Skin temperature measurement using an infrared thermometer on patients who have been exposed to cold

A Comparative Study of Forehead Temperature and Core Body Temperature under Varying Ambient Temperature Conditions

When the ambient temperature, in which a person is situated, fluctuates, the body's surface temperature will alter proportionally. However, the body's core temperature will remain relatively steady. Consequently, using body surface temperature to characterize the core body temperature of the human body in varied situations is still highly inaccurate. This research aims to investigate and establish the link between human body surface temperature and core body temperature in a variety of ambient conditions, as well as the associated conversion curves.

METHODS

Plan an experiment to measure temperature over a thousand times in order to get the corresponding data for human forehead, axillary, and oral temperatures at varying ambient temperatures (14-32 °C). Utilize the axillary and oral temperatures as the core body temperature standards or the control group to investigate the new approach's accuracy, sensitivity, and specificity for detecting fever/non-fever conditions and the forehead temperature as the experimental group. Analyze the statistical connection, data correlation, and agreement between the forehead temperature and the core body temperature.

RESULTS

A total of 1080 tests measuring body temperature were conducted on healthy adults. The average axillary temperature was (36.7 ± 0.41) °C, the average oral temperature was (36.7 ± 0.33) °C, and the average forehead temperature was (36.2 ± 0.30) °C as a result of the shift in ambient temperature. The forehead temperature was 0.5 °C lower than the average of the axillary and oral temperatures. The Pearson correlation coefficient between axillary and oral temperatures was 0.41 (95% CI, 0.28-0.52), between axillary and forehead temperatures was 0.07 (95% CI, -0.07-0.22), and between oral and forehead temperatures was 0.26 (95% CI, 0.11-0.39). The mean differences between the axillary temperature and the oral temperature, the oral temperature and the forehead temperature, and the axillary temperature and the forehead temperature were -0.08 °C, 0.49 °C, and 0.42 °C, respectively, according to a Bland-Altman analysis. Finally, the regression analysis revealed that there was a linear association between the axillary temperature and the forehead temperature, as well as the oral temperature and the forehead temperature due to the change in ambient temperature.

CONCLUSION

The changes in ambient temperature have a substantial impact on the temperature of the forehead. There are significant differences between the forehead and axillary temperatures, as well as the forehead and oral temperatures, when the ambient temperature is low. As the ambient temperature rises, the forehead temperature tends to progressively converge with the axillary and oral temperatures. In clinical or daily applications, it is not advised to utilize the forehead temperature derived from an uncorrected infrared thermometer as the foundation for a body temperature screening in public venues such as hospital outpatient clinics, shopping malls, airports, and train stations.

Reliability of Non-Contact Infrared Thermometers for Fever Screening Under COVID-19

Purpose

Fever is one of the most typical clinical symptoms of coronavirus disease 2019 (COVID-19), and non-contact infrared thermometers (NCITs) are commonly used to screen for fever. However, there is a lack of authoritative data to define a “fever” when an NCIT is used and previous studies have shown that NCIT readings fluctuate widely depending on ambient temperatures and the body surface site screened. The aim of this study was to establish cut-off points for normal temperatures of different body sites (neck, forehead, temples, and wrist) and investigate the accuracy of NCITs at various ambient temperatures to improve the standardization and accuracy of fever screening.

Patients and Methods

A prospective investigation was conducted among 904 participants in the outpatient and emergency departments of Chengdu Women’s and Children’s Central Hospital. Body temperature was measured using NCITs and mercury axillary thermometers. A receiver operating characteristic curve was used to determine the accuracy of body temperature detection at the four body surface sites. Data on participant characteristics were also collected.

Results

Among the four surface sites, the neck temperature detection group had the highest accuracy. When the neck temperature was 37.35°C as the optimum fever diagnostic threshold, the sensitivity was 0.866. The optimum fever diagnostic thresholds for forehead, temporal, and wrist temperature were 36.65°C, 36.65°C, and 36.75°C, respectively. Moreover, triple neck temperature detection had the highest sensitivity, up to 0.998, whereas the sensitivity of triple wrist temperature detections was 0.949. Notably, the accuracy of NCITs significantly reduced when the temperature was lower than 18°C.

Conclusion

Neck temperature had the highest accuracy among the four NCIT temperature measurement sites, with an optimum fever diagnostic threshold of 37.35°C. Considering the findings reported in our study, we recommend triple neck temperature detection with NCITs as the fever screening standard for COVID-19.

