Differences in noninvasive thermometer measurements in the adult emergency department

Thermoregulation: A journey from physiology to computational models and the intensive care unit

Thermoregulation plays a vital role in homeostasis. Many species of animals as well as humans have evolved various physiological mechanisms for body temperature control, which are characteristically flexible and enable a fine-tuned spatial and temporal regulation of body temperature in different environmental conditions and circumstances. Human beings normally maintain a core body temperature at around 37°C, and maintenance of this relatively high temperature is critical for survival. Therefore, principles of thermoregulatory control have also important clinical implications. Infections can cause the body temperature to rise internally and several diseases can cause a dysfunction of thermoregulatory mechanisms. Moreover, the utilization of thermotherapies in treating various diseases has been known for thousands of years with a recent resurgence of interest. An increasing amount of research suggests that targeted temperature management is of paramount importance to patient outcomes in certain clinical scenarios. We provide a concise summary of the basic concepts of thermoregulation. Emphasis is given to the principles of thermoregulation in humans in basic pathological states and to targeted temperature management strategies in the clinical environment, with special attention on therapeutic hypothermia in postcardiac arrest patients. Finally, the discussion is focused on the potential offered by computational thermophysiological models for predicting thermal responses of patients in various clinical circumstances, for proposing new perspectives in the design of novel thermal therapies, and to optimize targeted temperature management strategies. This article is categorized under: Cardiovascular Diseases > Cardiovascular Diseases>Computational Models Cardiovascular Diseases > Cardiovascular Diseases>Environmental Factors Cardiovascular Diseases > Cardiovascular Diseases>Biomedical Engineering.

Temporal Artery Thermometry in Pediatric Patients: Systematic Review and Meta-Analysis

PROBLEM

Non-invasive thermometry methods have been used as substitutes for intra-corporeal ones in order to decrease patient discomfort and risk for complications, yet the evaluation of their performance is necessary. Our aim was to synthesize the evidence on the accuracy and precision of temporal artery (TA) thermometry, as well as on its sensitivity and specificity for fever detection.

ELIGIBILITY CRITERIA

This systematic review and meta-analysis included method-comparison studies, which compared TA temperature measurements with invasive thermometry ones, were published between 2000 and 2018, and were conducted on patients aged <18 years.

SAMPLE

Thirty articles were selected for inclusion in the final analysis after screening those identified by searches in CINAHL, PubMed, Web of Science, Cochrane Library, EMBASE and Scopus.

RESULTS

Quantitative synthesis indicated that pooled mean TA temperature was lower than core temperature by 0.01 °C (95% limits of agreement, -0.06 °C to 0.03 °C). Average summary sensitivity and specificity for fever detection were 0.72 (95% confidence interval, 0.66-0.79) and 0.91 (95% confidence interval, 0.86-0.93) respectively. Subgroup analysis indicated a trend toward larger temperature underestimation in febrile patients and in ages ≤4 years.

CONCLUSIONS

Despite its satisfactory accuracy, precision and specificity, TA thermometry has low sensitivity when used in pediatric patients, which does not allow satisfactory fever detection.

IMPLICATIONS

TA thermometry cannot be recommended for replacing rectal temperature measurement methods in children, due to its high proportion of false negative readings during screening for fever.

Development of Body-Tissue Temperature-Control Transducer

The aim of this study was to develop a transducer for non-invasive temperature measurement in deeper tissue layers during tissue cooling. Simulation of the temperature field distribution in human tissues and the transducer were done, and the influence of transducer structure and material properties were studied. Using simulation results, the experimental transducer was designed for temperature measurement in deeper tissue layers during cooling. The temperature measurements with the needle thermometer and the transducer were well correlated at both before tissue cooling r = 0.723 and after cooling r = 0.945, and the temperature difference was no more than ±0.2 °C.