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At least 361 records · Page 20Linked to original sources
PubMed1991

Infrared, thermistor, and glass-mercury thermometry for measurement of body temperature in children with cancer.

Body temperature is often the sole determinant of whether or not the neutropenic cancer patient is admitted to the hospital for empiric antibiotic therapy. Recently developed infrared tympanic thermometers offer rapid readings, but their accuracy has not been established. We studied two infrared thermometers (FirstTemp and Thermoscan) and a thermistor (IVAC) in children with cancer. Mean infrared measurements did not differ significantly between right and left ear canals, and the mean IVAC temperature did not differ significantly from the left to the right axilla (P greater than 0.05, paired t test). IVAC predictive mode mean temperature was 0.2 degrees C lower than monitor mode mean temperature in the axilla (P less than 0.0001), but 0.1 degree C higher than monitor mode orally (P less than 0.0001). Aiming the infrared instrument at the tympanic membrane using an ear tug resulted in a 0.2 degree C higher mean temperature than casual placement in the ear canal (P less than 0.0001). After compensation for the mean difference in reference oral glass-mercury versus test instrument temperatures, the FirstTemp, Thermoscan, and oral and axillary predictive mode IVAC measurements yielded sensitivities for the detection of fever of 84%, 84%, 82%, and 86%; specificities of 100%, 99%, 100%, and 100%; positive predictive values of 100%, 93%, 100%, and 100%; and negative predictive values of 95%, 98%, 98%, and 98%, respectively. We conclude that each of these instruments detects fever with comparable reliability. Infrared instruments are especially attractive alternatives due to their time efficiency.

Age Factors↗
PubMed1991

Effect of otitis media on infrared tympanic thermometry.

This study was designed to determine if temperature readings using a new tympanic thermometer are affected by otitis media. These readings were also compared to a rectal or oral temperature. Eighty-four children with unilateral suppurative or non-suppurative otitis media diagnosed clinically by their pediatricians were enrolled in the study. Temperatures were measured in both ears using the Thermoscan PRO-1 Instant Thermometer and rectally or orally by a glass or electronic predictive thermometer. For 67 children with unilateral suppurative otitis media the mean temperature in infected ears was 0.38 degrees Fahrenheit higher than in uninfected ears (p = .005). Neither temperatures measured in affected nor those from unaffected ears differed significantly from oral or rectal control readings. For 17 children with unilateral non-suppurative otitis media there was no statistically significant difference between temperatures in affected and unaffected ears or between the temperatures in either ear and the oral or rectal control. Our data show that temperatures taken in ears with suppurative otitis media are slightly higher than those in normal ears. This difference is of minimal clinical significance and does not affect the accuracy when compared to oral or rectal control readings.

Body Temperature↗
PubMed1999

Neonatal infrared axillary thermometry.

The authors compared axillary skin temperatures (AT) measured with an infrared (IR) thermometer (Lightouch Neonate, Exergen Corp) with rectal temperatures (RT) in 16 newly born term infants under radiant warmers (RW) and in cribs. Twelve stable, growing premature infants in incubators were also studied. This new device may be useful because of safety and rapid results (1 second), but clinical accuracy is unknown. For term infants, mean (SD) RT-AT difference was 0.1 (0.48) degree C under RW and 0.25 (0.17) degree C 2 hours later in cribs. For premature infants in incubators the mean RT-AT difference was 0.09 (0.16) degree C. Axillary temperatures measured by IR thermometer approximate RT for newly born term infants in cribs and stable premature infants in incubators. For newly born term infants under RW, RT-AT differences vary more widely, limiting clinical usefulness in this setting. The device, the unique age of this population, and the RW environment may play a role.

Axilla↗
PubMed1981

Aural thermometry during profound hypothermia.

External auditory canal temperature changes during profound hypothermia were studied experimentally in ten dogs and clinically in 20 patients undergoing open-heart surgery. The results were compared with nasopharyngeal and lower oesophageal temperatures. Tympanic membrane temperature provided a better approximation to brain temperatures measured in four dogs to below 20 degrees C than did either of the other two methods. In patients, auditory canal temperature showed less variability with respect to oesophageal temperature and fell at a faster rate than did nasopharyngeal temperature. It did not appear to be subject to positional or other artefacts but four patients showed evidence of auditory canal trauma. The precise relationship between auditory canal or tympanic membrane temperature and brain temperature during profound hypothermia is not established. Routine otoscopic examination should accompany the use of an ear probe.

