Tympanic Membrane Temperature Research Articles

Correlation of Continuously Recorded Rectal and Axillary Temperatures with Tympanic Membrane Temperature in Children † 692

Correlation of Continuously Recorded Rectal and Axillary Temperatures with Tympanic Membrane Temperature in Children † 692

Maternal temperature during labour using low-dose (ambulatory) epidural analgesia with bupivacaine and fentanyl

Maternal temperature is known to increase during labour with conventional epidural analgesia mixtures. To date, the effect of newer low-dose (ambulatory) epidural concentrations on maternal temperature has not been studied. Twenty-six women in established labour received epidural analgesia with 0.1% bupivacaine and 2 μg/ml fentanyl. Tympanic membrane (core) temperature was measured every 30 min during labour. There was no significant overall rise in maternal temperature during labour with the use of an ambulatory epidural mixture. One patient exhibited an increase in temperature of 0.8°C to 38°C after 720 min and another of 1.1°C to 38.1°C after 630 min. We conclude that, whilst overall maternal temperature does not increase following low-dose epidural analgesia, individual increases may still occur after 10 h.

Comparative effects of ringer's acetate and lactate solutions on intraoperative central and peripheral temperatures

Study Objectives: To compare the effects of Ringer's lactate (LR) and Ringer's acetate (AR) solutions on core body and peripheral temperatures during isoflurane or sevoflurane anesthesia. Design: Prospective, randomized study. Setting: Operating rooms of a university hospital. Patients: 60 ASA physical status I and II patients undergoing general surgery. Interventions: Following induction with 5 mg/kg of thiamylal and 0.1 mg/kg of vecuronium, patients were randomly assigned to one of four groups (15 patients per group). They received inhalation anesthetics (66% nitrous oxide [N 2O] and 1.0% to 2.0% isoflurane or 1.3% to 2.6% sevoflurane) and LR or AR. Measurements and Main Results: Tympanic membrane (central) temperatures, forearm temperatures, and fingertip temperatures were recorded during surgery every 30 minutes. Tympanic membrane temperatures in the patients given AR were significantly higher than those given LR during isoflurane anesthesia 5 and 30 minutes after induction of anesthesia. However, this was not the case for sevoflurane anesthesia. There were no significant differences in forearm and fingertip temperatures or fingertip blood flow among the four groups. Conclusion: There was no significant difference between AR and LR in the preservation of heat during either sevoflurane or isoflurane anesthesia. However, AR may be superior to LR for maintaining central temperature during the early period of isoflurane anesthesia.

Lateralized changes in tympanic membrane temperature in relation to different cognitive tasks in chimpanzees (Pan troglodytes).

Lateralized changes in tympanic membrane (TM) temperature were assessed in chimpanzees. Subjects were engaged in 1 of 3 different cognitive tasks, including matching-to-sample, visual-spatial discrimination, and a motor task. During execution of each task, TM temperatures were taken from each ear over a 20-min time period. The TM temperatures at each time interval were subtracted from a baseline measure to assess relative change in blood flow. For the matching-to-sample and visual-spatial discrimination tasks, significant lateralized changes in TM temperature were found, with left-ear temperature increasing and right-ear temperature decreasing. No laterality effects were found for the motor or control tasks. These data provide the first evidence of laterality in physiological functioning in chimpanzees and suggest that transient asymmetries in cognitive functions are associated with changes in cerebral blood flow as assessed by TM temperature change.

Lateralized changes in tympanic membrane temperature in relation to different cognitive tasks in chimpanzees (Pan troglodytes).

Lateralized changes in tympanic membrane temperature in relation to different cognitive tasks in chimpanzees (Pan troglodytes).

The Effect of One Night's Sleep Deprivation on Temperature, Mood, and Physical Performance in Subjects with Different Amounts of Habitual Physical Activity

Eleven healthy males were studied twice. On one occasion (control, C), they slept (night 1) and then underwent a battery of tests at 4h intervals from 06: 00 day 1 to 02: 00 day 2; then, after a normal sleep (night 2), they were tested from 10: 00 to 22: 00 on day 2. On the second occasion (sleep deprivation, SD), the subjects remained awake during night 1. Each battery of tests consisted of measurements of tympanic membrane temperature, profile of mood states (POMS), muscle strength, self-chosen work rate (SCWR), perceived exertion, and heart rate (HR) while exercising on a stationary cycle ergometer. Subjects also kept a diary of their activities during the two days and answered a questionnaire about their habitual physical activity. Results showed a significant negative effect of sleep deprivation on most mood states on day 1, but no effect on the other variables. By day 2, mood had tended to recover, though muscle strength tended to be worse in both control and sleep-deprivation experiments. There was also a more general tendency for negative effects to be present at the end of day 1 (02: 00) or at the beginning of day 2 (10: 00). There was limited support for the view that subjects who were habitually more active showed less negative effects after sleep deprivation and responded less adversely to the poor sleep achieved on the university premises (night 2). These results stress the considerable interindividual variation in the responses to sleep loss and, therefore, the difficulty associated with giving general advice to individuals about work or training capability after sleep loss.

