Theoretical basis for the use of non-invasive thermal measurements to assess the brain injury in newborns undergoing therapeutic hypothermia

Abstract

The aim of this paper is to propose a new non-invasive methodology to estimate thermogenesis in newborns with perinatal asphyxia (PA) undergoing therapeutic hypothermia (TH). Metabolic heat production (with respect to either a neonate’s body mass or its body surface) is calculated from the newborn’s heat balance, estimating all remaining terms of this heat balance utilising results of only non-invasive thermal measurements. The measurement devices work with standard equipment used for therapeutic hypothermia and are equipped with the Global System for Mobile Communications (GSM), which allows one to record and monitor the course of the therapy remotely (using an internet browser) without disturbing the medical personnel. This methodology allows one to estimate thermogenesis in newborns with perinatal asphyxia undergoing therapeutic hypothermia. It also offers information about instantaneous values of the rate of cooling together with values of remaining rates of heat transfer. It also shows the trend of any changes, which are recorded during treatment. Having information about all components of the heat balance one is able to facilitate comparison of results obtained for different patients, in whom these components may differ. The proposed method can be a new tool for measuring heat balance with the possibility of offering better predictions regarding short-term neurologic outcomes and tailored management in newborns treated by TH.

Thermal Index for early non-invasive assessment of brain injury in newborns treated with therapeutic hypothermia: preliminary report

“…In our study, we used the methodology of the heat balance proposed by Bandoła et al 31 , further developed by Walas et al 32 . These authors presented examples of the measurements of the proposed parameters during TH in newborns, but they did not present the results of studies confirming the clinical usefulness of the proposed method.…”

“…As described by Walas et al 32 the heat balance for the neonate undergoing TH reads where Q m represents the rate of metabolic heat production, Q skin is the rate of heat dissipated through the skin (to the local indoor environment) while Q resp stands for the rate of heat exchanged due to respiration. These three heat rates are all expressed in watts (W).…”

“…A new methodology of analysing the cooling process (allowing to estimate thermogenesis) of newborns with HIE undergoing TH has been presented in 31 , 32 . The proposed method, with roots in heat transfer theory, takes into account more factors influencing the heat transfer and employs only the non-invasive thermal measurements.…”

Thermal Index for Early Non-invasive Assessment of Brain Injury in Newborns Treated With Therapeutic Hypothermia – Preliminary Report of Non-invasive Thermal Measurements

“…Thermal Index (TI): As described by Walas et al 32 the heat balance for the neonate undergoing TH reads (1) where Q m represents the rate of metabolic heat production, Q skin is the rate of heat dissipated through the skin (to the local indoor environment) while Q resp stands for the rate of heat exchanged due to respiration. These three heat rates are all expressed in watts (W).…”

“…A new methodology of analyzing the cooling process (allowing to estimate thermogenesis) of newborns with HIE undergoing TH has been presented in 31,32 . The proposed method, with roots in heat transfer theory, takes into account more factors in uencing the heat transfer and employs only the non-invasive thermal measurements.…”