Can we trust the new generation of infrared tympanic thermometers in clinical practice?

Effect of Auricular Position on Body Temperature Measurement with Tympanic Thermometers: A Quasi Experimental Study

BACKGROUND

With the COVID-19 pandemic, body temperature measurement has begun to be widely used in the diagnosis of the coronavirus disease. When measuring body temperature, it is important to obtain the core temperature measurement. This study compared the results of body temperature obtained with the tympanic membrane thermometer-which is one of the methods that best reflect the body temperature-with or without positioning the auricle.

AIMS

The aim of this study was to investigate the effect of auricle position on body temperature measurements made with tympanic membrane thermometer in adult patients.

MATERIALS AND METHODS

A quasi-experimental design that employed a pre-test and a post-test was used in this study. A total of 143 patients who fit the inclusion criteria of the study were included in the sample. For analysis of the data, frequencies, percentages, means and standard deviations were calculated, and the significance of the difference between paired values was tested in order to investigate the effects of auricle position on measurement values. Statistical Package for the Social Sciences (SPSS) 22.0 was used in analyzing the data obtained in this study.

RESULTS

The difference between the values of measurement taken in these two separate positions was found to be 0.31 0C, and the Bland-Altman plot showed that the differences were distributed systematically around the value 0.31.

CONCLUSIONS

It was found in the comparison of two positions that there was a significant difference between the tympanic thermometer measurements made by positioning the auricle and those without positioning.

Studying the Accuracy and Function of Different Thermometry Techniques for Measuring Body Temperature

The purpose of this study was to determine which thermometry technique is the most accurate for regular measurement of body temperature. We compared seven different commercially available thermometers with a gold standard medical-grade thermometer (Welch-Allyn): four digital infrared thermometers (Wellworks, Braun, Withings, MOBI), one digital sublingual thermometer (Braun), one zero heat flux thermometer (3M), and one infrared thermal imaging camera (FLIR One). Thirty young healthy adults participated in an experiment that altered core body temperature. After baseline measurements, participants placed their feet in a cold-water bath while consuming cold water for 30 min. Subsequently, feet were removed and covered with a blanket for 30 min. Throughout the session, temperature was recorded every 10 min with all devices. The Braun tympanic thermometer (left ear) had the best agreement with the gold standard (mean error: 0.044 °C). The FLIR One thermal imaging camera was the least accurate device (mean error: -0.522 °C). A sign test demonstrated that all thermometry devices were significantly different than the gold standard except for the Braun tympanic thermometer (left ear). Our study showed that not all temperature monitoring techniques are equal, and suggested that tympanic thermometers are the most accurate commercially available system for the regular measurement of body temperature.

Ear measurement of temperature is only useful for screening for fever in an adult emergency department

BACKGROUND

A new generation of ear thermometers with preheated tips and several measurements points should allow a more precise temperature measurement. The aim of the study was to evaluate if the ear temperature measured by this ear thermometer can be used to screen for fever and whether the thermometer is in agreement with the rectal temperature and if age, use of hearing devices or time after admission influences the temperature measurements.

METHODS

Open cross-sectional clinical single site study patients, > 18 years old, who were acutely admitted to the short stay unit at the ED. A sample size of 99 patient per subgroup was recruited as random convenience series. As ear thermometer Braun Thermoscan Pro 4000® and as rectal thermometer Omron Flex Temp Smart ® was used. For different cut off of temperature the AUC was calculated and Bland-Altman analysis for calculation of 95% limits of agreement with rectal temperature, with subgroup analysis concerning age, time span from admission time and use of hearing aid.

RESULTS

Among 599 patients the sensitivity to detect fever with an ear thermometer varied between 68 and 70% with AUC from 0.88-0.97. If the ear temperature was ≥37.5 oC, the sensitivity to detect patients with ≥38.0 oC rectally was 95% which raised to 100% for a rectal temperature of ≥38.3 oC. For the ear thermometer's ability to determine the exact temperature the 95% limits of agreement were +/- 0.8 oC. with no influence from age, duration of hospital stay or hearing aids.