Estimation of Contact Tympanic Membrane Temperature With a Noncontact Infrared Thermometer

Study objective: To investigate the agreement between contact tympanic membrane (TM) and noncontact infrared ear thermometers in children. Methods: Twenty-three children (ages .5 to 10 years) undergoing elective tympanostomy tube placement were studied. An assistant used standard technique to record temperature with an infrared ear thermometer before and after TM temperature was obtained with a bead thermistor placed against the anterior-inferior quadrant of the TM. Results: Mean temperatures were not significantly different: initial IR ear, 36.66°±.33° C; TM, 36.71°±.42° C; final infrared ear, 36.57°±.33° C. The mean bias (difference between initial individual IR ear and TM temperatures) of −.05°±.29° C and the 95% limits of agreement of +.53° to −.63° C indicate an acceptable confidence (error range within 3.2% of average TM temperature) for use of the initial infrared ear temperature as an estimate of TM temperature. Conclusion: The IR ear thermometer provides an accurate estimate of TM temperature in healthy children and may accurately reflect core body temperature. [Terndrup TE, Crofton DJ, Mortelliti AJ, Kelley R, Rajk J: Estimation of contact tympanic membrane temperature with a noncontact infrared thermometer. Ann Emerg Med August 1997;30:171-175.]

THERMOREGULATORY ADJUSTMENT DURING PREGNANCY PROTECTS FETUS FROM EXPOSURE OF EXERCISE-INDUCED HYPERTHERMIA 565

The purpose of this study was to determine whether moderate exercise determined by RPE during pregnancy elevates the deep trunk temperature of the mother, thus may expose the fetus to a potential hyperthermia. A total of 20 healthy women (10 pregnant; 10 non-pregnant), participated the study. Pregnant women's gestatio at the time of the data collection was 27 ± 7 week(mean ± SD). The Branching protocol with a treadmill was applied to reach the steady state at RPE 13 for 30 min. Body temperature (C°) was measured at the auditory canal, the back, the chest, and the rectum simultaneously at 5 minutes intervals before, during, after exercise, and until subjects reached to the resting values. Heart rate was also measured at 5 minutes intervals. The times at which each subject started sweating and returned to the resting core temperature were also recorded. Between two groups, there were no differences in age (29 ± 4 vs. 34 ± 11 years old. Body Mass Index (26 ± 4 vs. 24 ± 4),%Body Fat (30± 4 vs. 29 ± 4), time required to start sweating (10 ± 4 vs. 9 ± 8 min), and time to return to resting rectal temperature (38± 15 vs. 37 ± 16 min). Our results show that while skin temperature was higher in pregnant women during resting (34.4 ± 1.1 vs. 32.5 ± 1.8; p <.05) and exercising (33.0 ± 1.3 vs. 31.5± 1.8; p <.05), rectal temperature was lower in pregnant women during resting (37.1 ± 5 vs. 37.6 ± 3;p <.05) and exercising(37.5 ±.2 vs. 38.1 ±.2; p <.001). The exercise lowered skin temperature by 1 °C and elevated rectal temperature by.5 °C for both groups and caused no changes in tympanic membrane temperature, possibly indicating RPE 13 induced similar thermal changes for pregnant and non-pregnant women and that tympanic membrane temperature which reflects hypothalamic temperature was not affected by an acute exercise. We conclude that physiologic adjustment to pregnancy creates favorable thermal environment for fetus by increasing skin temperature and decreasing deep trunk temperature.