Adolescent↗
PubMed1993

A noninvasive transcutaneous alternative to rectal thermometry for continuous measurement of core temperature in the piglet.

Deep body temperature is an important and accepted index of health status in newborn infants. There are no easily used accurate methods for continuous deep body temperature measurements. Oral and tympanic membrane temperatures correlate well with rectal temperature but are not easily adapted to continuous measurement. We devised a noninvasive transcutaneous temperature sensor for continuous deep body temperature measurement that relies on the principle that, under steady state conditions, the temperature at the thermally insulated surface of a warm body, i.e. a zero heat loss surface, will be in equilibrium with the warmest part of the body. We used a standard clinical temperature probe placed between the skin and the mattress and attached to the skin with a foam adhesive disk. We used standard skin temperature probe attachment disks, which are also designed to provide thermal insulation to the skin temperature probe. We tested the hypothesis that this transcutaneous temperature would track body temperature as indicated by rectal temperature. In six anesthetized (pentobarbital) newborn piglets (1600 +/- 200 g) placed on their abdomen in a convectively warmed infant incubator, we measured continuously the following temperatures for 5 h: transcutaneous over lower and upper abdomen, brown fat, rectal, and descending aorta. To examine the influence of environment, we varied the incubator air temperature between 32 degrees and 36 degrees C. Both transcutaneous temperatures tracked the rectal temperature, within 0.2 degree C for transcutaneous over lower abdomen and within 0.3 degree C for transcutaneous over upper abdomen.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed2003

Usefulness of infrared thermometry in determining body temperature in mice.

The rectal temperature obtained using a standard electronic thermometer was compared with ear, back skin, tail skin, and sole skin temperatures obtained using an infrared thermometer in B6C3F1 mice. Using both methods, we investigated baseline temperatures, diurnal and 2-week variations in temperatures, and ethanol-induced hypothermia in these body locations. Ear and back temperatures were shown to be close to and consistent with rectal temperatures in various situations, and measured temperatures at these sites were almost constant, with very similar diurnal variation. Conversely, tail and sole temperatures were lower and much more variable. These results indicate that ear and back skin temperatures obtained using a convenient and non-invasive infrared thermometer are as reliable, and should be safer and less stressful to animal subjects, compared to standard rectal temperature measurements.

Animals↗
PubMed2005

Thermometry for turbulent flames by coherent anti-Stokes Raman spectroscopy with simultaneous referencing to the modeless excitation profile.

An optimal system for temperature measurements by coherent anti-Stokes Raman spectroscopy (CARS) in turbulent flames and flows is presented. In addition to a single-mode pump laser and a modeless dye laser, an echelle spectrometer with a cross disperser is used. This system permits simultaneous measurement of the N2 CARS spectrum and the broadband dye laser profile. A procedure is developed to use software to transform this profile into the excitation profile by which the spectrum is referenced. Simultaneous shot-to-shot referencing is compared to sequential averaged referencing for data obtained in flat flames and in room air. At flame temperatures, the resultant 1.5% imprecision is limited by flame fluctuations, indicating that the system may have a single-shot imprecision below 1%. At room temperature, the 3.8% single-shot imprecision is of the same order as the best values reported for dual-broadband pure-rotational CARS. Using the unique shot-to-shot excitation profiles, simultaneous referencing eliminates systematic errors. At 2000 and 300 K, the 95% confidence intervals are estimated to be +/- 20 and +/- 10 K, respectively.

Journal Article↗
PubMed2004

Rayleigh scattering cross sections of combustion species at 266, 355, and 532 nm for thermometry applications.

Rayleigh scattering cross sections are measured for nine combustion species (Ar, N2, O2, CO2, CO, H2, H2O, CH4, and C3H8) at wavelengths of 266, 355, and 532 nm and at temperatures ranging from 295 to 1525 K. Experimental results show that, as laser wavelengths become shorter, polarization effects become important and the depolarization ratio of the combustion species must be accounted for in the calculation of the Rayleigh scattering cross section. Temperature effects on the scattering cross section are also measured. Only a small temperature dependence is measured for cross sections at 355 nm, resulting in a 2-8% increase in cross section at temperatures of 1500 K. This temperature dependence increases slightly for measurements at 266 nm, resulting in a 5-11% increase in cross sections at temperatures of 1450 K.

Journal Article↗