CONCLUSION

The examined ear thermometer is able to detect fever, defined as ≥38 oC rectally in an adult ED population by using an ear cut-point of 37.5 oC, but not to measure the exact temperature. Used in this way around a fifth of the patients will still be in need of a rectal temperature measurement, but less than 5% with fever ≥38.0 oC will remain undetected and none with fever ≥38.3 oC. Age, admission time and use of hearing aid did not influence the temperature measurements.

TRIAL REGISTRATION

Clinical Trials: ID NCT02977481 , date 11/18/2016.

Hypothermia in trauma patients arriving at an emergency department by ambulance in Johannesburg, South Africa: a prospective study

Introduction

Normal body temperature is considered to be between 36 and 38°C. Temperatures that are too low may negatively affect physiological functions. In trauma cases, factors that promote the development of hypothermia include concomitant hypoxia, hypotension, decreased levels of consciousness, contact with cold surfaces, exposure to low ambient temperatures and the administration of cold fluids. Studies on emergency department related hypothermia in Africa are sparse. This study investigated instances of hypothermia in a sample of trauma cases arriving by ambulance to an emergency department in Johannesburg, South Africa.

Methods

Core body temperatures of 140 trauma cases were measured upon arrival and 30 minutes later. Ambient temperatures outside the hospital, inside the ED and in the resuscitation areas were also recorded. Additional information was gathered describing the equipment available to the ambulance crews for temperature, control and rewarming.

Results

Seventy-two (51%) of the cases were found to have core body temperatures less than 36°C upon arrival. Twenty-nine (21%) the cases were considered clinically hypothermic (core temperatures of less than <35°C). After 30 minutes, 79 (56%) of the participants had core body temperatures of less than 36°C and 39 (28%) remained lower than 35°C. Patients were not warming up in the ED as expected. Rather, some had become colder. The study also found that the ambient temperature in the triage area fluctuated and was recorded as less than the recommended 21°C in 95 (68%) of the cases. In addition, the majority of ambulances that transported these cases lacked appropriate equipment on board to properly facilitate temperature control and rewarming.

Conclusion

Fifty-one percent of the trauma cases arriving by ambulance had core temperature <36°C. Many became even colder in the ED. Attention needs to be given to the early identification of hypothermia, the regulation of ambient temperatures inside the ED including the provision of appropriate heating and rewarming devices on ambulances.

Forehead or ear temperature measurement cannot replace rectal measurements, except for screening purposes

BACKGROUND

Measuring rectal temperature in children is the gold standard, but ear or forehead measures are less traumatic and faster. The quality of non-invasive devices has improved but concerns remain whether they are reliable enough to substitute rectal thermometers. The aim was to evaluate in a real-life children population whether the forehead or ear temperature measurements could be used in screening to detect fever and if the agreement with the rectal temperature for different age groups is acceptable for clinical use.

METHODS

Cross-sectional clinical study comparing temporal and tympanic temperatures to rectal temperature in 0-18-year-old children. The ear thermometer was a Pro 4000 Thermoscan, the temporal Exergen TAT. Rectal temperature ≥ 38.0 °C was defined as fever.

RESULTS

Among 995 children, 39% had a fever. The ear thermometer had a significantly greater ability to detect fever than the temporal thermometer (AUC 0.972; 95% CI: 0.963-0.981 versus AUC 0.931; 95% CI: 0.915-0.947, p < 0.0001). Both devices had the lowest sensitivity in the youngest and oldest children, and only the ear thermometer reached a sensitivity above 90% in the 0.5-5-year age group. The Bland-Altman analysis showed that the 95% limits of agreement for the temporal thermometer was between - 1.2 to + 1.5 °C and for the ear thermometer between - 0.97 to + 1.07 °C.

