Tympanic Temperature Changes Research Articles

Physical and social warmth: Warmer daily body temperature is associated with greater feelings of social connection.

Growing evidence suggests that physical warmth and social warmth-feeling socially connected to others-are linked. In particular, thermoregulatory systems that maintain a relatively warm internal body temperature may also support feelings of social connection. However, it is unknown whether and how feelings of physical and social warmth fluctuate together across time in daily life. To this end, the current study examined tympanic temperature, a measure of internal body temperature, and feelings of social connection assessed multiple times a day over 1 week. Consistent with hypotheses, moment-to-moment changes in tympanic temperature covaried with feelings of social connection across assessments. Thus, warmer body temperatures, in the nonfebrile range, were associated with greater feelings of social connection, and cooler body temperatures were associated with lower feelings of social connection. These findings provide further evidence for the link between physical and social warmth and contribute to an understanding of the dynamic fluctuation of affective experience across time. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Hand heating lowers postprandial blood glucose concentrations: A double-blind randomized controlled crossover trial

ObjectivesExamine effect of single hand heating with and without negative pressure on fasting blood glucose (FBG) and postprandial blood glucose (PBG). DesignDouble-blind randomized controlled trial with crossover design. SubjectsFBG experiment: 17 healthy subjects (4 males). PBG experiment: 13 healthy subjects (1 males). InterventionsDevices included one providing heat only, one heat and negative pressure, and one acting as a sham. For the FBG experiment the devices were used for 30 min. For the PBG experiment the devices were used for one hour during an oral glucose tolerance test (OGTT). Outcome MeasuresBlood glucose measurements were used to determine change in FBG, peak PBG, area under the curve (AUC), and incremental AUC (iAUC). ResultsTemperature: Change in tympanic temperature was ≤ 0.15 °C for all trials. FBG: There was no effect on FBG. PBG: Compared to the sham device the heat plus vacuum and heat only device lowered peak blood glucose by 16(31)mg/dL, p = 0.092 and 18(28)mg/dL, p = 0.039, respectively. AUC and iAUC: Compared to the sham device, the heat plus vacuum device and heat only device lowered the AUC by 5.1(15.0)%, p = 0.234 and 7.9(11.1)%, p = 0.024 respectively and iAUC by 17.2(43.4)%, p = 0.178 and 20.5(34.5)%, p = 0.054, respectively. ConclusionsHeating a single hand lowers postprandial blood glucose in healthy subjects.

Physiologic Strain during Treadmill Electrocardiography in the Medical Evaluation of Candidates for Hazardous Materials Duty, with and without Added Heat Stress

added heat stress as part of medical evaluation for hazardous materials (hazmat) work requiring protective ensembles which block evaporative and convective heat transfer. Also, to extend comparison of PSI versus published values from hazmat simulations. Methods: Candidates for hazmat duty (N=203) underwent maximal, symptom-limited Bruce protocol treadmill electrocardiography (standard Bruce test wearing gym clothes, SBT) during which changes in tympanic temperature (TT) and heart rate (HR) enabled calculation of PSI. A subgroup of candidates (N=39) later performed a second Bruce test, wearing novel, inexpensive apparel chosen to impede dissipation of metabolic heat (Hot Bruce test, HBT). Thermal discomfort was gauged using the Young index (4, neutral; 8, maximal discomfort). Results: SBT duration was 12.2 ± 2.6 SD minutes and the rise in TT and PSI averaged 0.5 ± 0.4EšC and 5.9 ± 1.1, respectively. The rate of rise of TT was 0.038EšC per min. of treadmill exertion. In the subgroup of 39 candidates, HBT duration was 13.7 ± 3.3 min. (p>0.05). TT rose more after HBT than SBT: 1.3 ± 0.7EšC vs. 0.5 ± 0.4EšC (p<0.001). The rate of rise of TT during HBT was 0.10EšC per min. and was associated with greater physiological strain (PSI=7.4 vs. 6.2, p<0.001). The Young index was 6.2 ± 0.8 for SBT vs. 7.3 ± 0.6 (p<0.001) for HBT. Maximal heart rate was 181 bpm during both SBT and HBT. Conclusions: 1. The rate of rise of TT–0.038EšC per min. of SBT treadmill exertion -- is similar to that of two smaller studies, but less than the only other published report. 2. PSI during HBT exceeded that from SBT and was similar to PSI observed during hazmat simulations, suggesting that HBT, which also induced heavy sweating and thermal discomfort, may be more appropriate than SBT in the medical evaluation of hazmat candidates.

