Body temperature change and outcomes in patients undergoing long-distance air medical transport

Graphene-Enhanced Polydimethylsiloxane Patch for Wearable Body Temperature Remote Monitoring Application

In this work, we designed and implemented a wearable body temperature monitoring device, which was constructed by a graphene-enhanced polydimethylsiloxane patch and a temperature measurement chip. The body temperature patch adopts a completely flexible solution in combination with near field communication component, which provides the advantages of passive wireless, overall flexibility, and being comfortable to wear. The whole device can be bent and stretched in conformal contact with skin. In order to improve the temperature conduction ability of the patch and make the patch data more accurate, we adopted graphene nanoplates to improve the thermal conductivity of polydimethylsiloxane patch with a significant thermal conductivity increase of 23.8%. With the combination of hollow sandwich structure and small dimension. it will reduce the uncomfortable situation of wearing the device for extended periods and can be served to monitor the human body temperature for a long time. Ultimately, this device is combined with a reading software for analyzing and processing on a smart mobile terminal. The real-time and past temperature range can be a pre-warning; meanwhile, the historical data can be traced and analyzed. Therefore, this device can be utilized in multiple human body temperature measurement scenarios and complex public health situations.

Temperature loss by ventilation in a calorimetric bench model

In intensive care medicine heat moisture exchangers are standard tools to warm and humidify ventilation gases in order to prevent temperature loss of patients or airway epithelia damage. Despite being at risk of hypothermia especially after trauma, intubated emergency medicine patients are often ventilated with dry and in winter probably cold ventilation gases. We tried to assess the amount of temperature-loss due to ventilation with cold, dry medical oxygen in comparison to ventilation with warm and humidified oxygen. We ventilated a 50-kg water-dummy representing the calorimetric capacity of a 60-kg patient over a period of 2 hours (tidal volume 6.6 mL/kg = 400 mL; respiratory rate 13/min). Our formal null-hypothesis was that there would be no differences in temperature loss in a 50 kg water-dummy between ventilation with dry oxygen at 10°C vs. ventilation with humidified oxygen at 43°C. After 2 hours the temperature in the water-dummy using cold and dry oxygen was 29.7 ± 0.1°C compared to 30.4 ± 0.1°C using warm and humidified oxygen. This difference in cooling rates between both ventilation attempts of 0.7 ± 0.1°C after 2 hours represents an increased cooling rate of ~0.35°C per hour. Ventilation with cool, dry oxygen using an automated transport ventilator resulted in a 0.35°C faster cooling rate per hour than ventilation with warm humidified oxygen in a bench model simulating calorimetric features of a 60-kg human body.

Aeromedical Transport of Critically Ill Patients: A Literature Review

The aeromedical transport of critically ill patients has become an integral part of practicing medicine on a global scale. The development of reliable portable medical equipment allows physicians, emergency medical technicians, and nurses to transport wounded and diseased patients under constant critical care attention. Air transportation involves utilizing a fixed-wing (airplane) or rotor-wing (helicopter) aircraft to accomplish different types of transports ranging from scene responses to international transfers. The proper preparation and management of patients undergoing aeromedical transport require a basic understanding of the physiological changes and unique challenges encountered within the aircraft environment at 8,000 ft above sea level. The purpose of this paper is to review the literature and provide guidelines for approaching the aeromedical transportation of critically ill patients.

Temperature Elevation During Neonatal and Pediatric Fixed Wing Transport in a Subtropic Climate: A Descriptive Study

OBJECTIVE

We sought to describe the degree of temperature elevation (∆T) among children transported in a subtropical climate (Florida) via fixed wing aircraft and identify potential relationships between patient weight and ∆T.

METHODS

We performed a retrospective cohort study in children < 18 years of age undergoing interfacility transport via fixed wing aircraft from January 2016 through July 2020. The study outcomes were ∆T, maximum patient temperature, ambient temperature, and heat index. Bivariate cohorts defined by patient weight (5 kg) were compared using Fisher exact, Student t-, and Wilcoxon rank sum analyses. Exploratory testing included receiver operator characteristic curve analyses and unadjusted logistic regression.

RESULTS

Of the 58 children studied, 25 (43%) were ≤ 5 kg, and 33 (57%) were > 5 kg. Compared with children > 5 kg, those ≤ 5 kg had greater ∆T (0.8° ± 0.6°C vs. 0.2° ± 0.3°C), maximum patient temperature (37.3° ± 0.6°C vs. 36.8° ± 0.4°C), and proportion with ≥ 1°C ∆T (36% vs. 3%). No child > 5 kg had a temperature > 38°C, and no differences were observed for heat index or ambient temperature. Receiver operating characteristic analysis of patient weight on ∆T ≥ 1°C yielded an area under the curve of 0.86 (cutoff of 3.5 kg; sensitivity = 81.3%, specificity = 80%). Patient weight was inversely associated with ∆T ≥ 1°C (odds ratio = 0.69; 95% confidence interval, 0.49-0.96).

CONCLUSIONS

Young children appear at greatest risk for developing environmental hyperthermia during interfacility fixed wing transport.