Estimation of Blood Loss in Oral and Maxillofacial Surgery by Measurements of Low Haemoglobin Levels in Mixtures of Blood, Saliva and Saline: a Laboratory Study

Objectives

Estimating blood loss is an important factor in several surgical procedures. The accuracy of blood loss measurements in situations where blood is mixed with saliva and saline is however uncertain. The purpose of this laboratory study was to ascertain if blood loss measurements in mixtures of blood, saline, and saliva are reliable and could be applicable in a clinical setting.

Material and Methods

Venous blood and resting saliva were collected from six volunteers. Saliva, saline, and combinations thereof were mixed with blood to obtain different concentrations. A portable spectrophotometer was first used to measure the haemoglobin concentration in undiluted venous blood followed by measurements of the haemoglobin concentration after each dilution. To examine the strength of linear relationships, linear regression and Pearson correlations were used.

Results

The measurements of haemoglobin concentrations in mixtures of blood, saline, and saliva were proven to be accurate for haemoglobin measurements > 0.3 g/dl (correlation = 0.986 to 1). For haemoglobin measurements < 0.3 g/dl, a small increase in haemoglobin values were reported, which was directly associated to the saliva concentration in the solution (correlation = 0.983 to 1). This interference of saliva was significantly eliminated by diluting the samples with saline, mimicking the clinical situation.

Conclusions

The results suggest that a portable spectrophotometer can be used clinically to preoperatively measure the haemoglobin value of a venous blood sample and postoperatively measure the haemoglobin value of the collected liquids, including shed blood, thereby achieving a highly accurate method of measuring blood loss during oral and maxillofacial surgery.

Dental Education during the COVID-19 Pandemic in a German Dental Hospital

Due to the SARS-CoV-2 pandemic, dental treatment performed by undergraduate students at the University of Marburg/Germany was immediately stopped in spring 2020 and stepwise reinstalled under a new hygiene concept until full recovery in winter 2020/21. Patient treatment in the student courses was evaluated based on three aspects: (1) Testing of patients with a SARS-CoV-2 Rapid Antigen (SCRA) Test applied by student assistants (SA); (2) Improved hygiene regimen, with separated treatment units, cross-ventilation, pre-operative mouth rinse and rubber dam application wherever possible; (3) Recruitment of patients: 735 patients were pre-registered for the two courses; 384 patients were treated and a total of 699 tests with the SCRA test were performed by SAs. While half of the patients treated in the course were healthy, over 40% of the patients that were pre-registered but not treated in the course revealed a disease being relevant to COVID (p < 0.001). 46 patients had concerns to visit the dental hospital due to the increase of COVID incidence levels, 14 persons refused to be tested. The presented concept was suitable to enable patient treatment in the student course during the SARS-CoV-2 pandemic.

Changes in body temperature of critically ill patients submitted to bed bathing: a crossover clinical trial

OBJECTIVES

to compare tympanic and axillary body temperature values of critical patients before and after the traditional and dry bed bath.

METHODS

this is a randomized, open crossover clinical trial conducted with 50 adult critical patients. All patients received both types of bed bathing. The tympanic and axillary temperature values were measured at the beginning and end of the baths. The Wilcoxon test or paired Student's t test was used.

RESULTS

elderly and male patients predominated. There was no significant difference between tympanic temperature medians measured during the traditional bed bath (p=0.707) and dry bath (p=0.101). Axillary temperature means reduced at the end of the baths (p=0.001), being 36.12ºC in the traditional bath and 35.92ºC in dry bath.

CONCLUSIONS

bed bath, regardless of the method used, caused a reduction in critical patients' axillary temperature.

Return to school in the COVID-19 era: considerations for temperature measurement

COVID-19 pandemics required a reorganisation of social spaces to prevent the spread of the virus. Due to the common presence of fever in the symptomatic patients, temperature measurement is one of the most common screening protocols. Indeed, regulations in many countries require temperature measurements before entering shops, workplaces, and public buildings. Due to the necessity of providing rapid non-contact and non-invasive protocols to measure body temperature, infra-red thermometry is mostly used. Many countries are now facing the need to organise the return to school and universities in the COVID-19 era, which require solutions to prevent the risk of contagion between students and/or teachers and technical/administrative staff. This paper highlights and discusses some of the strengths and limitations of infra-red cameras, including the site of measurements and the influence of the environment, and recommends to be careful to consider such measurements as a single "safety rule" for a good return to normality.