I.m. midazolam as premedication produces a concentration-dependent decrease in core temperature in male volunteers

We tested the hypothesis that premedication with i.m. midazolam decreases core temperature dose-dependently. We studied six male volunteers, in random order, on 3 days: (1) no midazolam administration (control day), (2) midazolam 0.025 mg kg-1 i.m., (3) midazolam 0.075 mg kg-1 i.m. On the first day, subjects were maintained alert during a 30-min control period. On the second and third days, midazolam 0.025 or 0.075 mg kg-1 was administered i.m. Core temperatures were measured at the right tympanic membrane. Four adhesive skin surface probes were fixed on the chest, upper right arm, lateral calf and thigh. Finger tip perfusion was evaluated using forearm minus fingertip and calf minus toe, skin surface temperature gradients. Thirty minutes after midazolam i.m., the level of sedation in the volunteers was assessed. Peripheral venous blood was obtained immediately after the assessment of the level of sedation. Tympanic membrane temperatures after administration of midazolam 0.075 mg kg-1 i.m. were significantly lower than those on the control and midazolam 0.025 mg kg-1 i.m. days at 20 and 30 min. The decreases in tympanic membrane temperatures at 30 min after midazolam i.m. became larger as the volunteers were more deeply sedated. i.m. midazolam produced a concentration-dependent decrease in tympanic membrane temperature at 30 min after midazolam 0.025 and 0.075 mg kg-1 i.m. We conclude that midazolam impaired tonic thermoregulatory vasoconstriction, allowing core-to-peripheral heat redistribution in a dose-dependent manner after i.m. administration.

A Study in the Comparison of Body Temperature Change between General Anesthesia and Epidural Anesthesia

Background : Core hypothermia after induction of anesthesia results from an core-to-peripheral redistribution of body heat and a loss of body heat to environment. The purpose of this study is finding body temperatures during operation by either general of epidural anesthesia and evaluates content of total body heat. Methods : We measured tympanic membrane temperature, 4 point skin temperature (mid calf, mid thigh, upper extremity, nipple). And we calculate mean skin temperature, mean body temperature, total body heat content changes based on tympanic membrane temperature and 4 point skin temperature. Results : Tympanic membrane temperature of the first group decreased significantly after 10 minutes of induction(P＜0.005), the second group decreased after 45 minutes of induction. Although upper extremity temperature has continuously increased as time passed, there was no significant difference in both group. Lower extremity temperature has significantly increased after 30 minutes of induction in the first group, and the second group has significantly increased after 10 minutes of induction(P＜0.05). Mean skin temperature hasdecreasd temperaturily in both group after 10 minutes of induction and increased as time passed. Mean body temperature of the first group has significantly decreased after 10 minutes of induction(P＜0.05) and second group has no significant changes. Total body heat content has continuously decreased after induction with no significance. Conclusions : General anesthesia reveals more significant decrease than epidural anesthesia. Both groups show significant decrease of body temperature after induction. We think that we need to close attention to temperature changes after induction for preventing possible side effects due to core hypothermia. (Korean J Anesthesiol 1997; 33: 477∼484)

Mesure de la température corporelle en pratique quotidienne

Accurate measurement of body temperature is essential in routine medical practice. Development of new measurement methods, and awareness of mercury hazards are leading to the modification of our current practices. The range of body temperature in healthy individuals is 36.8 +/- 0.4 degrees C, but it may be influenced by many factors. Therefore, body temperature should be measured in a standardized fashion, preferably at rest, in the morning on waking. Febrile state is generally defined as a morning rectal temperature above 37.5 degrees C. Body temperature is largely dependent of the site of measurement. Rectal temperature is the highest, and oral temperature measured in the sublingual pocket close to the lingual artery generally the lowest. Tympanic membrane temperature is assumed to best reflect the core temperature. Axillary and cutaneous measures are unreliable. Mercury-in-glass thermometer used to measure rectal temperature still remains the reference in France. However, rectal measurement is inconvenient and associated with a risk of rectal injury and cross-infection. Moreover, mercury-in-glass thermometer results in high mercury pollution. Tendency is to replace it by either electronic thermometer to measure oral temperature, or infrared thermometer for tympanic membrane measure. Although reliable, chemical measures are still underused.

Thermoregulatory vasococonstriction and shivering impede therapeutic hypothermia in acute ischemic stroke patients

We tested the hypothesis that vasoconstriction and shivering thresholds are sufficiently reduced by acute stroke to permit induction of therapeutic hypothermia without additional pharmacological inhibition of thermoregulatory control. We studied eight patients 2 +/- 1 days after ischemic stroke. Forced-air cutaneous cooling was administered until the patients shivered continuously or reached a tympanic membrane (ie, core) temperature of 34 degrees C. The tympanic membrane temperatures triggering vasoconstriction and shivering identified the thresholds for each response. Patients had a mean age of 68 +/- 8 years and a mean National Institutes of Health Stroke Scale (NIHSS) score of 5. No patient reached the target core temperature of 34 degrees C. Vasoconstriction and shivering thresholds were 37.1 +/- 0.4 degrees C and 36.6 +/- 0.4 degrees C, respectively. Vasoconstriction and shivering were initiated at roughly normal temperatures in ischemic stroke patients, and these thermoregulatory responses prevented induction of therapeutic hypothermia. Pharmacological reduction of the vasoconstriction and shivering thresholds will be required if therapeutic hypothermia for stroke patients is to be induced easily by surface cooling.

