Accuracy of a noninvasive temporal artery thermometer for use in infants

OBJECTIVES: To assess the accuracy of a new noninvasive temporal artery (TA) thermometer in infants; to compare the accuracy of the TA thermometer with that of a tympanic thermometer, using rectal thermometry as the criterion standard; and to compare the tolerability of the TA thermometer with that of the tympanic and rectal thermometers. DESIGN: Prospective evaluation of the accuracy of TA and tympanic thermometry, using rectal thermometry as the criterion standard. SETTING: Emergency department of an urban pediatric hospital. SUBJECTS: Convenience sample of 304 infants younger than 1 year presenting for care. MAIN OUTCOME MEASURES: Temperatures were measured using TA, tympanic, and rectal thermometers for all infants. Agreement between TA or tympanic and rectal temperatures was assessed. The sensitivity and specificity of TA or tympanic thermometers for detecting rectal fever were determined. Discomfort scores, using a standardized scale, were assessed by trained observers after each temperature measurement was made. RESULTS: Linear regression analysis of the relation between TA and rectal temperatures yielded a model with a slope of 0.79 (vs a slope of 0.68 for tympanic vs rectal temperature; P =.02) and an r of 0.83 (vs r = 0.75 for tympanic vs rectal temperature; P<.001). Among 109 patients with a rectal temperature of 38 degrees C or higher, the TA thermometer had a sensitivity of 0.66 compared with the tympanic thermometer's sensitivity of 0.49 (P<.001). Discomfort scores with TA thermometry were significantly lower than with rectal thermometry (P =.007). CONCLUSIONS: The TA thermometer has limited sensitivity for detecting cases of rectal fever in infants. However, the TA thermometer is more accurate than the tympanic thermometer in infants, and it is better tolerated by infants than rectal thermometry.     

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.     

Comparison of Temporal Artery Thermometry with Axillary and Rectal Thermometry in Full Term Neonates

Objective

To assess the efficacy of temporal artery thermometer in febrile and hypothermic neonates in comparison to axillary thermometer.

Methods

It was a cross sectional observational study. Study participants included 210 neonates admitted in neonatal intensive care unit of a tertiary care teaching hospital, divided into three groups of 70 each, namely normothermic, febrile and hypothermic. Temperatures were measured using temporal artery, axillary and rectal thermometers in each patient.

Results

Mean rectal temperature was found to be comparable to mean temporal artery temperature in normothermic babies. Temporal artery thermometer had a better sensitivity to diagnose fever, than hypothermia. Also, temporal artery temperature showed a good correlation with rectal temperature in normothermic and febrile group and not in hypothermic neonates.

Conclusions

Temporal artery thermometer can accurately detect temperature in febrile and normothermic fullterm neonates but not in hypothermic neonates. Further studies are required before advocating temporal artery thermometry as a replacement of rectal thermometry among this group of population.

     

Infrared thermometry of newborn infants

An infrared thermometer, the FirstTemp, was tested among newborn infants by comparing tympanic membrane temperature measurements in three operating modes, "Cal-tympanic," "Cal-surface," and "Cor-tympanic," with nearly simultaneous tympanic membrane, rectal, and axillary temperature measurements using other standard methods. The FirstTemp underestimated other measurements of body temperature in the "Cal-tympanic" mode and overestimated them in the "Cor-tympanic" mode. In the "Cal-surface" mode, the First-Temp readings were significantly lower than tympanic membrane temperatures measured with a thermistor probe and electronic thermometer (mean difference 0.2 degrees C) but not significantly different from rectal or axillary temperatures. According to these results, the FirstTemp can be used reliably in the "Cal-surface" mode but not in the "Cal-tympanic" or "Cor-tympanic" mode. Its speed and ease of operation offer significant advantages over traditional clinical methods of temperature measurement.     

Comparison of temporal artery thermometer to standard temperature measurements in pediatric intensive care unit patients.

