Accuracy and precision of a novel non-invasive core thermometer

Journal of Clinical Monitoring and Computing, 2020

In pediatric anesthesia, deviations from normothermia can lead to many complications, with infants and young children at the highest risk. A measurement method for core temperature must be clinically accurate, precise and should be minimally invasive. Zero-heat-flux (ZHF) temperature measurements have been evaluated in several studies in adults. We assessed the agreement between the 3M Bair Hugger™ temperature measurement sensor (TZHF) and esophageal temperature (TEso) in children up to and including 6 years undergoing surgery with general anesthesia. Data were recorded in 5 min-intervals. We investigated the accuracy of the ZHF sensor overall and in subgroups of different age, ASA classification, and temperature ranges by Bland–Altman comparisons of differences with multiple measurements. Change over time was assessed by a linear mixed model regression. Data were collected in 100 children with a median (1st–3rd quartile) age of 1.7 (1–3.9) years resulting in 1254 data pairs. Compar...

2021

Background: Precisely measuring the core body temperature during targeted temperature management after return of spontaneous circulation is mandatory, as deviations from the recommended temperature might result in side effects such as electrolyte imbalances or infections. However, previous methods are invasive and lack easy handling. A disposable, non-invasive temperature sensor using the heat flux approach (Double Sensor), was tested against the standard method: an esophagus thermometer. Methods: The sensor was placed on the forehead of adult patients (n = 25, M/F, median age 61 years) with return of spontaneous circulation after cardiac arrest undergoing targeted temperature management. The recorded temperatures were compared to the established measurement method of an esophageal thermometer. A paired t-test was performed to examine differences between methods. A Bland-Altman-Plot and the intraclass correlation coefficient were used to assess agreement and reliability. To rule out...

American journal of critical care : an official publication, American Association of Critical-Care Nurses, 2003

Recent research indicates that oral measurement of body temperature is a reliable option in orally intubated patients. In situations such as protective isolation, where dedicated electronic thermometers are not available, are single-use chemical dot thermometers an acceptable alternative? To determine the accuracy of single-use chemical dot thermometers in orally intubated adult patients. Subjects included a convenience sample of 85 adult patients admitted to 1 of 2 intensive care units (surgical trauma and neuroscience). For each patient, oral temperatures were measured concurrently (within 5 minutes) with a chemical dot thermometer and an electronic thermometer. The sequence of temperature measurements was alternated with each subsequent patient. Both thermometers were placed in the same posterior sublingual pocket opposite the side of the endotracheal tube. Measurements obtained with electronic and single-use chemical dot thermometers correlated strongly (r = 0.937). With the che...

Scottish medical journal, 2005

Temperature measurement is a routine task of patient care, with considerable clinical impact, especially in the ICU. This study was conducted to evaluate the accuracy and variability of the Temporal Artery Thermometer (TAT) in ICU-patients. Therefore, a convenience sample of 57 adult patients, with indwelling pulmonary artery catheters (PAC) in a 40-bed intensive care unit in a university teaching hospital was used. The study design was a prospective, descriptive comparative analysis. Body temperature was thereby measured simultaneously with the TAT and the Axillary Thermometer (AT), and was compared with the temperature recording of the PAC. The use of vasoactive medication was recorded. Mean temperature of all measurements was: PAC: 37.1 degrees C (SD: 0.87), TAT 37.0 degrees C (SD: 0.68) and axillary thermometer: 36.6 degrees C (SD: 0.94). The measurements of the TAT and the PAC were not significantly different (man differnce: 0.14 degrees C; SD: 0.51; p = 0.33); whereas the meas...

Anesthesiology, 2008

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 non-invasive and easy to use — especially in patients not having general anesthesia. Nonetheless, temperature can be reliably measured in most patients. Body temperature should be measured in patients having general anesthesia exceeding 30 minutes in duration, and in patients having major operations under 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 arterio-venous shunt vasoconstriction and shivering. Anesthetic-induced impairment of normal thermoregulatory control, and 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 extant than general anesthesia. Prolonged epidural analgesia is associated with hyperthermia whose cause remains unknown.

Anesthesiology, 2009

Background: Initial postoperative core temperature is a physician and hospital performance measure. However, the extent to which core temperature changes during emergence from anesthesia and transport from the operating room to the postanesthesia care unit (PACU) remains unknown. Similarly, the accuracy of many noninvasive temperature-monitoring methods used in the PACU has yet to be quantified. This study, therefore, quantified the change in core temperature occurring during emergence and transport and evaluated the accuracy and precision of eight noninvasive thermometers in the PACU.

