Is axillary temperature an appropriate surrogate for core temperature?

Skin-interfacing wearable biosensors for smart health monitoring of infants and neonates

Health monitoring of infant patients in intensive care can be especially strenuous for both the patient and their caregiver, as testing setups involve a tangle of electrodes, probes, and catheters that keep the patient bedridden. This has typically involved expensive and imposing machines, to track physiological metrics such as heart rate, respiration rate, temperature, blood oxygen saturation, blood pressure, and ion concentrations. However, in the past couple of decades, research advancements have propelled a world of soft, wearable, and non-invasive systems to supersede current practices. This paper summarizes the latest advancements in neonatal wearable systems and the different approaches to each branch of physiological monitoring, with an emphasis on smart skin-interfaced wearables. Weaknesses and shortfalls are also addressed, with some guidelines provided to help drive the further research needed.

Pharmacological antagonism of receptor for advanced glycation end products signaling promotes thermogenesis, healthful body mass and composition, and metabolism in mice

OBJECTIVE

Optimal body mass and composition as well as metabolic fitness require tightly regulated and interconnected mechanisms across tissues. Disturbances in these regulatory networks tip the balance between metabolic health versus overweight and obesity and their complications. The authors previously demonstrated roles for the receptor for advanced glycation end products (RAGE) in obesity, as global- or adipocyte-specific deletion of Ager (the gene encoding RAGE) protected mice from high-fat diet-induced obesity and metabolic dysfunction.

METHODS

To explore translational strategies evoked by these observations, a small molecule antagonist of RAGE signaling, RAGE229, was administered to lean mice and mice with obesity undergoing diet-induced weight loss. Body mass and composition and whole body and adipose tissue metabolism were examined.

RESULTS

This study demonstrates that antagonism of RAGE signaling reduced body mass and adiposity and improved glucose, insulin, and lipid metabolism in lean male and female mice and in male mice with obesity undergoing weight loss. In adipose tissue and in human and mouse adipocytes, RAGE229 enhanced phosphorylation of protein kinase A substrates, which augmented lipolysis, mitochondrial function, and thermogenic programs.

CONCLUSIONS

Pharmacological antagonism of RAGE signaling is a potent strategy to optimize healthful body mass and composition and metabolic fitness.

Associations among serum VEGF and CGRP levels with the peripheral vascular blood flow of the skin of the hands in women with Fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a long-term condition of unknown physiopathology, whose hallmark symptoms are diffuse musculoskeletal chronic pain and fatigue.

OBJECTIVES

We aimed to analyze the associations among serum vascular endothelial growth factor (VEGF) and calcitonin gene-related peptide (CGRP) levels with the peripheral temperature of the skin of both hands and the core body temperature in patients with FM and healthy controls.

METHODS

We conducted a case-control observational study with fifty-three women diagnosed with FM and twenty-four healthy women. VEGF and CGRP levels were spectrophotometrically analyzed in serum by enzyme-linked immunosorbent assay. We used an infrared thermography camera to assess the peripheral temperature of the skin of the dorsal thumb, index, middle, ring, and pinkie fingertips and dorsal centre as well as the palm thumb, index, middle, ring, and pinkie fingertips, palm centre and thenar and hypothenar eminences of both hands and an infrared thermographic scanner to record the tympanic membrane and axillary temperature.

RESULTS

Linear regression analysis adjusting for age, menopause status, and body mass index showed that serum VEGF levels were positively associated with the maximum (β = 65.942, 95% CI [4.100,127.784], p = 0.037), minimum (β = 59.216, 95% CI [1.455,116.976], p = 0.045), and mean (β = 66.923, 95% CI [3.142,130.705], p = 0.040) temperature of the thenar eminence of the non-dominant hand, as well as with the maximum temperature of the hypothenar eminence of the non-dominant hand (β = 63.607, 95% CI [3.468,123.747], p = 0.039) in women diagnosed with FM.

CONCLUSIONS

Mild associations were observed between serum VEGF levels and the peripheral temperature of the skin in hand areas in patients with FM; therefore, it is not possible to establish a clear relationship between this vasoactive molecule and vasodilation of the hands in these patients.

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.

Assessment of Alternative Body Points for Temperature Screening As Precautionary Screening During the Pandemic Using Infrared Thermometry

BACKGROUND

The recent coronavirus disease 2019 (COVID-19) pandemic, which swept across the globe in a short period, demonstrated that disease transmission management is a critical step in preventing an outbreak, as is good viral infectious disease screening. Infrared thermography (IRT) has long been considered ideal for screening body temperatures during pandemics.

METHODS

Single-centre cross-sectional study with 159 participants. Using infrared thermometry, participants were subjected to temperature measurement twice daily on various sites. This was compared to oral temperature.

RESULTS

The findings of the study revealed that infrared thermometry could be utilised as a proxy approach for screening by both individuals and medical professionals when employed at the glabella, cubits, or axillae.

CONCLUSION

 Temperature screening is implied as a prophylactic method during pandemics. Owing to contact limitations, oral thermometry cannot be used for mass screening during the pandemic. Infrared thermometry is a noncontact method of temperature screening that can readily be applied for mass temperature screening in congested venues such as airports, shopping malls, places of public convenience, and other similar locations.