OBJECTIVES: To determine the accuracy of noninvasive infrared temporal artery thermometry compared with rectal, axillary, and pulmonary artery catheter measurements in pediatric intensive care patients, and to determine whether temporal artery temperatures are affected by circulatory shock or by vasopressor use. We hypothesized that temporal artery temperatures do not differ from axillary and rectal temperatures in critically ill children, but temporal artery accuracy is decreased by shock or vasopressor use. DESIGN: Observational study, unblinded. SETTING: Pediatric intensive care unit of a quarternary referral children's hospital. PATIENTS: Seventy-five temperature comparison pairs were obtained in 44 pediatric intensive care unit patients. INTERVENTIONS: Temperature measurements were made using a temporal artery thermometer with simultaneously obtained rectal, axillary, and, when available, pulmonary artery catheter measurements. MEASUREMENTS AND MAIN RESULTS: Mean bias was calculated between comparison pairs using each temperature method. Bland-Altman analysis demonstrated wide variability between methods. No significant differences in mean bias were seen between method pairs for all temperatures, but bias was significantly less in pulmonary artery catheter-rectal pairs compared with other method pairs. In febrile (> 38 degrees C) patients, bias in rectal-temporal artery and rectal-axillary was significantly greater than in temporal artery-axillary pairs (p < .001). Mean bias in pulmonary artery catheter-rectal pairs was also significantly smaller than in other pairs for all patients (p = .008) and febrile patients (p = .049). Presence of shock or vasopressor use did not significantly increase bias in any comparison pair. Sensitivity and specificity of both temporal artery and axillary for diagnosing fever were similar and improved with fever definition at temperatures > 38.5 degrees C. CONCLUSIONS: Temporal artery and axillary temperature measurements showed variability to rectal temperatures but had marked variability in febrile children. Neither was sufficiently accurate to recommend replacing rectal or other invasive methods. As temporal artery and axillary provide similar accuracy, temporal artery thermometers may serve as a suitable alternative for patients in whom invasive thermometry is contraindicated.     

Comparison of tympanic and rectal temperatures in febrile children

The present study was designed to assess the accuracy of tympanic membrane temperature (TMT) in predicting "core" body temperature and to compare rectal temperature (RT) and TMT in febrile pediatric patients with and without meningitis. Sixty children diagnosed as having meningitis by cerebro-spinal fluid (CDF) analysis formed the cases and 60 non-meningitic febrile patients, chosen as continuous enrollment, formed the controls. Rectal and ear temperatures were assessed in both groups. Ear temperature was significantly higher in cases as compared to controls. The difference between reading of ear temperature and rectal temperature was also significantly higher in cases as compared to controls. Significant correlations were seen between ear temperature and various parameters of CSF profile.     

Comparison of temporal artery, rectal and esophageal core temperatures in children: Results of a pilot study

BACKGROUND:

Rectal thermometry correlates with core temperature and represents the criterion standard of measuring temperatures in young children. However, it has numerous disadvantages, and thus, an alternative method of measuring temperature with similar agreement with the core temperature as rectal thermometry is desired. A new, noninvasive temporal artery (TA) thermometer synthesizes the skin surface and ambient temperatures to produce an arterial temperature.

OBJECTIVE:

To examine the agreement between the TA and esophageal core thermometers, and to compare it with that between rectal and esophageal temperatures.

METHODS:

In the present prospective, cross-sectional agreement study, intubated surgical outpatients younger than 18 years of age had temperatures measured with esophageal and rectal probes, and rectal electronic and TA thermometers. The agreement between esophageal versus rectal and TA thermometers was analyzed by intraclass correlation coefficients and by differences between esophageal versus TA and rectal temperatures with 95% CIs. The esophageal-rectal and esophageal-TA slopes were compared by Student’s t test.

RESULTS:

In 80 enrolled children, the intraclass correlation coefficients for the esophageal probe versus rectal probe, rectal electronic thermometer and TA thermometer were 0.91, 0.95 and 0.88, respectively. The mean esophageal-rectal difference was 0.00±0.18°C and esophageal-TA difference was 0.14±0.20°C. Linear regression analysis of the relation between esophageal probe versus rectal probe, rectal thermometer and TA thermometer yielded slopes of 0.93, 0.94 and 0.89, respectively. The slopes were neither different from each other (P=0.70) nor from the value of 1.

CONCLUSION:

The TA and esophageal thermometers agree well, and the esophageal-TA and esophageal-rectal temperature agreements are not significantly different.     