Seasonal acclimatization to the hot summer over 60 days in the Republic of Korea suppresses sweating sensitivity during passive heating

The main objective of this study was to determine the central mechanisms involved in suppression of thermal sweating after seasonal acclimatization (SA) during passive heating (immersing the legs in 43°C hot water for 30min). Testing was performed in July (before-SA) and August (after-SA) [25.2±2.2°C, 73.9±10.3% relative humidity (RH), Cheonan (Chungnam,126° 52′N, 33.38′E), in the Republic of Korea. All experiments were carried out in an automated climatic chamber (25.0±0.5°C and RH 60.0±3.00%). Twelve healthy men (height, 174.6±5.40cm; weight, 65.4±5.71kg; age, 22.7±2.90yr) participated. The local sweat onset time was delayed in the after-SA compared to that in the before-SA (p<0.001). The local sweat rate and whole body sweat loss volume decreased in the after-SA compared to those in the before-SA (p<0.001). In addition, evaporative loss volume decreased significantly in the after-SA compared to that in the before-SA [chest, upper-back, thigh and forearm (p<0.001)]. Changes in tympanic temperature and mean body temperature were significantly lower (p<0.05) and the basal metabolic rate decreased significantly in the after-SA compared to those in the before-SA (p<0.001). These results suggest that maintenance of a lower body temperature and basal metabolic rate can occur and blunt the central sudomotor mechanisms following seasonal acclimatization, which suppresses sweating sensitivity.

Temperature changes among organophosphate poisoned patients, Tehran- Iran

BackgroundAcute poisoning with organophosphorus compounds (OPs) is a major global clinical problem in the developing countries. There have been many animal studies and few human surveys on the effects of organophosphorus pesticide (OP) poisoning on thermoregulation. The aim of this prospective study was to document the pattern of tympanic temperature changes among OP poisoned patients throughout the length of their hospital stay.Methods60 patients with diagnose of organophosphate poisoning were included in this study. Questioner was filled out by trained nurses including demographic, clinical and paraclinical data. Tympanic temperature and Pulse rate data of the cases were collected on five- occasions after admission.ResultsThere were 41 (68.3%) male and 19 (31.7%) female, with a mean age of 34.4 ±19.4 years (range 13–89 years). Forty five patients had intentional poisoning for suicidal attempt. At the time of entry, the mean tympanic temperature, pulse rate, respiratory rate and blood pressure (systolic and diastolic) of the OP poisoned patients were respectively 37.1+/−0.6°C (36.0- 39.5), 91+/−18 (55–145), 18+/−5.6 (8–44), 116+/−20 mm Hg (70–170) and 75+/−11.6 mm Hg (40–110). 41.7% of the cases had serum butyryl cholinesterase activities (BChE) ≥ 50% normal (≥1600 mU/ml). Our patients had normal temperature at the time entry (mean = 37.1). Tympanic temperature decreasing below 36°C was not detected among the patients during the study period. A rise in mean tympanic temperature was found after atropine administration.ConclusionOur study showed hypothermia was not considerable factor among organophosphate poisoned patients, although more studies with similar situations in tropical countries are needed.

Changes in tympanic temperature during the exposure to electromagnetic fields emitted by mobile phone

Mobile phones generate microwave radiation which is absorbed by exposed tissue and converted into heat. It may cause detrimental health effects. The aim of the experiment was to check if exposure to EMF emitted by mobile phone influenced the tympanic temperature. Human volunteer study was performed on ten healthy young men, aged 22.1±4.7 years, examined three times: 1. on a day with 2×60 min of no exposure (sham day), 2. on a day with continuous, 60 min exposure and 60 min of no exposure, 3. on a day with intermittent exposure (4×15 min "on" and 4×15 min "off"). Exposure was generated by mobile phone (frequency 900 MHz, SAR 1.23 W/kg). The study was double-blind, performed under controlled conditions (at 24°C and 70% humidity). The tympanic temperature (T(ty)) was monitored every 10 sec by a thermistor probe placed close to the aural canal membrane in the ear opposite the one in contact with mobile phone (contralateral position). Multivariate repeated-measures analysis of variance was used to calculate the results. The mean T(ty) in the whole group during continuous exposure was significantly higher than during sham exposure (p = 0.0001). During intermittent exposure the temperature was lower than during sham day (difference was up to 0.11°C). Within an hour after continuous exposure, T(ty) was higher by 0.03°C and after intermittent exposure T(ty) was lower by 0.18°C in comparison with sham day. Two hours after exposure T(ty) was significantly lower (p = 0.0001) than after sham exposure (0.06°C and 0.26°C respectively). The trends in T(ty) during experiment differed significantly in relation to exposure conditions (p < 0.05). The results of this analysis indicate that the physiological response to EMF exposure from mobile phone was mostly related to type of exposure (continuous or intermittent).