Agreement Between Rectal and Tympanic Membrane Temperatures in Marathon Runners

Study objective: To determine the agreement between rectal temperature and infrared tympanic membrane temperatures in marathon runners presenting to a field hospital at the finish line. Methods: The subjects of this prospective, blinded, controlled study were runners 18 years or older who were triaged to the acute care medical area at the finish line for suspected hypothermia, hyperthermia, dehydration, or altered mental status. Rectal and tympanic temperatures were measured simultaneously in all subjects for whom rectal temperature measurement had been deemed necessary and recorded on separate data cards. Results: Of the 239 runners treated in the acute care medical area, 37 required rectal temperature measurement and were enrolled in the study. The mean rectal temperature was 38.45º±1.20º C (range, 35.9º to 41.5º C). The mean tympanic membrane temperature was 37.81º±.95º C (range, 36.3º to 40.4º C). Pearson's correlation coefficient revealed a moderate correlation (r=.6902, P=.00023). The mean temperature difference between the two thermometers, mean rectal minus mean tympanic membrane, was .64º C (95% confidence interval, .35º to .93º C). Sixty-two percent of the tympanic membrane readings were within 1º C of their rectal counterparts. Agreement ranged from 1.16º (+2 SD) to -2.95º (-2 SD). The 95% confidence interval was 1.67º to -2.95º C. Conclusion: We were able to demonstrate only a moderate correlation between the two thermometer readings, with a wide spread between the limits of agreement. This spread could be clinically significant and therefore limits the usefulness of tympanic temperature in the marathon race setting. Because of the potentially large and clinically significant differences in rectal and tympanic temperatures and the limitations inherent in our study, we cannot endorse the use of tympanic temperature in the setting of a marathon event. [Roth RN, Verdile VP, Grollman LJ, Stone DA: Agreement between rectal and tympanic membrane temperatures in marathon runners. Ann Emerg Med October 1996;28:414-417.]

The tympanic membrane thermometer in paediatrics: a review of the literature

This literature review looks at published works on the accuracy, reliability and sensitivity of the tympanic membrane thermometer in the paediatric population, particularly in relation to those who present in the Accident and Emergency department. Decisions that influence patient care outcomes are often based on information obtained from taking the child's temperature. Numerous studies have been conducted to examine temperature sites and instruments used. The most recent temperature measuring device to be used by nurses in assessing their patients is the tympanic membrane thermometer. The advantages of tympanic membrane temperature measurement include ease of use, rapid results and convenience for both nurse and child. However, inconsistent study reports have revealed some concerns about the use of the tympanic membrane thermometer as a routine measurement tool of body temperature in children. To meet the goal of accurate assessment of body temperature the practitioner must understand the principles behind the use of the tympanic membrane thermometer and thus use it appropriately.

Assessment of two devices for measuring tympanic membrane temperature in swine, dairy cattle, and dairy calves

We compared tympanic membrane temperature readings obtained by 2 commercially available devices with rectal temperature readings obtained with a standard mercury thermometer in dairy cattle, dairy calves, and swine.&#x0D; Full article published in Journal American Veterinary Medical Association (1996); 208, 1700-1701

Comparison of esophageal, tympanic, and forehead skin temperatures in adult patients

Study Objective: To compare esophageal, tympanic membrane, and forehead skin temperatures in patients undergoing elective surgeries. Design: Prospective clinical study. Setting: Operating room and postanesthesia care unit of a tertiary care teaching hospital. Patients: 40 adult ASA status I, II and III patients requiring anesthesia and surgery. Intervention: Application of crystalline thermometry strips to the forehead of patients. Measurements and Main Results: Concurrent forehead skin, tympanic membrane, and lower esophageal temperatures were measured and compared. The overall bias between esophageal and skin temperatures was 0.3 °C, between tympanic membrane and skin was 0.5 °C, and between esophageal and tympanic membrane was −0.1 °C. The limits of agreement (precision) between esophageal and skin temperatures were: −1.64 °C to +2.32 °C, between esophageal and tympanic membrane were: −1.02 °C to +0.74 °C, and between tympanic membrane and skin were: −1.48 °C to +2.52 °C. There was no significant relation between the change in skin temperature and change in esophageal temperature, whereas there was a weak linear relation between change in skin temperature and change in tympanic membrane temperature (y = −0.03 + 0.09, r = 0.12). Conclusion: There was a lack of precision between the clinically accepted measurements (lower esophageal and tympanic membrane) and the skin temperature measurement. The data suggest that forehead skin temperature is not interchangeable with standard core temperature measurements, and that sole reliance on the forehead skin measurement in the perioperative setting could adversely affect patient care.