Validity of the Use of Wrist and Forehead Temperatures in Screening the General Population for COVID-19: A Prospective Real-World Study

Background

We aimed to compare the accuracy of individuals' wrist and forehead temperatures with their tympanic temperature under different circumstances.

Methods

We performed a prospective observational study in a real-life population in Ningbo First Hospital in China. We consecutively recorded individuals' wrist and forehead temperatures in Celsius (°C) using a non-contact infrared thermometer (NCIT). We also measured individuals' tympanic temperature using a tympanic thermometer (IRTT) and defined fever as a tympanic temperature of ≥37.3 °C.

Results

We enrolled 528 participants, including 261 indoor and 267 outdoor participants. We grouped the outdoor participants into four groups according to their means of transportation to the hospital: by foot, by bicycle/electric vehicle, by car, or as a passenger in a car. Under different circumstances, the mean difference in the forehead measurement ranged from -1.72 to -0.56 °C across groups, and that in the wrist measurement ranged from -0.96 to -0.61°C. Both measurements had high fever screening abilities in indoor patients. (Wrist: AUC 0.790; 95% CI: 0.725-0.854, P<0.001; forehead: AUC 0.816; 95% CI: 0.757-0.876, P <0.001). The cut-off value of the wrist measurement for detecting a tympanic temperature of ≥37.3 °C was 36.2 °C, with 86.4% sensitivity and 67.0% specificity, and the best threshold for the forehead measurement was 36.2 °C, with 93.2% sensitivity and 60.0% specificity.

Conclusion

Wrist measurements are more stable than forehead measurements under different circumstances. Both measurements have favorable fever screening abilities in indoor patients. The cut-off values were both 36.2 °C.

A detailed report on the measures taken in the Department of Conservative Dentistry and Periodontology in Munich at the beginning of the COVID-19 outbreak

Objectives

The corona disease (COVID-19) is developing into one of the greatest challenges for healthcare professionals around the world. In this article, we report the detailed actions taken in the Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University (LMU), Munich, Germany, during the early phase of the COVID-19 pandemic.

Material and methods

After a joint on-site inspection of the dental clinic with the Department of Clinical Microbiology and Hospital Hygiene, existing clinical and hygiene protocols were adapted for COVID-19 patients.

Results

A comprehensive summary of the preparation of the facilities as well as pre- treatment, treatment and posttreatment protocols are described and arising problems are being discussed.

Conclusions

The importance of rigorous hygiene and treatment protocols as well as a sufficient supply of PPE for dental offices and hospitals is highlighted. The measures reported may be subject to change due to the dynamics of the pandemic.

Clinical relevance

The modes of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (e.g., droplets, aerosols, and fomites) can pose a risk for dental healthcare professionals and patients alike. The presented measures may guide dental faculties and dental practices during the early stage of the COVID-19 crisis.

Infrared cameras are potential traceable "fixed points" for future thermometry studies

The National physical laboratory (NPL) requires "fixed points" whose temperatures have been established by the International Temperature Scale of 1990 (ITS 90) be used for device calibration. In practice, "near" blackbody radiators together with the standard platinum resistance thermometer is accepted as a standard. The aim of this study was to report the correlation and limits of agreement (LOA) of the thermal infrared camera and non-contact infrared temporal thermometer against each other and the "near" blackbody radiator. Temperature readings from an infrared thermography camera (FLIR T650sc) and a non-contact infrared temporal thermometer (Hubdic FS-700) were compared to a near blackbody (Hyperion R blackbody model 982) at 0.5 °C increments between 20-40 °C. At each increment, blackbody cavity temperature was confirmed with the platinum resistance thermometer. Measurements were taken initially with the thermal infrared camera followed by the infrared thermometer, with each device mounted in turn on a stand at a fixed distance of 20 cm and 5 cm from the blackbody aperture, respectively. The platinum thermometer under-estimated the blackbody temperature by 0.015 °C (95% LOA: -0.08 °C to 0.05 °C), in contrast to the thermal infrared camera and infrared thermometer which over-estimated the blackbody temperature by 0.16 °C (95% LOA: 0.03 °C to 0.28 °C) and 0.75 °C (95% LOA: -0.30 °C to 1.79 °C), respectively. Infrared thermometer over-estimates thermal infrared camera measurements by 0.6 °C (95% LOA: -0.46 °C to 1.65 °C). In conclusion, the thermal infrared camera is a potential temperature reference "fixed point" that could substitute mercury thermometers. However, further repeatability and reproducibility studies will be required with different models of thermal infrared cameras.