The efficacy of infrared filter window film to prevent hyperthermia in neonatal hyperbilirubinemia with conventional phototherapy: a randomized control trial

BACKGROUND

Phototherapy is the first-line treatment of neonatal hyperbilirubinemia. Possible side effects caused by phototherapy include hyperthermia and dehydration. Currently, there are many types of infrared blocking film for potential use in reducing infrared radiation exposure and preventing hyperthermia. This study aims to evaluate the efficacy of infrared blocking film in preventing hyperthermia during the first 24 h of phototherapy.

METHODS

The randomized controlled trial study was carried out in 44 newborns with hyperbilirubinemia. Infrared filter film with 75% visible light transmission and 90% infrared rejection was used in the study. Body temperature was measured for the assessment of the efficacy of filter film from axillary and rectal routes.

RESULTS

There was a significantly lower incidence of hyperthermia from the axillary temperature in the group with infrared blocking film compared to the control group (p = 0.031). The axillary temperature between before and after initiation of phototherapy in filter film group was significantly better (p = 0.008). According to efficacy of treatment, the study demonstrated that infrared filter film did not interfere with the efficacy of phototherapy in reducing bilirubin level.

CONCLUSIONS

The infrared filter film was significantly more effective in preventing hyperthermia from phototherapy in the first 24 h without causing any significant difference in reduction of bilirubin level.

THAI CLINICAL TRIALS REGISTRY

TCTR20190619001.

The Accuracy of a Wireless Axillary Thermometer for Core Temperature Monitoring in Pediatric Patients Having Noncardiac Surgery: An Observational Study

PURPOSE

A wireless and wearable axillary thermometer (iThermonitor) has been validated for perioperative core temperature monitoring in adults. The purpose of this study was to evaluate its accuracy in pediatrics having non-cardiac surgery.

DESIGN

Prospective observational study.

METHODS

From January 2019 to December 2019, 70 children aged younger than 14 years undergoing surgery in a tertiary hospital were selected. Pairs of esophageal temperatures (T_Eso), rectal temperatures (T_Rec), and axillary temperatures monitored by the iThermonitor (T_iTh) were collected every 5 min during surgery. Taking T_Eso as reference, the bias between T_Eso and T_iTh and the proportion of bias within ±0.5°C were calculated. Bland-Altman method was used to analyze the 95% of limits of agreement (LOA) between T_iTh and T_Eso. The same analyses were done for T_Rec. FINDINGS: A total of 2232 pairs of temperatures were collected. The bias (mean ± SD) between T_iTh and T_Eso was -0.07 °C ± 0.25°C, and 95% LOA was -0.07°C ± 0.50°C. The proportion of bias within ±0.5°C accounted for 96% (95% Confidence Interval [CI], 92-98%). Higher bias and 95% LOA, and lower proportion of bias within ± 0.5°C were found between T_Rec and T_Eso than those between T_iTh and T_Eso.

CONCLUSION

During pediatric non-cardiac surgery, axillary temperature derived from iThermonitor is in good agreement with esophageal temperature and can be used as an alternative to core temperature.

Axillary Thermometry Demonstrates Greater Reliability Compared With Rectal Thermometry in Healthy Neonates

Rectal thermometry (RT) is considered the gold standard for measuring temperature in newborns, despite increasing use of temporal artery thermometry (TT) and axillary thermometry (AT) methods. Few prospective studies compare RT, TT, and AT in a newborn nursery setting. To determine the accuracy and reliability of these methods, we enrolled 205 healthy, full-term newborns. TT displayed higher mean temperatures than RT by 0.25 °F (standard error [SE] = 0.04, P < .001). AT and RT measurements did not significantly differ, with their means differing only by 0.02 °F (SE = 0.04, P = .87). For reliability, RT measurements differed by 0.45 °F (SE = 0.03) in either direction of the models' predicted mean for each subject. AT and TT measurements varied much less from their predicted means 0.32 °F (SE = 0.02) and 0.34 °F (SE = 0.02), respectively (both P < .001). Assuming mean RT is correct, TT is less accurate than AT. RT showed poor reliability between measurements. AT is an accurate and reliable method of temperature screening in healthy neonates.

Smart Patch for Skin Temperature: Preliminary Study to Evaluate Psychometrics and Feasibility

There is a need for continuous, non-invasive monitoring of biological data to assess health and wellbeing. Currently, many types of smart patches have been developed to continuously monitor body temperature, but few trials have been completed to evaluate psychometrics and feasibility for human subjects in real-life scenarios. The aim of this feasibility study was to evaluate the reliability, validity and usability of a smart patch measuring body temperature in healthy adults. The smart patch consisted of a fully integrated wearable wireless sensor with a multichannel temperature sensor, signal processing integrated circuit, wireless communication feature and a flexible battery. Thirty-five healthy adults were recruited for this test, carried out by wearing the patches on their upper chests for 24 h and checking their body temperature six times a day using infrared forehead thermometers as a gold standard for testing validity. Descriptive statistics, one-sampled and independent t-tests, Pearson’s correlation coefficients and Bland-Altman plot were examined for body temperatures between two measures. In addition, multiple linear regression, receiver operating characteristic (ROC) and qualitative content analysis were conducted. Among the 35 participants, 29 of them wore the patch for over 19 h (dropout rate: 17.14%). Mean body temperature measured by infrared forehead thermometers and smart patch ranged between 32.53 and 38.2 °C per person and were moderately correlated (r = 0.23–0.43) overall. Based on a Bland-Altman plot, approximately 94% of the measurements were located within one standard deviation (upper limit = 4.52, lower limit = −5.82). Most outliers were identified on the first measurement and were located below the lower limit. It is appropriate to use 37.5 °C in infrared forehead temperature as a cutoff to define febrile conditions. Users’ position while checking and ambient temperature and humidity are not affected to the smart patch body temperature. Overall, the participants showed high usability and satisfaction on the survey. Few participants reported discomfort due to limited daily activity, itchy skin or detaching concerns. In conclusion, epidermal electronic sensor technologies provide a promising method for continuously monitoring individuals’ body temperatures, even in real-life situations. Our study findings show the potential for smart patches to monitoring non-febrile condition in the community.

