sd = 0.85). However, at the low end of the rectal temperature scale, ear temperatures tended to be higher, and at the high end of the rectal temperature scale, ear temperatures tended to be lower. There were 292 readings with a rectal temperature > or = 38.0 degrees C and in 204 (70%) the ear temperature was also > or = 38.0 degrees C. A retrospective analysis of 53 children who became febrile in hospital (ear or rectal temperature > or = 38.0 degrees C) showed that fever was detected first by rectal measurement in seven, by ear measurement in 31 (59%), and by both in 15 (28%). These data indicate that, on the average, rectal and ear temperature measurements are not different. Fever that developed in children after hospitalization was more likely to be first detected by ear than by rectal measurement.

The "ear fever thermometer"--studies of ear thermography

Though rarely mentioned in the ENT literature, the "ear thermometer" has become more and more popular in recent years, not only in hospitals but also in households. These instruments are easy to use, and their infrared technology is said to provide precise measurements. The purpose of this study was to verify these claims. Infrared thermometers were tested in various conditions, and the results were compared. We assessed the effects of "distending" the outer ear canal, different body positions, and irritation of the ear (slight external otitis, hearing aids, otitis media, etc.). We did not specifically test effects of ear wax, as it had sufficiently been studied in pediatric or anesthesiological papers before (almost no effect, except in cases of occlusion of the auditory canal). Using the ear thermometer we found small but statistically significant differences in febrile patients in different body positions. Irritated ears always showed higher temperatures than the normal contralateral ears. The most significant differences were found in persons lying on one side. The "pillow ear" was found 0.7 degree C (average) warmer than the contralateral ear. Ear thermometers for estimating the body temperature permit easy and fast measurements. However, they include possible sources of measurement error. This study describes possible errors that the therapists should be aware of to avoid misinterpreting the course of a disease.

Infrared tympanic thermometry

The accuracy of this method is attributed to the tympanic membrane's close anato~nic proximity to the hypothalamic thermore-gulatory centre and common blood supply from the carotid artery. Since temperature is displayed within one second, the ear thermometer (which is marketed in the shape of an otoscope) offers a les stressful and faster method of temperature measurement, Therefore, it is especially useful in children. Neither cerumen nor otitis media significantly affect the readings. So, infrared tympanic thermometry offers a relatively noninvasive, comfortable and faster option compared to conventional thermometry.

A comparison of temperature measurements using three ear thermometers

Following anecdotal and research-based reports of inaccuracies encountered with the use of ear thermometers in patient care settings, this two-phase study was designed to compare the accuracy of three ear thermometers when used in a multioperator environment. The within-subject variation (limits of agreement) in ear temperature measurements obtained with the three ear thermometers in a multioperator condition by using an oral temperature reference standard ranged from +/- 1.25 degrees F to 1.85 degrees F. In multioperator, multisubject patient care environments using a pulmonary artery catheter core temperature as the reference standard, the limits of agreement for ear temperature measurements obtained with the three different ear thermometers ranged from +/- 2.19 degrees F to 2.85 degrees F. These results suggest that there is substantial variation in ear measurements and raise questions about the use of ear thermometers when there are multiple personnel taking temperatures, as occurs in hospital-based clinical practice environments. Handedness of the operator, position of the patient, and the ear used for measurement did not produce clinically significant variability in ear temperature measurements.

Estimation of Contact Tympanic Membrane Temperature With a Noncontact Infrared Thermometer

Study objective: To investigate the agreement between contact tympanic membrane (TM) and noncontact infrared ear thermometers in children. Methods: Twenty-three children (ages .5 to 10 years) undergoing elective tympanostomy tube placement were studied. An assistant used standard technique to record temperature with an infrared ear thermometer before and after TM temperature was obtained with a bead thermistor placed against the anterior-inferior quadrant of the TM. Results: Mean temperatures were not significantly different: initial IR ear, 36.66°±.33° C; TM, 36.71°±.42° C; final infrared ear, 36.57°±.33° C. The mean bias (difference between initial individual IR ear and TM temperatures) of −.05°±.29° C and the 95% limits of agreement of +.53° to −.63° C indicate an acceptable confidence (error range within 3.2% of average TM temperature) for use of the initial infrared ear temperature as an estimate of TM temperature. Conclusion: The IR ear thermometer provides an accurate estimate of TM temperature in healthy children and may accurately reflect core body temperature. [Terndrup TE, Crofton DJ, Mortelliti AJ, Kelley R, Rajk J: Estimation of contact tympanic membrane temperature with a noncontact infrared thermometer. Ann Emerg Med August 1997;30:171-175.]