Assessment of an aural infrared sensor for body temperature measurement in children

A newly marketed device measures body temperature using an ear probe that detects infrared radiation from the tympanic membrane. It is simple to use and gives a reading in 1-2 seconds. Its accuracy was evaluated in a group of children, aged 1 month through 10 years, by comparing it with either rectal (n = 65), or oral (n = 48) temperatures obtained with a standard electronic thermometer, IVAC (San Diego, CA). The average elapsed time between readings was 11 minutes. Overall, 60 rectal and 40 oral temperatures (88.5%) were higher with IVAC than with the aural sensor. The difference ranged from -0.7 degrees C to +2.5 degrees C. The correlations between the infrared ear-probe values and the rectal and oral temperature readings were 0.77 and 0.75, respectively. Because the average reading using the aural sensor was lower than that using the IVAC, the sensitivity of the aural sensor for detecting clinically important levels of fever was low. None of seven patients with a rectal temperature of 39 degrees C or more and only 7 of 27 with a rectal temperature of 38 degrees C or more were identified by the aural sensor as having temperatures above these cutoff levels. Similarly, none of three patients with an oral temperature of 39 degrees C or more and only three of eight with an oral temperature of 38 degrees C or more were identified correctly by the aural sensor. The authors conclude that the aural sensor is unsatisfactory for detecting clinically significant fevers in a pediatric outpatient setting.     

Non-contact infrared thermometry temperature measurement for screening fever in children

BACKGROUND: During the SARS epidemic, mass fever screening at border control points and public hospitals was done by measuring forehead temperature by non-contact infrared thermometry. However, its accuracy is not well documented. METHODS: We evaluated the agreement of non-contact infrared forehead temperature (NIFT) measurement by comparing NIFT readings with tympanic temperatures taken in children (1 mth to 18 yrs) admitted to the general paediatric wards of Kwong Wah Hospital, Hong Kong. RESULTS: A total of 567 patients were recruited and 1000 pairs of readings were obtained. The incidence of fever, defined as tympanic temperature (in rectal model) >38 degrees C (100.4 degrees F), was 12.3%. The mean difference between NIFT and tympanic temperature was 2.34 degrees C (4.21 degrees F) and the 95% limit of agreement between NIFT and tympanic temperature was 0.26-4.42 degrees C (0.47-7.96 degrees F). NIFT was significantly lower than tympanic temperature readings. The optimal cut-off point of NIFT derived from the receiver-operator characteristics curve for fever definition was 35.1 degrees C (95.2 degrees F). The sensitivity, specificity, positive predictive value and negative predictive value of this cut-off point for fever screening were 89.4%, 75.4%, 33.7% and 98.1%, respectively. CONCLUSIONS: NIFT measurement has a reasonable accuracy in detecting tympanic fever in children. However, one should be aware of the high false-positive rate of fever screening using NIFT.     

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)     

Infrared tympanic thermometry in comparison with other temperature measurement techniques in febrile children.

OBJECTIVE:: To determine whether infrared tympanic thermometry (ITT) measurements more accurately reflect core body temperatures than axillary, forehead, or rectal measurements during fever cycles in children. DESIGN:: Prospective cohort study. SETTING:: Pediatric and cardiac intensive care units at a tertiary care children's hospital. PATIENTS:: Critically ill children <7 yrs of age with indwelling bladder catheters. INTERVENTIONS:: Simultaneous temperatures were recorded during both febrile and nonfebrile periods using ITT, indwelling bladder (core), axillary, forehead, and indwelling rectal measurements in 36 children. MEASUREMENTS AND MAIN RESULTS:: Overall ITT measurements were 0.03 +/- 1.43 degrees F less than core temperature measurements. In comparison, rectal, forehead, and axillary measurements averaged 0.62 +/- 1.44, 0.56 +/- 1.81, and 1.25 +/- 1.73 degrees F less than core temperature measurements. ITT measurements had better agreement with core measurements during increasing and decreasing temperature cycles. Receiver operating characteristic analysis performed on increasing and decreasing temperature cycle data revealed that ITT measurements performed well, with an area under the curve of 0.855 (95% confidence interval, 0.797-0.913) in comparison with rectal measurement area under the curve of 0.777 (95% confidence interval, 0.701-0.853), forehead measurement area under the curve of 0.710 (95% confidence interval, 0.715-0.888), and axillary measurement area under the curve of 0.664 (95% confidence interval, 0.579-0.750). CONCLUSIONS:: ITT measurements more accurately reflect core temperatures than any other measurement site during febrile and nonfebrile periods in children. ITT measurements are a reproducible and relatively noninvasive substitute for bladder or rectal measurements in febrile children.     

