Lange H, Gräber T, Schwickardi M
Department of Nephrology, Philipps-University of Marburg, Marburg/Lahn, Germany.
Eur J Appl Physiol Occup Physiol. 1995;71(1):58-64. doi: 10.1007/BF00511233.
A simplified procedure of direct calorimetry (SPDC) for determination of resting metabolic rate of respiratory uncompromised subjects in a supine position is presented. This procedure was based on computer-assisted measurements of heat losses due to evaporation, radiation, conduction, and convection. The subject's total loss of mass was recorded hydraulically with a beam scale and afterwards transformed into a digital electric signal. Differences between dry bulb temperature and mean skin temperature were measured by semiconductor thermistors and also transformed into digital signals. With special software an interfaced personal computer assisted in performing SPDC and in calculating heat losses due to evaporation, radiation, and conduction. In a thermoneutral environment, six healthy volunteers were investigated to determine the mean convective heat transfer coefficient (hc) from the difference in an individual between the metabolic energy transformation (M) measured by indirect calorimetry (IC) and the sum of heat losses by radiation, conduction, and evaporation. The room-specific value of hc of 2.12 (SD 0.22) W.m-2.degrees C-1 was in good agreement with data in the literature. Compared to the results of M from a second series of IC, the total heat loss (THL) measured by SPDC in a thermoneutral environment was calculated as 100.5 (SD 6.0)%. The THL by SPDC performed three times at 3-h intervals on ten other volunteers revealed a mean difference of 0.22 (SD 1.74) W.m-2. Thus, SPDC would seem to be a valid and reproducible method under conditions of thermal neutrality.
本文介绍了一种简化的直接量热法（SPDC），用于测定仰卧位呼吸功能正常受试者的静息代谢率。该方法基于计算机辅助测量因蒸发、辐射、传导和对流造成的热量损失。受试者的总质量损失通过梁式秤进行液压记录，然后转换为数字电信号。干球温度与平均皮肤温度的差值由半导体热敏电阻测量，并同样转换为数字信号。借助专用软件，接口个人计算机协助执行SPDC并计算因蒸发、辐射和传导造成的热量损失。在热中性环境中，对6名健康志愿者进行了研究，以根据间接量热法（IC）测量的个体代谢能量转换（M）与辐射、传导和蒸发造成的热量损失总和之间的差异，确定平均对流热传递系数（hc）。hc的房间特定值为2.12（标准差0.22）W·m-2·℃-1，与文献数据吻合良好。与第二轮IC测量的M结果相比，在热中性环境中SPDC测量的总热量损失（THL）计算为100.5（标准差6.0）%。对另外10名志愿者每隔3小时进行三次SPDC测量，其THL的平均差异为0.22（标准差1.74）W·m-2。因此，在热中性条件下，SPDC似乎是一种有效且可重复的方法。