Critical Care Medicine, 2007

Accurate measurement of temperature is vital in the intensive care setting. A prospective trial was performed to compare the accuracy of tympanic, urinary, and axillary temperatures with that of pulmonary artery (PA) core temperature measurements. Design: A total of 110 patients were enrolled in a prospective observational cohort study. Setting: Multidisciplinary intensive care unit of a university teaching hospital. Patients: The cohort was (mean ؎ SD) 65 ؎ 16 yrs of age, Acute Physiology and Chronic Health Evaluation (APACHE) II score was 25 ؎ 9, 58% of the patients were men, and 76% were mechanically ventilated. The accuracy of tympanic (averaged over both ears), axillary (averaged over both sides), and urinary temperatures was referenced (as mean difference, ⌬ degrees centigrade) to PA temperatures as standard in 6,703 recordings. Lin concordance correlation (p c) and Bland-Altman 95% limits of agreement (degrees centigrade) described the relationship between paired measurements. Regression analysis (linear mixed model) assessed covariate confounding with respect to temperature modes and reliability formulated as an intraclass correlation coefficient. Measurements and Main Results: Concordance of PA temperatures with tympanic, urinary, and axillary was 0.77, 0.92, and 0.83, respectively. Compared with PA temperatures, ⌬ (limits of agreement) were 0.36°C (؊0.56°C, 1.28°C), ؊0.05°C (؊0.69°C, 0.59°C), and 0.30°C (؊0.42°C, 1.01°C) for tympanic, urinary, and axillary temperatures, respectively. Temperature measurement mode effect, estimated via regression analysis, was consistent with concordance and ⌬ (PA vs. urinary, p ‫؍‬ .98). Patient age (p ‫؍‬ .03), sedation score (p ‫؍‬ .0001), and dialysis (p ‫؍‬ .0001) had modest negative relations with temperature; quadratic relationships were identified with adrenaline and dobutamine. No interactions with particular temperature modes were identified (p > .12 for all comparisons) and no relationship was identified with either mean arterial pressure or APACHE II score (p > .64). The average temperature mode intraclass correlation coefficient for test-retest reliability was 0.72. Conclusion: Agreement of tympanic with pulmonary temperature was inferior to that of urinary temperature, which, on overall assessment, seemed more likely to reflect PA core temperature.

Journal of Multidisciplinary Healthcare

Perioperative hypothermia prevention requires regular, accurate, and consistent temperature monitoring. Zero-heat-flux (ZHF) thermometry offers a non-invasive, measurement method that can be applied across all surgical phases. The purpose of this study was to measure agreement between the zero-heat-flux device and esophageal monitoring, sensitivity, and specificity to detect hypothermia and patient acceptability amongst patients undergoing upper and lower limb orthopedic surgery. Patients and Methods: This prospective, observational study utilized Bland-Altman analysis and Lin's concordance coefficient to measure agreement between devices, sensitivity and specificity to detect hypothermia and assessed patient acceptability amongst 30 patients between December 2018 and June 2019. Results: Bias was observed between devices via Bland Altman, with bias dependent on actual temperature. The mean difference ranged from −0.16°C at 34.9°C (where the mean of ZHF was lower than the esophageal device) to 0.46°C at 37.25°C (where the mean of ZHF was higher than esophageal device), with 95% limits of agreement (max) upper LOA = 0.80 to 1.41, lower LOA = −1.12 to −0.50. Seventy-five percentage of zero-heat-flux measurements were within 0.5°C of esophageal readings. Patient acceptability was high; 96% (n=27) stated that the device was comfortable. Conclusion: ZHF device achieved lesser measurement accuracy with core (esophageal) temperature compared to earlier findings. Nonetheless, due to continuous capability, noninvasiveness and patient reported acceptability, the device warrants further evaluation.

Ain-Shams Journal of Anesthesiology

Background Perioperative hypothermia is an unintended decrease in the core temperature of patients. Hypothermia has many proven complications. The aim of this study is to investigate the perioperative temperature monitoring rates and the difficulties encountered during monitoring, particularly in patients undergoing neuraxial anesthesia. Methods Two hundred anesthesiologists were included in the study who work in Turkey and actively work in an operating room. A questionnaire was applied to the participants via printed form or e-mail. Results In Turkey, the overall temperature monitoring ratio was measured as 5.5%. Temperature monitoring was the most frequently used for cardiovascular surgery patients group. In neuraxial anesthesia, temperature monitoring was only 1.5%. The most common reason for not using a temperature monitor was the lack of appropriate equipment (45%). The most common temperature monitoring area was the axillary zone (48%). Conclusion Participants were aware of th...