CONCLUSIONS

Based on a large sample of children, the temporal measurement of temperature is not currently recommendable, but with the technology used in this study the ear measurement proved useful for screening purposes, especially among children aged 6 months to 5 years. For the exact measurement of temperature, the rectal method is still recommended.

An optimal two-bout strategy with phase change material cooling vests to improve comfort in hot environment

Cooling vests incorporating phase change material (PCM) packets are used to improve comfort of workers in hot environments. This work aims to investigate by modeling and experimentation the effect of dividing the working duration into two bouts, where different PCM melting temperatures are used in each bout. An integrated bio-heat and fabric-PCM model predictions of physiological and subjective votes are validated via active human subject testing at hot conditions. A parametric study is performed to select, at two conditions (40°C and 45°C), the optimal PCM melting temperatures of the two bouts that would result with similar thermal comfort and sensation to the optimal single-bout case. The optimal case achieves most reductions in energy use for PCM regeneration, PCM carried weight and material cost. The results of the parametric study showed that heat storage is reduced in the second bout due to wearing the second vest with lower PCM melting temperature, thus thermal comfort and sensation are significantly improved. The optimal case at the 40°C environment uses a vest with 21°C PCMs in the first bout and a vest with 21°C PCMs in the second bout (V21→V21). At 45°C, the optimal case is V18→V10 with significant PCM weight reductions from the reference single bout case by a minimum of 47%. Thus, the issue of extra carried weight that affect metabolism and ease of movement when applying continuous cooling during work have been mitigated by using the two-bout strategy.

Temperature measurements in trauma patients: is the ear the key to the core?

Introduction

It is important to monitor the core temperature in a severely injured patient. The choice of method is controversial, and different thermometers and sites for measurement are used. The aim of this study was to investigate continuous epitympanic temperature measurement using an auditory canal sensor in potentially severely injured patients and to compare this method with other commonly used devices.

Methods

In this cohort of potentially severely injured patients, the core temperature was registered continuously using an epitympanic sensor in the auditory canal, beginning at the accident scene through the first hours after admittance to the hospital. According to clinical practice, other methods of measurement were employed during pre- and in-hospital diagnostics and therapeutics. The consistency between different methods was analysed using Bland-Altman plots, and the limits of agreement (LOA) and bias between methods was estimated.

Results

During the study period, 18 patients were included. A total of 393 temperature measurements were obtained using seven different methods. We found that temperature measurements in the auditory canal agreed satisfactorily with most other types of measurements. The most consistent measurement was observed with bladder measurements (bias 0.43 °C, LOA −0.47, 1.33 °C), which was constant over the temperature range investigated (30.0 - 38.3 °C).

Conclusion

Epitympanic temperature measurement in potentially severely injured patients was consistent with other methods that were commonly used to measure core temperature. The difference between measurement methods appeared to be constant over the relevant temperature range. Continuous epitympanic thermometry can be considered a reliable, cost-effective and simple alternative compared with more invasive methods of thermometry.

Clinical Performance of Infrared Consumer-Grade Thermometers

Background and Purpose: Technology of ear infrared (IR) thermometers has improved. This study compared a modern ear thermometer to forehead or temporal artery thermometers. Methods: Temperatures were measured with a heated-tip ear thermometer, a temporal artery thermometer, 3 forehead thermometers, and a thermistor-based reference thermometer in monitor mode. Results: In 171 subjects, mean bias with the forehead thermometers was significantly higher (p< .001) than with the ear thermometer (0.01 °C ± 0.41 °C). In 64 febrile subjects, bias with the ear thermometer was significantly lower than with 3 of the other thermometers. A false-negative reading was less likely with the ear thermometer (8%) versus the others (55%, 56%, 28%, and 47%). Conclusions: Modern ear thermometry provides more precise measurements closer to those of a reference thermometer and is less likely to give false-negative readings than forehead or temporal artery measurements.