The relationship between epidural analgesia and intrapartum maternal fever and the consequences for maternal and neonatal outcomes: a prospective observational study

AIM

To use continuous real-time monitoring of maternal core body temperature during labor and investigate the association between epidural analgesia, intrapartum maternal fever, and maternal and neonatal outcomes.

METHODS

Among 201 pregnant women attending our institution for a vaginal in-hospital delivery, 159 women received epidural analgesia and 42 women did not receive epidural analgesia. Women's core body temperature was continuously monitored for the duration of labor using a smartphone/iPad-connected wireless thermometer positioned in an axilla. The primary outcome was a change in maternal core body temperature during labor. Among women receiving epidural analgesia, maternal and neonatal outcomes were compared in women who developed an intrapartum fever and those who had no intrapartum temperature elevation.

RESULTS

Of the women receiving epidural analgesia, 26.4% (n = 42/159) developed intrapartum fever ≥38 °C compared to 7.1% (n = 3/42) of women not receiving epidural analgesia. Among those receiving epidural analgesia, women who developed intrapartum fever had a significantly longer first stage of labor and a higher incidence of cesarean section, assisted vaginal delivery, intrapartum hemorrhage, and turbid amniotic fluid compared to women with no intrapartum temperature elevation. Neonates of women who developed intrapartum fever had lower 1- and 5-min Apgar scores compared to neonates of women with no intrapartum temperature elevation; however, the difference was not significant.

CONCLUSION

This study used a precise and accurate method to monitor core body temperature among women receiving epidural analgesia. Results showed that the use of epidural analgesia during labor was associated with intrapartum maternal fever in all stages of labor. Fever after epidural analgesia was associated with adverse maternal outcomes, independent of neonatal complications.

Temperature Monitoring Devices in Neonates

Introduction: Accurate temperature monitoring of neonates is vital due to the significant morbidities and mortality associated with neonatal hypothermia. Many studies have compared different thermometers in neonates, however, there is a lack of consensus regarding which of the currently available thermometers is most suitable for use in neonates. Objectives: The aim of this review was to identify and compare current methods available for temperature monitoring of neonates beyond the delivery room, including the accuracy, advantages and disadvantages of each. Methods: A recent search and narrative synthesis of relevant studies published between January 1, 1949 and May 5, 2021 on the OVID Medline, PubMed and Google Scholar databases. Results: A total of 160 papers were retrieved for narrative synthesis. The main methods available for temperature monitoring in neonates are human touch and mercury-in-glass, electronic, infrared tympanic and other infrared thermometers. Newer innovations that are also available include liquid crystal thermometers and the BEMPU TempWatch. This paper discusses the current evidence available regarding the utility of these devices, and identifies barriers to valid comparison of different thermometry methods. Conclusion: Many methods for temperature monitoring in neonates are currently available, each with their own advantages and disadvantages. However, the accuracies of different devices are hard to determine due to variable methodologies used in relevant studies and hence, further research that addresses these gaps is needed.

Evaluation of sympathetic adrenergic branch of cutaneous neural control throughout thermography and its relationship to nitric oxide levels in patients with fibromyalgia

BACKGROUND

Fibromyalgia syndrome is defined as a complex disease, characterized by chronic widespread musculoskeletal pain and other symptoms. The factors underlying physiopathology of fibromyalgia are not well understood, complicating its diagnosis and management.

OBJECTIVES

To evaluate the peripheral vascular blood flow of the skin of the hands and the core body temperature as indirect measures of sympathetic adrenergic activity of the nervous system and its relationship to nitric oxide levels (NO) in women with fibromyalgia compared with healthy controls.

METHODS

Forty-two women with fibromyalgia and 52 healthy women were enrolled in this observational pilot study. We used infrared thermography of the hands and an infrared dermal thermometer to evaluate the peripheral vascular blood flow and tympanic and axillary core body temperature, respectively. We measured NO levels using the ozone chemiluminescence-based method.

RESULTS

Two-way analysis of covariance (ANCOVA) showed that the tympanic (P=0.002) and hand temperatures were significantly higher in the patients with fibromyalgia than in the controls (P≤0.001). Significant associations were also found between serum NO levels and minimum temperatures at the dorsal center of the dominant hand (β=-3.501; 95% confidence interval [CI] -6.805, ‑0.198; P= 0.038), maximum temperature (β=-5.594; 95% CI ‑10.106, ‑1.081; P=0.016), minimum temperature (β=-4.090; 95% CI ‑7.905, ‑0.275; P=0.036), and mean temperature (β=-5.519; 95% CI ‑9.933, ‑1.106; P=0.015) of the center of the palm of the non-dominant hand, maximum temperature at the thenar eminence of the dominant hand (β=-5.800; 95% CI ‑10.508, ‑1.092; P=0.017), and tympanic temperature (β=-9.321; 95% CI ‑17.974, ‑0.669; P=0.035) in the controls.

