Research progress in core body temperature measurement during target temperature management

Core body temperature(CBT)is increasingly attracting attention as crucial data during target temperature management(TTM).Accurate and continuous measurement of human CBT can effectively identify and monitor central high fever,and provide a basis for the effective implementation during TTM,which is therefore of great significance for human health care and disease monitoring.The reliable core measurement sites are nasopharynx,esophagus,bladder,rectum,pulmonary artery,etc.,but the measurement methods in these sites are all invasive.At present,the medical field is more inclined to noninvasive data collection methods through monitoring an appropriate site(such as forehead,mouth,or axilla)depending on clinical circumstances,so as to ensure the comfort and security of patients to the greatest extent.This review will provide reference choosing more safe and accurate temperature measurement methods for patients during TTM by reviewing the sites and accuracy of invasive and noninvasive CBT measurements.

Sufficiently Elevated Core Body Temperature May Be Necessary to Maintain Cerebral Blood Flow Response throughout the Morning

In comparison to a carbohydrate-rich breakfast, a nutritionally balanced breakfast reportedly leads to a higher core body temperature because of diet-induced thermogenesis (DIT) and also results in higher task performance. This study aimed to examine the relationships among the core body temperature, blood glucose level, cerebral blood flow, and cognitive performance when the core body temperature is raised to a similar extent as in DIT in the morning. This crossover study included 18 male participants who performed four sets of cognitive tests in the morning with four different foot baths and glucose intake conditions. In elevated body temperature (EBT) conditions, the core body temperature was increased by a foot bath at 42˚C or 39˚C, while in low body temperature (LBT) conditions, it was maintained at 35˚C by a foot bath;the participants received no glucose or two intakes of 20-g glucose for each thermal condition. In addition to the core body temperature measurement, the cerebral blood flow in the dorsolateral prefrontal cortex (DLPFC) was measured using near-infrared spectroscopy. Three blood collections were performed to measure the changes in blood glucose levels. The results revealed that in the EBT conditions, the core body temperature remained 0.3˚C - 0.5˚C higher than that at wake-up time, while the glucose intake conditions increased blood glucose levels which remained higher than those during fasting. No significant between-treatment difference was observed in the results of cognitive tests. However, the blood flow in the DLPFC increased during the second test period in the EBT/glucose and LBT/glucose conditions, whereas during the fourth test period, it increased solely in the EBT/glucose condition. Thus, in addition to the blood glucose level, an elevated core body temperature within the physiological range may be needed for long-term maintenance of the cerebral blood flow response.