Influence of season on plasma antidiuretic hormone, angiotensin II, aldosterone and plasma renin activity in young volunteers

We investigated seasonal changes in hormonal and thermoregulatory responses. Eight volunteers were subjected to the experiment at four times of the year: around the vernal and autumnal equinoxes, and at the summer and winter solstices at latitude 35 degrees N. Plasma antidiuretic hormone (ADH), angiotensin II (ANG II), aldosterone (ALD) and plasma renin activity (PRA) were analyzed before and after water immersion. Seasonal changes in thermoregulatory responses were assessed by measuring core temperature and sweat rate during immersion of the leg in hot water (at 42 degrees C) for 30 min in a room maintained at 26 degrees C. The concentration of plasma ADH and ALD before water immersion was significantly higher in summer than in other seasons. The concentrations of ANG II and PRA did not show seasonal variations. Changes in tympanic temperature during water immersion showed significant differences between seasons, and were higher in winter than in other seasons. The sweat rate was significantly higher in summer than in other seasons. In summary, ADH and ALD concentrations displayed a seasonal rhythm with marked elevation in summer; this may be a compensative mechanism to prevent dehydration from increased sweat loss during summer due to heat acclimatization.

Effect of Hydration Status on High-Intensity Rowing Performance and Immune Function

This study determined the effect of dehydration and rehydration (DR) on performance, immune cell response, and tympanic temperature after high-intensity rowing exercise. Seven oarswomen completed two simulated 2000-m rowing race trials separated by 72 h in a random, cross-over design. One trial was completed in a euhydrated (E) condition and the other using a DR protocol. The DR condition resulted in a 3.33+/-0.14% reduction in body mass (P<.05) over a 24-h period followed by a 2-h rehydration period immediately before the simulated rowing race. There was a greater change in tympanic temperature observed in the DR trial (P<.05). There were increases in the blood concentration of leukocytes, lymphocytes, lymphocyte subsets (CD3+, CD3+/4+, CD3+/8+, CD3-/16+, CD4+/25+; P<.05) and decreases in lymphocyte proliferation and neutrophil oxidative burst activity immediately following the simulated race (P<.05) in both trials. Blood leukocyte and neutrophil concentrations were greater after exercise in the DR trial (P<.05). Whereas most immune measures returned to resting values after 60 min of recovery in both trials, lymphocyte proliferation and the concentrations of CD3+/4+ and CD4+/25+ cells were significantly lower than before exercise. Blood leukocyte and neutrophil concentrations were significantly higher before and after exercise in the E trial. The effects of dehydration/rehydration did not negatively influence simulated 2000-m rowing race performance in lightweight oarswomen but did produce a higher tympanic temperature and had a differential effect on blood leukocyte, neutrophil, and natural killer (CD3-/16+) cell concentrations after exercise compared with the euhydrated state.

Burning issues: Early cooling of the brain after resuscitation using burn dressings. A proof of concept observation

Early cooling of resuscitated patients improves neurological outcome. Out-of hospital initiation of cooling is uncommon however for mainly practical reasons. Using burn dressings in the out-of-hospital care could initiate brain cooling in an early stage and therefore be of value; the method is easily adaptable by ambulance crews. The influence of burn dressings on brain temperature is however unknown. We determined tympanic temperature changes as proxy for brain temperature in healthy volunteers after the application of cooling dressings to face and neck as a proof of concept study. In 10 healthy human volunteers tympanic temperatures were measured in 30s intervals before, during and after the application of burn-dressings, special trauma burn-care dressings that are designed for the acute treatment of skin burns (Burnshield emergency burn care sterile trauma burn dressings, Burnshield Ltd., Wadefield, South Africa) for the duration of 20min for each episode. In all study subjects the tympanic temperature was significantly lowered after 20min of the application of the burnshields. The mean difference between baseline and 2nd half of the exposure period was 0.43 degrees C (p<0.0001), ranging from 0.10 to 1.18 degrees C. Burn dressings could be of value in the early initiation of brain cooling in resuscitated patients. This study warrants further research to the effect of burnshield dressings on neurological activity and the effect on outcome after resuscitation.