CONCLUSIONS

Our findings indicate that the women with fibromyalgia showed higher tympanic core body and hand temperature than the healthy controls. Moreover, there were negative associations between hand peripheral vasodilation and NO in the healthy women but not in those with fibromyalgia, suggesting a dysfunction of sympathetic cutaneous neural control.

The effect of mirabegron on energy expenditure and brown adipose tissue in healthy lean South Asian and Europid men

AIM

To compare the effects of cold exposure and the β3-adrenergic receptor agonist mirabegron on plasma lipids, energy expenditure and brown adipose tissue (BAT) activity in South Asians versus Europids.

MATERIALS AND METHODS

Ten lean Dutch South Asian (aged 18-30 years; body mass index [BMI] 18-25 kg/m² ) and 10 age- and BMI-matched Europid men participated in a randomized, double-blinded, cross-over study consisting of three interventions: short-term (~ 2 hours) cold exposure, mirabegron (200 mg one dose p.o.) and placebo. Before and after each intervention, we performed lipidomic analysis in serum, assessed resting energy expenditure (REE) and skin temperature, and measured BAT fat fraction by magnetic resonance imaging.

RESULTS

In both ethnicities, cold exposure increased the levels of several serum lipid species, whereas mirabegron only increased free fatty acids. Cold exposure increased lipid oxidation in both ethnicities, while mirabegron increased lipid oxidation in Europids only. Cold exposure and mirabegron enhanced supraclavicular skin temperature in both ethnicities. Cold exposure decreased BAT fat fraction in both ethnicities. After the combination of data from both ethnicities, mirabegron decreased BAT fat fraction compared with placebo.

CONCLUSIONS

In South Asians and Europids, cold exposure and mirabegron induced beneficial metabolic effects. When combining both ethnicities, cold exposure and mirabegron increased REE and lipid oxidation, coinciding with a higher supraclavicular skin temperature and lower BAT fat fraction.

Axillary and Tympanic Temperature Measurement in Children and Normal Values for Ages

AIM

The aim of the study was define the normal values of tympanic and axillary body temperature in healthy children.

METHODS

This observational cross-sectional study was performed in healthy children aged 0 to 17 years who visited the ambulatory general pediatric of Istanbul Medical Faculty.

RESULTS

Of 1364 children, 651 (47.7%) were girls and 713 were boys, the mean (SD, range) age was 72.5 (53.6, 1-204) months. The mean (SD) axillary body temperature was 36.04°C (0.46°C; minimum, 35.0°C; maximum, 37.6°C). The 95th and 99th percentiles were 36.8°C and 37.0°C, respectively. The mean (SD) tympanic body temperature was 36.91°C (0.46°C; minimum, 35.15°C; maximum, 37.9°C). The 95th and 99th percentiles were 37.6°C and 37.8°C, respectively. There were statistically significant differences between sexes for only tympanic body temperatures. Both axillary and tympanic body temperatures were statistically higher in 0 to 2 months compared with other age groups. For this age group, the 99th percentile was 37.5°C for axillary and 37.85°C for tympanic temperature.

CONCLUSIONS

Axillary and tympanic body temperatures should be considered as fever when they are more than 37.0°C and 37.8°C, respectively. For 0 to 2 months, fever is 37.5°C and 37.85°C in axillary and tympanic temperatures, respectively.

Use of noncontact infrared thermography to measure temperature in children in a triage room

We compared the accuracy and utility of 3 infrared (IFR) thermographs fitted with axillary digital thermometers used to measure temperature in febrile and afebrile children admitted to an emergency triage room.A total of 184 febrile and 135 afebrile children presenting to a triage room were consecutively evaluated. Axillary temperature was recorded using a digital electronic thermometer. Simultaneously, IFR skin scans were performed on the forehead, the neck (over the carotid artery), and the nape by the same nurse. Fever was defined as an axillary temperature ≥37.5°C. The temperature readings at the 4 sites were compared.For all subjects, the median axillary temperature was 37.7 ± 1.5°C, the IFR forehead temperature was 37 ± 1.1°C, the IFR neck temperature was 37.6 ± 1.5°C, and the IFR nape temperature was 37 ± 1.2°C. A Bland-Altman plot of the differences suggested that all agreements between IFR and axillary measures were poor (the latter measure was considered the standard). The forehead measurements had a sensitivity of 88.6% and a specificity of 60% in patients with temperatures ≥36.75°C. The sensitivities of the neck measurement at cut-offs of ≥37.35°C and ≥36.95 were 95.5% and 78.8% for those aged 2 to 6 years. Thus, 11.4% of febrile subjects were missed when forehead measurements were performed.An IFR scan over the lateral side of neck is a reliable, comfortable, rapid, and noninvasive method for fever screening, particularly in children aged 2 to 6 years, in busy settings such as pediatric triage rooms.

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.

