Infrared ear thermometry in the critically ill patient

Clinical accuracy and agreement between tympanic and forehead body temperature measurements for screening of patients with COVID-19

AIM

To investigate the accuracy, reliability and agreement between infrared forehead thermometers versus infrared tympanic thermometers temperature, a cross-sectional study was conducted in April 2020.

METHODS

The forehead and tympanic temperatures of 615 subjects were measured simultaneously in three exposed SARS-COV-2 groups at one hospital in Iran, during April 2020. These comparisons were evaluated by Bland-Altman Plot, repeatability, Passing-Bablok regression and Lin's concordance correlation coefficient. The receiver operating characteristic (ROC) analysis was done to describe the discrimination accuracy of a diagnostic test. The study adhered to STROBE checklist for cross-sectional studies.

RESULTS

A Bland-Altman plot indicated that the limits of agreement between the forehead and tympanic temperature were -0.259 to +0.19°C. Passing-Bablok regression analysis illustrated that the infrared forehead was not linearly related to tympanic temperatures (reference method), with a slope estimate that was significantly different from 1.00. The infrared forehead thermometer showed poor precision and lower accuracy than the tympanic. The forehead temperature readings had 60.0% sensitivity and 44.4% specificity (p > .05) to predict disease.

CONCLUSION

According to the results of study, there is no evidence that the assessment of temperature by infrared forehead thermometer could discriminate between the two groups (positive and negative).

The diagnostic accuracy of digital, infrared and mercury-in-glass thermometers in measuring body temperature: a systematic review and network meta-analysis

Not much is known about how accurate and reproducible different thermometers are at diagnosing patients with suspected fever. The study aims at evaluating which peripheral thermometers are more accurate and reproducible. We searched Medline, Embase, Scopus, WOS, CENTRAL, and Cinahl to perform: (1) diagnostic accuracy meta-analysis (MA) using rectal mercury-in-glass or digital thermometry as reference, and bivariate models for pooling; (2) network MA to estimate differences in mean temperature between devices; (3) Bland-Altman method to estimate 95% coefficient of reproducibility. PROSPERO registration: CRD42020174996. We included 46 studies enrolling more than 12,000 patients. Using 38 °C (100.4 ℉) as cut-off temperature, temporal infrared thermometry had a sensitivity of 0.76 (95% confidence interval, 0.65, 0.84; low certainty) and specificity of 0.96 (0.92, 0.98; moderate certainty); tympanic infrared thermometry had a sensitivity of 0.77 (0.60,  0.88; low certainty) and specificity of 0.98 (0.95, 0.99; moderate certainty). For all the other index devices, it was not possible to pool the estimates. Compared to the rectal mercury-in-glass thermometer, mean temperature differences were not statistically different from zero for temporal or tympanic infrared thermometry; the median coefficient of reproducibility ranged between 0.53 °C [0.95 ℉] for infrared temporal and 1.2 °C [2.16 ℉] for axillary digital thermometry. Several peripheral thermometers proved specific, but not sensitive for diagnosing fever with rectal thermometry as a reference standard, meaning that finding a temperature below 38 °C does not rule out fever. Fixed differences between temperatures together with random error means facing differences between measurements in the order of 2 °C [4.5 ℉]. This study informs practitioners of the limitations associated with different thermometers; peripheral ones are specific but not sensitive.

Investigation of the Impact of Infrared Sensors on Core Body Temperature Monitoring by Comparing Measurement Sites

Many types of thermometers have been developed to measure body temperature. Infrared thermometers (IRT) are fast, convenient and ease to use. Two types of infrared thermometers are uses to measure body temperature: tympanic and forehead. With the spread of COVID-19 coronavirus, forehead temperature measurement is used widely to screen people for the illness. The performance of this type of device and the criteria for screening are worth studying. This study evaluated the performance of two types of tympanic infrared thermometers and an industrial infrared thermometer. The results showed that these infrared thermometers provide good precision. A fixed offset between tympanic and forehead temperature were found. The measurement values for wrist temperature show significant offsets with the tympanic temperature and cannot be used to screen fevers. The standard operating procedure (SOP) for the measurement of body temperature using an infrared thermometer was proposed. The suggestion threshold for the forehead temperature is 36 °C for screening of fever. The body temperature of a person who is possibly ill is then measured using a tympanic infrared thermometer for the purpose of a double check.

Assessment of axillary temperature for the evaluation of normal body temperature of healthy young adults at rest in a thermoneutral environment

Background

The aims of this study were to (1) evaluate whether recently introduced methods of measuring axillary temperature are reliable, (2) examine if individuals know their baseline body temperature based on an actual measurement, and (3) assess the factors affecting axillary temperature and reevaluate the meaning of the axillary temperature.

Methods

Subjects were healthy young men and women (n = 76 and n = 65, respectively). Three measurements were obtained: (1) axillary temperature using a digital thermometer in a predictive mode requiring 10 s (T_ax-10 s), (2) axillary temperature using a digital thermometer in a standard mode requiring 10 min (T_ax-10 min), and (3) tympanic membrane temperature continuously measured by infrared thermometry (T_ty). The subjects answered questions about eating and exercise habits, sleep and menstrual cycles, and thermoregulation and reported what they believed their regular body temperature to be (T_reg).

Results

T_reg, T_ax-10 s, T_ax-10 min, and T_ty were 36.2 ± 0.4, 36.4 ± 0.5, 36.5 ± 0.4, and 36.8 ± 0.3 °C (mean ± SD), respectively. There were correlations between T_ty and T_ax-10 min, T_ty and T_ax-10 s, and T_ax-10 min and T_ax-10 s (r = .62, r = .46, and r = .59, respectively, P < .001), but not between T_reg and T_ax-10 s (r = .11, P = .20). A lower T_ax-10 s was associated with smaller body mass indices and irregular menstrual cycles.

