Dickerson R N, Murrell J E, Brown R O, Kudsk K A, Leeper K V
Department of Clinical Pharmacy, University of Tennessee, Memphis 38163, USA.
Nutrition. 1995 Mar-Apr;11(2):145-8.
To evaluate the efficacy of adding a volume reservoir to reduce variability in ventilator-induced fluctuation in inspired oxygen concentration (FiO2) and to reduce oxygen consumption measurement error, we evaluated two ventilators (Puritan-Bennett 7200 and Bear 2) at three inspired oxygen concentrations ranging from 35% to 60%. Continuous sampling of oxygen concentration was conducted for each ventilator. The maximum variability in oxygen concentration was recorded at each minute and oxygen consumption error sensitivity was calculated for both ventilators at three different oxygen concentrations, with and without the use of a baffled 3-L reservoir placed into the inspiratory circuit between the ventilator and test lung. The use of a baffled 3-L reservoir reduced oxygen consumption error sensitivity with the Puritan-Bennett 7200 ventilator at all three oxygen concentrations (p < 0.01). Similar results were found with the Bear 2 ventilator except at the highest FiO2, at which oxygen consumption error sensitivity was not altered. Use of a baffled volume reservoir can significantly reduce ventilator-dependent errors in measuring oxygen consumption via indirect calorimetry. However, when the FiO2 is widely variable, the reservoir is not helpful in reducing error at higher FiO2 concentrations.
为评估增加一个容量储存器以减少呼吸机引起的吸入氧浓度（FiO2）波动的变异性以及减少氧耗测量误差的效果，我们在35%至60%的三种吸入氧浓度下评估了两台呼吸机（伟康7200和熊牌2型）。对每台呼吸机进行氧浓度的连续采样。记录每分钟氧浓度的最大变异性，并计算两台呼吸机在三种不同氧浓度下使用和不使用置于呼吸机与测试肺之间吸气回路中的带挡板3升储存器时的氧耗误差敏感性。在所有三种氧浓度下，使用带挡板的3升储存器均降低了伟康7200呼吸机的氧耗误差敏感性（p < 0.01）。熊牌2型呼吸机也得到了类似结果，但在最高FiO2时，氧耗误差敏感性未改变。使用带挡板的容量储存器可显著减少通过间接量热法测量氧耗时呼吸机相关的误差。然而，当FiO2变化很大时，该储存器在较高FiO2浓度下无助于减少误差。