Temperature Measurement in Critical Care Adults: A Comparison of Thermometry and Measurement Routes

Purpose. To describe within- and between-subject mean differences between and among temperature sites (oral, axilla, PA) and instruments.

Methods. A convenience sample (N = 35) of volunteering, adult (18 years), 1st-day postcardiac surgery inpatients was obtained. Temperature-sensing instruments included Geratherm DataTherm and SolarTherm, and Abbott Opticath fiber optic PA catheters. For 21 min, simultaneous temperature readings (°C) at 4 temperature sites with 3 thermometry devices were monitored.

Results. Mean difference at 21 min PA and between DataTherm axilla and PA = 0.72°C (SD 0.30); between PA and SolarTherm oral = 0.62°C (SD 0.34); and between PA and SolarTherm axilla = 0.46°C (SD 0.16). Temperature levels were not a factor relative to difference scores between study and reference devices.

Conclusions. Both test devices, SolarTherm (an intermittent-use device) and DataTherm (a temperature-monitoring device), performed well, and correlated strongly with PA temperature assesments.

Comparison of axillary and rectal temperatures for healthy Beagles in a temperature- and humidity-controlled environment

OBJECTIVE

To compare axillary and rectal temperature measurements obtained with a digital thermometer for Beagles in a temperature- and humidity-controlled environment.

ANIMALS

26 healthy Beagles (17 sexually intact males and 9 sexually intact females).

PROCEDURES

Dogs were maintained in a temperature- and humidity-controlled environment for 56 days before rectal and axillary temperatures were measured. Axillary and rectal temperatures were obtained in triplicate for each dog by use of a single commercially available manufacturer-calibrated digital thermometer.

RESULTS

Mean rectal and axillary temperatures of Beagles maintained in a temperature- and humidity-controlled environment were significantly different, with a median ± SD difference of 1.4° ± 0.15°C (range, 0.7° to 2.1°C). Mean rectal and axillary temperatures were 38.7°C (range, 37.6° to 39.5°C) and 37.2°C (range, 36.6° to 38.3°C), respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of this study indicated that the historical reference of a 0.55°C gradient between rectal and axillary temperatures that has been clinically used for veterinary patients was inaccurate for healthy Beagles in a temperature- and humidity-controlled environment. Rectal and axillary temperatures can be measured in veterinary patients. Reliable interpretation of axillary temperatures may accommodate patient comfort and reduce patient anxiety when serial measurement of temperatures is necessary. Further clinical studies will be needed.

Axillary, Oral and Rectal Routes of Temperature Measurement During Treatment of Acute Kawasaki Disease

BACKGROUND

Important therapeutic decisions are made based on the presence or absence of fever in patients with Kawasaki disease (KD), yet no standard method or threshold exists for temperature measurement during the diagnosis and treatment of these patients. We sought to compare surface and internal (rectal or oral) routes of temperature measurement for the detection of fever as a marker of treatment resistance.

METHODS

From a randomized, placebo-controlled trial of infliximab as an adjunct to primary intravenous immunoglobulin treatment for acute KD, we collected concurrent (within 5 minutes) axillary and internal temperature measurements and performed receiver-operating characteristic and Bland-Altman analyses. We also determined the ability of surface temperatures to detect treatment resistance defined by internal temperature measurements.

RESULTS

Among 452 oral-axillary and 439 rectal-axillary pairs from 159 patients, mean axillary temperatures were 0.25 and 0.43 °C lower than oral and rectal temperatures and had high receiver-operating characteristic areas under curves. However, axillary temperatures ≥ 38.0 °C had limited sensitivity to detect fever defined by internal temperatures. Axillary thresholds of 37.5 and 37.2 °C provided maximal sensitivity and specificity to detect oral and rectal temperatures ≥ 38.0 °C, respectively.

CONCLUSIONS

Axillary temperatures are an insensitive metric for fevers defining treatment resistance. Clinical trials should adopt temperature measurement by the oral or rectal routes for adjudication of treatment resistance in KD.

Accuracy of peripheral thermometers for estimating temperature: a systematic review and meta-analysis

BACKGROUND

Body temperature is commonly used to screen patients for infectious diseases, establish diagnoses, monitor therapy, and guide management decisions.

PURPOSE

To determine the accuracy of peripheral thermometers for estimating core body temperature in adults and children.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL Plus from inception to July 2015.

STUDY SELECTION

Prospective studies comparing the accuracy of peripheral (tympanic membrane, temporal artery, axillary, or oral) thermometers with central (pulmonary artery catheter, urinary bladder, esophageal, or rectal) thermometers.

DATA EXTRACTION

2 reviewers extracted data on study characteristics, methods, and outcomes and assessed the quality of individual studies.

DATA SYNTHESIS

75 studies (8682 patients) were included. Most studies were at high or unclear risk of patient selection bias (74%) or index test bias (67%). Compared with central thermometers, peripheral thermometers had pooled 95% limits of agreement (random-effects meta-analysis) outside the predefined clinically acceptable range (± 0.5 °C), especially among patients with fever (-1.44 °C to 1.46 °C for adults; -1.49 °C to 0.43 °C for children) and hypothermia (-2.07 °C to 1.90 °C for adults; no data for children). For detection of fever (bivariate random-effects meta-analysis), sensitivity was low (64% [95% CI, 55% to 72%]; I2 = 95.7%; P < 0.001) but specificity was high (96% [CI, 93% to 97%]; I2 = 96.3%; P < 0.001). Only 1 study reported sensitivity and specificity for the detection of hypothermia.