Assessing and Managing the Febrile Child

A fever is defined as a rectal temp over 100.4 degrees F. Fever occurs when the hypothalamic thermoregulation center resets the temperature set point in response to a chain of events initiated by the inflammatory response. Glass thermometers remain the gold standard and electronic thermometers are generally acceptable, but studies do not consistently support the use of infrared ear thermometers in children under 3. Evaluation of the sick child includes observation, assessment of age and temperature risk factors, history and physical, and lab tests. To aid in the assessment of how ill or "toxic" a child appears, the Yale Observation Scale is used. Acetaminophen remains the antipyretic of choice. Febrile seizures are generally benign. Tepid sponge baths are only slightly more effective than acetaminophen alone in reducing fevers, but may be useful for children with a history of febrile seizures or liver disease. While there are many causes of pediatric fevers, they can be grouped into three general categories: fever with localizing signs, fever without localizing signs, and fever of unknown origin. Children with a localized infection are treated with antibiotics, antipyretics, and parent education; children with fever of unknown origin are referred for more in-depth evaluation. The management of children presenting with fever without a source is discussed in detail.

EFFECT OF ALCOHOL ON BODY CORE TEMPERATURE DURING COLD‐WATER IMMERSION

SUMMARY This study investigates the influence of alcohol on body core temperature during cold‐water immersion in human volunteers. In this randomised, double‐blind, placebo‐controlled crossover trial, 8 healthy male volunteers were randomised to drink 1 litre of beverage containing 50 g alcohol or placebo before 20°C cold‐water immersion for 1 hour. Body core temperature was measured before cooling and after 1 hour of immersion with an infrared ear thermometer. After a 1‐week interval subjects crossed to the other study branch. In the placebo test, mean temperature decreased after immersion by 0.66°C; after the alcohol mean temperature decreased by 1.0°C (mean difference 0.34, 95% CI 0.14‐0.53, P=0.002).

A comparison of five methods of temperature measurement in febrile intensive care patients

A clinically useful temperature measurement method should correlate well with the body's core temperature. Although previous investigators have studied temperature readings from different sites in hypothermic and normothermic patients, none have compared methods specifically in febrile patients. To compare temperature measurement methods in febrile intensive care patients. Temperature readings were obtained in rapid sequence from an electronic thermometer for oral and axillary temperature, rectal probe, infrared ear thermometer on "core" setting, and pulmonary artery catheter, approximately every hour during the day and every 4 hours at night. The sample consisted of 13 patients with pulmonary artery catheters and with temperatures of at least 37.8 degrees C. Rectal temperature correlated most closely with pulmonary artery temperature. Rectal temperature showed closest agreement with pulmonary artery temperature, followed by oral, ear-based, and axillary temperatures. Rectal and ear-based temperatures were most sensitive in detecting temperatures greater than 38.3 degrees C. Likelihood ratios for detecting hyperthermia were 5.32 for oral, 2.46 for rectal, and 1.97 for ear-based temperature. Rectal and ear-based temperatures had the lowest negative likelihood ratios, indicating the least chance of a false negative reading. Axillary temperature had a negative likelihood ratio of 0.86. Rectal temperature measurement correlates most closely with core temperature. If the rectal site is contraindicated, oral or ear-based temperatures are acceptable. Axillary temperature does not correlate well with pulmonary artery temperature. These results underscore the importance of consistency in method when establishing temperature trends, and of awareness of method when interpreting clinical data.

Determination of Normal Ear Temperature with an Infrared Emission Detection Thermometer

See related editorial, "What's Hot and What's Not: The Gold Standard for Thermometry in Emergency Medicine." Study Objective: To determine normal body temperature with an infrared emission detection ear thermometer. Design: Cross-sectional convenience sample. Setting: Four acute and long-term health care facilities. Participants: Subjects who denied recent potentially febrile illness and ingestion of medications affecting normal body temperature. Results: Two thousand four hundred forty-seven subjects aged 12 hours to 103 years were enrolled. Ear temperatures were normally distributed for each of eight age groups. There were differences in mean temperature among different age groups ( P<.001, by ANOVA) and a striking cutoff at adolescence; the mean temperature for children aged 3 days to 10 years was 36.78±0.47°C, as compared to 36.51±0.46°C for subjects 11 years and older ( P<.001, by t test). Temperatures were higher in female subjects and showed the characteristic diurnal variation of normal body temperature in five subjects studied longitudinally. The reproducibility of the ear thermometer was better than that of a commonly used electronic thermometer at the oral and axillary sites. Conclusion: The infrared emission detection ear thermometer is an accurate means of assessing normal body temperature without using corrective offsets to estimate temperature at other body sites. On the basis of these data, the 95th percentile for infrared emission detection temperature in children younger than 11 years old was 37.6°C. The 99th percentile was 37.9°C for children younger than 11 years old and 37.6°C for people 11 years or older. Because only 1% of normal people have an infrared emission detection temperature higher than these values, these may represent appropriate cutoffs for fever screening using this device. [Chamberlain JM, Terndrup TE, Alexander DT, Silverstone FA, Wolf-Klein G, O'Donnell R, Grandner J: Determination of normal ear temperature with an infrared emission detection thermometer. Ann Emerg Med January 1995;25:15-20.]