Conclusions

Modern devices for measuring axillary temperature may have changed the range of body temperature that is recognized as normal. Core body temperature variations estimated by tympanic measurements were smaller than those estimated by axillary measurements. This variation of axillary temperature may be due to changes in the measurement methods introduced by modern devices and techniques. However, axillary temperature values correlated well with those of tympanic measurements, suggesting that the technique may reliably report an individual’s state of health. It is important for individuals to know their baseline axillary temperature to evaluate subsequent temperature measurements as normal or abnormal. Moreover, axillary temperature variations may, in part, reflect fat mass and changes due to the menstrual cycle.

Accuracy and precision of four common peripheral temperature measurement methods in intensive care patients

INTRODUCTION

An accurate determination of body temperature in critically ill patients is a fundamental requirement for initiating the proper process of diagnosis, and also therapeutic actions; therefore, the aim of the study was to assess the accuracy and precision of four noninvasive peripheral methods of temperature measurement compared to the central nasopharyngeal measurement.

METHODS

In this observational prospective study, 237 patients were recruited from the intensive care unit of Imam Ali Hospital of Kermanshah. The patients' body temperatures were measured by four peripheral methods; oral, axillary, tympanic, and forehead along with a standard central nasopharyngeal measurement. After data collection, the results were analyzed by paired t-test, kappa coefficient, receiver operating characteristic curve, and using Statistical Package for the Social Sciences, version 19, software.

RESULTS

There was a significant meaningful correlation between all the peripheral methods when compared with the central measurement (P<0.001). Kappa coefficients showed good agreement between the temperatures of right and left tympanic membranes and the standard central nasopharyngeal measurement (88%). Paired t-test demonstrated an acceptable precision with forehead (P=0.132), left (P=0.18) and right (P=0.318) tympanic membranes, oral (P=1.00), and axillary (P=1.00) methods. Sensitivity and specificity of both the left and right tympanic membranes were more than for other methods.

CONCLUSION

The tympanic and forehead methods had the highest and lowest accuracy for measuring body temperature, respectively. It is recommended to use the tympanic method (right and left) for assessing a patient's body temperature in the intensive care units because of high accuracy and acceptable precision.

Body temperature abnormalities in non-neurological critically ill patients: a review of the literature

Body temperature abnormalities, which occur because of several infectious and non-infectious etiologies, are among the most commonly noted symptoms of critically ill patients. These abnormalities frequently trigger changes in patient management. The purpose of this article was to review the contemporary literature investigating the definition and occurrence of body temperature abnormalities in addition to their impact on illness severity and mortality in critically ill non-neurological patients, particularly in patients with severe sepsis. Reports on the influence of fever on outcomes are inconclusive, and the presence of fever per se may not contribute to increased mortality in critically ill patients. In patients with severe sepsis, the impacts of elevated body temperature and hypothermia on mortality and the severity of physiologic decline are different. Hypothermia is significantly associated with an increased risk of mortality. In contrast, elevated body temperature may not be associated with increased disease severity or risk of mortality. In patients with severe sepsis, the effect of fever and fever control on outcomes requires further research.

Fever in the critically ill medical patient

Fever, commonly defined by a temperature of >or=38.3 degrees C (101 degrees F), occurs in approximately one half of patients admitted to intensive care units. Fever may be attributed to both infectious and noninfectious causes, and its development in critically ill adult medical patients is associated with an increased risk for death. Although it is widespread and clinically accepted practice to therapeutically lower temperature in patients with hyperthermic syndromes, patients with marked hyperpyrexia, and selected populations such as those with neurologic impairment, it is controversial whether most medical patients with moderate degrees of fever should be treated with antipyretic or direct cooling therapies. Although treatment of fever may improve patient comfort and reduce metabolic demand, fever is a normal adaptive response to infection and its suppression is potentially harmful. Clinical trials specifically comparing fever management strategies in neurologically intact critically ill medical patients are needed.

Occurrence and outcome of fever in critically ill adults

OBJECTIVE

Although fever is common in the critically ill, only a small number of studies have specifically investigated its epidemiology in the intensive care unit (ICU). The objective of this study was to describe the occurrence of fever in the critically ill and assess its effect on ICU outcome.

DESIGN

Retrospective cohort. Fever was defined by temperature > or = 38.3 degrees C and high fever by > or = 39.5 degrees C.

SETTING

Calgary Health Region during 2000-2006.

PATIENTS

All adults (> or = 18 yrs) admitted to ICUs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 24,204 ICU admission episodes occurred among 20,466 patients; 35% were classified as medical, 33% as cardiac surgical, 16% as other surgical, and 15% as trauma/neurologic. The cumulative incidence of fever and high fever was 44% and 8% and the incidence density was 24.3 and 2.7 per 100 days of ICU admission, respectively. The incidence density of fever was higher in trauma/neuro patients, males, younger patients, and was lower in those with admission Acute Physiology and Chronic Health Evaluation II scores > or = 25. Seventeen percent and 31% of patients with fever and high fever had associated positive cultures. Resolution of fever and high fever occurred in 27% and 53% of patients before ICU discharge and prolonged fever and high fever lasting for 5 or more days in the ICU occurred in 18% and 11% of febrile patients, respectively. Although the presence of fever was not associated with increased ICU mortality (13% vs. 12%; p = .08), high fever was associated with significantly increased risk for death (20.3% vs. 12%, p < .0001). After controlling for confounding factors using multivariable logistic regression models, the influence of fever on the ICU mortality varied significantly according to its timing of onset, degree, and main admission category.

CONCLUSIONS

Fever is common in patients admitted to the ICU and its occurrence and impact on outcome varies among defined patient populations.