LIMITATIONS

High-quality data for some temperature measurement techniques are limited. Pooled data are associated with interstudy heterogeneity that is not fully explained by stratified and metaregression analyses.

CONCLUSION

Peripheral thermometers do not have clinically acceptable accuracy and should not be used when accurate measurement of body temperature will influence clinical decisions.

PRIMARY FUNDING SOURCE

None.

Using axillary temperature to approximate rectal temperature in newborns

AIM

Various factors have been shown to potentially affect the difference between axillary and rectal temperature measurements in newborns. We aimed to explore their roles and, if possible, to construct a formula that explained the difference.

METHODS

The study was based on a consecutive sample of 175 infants, with a gestational age of 24-42 weeks, whose rectal and axillary temperatures were measured simultaneously at the neonatal unit at Skaraborg Hospital in Sweden. Data were analysed using multiple regressions.

RESULTS

Premature infants had a significantly smaller mean difference (0.33°C) between rectal and axillary temperatures than full-term infants (0.43°C). Significant associated factors for premature infants were chronological age (p = 0.025), time of day (p = 0.004) and axillary temperature (p < 0.001). For full-term infants, the only significant associated factor was axillary temperature (p = 0.015).

CONCLUSION

Although it is possible to construct a formula that estimates neonate rectal temperature based on axillary temperature with a slightly higher reliability than simply adding a fixed value like 0.4°C, such a formula would be too complex to apply in practice. Adding 0.3°C or 0.4°C to the measured axillary temperature for premature infants or full-term infants, respectively, yields acceptable approximations in most cases.

Hypothermia and hyperthermia in the ambulatory surgical patient

Homeotherms, including humans, are able to maintain a relatively constant temperature despite variations in their thermal environment. We normally maintain a narrow thermoregulatory threshold range of approximately 0.2°C, and little change in core temperature is required to trigger compensatory mechanisms to either cool or warm our core temperature back to normothermia. This article focuses on the mechanisms and consequences of hypothermia and hyperthermia in the surgical patient and reviews techniques to prevent and treat these conditions.

Accuracy of tympanic temperature measurement using an infrared tympanic membrane thermometer

Background

During investigation and diagnosis of patients, accurate temperature measurement is of great importance. The advantages of tympanic membrane thermometry are speed (temperature reading available within seconds), safety, and ease of use. The aim of this study was to compare the accuracy of infrared tympanic thermometers in comparison to mercury thermometers in measurement of body temperature.

Methods

Axillary and tympanic temperature was measured simultaneously in consecutive patients using mercury glass and infrared tympanic thermometers at Omdurman Hospital, Sudan during October 2012.

Results

In total, temperature was measured in 174 patients, 95 of whom (54.6%) were male. The mean (SD) patient age and weight was 33.18 (25.07) years and 52.13 (69.85) kg. There was no significant difference in mean (SD) temperature measurement between mercury and infrared tympanic membrane thermometers, 37.29°C (0.91) versus 37.38°C (0.95), P = 0.373, respectively. There was a significant positive correlation between axillary and tympanic body temperature measurements (r = 0.697, P < 0.001). The mean difference between the two readings (with limits of agreements) was - 0.093 (−0.20; 0.02) °C.

Conclusion

In this study, tympanic membrane thermometry is as reliable and accurate as axillary mercury glass thermometry. Thus, tympanic thermometry can be used in clinical practice, especially in the emergency setting, where ease of use and speed of obtaining the temperature reading are important.

Monitoring in the intensive care

In critical care, the monitoring is essential to the daily care of ICU patients, as the optimization of patient's hemodynamic, ventilation, temperature, nutrition, and metabolism is the key to improve patients' survival. Indeed, the decisive endpoint is the supply of oxygen to tissues according to their metabolic needs in order to fuel mitochondrial respiration and, therefore, life. In this sense, both oxygenation and perfusion must be monitored in the implementation of any resuscitation strategy. The emerging concept has been the enhancement of macrocirculation through sequential optimization of heart function and then judging the adequacy of perfusion/oxygenation on specific parameters in a strategy which was aptly coined “goal directed therapy.” On the other hand, the maintenance of normal temperature is critical and should be regularly monitored. Regarding respiratory monitoring of ventilated ICU patients, it includes serial assessment of gas exchange, of respiratory system mechanics, and of patients' readiness for liberation from invasive positive pressure ventilation. Also, the monitoring of nutritional and metabolic care should allow controlling nutrients delivery, adequation between energy needs and delivery, and blood glucose. The present paper will describe the physiological basis, interpretation of, and clinical use of the major endpoints of perfusion/oxygenation adequacy and of temperature, respiratory, nutritional, and metabolic monitorings.

Rectal versus axillary temperatures: is there a significant difference in infants less than 1 year of age?

There are identified gaps regarding the accuracy of axillary temperatures as a means of predicting core temperatures in infants and children. This article discusses the relationship between rectal and axillary temperatures in infants less than 1 year of age. This quality improvement project evaluated 425 paired temperature measurements in 86 infants admitted to an inpatient pediatric unit over a 2-month period. A correlation analysis showed statistically significant differences between the two measurements. The results of this project promoted the development of a standard of care for temperature measurement at the project facility.