CIRCADIAN PREFERENCE AND COGNITIVE FUNCTIONING AMONG REHABILITATION INPATIENTS

The influence of circadian preference was examined among 56 morning-oriented rehabilitation inpatients with cognitive (n = 28) and noncognitive (n = 28) impairments. Each individual was tested twice: morning (preferred time) and evening (nonpreferred time); sessions and test batteries were counterbalanced to control for practice effects. Standard measures assessed attention, language, memory, visuospatial, and executive functions. Persons with cognitive impairment showed disproportionate vulnerability to the effects of circadian preference and time of testing, performing more poorly at nonpreferred than preferred times. Substantial effects (eta2 .12 to .48) were found on tests of executive functioning and tasks incorporating similar higher-order demands (e.g., complex figure copy). Results are supported by tympanic temperature changes during a vigilance task, an index of cerebral blood flow in response to cognitive challenge. Cognitive reserve theory is suggested as an explanation for the differential effects. These findings may have implications for inpatient therapeutic interventions and discharge planning.

Proposal for Evaluation Index for Comfortable and Safe Thermal Effect Based on Estimated Tympanic Temperature Changes during Bathing in Winter

Proposal for Evaluation Index for Comfortable and Safe Thermal Effect Based on Estimated Tympanic Temperature Changes during Bathing in Winter

Attenuated thermoregulatory sweating and cutaneous vasodilation after 14-day bed rest in humans.

We investigated the effect of head-down bed rest (HDBR) for 14 days on thermoregulatory sweating and cutaneous vasodilation in humans. Fluid intake was ad libitum during HDBR. We induced whole body heating by increasing skin temperature for 1 h with a water-perfused blanket through which hot water (42 degrees C) was circulated. The experimental room was air-conditioned (27 degrees C, 30-40% relative humidity). We measured skin blood flow (chest and forearm), skin temperatures (chest, upper arm, forearm, thigh, and calf), and tympanic temperature. We also measured sweat rate by the ventilated capsule method in which the skin area for measurement was drained by dry air conditioned at 27 degrees C under similar skin temperatures in both trials. We calculated cutaneous vascular conductance (CVC) from the ratio of skin blood flow to mean blood pressure. From tympanic temperature-sweat rate and -CVC relationships, we assessed the threshold temperature and sensitivity as the slope response of variables to a given change in tympanic temperature. HDBR increased the threshold temperature for sweating by 0.31 degrees C at the chest and 0.32 degrees C at the forearm, whereas it reduced sensitivity by 40% at the chest and 31% at the forearm. HDBR increased the threshold temperature for cutaneous vasodilation, whereas it decreased sensitivity. HDBR reduced plasma volume by 11%, whereas it did not change plasma osmolarity. The increase in the threshold temperature for sweating correlated with that for cutaneous vasodilation. In conclusion, HDBR attenuated thermoregulatory sweating and cutaneous vasodilation by increasing the threshold temperature and decreasing sensitivity. HDBR increased the threshold temperature for sweating and cutaneous vasodilation by similar magnitudes, whereas it decreased their sensitivity by different magnitudes.

Tympanic temperature reflects intracranial temperature changes in humans.

The purpose of the study was to identify extracranial locations in which temperature changes in humans reflect those of intracranial temperature in a reliable and repeatable way. This was achieved by subjecting 14 non-anaesthetized patients after neurosurgery to face fanning while intracranial and extracranial temperatures were continuously measured. In all patients the cranium was closed and the group included both febrile and non-febrile as well as hyperthermic and normothermic patients. The patients' faces were fanned for 20-30 min, with a small fan at an air speed of 3.25 m s(-1). This gave intracranial temperature changes measured in the subdural space ( T(sd)) that were highly and significantly correlated ( r=0.91, P<0.05, n=14) with changes in tympanic temperatures ( T(ty)). A low, statistically insignificant correlation ( r=0.40, P>0.05, n=12) was found between T(sd) and oesophageal temperatures. In conclusion, intracranial temperature changes, induced by face fanning, were reliably reflected by the changes in T(ty).