Tympanic membrane vs rectal temperature measurement in marathon runners

Tympanic membrane vs rectal temperature measurement in marathon runners

Tympanic Membrane vs Rectal Temperature Measurement in Marathon Runners

To the Editor. —Exertional heat illness may encompass a variety of syndromes, including heat cramps, heat exhaustion, and heat stroke. All of these are more likely to occur in conditions of high heat and humidity such as may prevail at the Summer Olympic Games in Atlanta, Ga. Athletes with heat illness may sustain severe consequences, including acute renal failure and fatality. Therefore, it is essential that body temperature be assessed accurately in those who may be at risk. Endurance events such as the marathon and triathlon place athletes at greatest risk. 1 Most authors have recommended monitoring rectal temperatures as the best measure of core temperature in the setting of exertional thermal illness. Core temperature reflects the clinical status of these patients. Higher temperatures (especially those >40.6°C [>105°F]) imply heat stroke and portend a poorer prognosis. 1 Rectal temperature has been demonstrated to reflect core temperature measured at the pulmonary

THE USE OF A TYMPANIC MEMBRANE THERMOMETER FOR ASSESSING HYPERTHERMIA IN BIGHORN SHEEP

In November 1992, 45 desert bighorn sheep (Ovis canadensis nelsoni) were captured at Old Dad Peak and the Kelso Mountains of southern California (USA) using a netgun fired from a helicopter. Tympanic membrane temperature was compared to rectal temperature for 22 sheep to determine if tympanic membrane temperature was a reliable indicator of hyperthermia and capture stress. All animals captured had elevated rectal temperatures after capture and arrival to the processing area. The group of 22 sheep had a mean +/- SD rectal temperature of 40.9 +/- 0.7 C (range 39.5 to 42.1 C) at arrival. During processing of these sheep, mean +/- SD rectal temperatures were 40.9 +/- 0.29 C (range 40.0 to 41.7 C) with mean +/- SD tympanic temperatures of 38.4 +/- 0.5 C (range 35.7 to 40.5 C). Mean tympanic temperatures were significantly lower than mean rectal temperatures when comparing all measurements and paired tympanic and rectal temperature measurements. Three animals had rectal and tympanic temperatures greater than 41.0 C and 39.7 C, respectively, one of which died after capture. Tympanic membrane temperature measurement may provide a method for evaluation of hyperthermia and capture stress by separating retained body heat due to exertion from critical elevations in core body temperature which may affect post-capture survival.

Reduction in the Shivering Threshold Is Proportional to Spinal Block Height

Hypothermia is nearly as common, and may be as severe, during spinal and epidural anesthesia as during general anesthesia. The authors have proposed that thermoregulatory failure results when regional anesthesia increases apparent leg skin temperature to a level far exceeding actual leg skin temperature. Extensive dermatomal blocks will alter thermal input to the hypothalamus from a greater skin-surface area more than less extensive ones and thus might be expected to impair central thermoregulatory control more. Accordingly, they tested the hypothesis that reduction in the shivering threshold is directly related to the number of dermatomes blocked during spinal anesthesia. Eleven men, aged 62 +/- 6 yr (mean +/- SD), undergoing urologic surgery were studied. Ice-cold lactated Ringer's solution was administered intravenously before spinal blockade and the shivering threshold (triggering core temperature) was established. Spinal anesthesia then was induced using a randomly assigned dose of 0.5% bupivacaine (2-4 ml). Again, sufficient cold lactated Ringer's solution was given to induce shivering. Tympanic membrane, ambient and skin temperatures were measured, and extent of block was defined by loss of temperature discrimination. Presence of shivering was evaluated by a blinded observer. Mean upper-body skin and ambient temperatures, cooling rates and intravenous fluid volumes at the two thresholds were compared using paired, two-tailed t tests (P < 0.05). Linear regression defined the relationship between reduction in shivering threshold and the number of dermatomes blocked. There were no significant differences between mean upper-body skin and ambient temperatures, cooling rates or intravenous fluid volumes at the control and spinal shivering thresholds. Spinal anesthesia reduced the shivering threshold in direct relation to the number of dermatomes blocked: delta threshold = 0.74 - 0.06 (dermatomes blocked); r2 = 0.58, P < 0.006. Extensive spinal blockade impairs central thermoregulatory control more than less extensive blockade. Clinicians can thus anticipate more core hypothermia during extensive than during restricted spinal blockade.