Intrapartum temperature elevation, epidural use, and adverse outcome in term infants

OBJECTIVES

To examine the association of intrapartum temperature elevation with adverse neonatal outcome among low-risk women receiving epidural analgesia and evaluate the association of epidural with adverse neonatal outcome without temperature elevation.

METHODS

We studied all low-risk nulliparous women with singleton pregnancies ≥37 weeks delivering at our hospital during 2000, excluding pregnancies where infants had documented sepsis, meningitis, or a major congenital anomaly. Neonatal outcomes were compared between women receiving (n = 1538) and not receiving epidural analgesia (n = 363) in the absence of intrapartum temperature elevation (≤99.5°F) and according to the level of intrapartum temperature elevation within the group receiving epidural (n = 2784). Logistic regression was used to evaluate neonatal outcome while controlling for confounders.

RESULTS

Maternal temperature >100.4°F developed during labor in 19.2% (535/2784) of women receiving epidural compared with 2.4% (10/425) not receiving epidural. In the absence of intrapartum temperature elevation (≤99.5°F), no significant differences were observed in adverse neonatal outcomes between women receiving and not receiving epidural. Among women receiving epidural, a significant linear trend was observed between maximum maternal temperature and all neonatal outcomes examined including hypotonia, assisted ventilation, 1- and 5-min Apgar scores <7, and early-onset seizures. In regression analyses, infants born to women with fever >101°F had a two- to sixfold increased risk of all adverse outcomes examined.

CONCLUSIONS

The proportion of infants experiencing adverse outcomes increased with the degree of epidural-related maternal temperature elevation. Epidural use without temperature elevation was not associated with any of the adverse outcomes we studied.

Thermal parameters measurement on fire fighter during intense fire exposition

To improve rescuer safety, coordination and efficiency, the European program ProeTEX aims at developing new equipment for the intervention staff. This equipment is based on micro and nanotechnologies and consisted of smart textile integrated sensor to monitor physiological parameters, environment of the rescuer but also acquisition module and communication module. Thermal parameters are of primer interest. Internal temperature, external temperature and heat flux are relevant parameters to prevent heat stroke in fire fighter when exposed to intense fire. These parameters are recorded during fire exposition and highlight, on one hand, that the outer garment of fire fighters' equipment insulates the fire fighter from the external environment, and on the other hand, that the thermal monitoring is relevant.

Altered thermoregulation in ambulatory schizophrenia patients: a naturalistic study

BACKGROUND

Schizophrenia patients may exhibit alterations in core/body temperature. Hence, we intended to examine the potential existence of thermoregulatory abnormalities in ambulatory schizophrenia patients.

METHODS

Anonymous electronic patient record data of the Leumit Health Fund (Israel) were screened for all schizophrenia patients who have no other apparent chronic co-morbidity (mental or non-mental) and had their oral temperature assessed during routine follow-ups (Schiz-rFUs) or for various transitory infectious/inflammatory processes (Schiz-Infect) during the years 1999-2005 (n = 535). The comparison group consisted of a comparable sample (n = 560) of healthy subjects (Control-rFUs and Control-Infect).

RESULTS

The sub-group of Schiz-rFUs (n = 216) exhibited significantly lower mean oral temperature compared to the matched group of Control-rFUs (n = 140) (36.72 +/- 0.54 vs. 36.94 +/- 0.64C, respectively; P<0.05). There was no significant difference in mean oral temperatures between the Schiz-Infect (n = 319) and the Control-Infect (n = 420) (37.32 +/- 0.92 vs. 37.28 +/- 0.98C, respectively; NS).

CONCLUSIONS

Ambulatory schizophrenia patients without a concomitant infectious/inflammatory process exhibit altered thermoregulation manifested by a substantial (about 0.2 C) and significantly lower oral temperature compared to healthy comparison subjects as well as a potential exaggerated increase in oral temperature during transitory infectious/inflammatory processes. The relevance of these phenomena to the pathophysiology of schizophrenia as well as the potential immune-mediated pathologies in schizophrenia merit further investigation.

Temperature monitoring and perioperative thermoregulation

Most clinically available thermometers accurately report the temperature of whatever tissue is being measured. The difficulty is that no reliably core-temperature-measuring sites are completely noninvasive and easy to use-especially in patients not undergoing general anesthesia. Nonetheless, temperature can be reliably measured in most patients. Body temperature should be measured in patients undergoing general anesthesia exceeding 30 min in duration and in patients undergoing major operations during neuraxial anesthesia. Core body temperature is normally tightly regulated. All general anesthetics produce a profound dose-dependent reduction in the core temperature, triggering cold defenses, including arteriovenous shunt vasoconstriction and shivering. Anesthetic-induced impairment of normal thermoregulatory control, with the resulting core-to-peripheral redistribution of body heat, is the primary cause of hypothermia in most patients. Neuraxial anesthesia also impairs thermoregulatory control, although to a lesser extent than does general anesthesia. Prolonged epidural analgesia is associated with hyperthermia whose cause remains unknown.