Effectiveness and tolerability of ibuprofen‐arginine versus paracetamol in children with fever of likely infectious origin

The aim of this multicentre, double‐blind, randomized study was to assess the paediatric antipyretic efficacy of a new ibuprofen formulation containing L‐arginine for gastric protection, compared with the efficacy of paracetamol. For this purpose 100 patients were given ibuprofen‐arginine (1 drop/kg: 6.67mg/kg) and 99 paracetamol (4 drops/kg: 10.65 mg/kg). The main efficacy endpoint was the mean change in tympanic temperature 4 h after drug intake. Twelve patients were excluded because of early vomiting or spitting out the medication. The resulting efficacy analysis population included a total of 88 patients treated with ibuprofen‐arginine and 87 with paracetamol. Mean change in tympanic temperature (°C) showed no difference between groups (p= 0.527) but more patients in the ibuprofen‐arginine group attained a temperature reduction greater than 2°C (p= 0.043). A total of 107 patients required antipyretic rescue medication, with a smaller proportion in the ibuprofen‐arginine group. Although this was not statistically significant, a trend towards improved activity was observed (p= 0.100). Overall efficacy was judged from the recovery or improvement in 68.8% of patients in the ibuprofen‐arginine group compared with 65.5% in the paracetamol group. Nineteen patients reported adverse events, with vomiting being the most common complaint, but no differences were detected between treatments. Conclusion: Based on the present results, ibuprofen‐arginine oral drops have shown to be a safe, well‐tolerated and potent paediatric antipyretic agent. Hence, ibuprofen‐arginine should be considered as an adequate choice for the control of paediatric fever of likely infectious aetiology.

Specialized brain cooling in humans?

Humans, compared to other species, have exceptional capability for dissipation of heat from the entire skin surface. We can secrete more than two liters per hour of sweat, indefinitely. The corresponding potential for evaporative cooling is near a thousand watts, sufficient to compensate for the extreme high levels of heat production during exercise. Also, the blood vessels of our skin have exceptional capability to dilate and deliver heat to the body surface. These are our special adaptations for thermal stress. They allow prolonged heavy exercise with modest elevations in the temperature of the fluid that cools all the internal organs, not just the brain-arterial blood. The vascular architecture of the human head is radically different from that of animals that exhibit SBC. These species have special adaptations that reflect their dependence on respiratory evaporation, particularly the limitation imposed on capability to dispose of heat produced during exercise. The increase in blood temperature in an intense sprint would heat the well-perfused brain rapidly. But the heat exchange over the large surface area of contact between a venous plexus cooled by respiratory evaporation and the meshwork of arterial vessels in the carotid rete precools blood bound for the brain. Specialized cooling of the brain (SBC) has not been demonstrated by direct measurements in humans. Changes in tympanic temperature (Tty) are taken as evidence for SBC. This continues an unfortunate tradition of exaggeration of the significance of Tty. In the only direct measurements available, brain temperature was unaffected by fanning the face although Tty did fall. What may appear to be a remnant of the carotid rete heat exchanger in humans is the intimate association between a short segment of the internal carotid artery and the plexus of veins in the cavernous sinus. Fortunately, the brain need not rely for its cooling on countercurrent heat exchange across this small surface area of contact. In humans, SBC stands for skin: the body cooler--we use our entire skin surface for heat dissipation.

Tympanic temperature is a core temperature in humans

1. 1.The validity of lympanic temperature as an index of core temperature can be questioned since it has been found to be affected by ambient temperature during exposure to cold. This work has been undertaken to explore the possible influence of head skin temperature on tympanic temperature. 2. 2.In a group of ten subjects at rest, mean temperature on the lower anterior quarter of the tympanic membrane was 0.1°C higher than oesophageal temperature. 3. 3.Tympanic, oesophageal, interdigital, and mastoid skin temperatures were recorded in 6 subjects during 30 min exposure to cold at 0°C and the following 15 min (control). When the thermocouple was placed on the lower anterior quarter of the tympanic membrane, the influence of skin temperature on tympanic temperature was as low as 0.006°C per °C fall in skin temperature, and the influence of air temperature as low as 0.0025°C per °C fall in air temperature. At cold ambient temperature, the changes in tympanic temperature were strikingly parallel to those of oesophageal temperature whereas skin temperature generally evolved in the opposite direction. 4. 4.These results suggest that tympanic temperature, when measured accurately, is a good index of core temperature and that its variations may reflect variations in brain temperature.