Limited accuracy and reliability of infrared axillary and aural thermometers in a pediatric outpatient population

OBJECTIVE: To evaluate the accuracy and reliability of infrared axillary and aural thermometers in the outpatient setting. STUDY DESIGN: A prospective observational study of infrared axillary, aural, and digital rectal temperature values from 198 children, aged 3 to 36 months (mean, 1.3 years). RESULTS: Sensitivity and specificity of the axillary thermometer for rectal fever were 63.5% and 92.6%, respectively (diagnostic accuracy, 83.3%); those for the aural thermometer were 68.3% and 94.8%, respectively (diagnostic accuracy, 86.4%). For all patients, the mean biases of the axillary and aural temperatures were -0.33 degrees F and -0.24 degrees F, respectively. The biases of both thermometers' measurements were significantly correlated with rectal temperature (P <.02); thus, as rectal temperature increased, the accuracy of the compared axillary and aural temperature decreased. Underestimation of rectal temperature was greatest among febrile 1- to 3-year-old children (axillary bias, -1.20; aural bias, -0.36). Age was correlated with an axillary temperature bias (P <.01). CONCLUSION: Axillary and aural infrared thermometers were comparable, albeit significantly different than rectal temperature measurements, particularly as the child's age and rectal temperature increased. These thermometers may be useful as noninvasive screening methods in outpatient settings for children who are at least 3 months old, but rectal values should be used for clinical accuracy.     

Modern electronic and chemical thermometers used in the axilla are inaccurate

Rectal and axillary temperatures were measured simultaneously in 83 children using three different thermometer devices providing 166 pairs of results. In the first series consisting of 22 febrile children (44 measurements) and 20 afebrile children (40 measurements), the rectal mercury measurement was compared to an axillary mercury and axillary Tempa-DOT thermometer. The axillary mercury had sensitivity of 14/22 (64%) and specificity of 20/20 (100%) while the Tempa-DOT had sensitivity of 15/22 (68%) and specificity of 19/20 (95%). In the second series comprising 21 febrile children (42 measurements) and 20 afebrile children (40 measurements) the axillary mercury had sensitivity of 11/21 (52%) and specificity of 20/20 (100%) while the electronic thermometer had sensitivity of 10/21 (48%) and specificity of 20/20 (100%). Regardless of the thermometer used , the axilla is a poor alternative to rectal measurements in the diagnosis of fever. Conclusion Mercury-free thermometers, when used in the axilla are as poor alternatives to rectal measurements as mercury-in-glass thermometers. Received: 14 November 1995 Accepted: 5 March 1996     

Parents' perspectives to childhood fever: Comparison of culturally diverse populations

Aim: To reveal the perceptions, knowledge and practices of our parents regarding children's fever and to discuss the differences between other populations. Methods: Parents of 200 febrile children aged 0–16 years were interviewed between October and November 2007 in the Pediatric Emergency Department at Dr Sami Ulus Children's Health and Diseases Training and Research Hospital. Questions about socio‐demographical data, children's previous history about fever, parental beliefs and practices concerning fever were asked. Results: Of the parents, 56.5% stated that fever could be determined by touching the forehead. Of the parents, 43.5% determined children's fever by using thermometer. Only 27.5% of parents knew the correct temperature for fever. Mercury‐in‐glass thermometer was the preferred one to measure children's fever. The preferred route of measuring temperature was the axillary site. Maternal educational level was significantly associated with knowledge on correct definition of fever and proper use of thermometer (P < 0.05) in accordance with the literature. If fever was untreated, of the parents, 84% believed febrile convulsions occur and 10.5% believed brain damage occur if fever was untreated. Parental age, parental educational status, parental knowledge about fever, median number of children in family and children's previous febrile convulsion history did not significantly effect parents' interventions and beliefs about fever (P > 0.05), corroborating the findings of studies from different populations. Conclusion: Parental education about ‘fever in childhood’ in our population may positively effect parental knowledge and approach to fever. However, parental education may not be effective in removing parental fear of fever in our population.     

Tympanic membrane temperature of term and preterm neonates

Deep body temperatures of 70 term and 24 preterm newborn infants were measured at two sites: deep rectum (5 cm beyond the anus) and tympanic membrane. A significant correlation was found between deep rectal and tympanic membrane temperatures in both term and preterm infants. Mean deep rectal and tympanic membrane temperatures in term infants were 37.01°C and 36.83°C, respectively. Mean deep rectal and tympanic membrane temperatures in preterm infants were both 36.69°C.     

