Unité de Recherche PériTox EA 4285-UMI 01 INERIS, Faculté de Médecine, Université de Picardie Jules Verne, 3 rue des Louvels, 80036, Amiens Cédex1, France.
Eur J Appl Physiol. 2012 Aug;112(8):2957-68. doi: 10.1007/s00421-011-2265-9. Epub 2011 Dec 10.
In closed incubators, radiative heat loss (R) which is assessed from the mean radiant temperature (Tr) accounts for 40-60% of the neonate's total heat loss. In the absence of a benchmark method to calculate Tr--often considered to be the same as the air incubator temperature-errors could have a considerable impact on the thermal management of neonates. We compared Tr using two conventional methods (measurement with a black-globe thermometer and a radiative "view factor" approach) and two methods based on nude thermal manikins (a simple, schematic design from Wheldon and a multisegment, anthropometric device developed in our laboratory). By taking the Tr estimations for each method, we calculated metabolic heat production values by partitional calorimetry and then compared them with the values calculated from V(O2) and V(CO2) measured in 13 preterm neonates. Comparisons between the calculated and measured metabolic heat production values showed that the two conventional methods and Wheldon's manikin underestimated R, whereas when using the anthropomorphic thermal manikin, the simulated versus clinical difference was not statistically significant. In conclusion, there is a need for a safety standard for measuring TR in a closed incubator. This standard should also make available estimating equations for all avenues of the neonate's heat exchange considering the metabolic heat production and the modifying influence of the thermal insulation provided by the diaper and by the mattress. Although thermal manikins appear to be particularly appropriate for measuring Tr, the current lack of standardized procedures limits their widespread use.
在封闭式培养箱中，由平均辐射温度（Tr）评估的辐射热损失（R）占新生儿总热损失的 40-60%。由于缺乏计算 Tr 的基准方法（通常认为 Tr 与空气培养箱温度相同），因此错误可能会对新生儿的热管理产生重大影响。我们比较了两种传统方法（使用黑球温度计和辐射“视角系数”方法测量 Tr）和两种基于裸体热人体模型的方法（来自 Wheldon 的简单示意设计和我们实验室开发的多节段人体模型）。通过对每种方法的 Tr 估计值，我们通过分区量热法计算了代谢产热量，然后将其与在 13 名早产儿中通过 V（O2）和 V（CO2）测量计算的值进行比较。计算出的代谢产热量值与测量值之间的比较表明，两种传统方法和 Wheldon 人体模型低估了 R，而使用人体模型时，模拟与临床之间的差异在统计学上没有显著性。总之，需要为封闭式培养箱中的 TR 测量制定安全标准。该标准还应提供考虑代谢产热和尿布以及床垫提供的热绝缘的所有新生儿热交换途径的估算方程。尽管热人体模型似乎特别适合测量 Tr，但当前缺乏标准化程序限制了它们的广泛使用。
