Semsroth M
Infusionsther Klin Ernahr. 1985 Dec;12(6):294-303.
A new device for continuous measuring oxygen uptake (VO2) and carbondioxide elimination (VCO2) in artificially ventilated or CPAP-system breathing children has been developed. A dual-channel analyzer system based on zirconiumoxyd cells measures oxygen fractions. This allows not only single measurements but also continuous determination of fraction differences for oxygen (delta FO2) (accuracy +/- 0.003 Vol%). Carbondioxide is measured by infrared absorption. A mixing device for inspiratory gas was designed to smooth fluctuations of inspired oxygen fractions almost completely. The reliable sampling system for expiratory gases has already been described [19]. The breathing-e.g. ventilating-system was modified in such a way that the total gas flow is independent of mode and breathing volume (equally 15 l/min). For which purpose we use a self aspirating, time-cycled, volume limited respirator or a high-flow-CPAP-system. The prototype described ran test performances on a specially developed pneumatic metabolic-lung-model. This new lung model enables free choice of respiratory quotient (R) by independent setting of O2-uptake and CO2-elimination. Under these controlled laboratory conditions gasvolume-balances correspond to expected values in children really as shown during simulated trials. In the metabolic-lung-model accuracy and reproduction averaged +/- 1% for VCO2. Both were independent of the mode of ventilatory support, FIO2, and R. Determinations of VO2 were more dependent on FIO2 and R. After computing primary data according to a special formula which equalizes differences between VI and VE the maximal error was +/- 7%. Maximum difference between preset and measured R-values ranging from 0.769 to 1.429 was -4.6%, determined at R = 1.429. By means of this independent test series insights into clinically expected measurement errors and dimensions of limits of accuracy could be demonstrated. It seems to be justified that our newly developed device for accurate measuring O2-uptake and CO2-elimination is highly recommendable for use in extremely difficult conditions as in ventilated children.
已开发出一种用于连续测量人工通气或持续气道正压通气（CPAP）系统呼吸的儿童的氧摄取量（VO₂）和二氧化碳排出量（VCO₂）的新设备。基于氧化锆电池的双通道分析仪系统测量氧分数。这不仅允许进行单次测量，还能连续测定氧的分数差（δFO₂）（准确度为±0.003体积%）。二氧化碳通过红外吸收进行测量。设计了一种吸气气体混合装置，几乎能完全消除吸入氧分数的波动。呼气气体的可靠采样系统已在文献[19]中描述。呼吸设备（如通气系统）经过改进，使总气体流量与模式和呼吸量无关（均为15升/分钟）。为此，我们使用自吸气、时间循环、容量受限的呼吸机或高流量CPAP系统。所描述的原型在专门开发的气动代谢肺模型上进行了测试性能。这种新的肺模型能够通过独立设置氧摄取量和二氧化碳排出量来自由选择呼吸商（R）。在这些受控的实验室条件下，气体体积平衡与模拟试验中儿童的预期值相符。在代谢肺模型中，VCO₂的准确度和重现性平均为±1%。两者均与通气支持模式、吸入氧分数（FIO₂）和R无关。VO₂的测定更依赖于FIO₂和R。根据一个特殊公式计算原始数据以平衡吸气量（VI）和呼气量（VE）之间的差异后，最大误差为±7%。预设R值与测量R值之间的最大差异范围为0.769至1.429，在R = 1.429时确定为-4.6%。通过这个独立的测试系列，可以证明对临床预期测量误差和准确度极限范围的深入了解。我们新开发的用于精确测量氧摄取量和二氧化碳排出量的设备在诸如通气儿童等极其困难的条件下使用是非常值得推荐的，这似乎是合理的。