Temporal artery temperature measurements in healthy infants,children, and adolescents

A noninvasive temporal artery thermometer that uses arterial heat balance technology has been compared to rectal and ear thermometry and is available in the marketplace. This study was undertaken to establish mean temperatures and temperatures 2 standard deviations above the mean for healthy infants, children, and adolescents. Temperatures were measured in healthy patients 0 to 18 years of age using a noninvasive temporal artery thermometer. Temperatures were measured in 2,346 patients. Mean temperatures and temperatures 2 standard deviations above the mean were: 37.1 degrees C (38.1 degrees C) for 383 infants 0 to 2 months; 36.9 degrees C (37.9 degrees C) for 860 children 3 to 47 months; 36.8 degrees C (37.8 degrees C) for 680 children 4 to 9 years; and 36.7 degrees C (37.8 degrees C) for 423 adolescents 10 to 18 years. There were no significant differences in temperatures in white compared to African-American children, children with or without perspiration on their forehead, or between measurements taken on the left compared to the right side of the forehead. This study provides information about temporal artery temperatures in healthy infants and children that can serve as a basis for interpreting temperature measurements in ill children when the same instrument is used.     

A Cross-sectional Study Characterizing Pediatric Temperature Percentiles in Children at Well-Child Visits

BackgroundTemperature measurement plays a central role in determining pediatric patients' disease risk and management. However, current pediatric temperature thresholds may be outdated and not applicable to children.ObjectiveTo characterize pediatric temperature norms and variation by patient characteristics, time of measurement, and thermometer route.MethodsIn this cross-sectional study, we analyzed 134,641 well-child visits occurring between 2014-2019 at primary care clinics that routinely measured temperature. We performed bivariate and multivariable quantile regressions with clustered standard errors to determine temperature percentiles and variation by age, sex, time of measurement, and thermometer route. We performed sensitivity analyses: 1) using a cohort that excluded visits with infectious diagnoses that could explain temperature aberrations and 2) including clinic as a fixed effect.ResultsThe median rectal temperature for visits of infants ≤12 months old was 37.2˚C, which was 0.4˚C higher than the median axillary temperature. The median axillary temperature for children 1–18 years old was 36.7˚C, which was 0.1˚C lower than the median values of all other routes. The 99th percentile for rectal temperatures in infants was 37.8˚C and the 99.9th percentile for axillary temperatures in children was 38.5˚C. Adjusted analyses did not demonstrate clinically significant variation in temperature by sex, age, or time of measurement.ConclusionsThese updated temperature norms can serve as reference values in clinical practice and should be considered in the context of thermometer route used and the clinical condition being evaluated. Variations in temperature values by sex, age, and time of measurement were not clinically significant.     

Lack of agreement of tympanic membrane temperature assessments with conventional methods in a private practice setting.

An infrared tympanic membrane thermometer (FIRST temp) said to approximate core temperature accurately is being marketed as a noninvasive, quick, and easy-to-use clinical instrument. The determination of tympanic membrane temperatures by this device was compared with the determination of oral, rectal, or axillary temperatures by a conventional glass thermometer. Subjects were patients of a pediatric group practice in Houston, Texas. FIRST temp and conventional temperature determinations on individual patients were completed within 5 minutes of each other. The presence or absence of otitis media was noted by the examining physician. Agreement between the two methods of temperature determination was assessed by calculating limits of agreement within which 95% (+/- 2 standard deviations) of individual differences would fall. The location of conventional thermometer (oral, rectal, axillary), time interval between the two separate measures, and the presence or absence of otitis media were entered into a multiple regression analysis to determine whether these factors influenced the observed differences between the two methods. A total of 144 patients were enrolled in the study; oral comparisons were obtained in 92 (57%) patients, rectal in 35 (24%), and axillary in 29 (19%). The upper and lower limits of agreement between temperature methods were 1.12 degrees C and 0.89 degrees C and the mean difference was -0.12 degrees C. Regression analysis revealed that only the site of conventional thermometer location (oral, rectal, axillary) was a significant predictor of FIRST temp/conventional differences. Each site had a range of agreement greater than 1.65% degrees C; axillary temperatures had the greatest range (-0.94 degree C to +1.30 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Temperature monitoring in newborns using thermospot

Objective: Hypothermia is a common problem in newborns. This is more so in community environment especially in lowbirth weight and preterm babies.Methods: A simple liquid crystal temperature monitoring device was used in 20 infants on a continuous basis to monitor for hypothermia. This was compared with the measurement of rectal temperature using a rectal thermometer.The colour changes and measures to be taken when hypothermia occurs was explained to the mothers and was well understood by all.Results : The Thermo Spot was in agreement with the rectal temperature in 310 out of 313 measurements. This includes 299 times when temperature was normal; and 11 times when the temperature was hypothermic. It underestimated the temperature of three infants, falsely indicating hypothermia in a normothermic child with normal body temperature. It correctly identified hypothermia in every case.Conclusion: ThermoSpot device is a simple accurate device allowing continuous thermal monitoring of low birth weight infants, especially in resource poor setting.