Repercusión del aseo en la estabilidad térmica del recién nacido de extremado bajo peso durante las primeras dos semanas de vida

INTRODUCTION

A prospective study was performed of a cohort of extremely low-birth-weight (ELBW) premature neonates (birth weight 500 to 1,000 g) consecutively admitted to the neonatal intensive care unit. The aim of this study was to examine the thermal changes that occur during all the hygiene-related interventions in ELBW infants in the first 2 weeks of life.

PATIENTS AND METHODS

The study was carried out for 10 consecutive months in the Neonatology Service of La Paz University Hospital. We studied all consecutively admitted ELBW infants who satisfied the following criteria: a) adequate weight for gestational age; b) survival for at least 1 week, and c) no major congenital malformations or dysmorphic features. The infants included in the study were managed according to a standard care protocol for maintaining thermal stability and preventing cold-induced stress. Central temperature (Tc) was measured in the axilla and peripheral temperature (Tp) was measured on the sole of the foot. Both temperatures were continuously monitored for a) a period of scheduled non-handling--baseline period--and b) during and after a series of "hygiene interventions". In each of these periods, Tc and Tp were continuously monitored and recorded at 10 min intervals for the first 30 minutes and then at 30 min intervals until completing a 180 min period.

RESULTS

Although incubator temperature was raised by a mean of 3 degrees C during hygiene interventions, hygiene was accompanied by a change in body temperature that remained fairly constant throughout the study period; Tc and Tp decreased by a mean of 1 degrees C with respect to baseline temperature. A fall in axillary temperature to less than 36.5 degrees C was observed in 87.4 % of recordings and a fall to less than 36 degrees C was observed in 45.5 %; axillary temperature remained below 36.5 degrees C for a mean duration of almost 1 hour. The differential temperature (Td 5 Tc - Tp), an indicator of thermal stress, was more than 1 degrees C for a mean duration of more than 80 min and > 2 degrees C for more than 20 minutes in both the first and second weeks of life.

CONCLUSIONS

During hygiene interventions, ELBW infants experienced a sharp fall in central and peripheral body temperature. After hygiene interventions, these neonates had a Td suggestive of prolonged thermal stress, despite the use of standardized care protocols designed to avoid or minimize the potential effects of hygiene interventions on neonatal temperature.

Maternal epidural analgesia and rates of maternal antibiotic treatment in a low-risk nulliparous population

BACKGROUND

Epidural analgesia is associated with an increased rate of fever in prospective randomized trials. While the evidence suggests that epidural fever is not infectious, epidural analgesia has been associated with increased rates of antibiotic use, the indications that prompt treatment have not been examined.

METHODS

We analyzed 1235 nulliparous women with singleton term pregnancies presenting in labor with a temperature of < 99.5 degrees F. Antibiotic use during labor was categorized by indication.

RESULTS

A total of 59.6% of women received epidural analgesia. The rate of antibiotic use was significantly higher in women receiving epidural analgesia (28 vs 10.8%). After adjusting for confounders using logistic regression, epidural analgesia was associated with a relative risk of 2.6 (95% CI 2.0, 3.4) for antibiotic treatment. The majority of the increased risk was due to significantly higher rates of antibiotic treatment for presumed chorioamnionitis (9.0 vs 0.4%) in the epidural analgesia group.

CONCLUSION

Epidural-related fever results in excess maternal antibiotic treatment for presumed chorioamnionitis.

A comparison of the suitabilities of rectal, gut, and insulated axilla temperatures for measurement of the circadian rhythm of core temperature in field studies

Eight healthy males were studied for a total of 13 subject-days to assess if gut (from an ingested pill) and axilla (from a thermally insulated skin probe) temperatures would act as a substitute for rectal temperature in field studies of the circadian rhythm of core temperature. Subjects slept and went about their activities, indoors and outdoors, normally. Regular recordings (at 6 min intervals) were made of temperatures from the three sites. In addition, activity was measured (by a sensor on the nondominant wrist) so that the raw temperature data could be "purified," that is, corrected for the direct effects of sleep and activity. Inspection of the raw data indicated that there was a close parallelism between rectal and gut temperatures, but that the parallelism between rectal and insulated axilla temperatures was less reliable. This parallelism was supported by initial calculations of the correlations between rectal and gut temperatures (high and positive) and between rectal and insulated axilla (lower, though still positive) temperatures. Calculation of the limits of agreement between the parameters of the cosine curves fitted to the raw data confirmed that the rectal and gut temperatures were far closer with regard to acrophase and amplitude than were rectal and insulated axilla temperatures (-0.31 +/- 0.89 vs. +0.75 +/- 6.03 h and +0.002 +/- 0.116 vs. +0.083 +/- 0.625 degrees C, respectively). After purification of the temperature data, the limits of agreement for the cosine parameters acrophase and amplitude still indicated that there was a closer agreement between rectal and gut temperatures than between rectal and insulated axilla temperatures (-0.30 +/- 1.12 vs. +0.58 +/- 6.69 h, and +0.007 +/- 0.116 vs. +0.104 +/- 0.620 degrees C, respectively). Part of the explanation of this difference was the unreliable relationships between temperature changes in insulated axilla temperature and bursts of activity and going to bed. It is concluded that, whereas gut temperature is a viable alternativ to rectal temperature (from the viewpoints of both user acceptability and the reliability of data obtained), insulated axilla temperature, though acceptable to subjects, is unreliable from an experimental viewpoint.