Infrared ear thermometry.

Many hospitals are considering using infrared (IR) ear thermometers (also called tympanic membrane thermometers) as an alternative to traditional temperature-measurement devices. IR technology allows users to quickly and noninvasively measure body temperature by inserting a directional probe into the ear canal. For infection control, ear thermometers offer the advantages of not contacting mucous membranes and eliminating the need for special handling procedures. For use on unconscious patients or those who are otherwise unwilling or unable to cooperate with traditional techniques, IR ear thermometers offer a more comfortable and less stressful method of temperature taking for both patients and nurses, especially where rectal temperatures are used. The recent entry into this market by major companies and distributors and the release of several new IR ear thermometers have helped to further stimulate interest in this technology. However, a complete transition to IR ear thermometers throughout the hospital may not be necessary and should be made only after these devices have been successfully used in selected clinical locations, such as emergency departments, critical care areas, recovery areas, and labor and delivery rooms. Clinical users must be familiar with the technique needed for temperature measurement with these instruments and understand the differences between temperatures taken in the ear canal and those obtained from traditional sites. In the following article, we first present an overview of clinical thermometry, describing traditional temperature-measurement sites and devices. We then discuss the advantages and disadvantages of using the ear canal, including the tympanic membrane (TM), as a site for temperature measurement. In addition, we guide readers in determining the usefulness of IR ear thermometers.(ABSTRACT TRUNCATED AT 250 WORDS)

Technology 1992-medical electronics

Advances of note during 1991 are reviewed. A microprocessor-based fiber-optic sensing system that monitors blood gas in real time was introduced. Also introduced was a tympanic or ear thermometer that measures infrared heat generated by the eardrum and surrounding tissue and displays the temperature in about 2 s. Interest in artificial heart research was reviewed. Images of the human brain as it performed the simple task of recalling a word showed that the recall process was going on in unexpected parts of the brain, not just in the hippocampus.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Reliability of Rectal Temperatures as an Index of Internal Body Temperature

ARTICLESReliability of Rectal Temperatures as an Index of Internal Body TemperatureJere Mead, and C. Lawrence BonmaritoJere MeadSearch for more papers by this author, and C. Lawrence BonmaritoSearch for more papers by this authorPublished Online:01 Aug 1949https://doi.org/10.1152/jappl.1949.2.2.97MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByPostmortem time estimation using body temperature and a finite-element computer model8 June 2004 | European Journal of Applied Physiology, Vol. 92, No. 6Comparison of infrared ear thermometer derived and equilibrated rectal temperatures in estimating pulmonary artery temperaturesCritical Care Medicine, Vol. 24, No. 9Validation of a temperature telemetry system during moderate and strenuous exerciseJournal of Thermal Biology, Vol. 18, No. 4Impact of operator technique and device on infrared emission detection tympanic thermometryThe Journal of Emergency Medicine, Vol. 10, No. 6Brain, blood and rectal temperature during whole body coolingComparative Biochemistry and Physiology Part A: Physiology, Vol. 79, No. 4MEASUREMENT OF CENTRAL VENOUS PRESSUREThe Lancet, Vol. 297, No. 7702WHERE TO MEASURE TEMPERATUREThe Lancet, Vol. 297, No. 7702PATTERN RECOGNITION FOR RADIOGRAPHERSThe Lancet, Vol. 297, No. 7702Body temperature and pulse rate in boys and young men prior to sporting contests. A study of emotional hyperthermia: With a review of the literatureJournal of Psychosomatic Research, Vol. 4, No. 3REGULATION OF BODY TEMPERATUREThe Lancet, Vol. 271, No. 7013INFANTILE GASTROENTERITISThe Lancet, Vol. 271, No. 7013 More from this issue > Volume 2Issue 2August 1949Pages 97-109 https://doi.org/10.1152/jappl.1949.2.2.97PubMed18135566History Published online 1 August 1949 Published in print 1 August 1949 Metrics