Dependence of the gradient between arterial and end-tidal P(CO(2)) on the fraction of inspired oxygen
Dependence of the gradient between arterial and end-tidal P(CO(2)) on the fraction of inspired oxygen
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动脉和潮气末 P(CO(2)) 之间的梯度对吸入氧分数的依赖性
DOI：
10.1093/bja/aer171
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Sobue K
中科院分区：
文献类型：
--
作者：
Yamauchi H;Ito S;Sasano H;Azami T;Fisher J;Sobue K
end -tidal pco2 （Pe 'CO2）通常用于临床通气充分性评估，因为它提供了paco2的估计。二氧化碳对二氧化碳的反射效果取决于它们之间的梯度，表示为ΔPa - e 'CO2。ΔPa - e ' co2的主要决定因素是肺泡死腔（Vdalv）。吸入O2（FiO2）的比例被认为对麻醉患者ΔPa - e ' co2没有实质性影响。我们假设，高fio2确实可能通过优先扩张血管灌注良好的肺泡而增加ΔPa - e ' co2，导致血流从灌注不良的肺泡重新分配到这些肺泡，并增加indalv。因此，我们研究了fio_2变化对ΔPa - e ' co2和vdalv的影响。方法经机构审查委员会批准和知情同意，我们研究了20例ASA I-II仰卧患者在全身和硬膜外联合麻醉下接受选择性下腹部手术。在一定的通风水平下，按随机顺序施加0.21、0.33、0.5、0.75和0.97的fio2水平，并计算ΔPa - e ' co2和vdalv。结果ΔPa−e’co2值按fio2的大小依次为{mean [standard error of mean (sem)]} 0.13（0.04）、0.28（0.08）、0.29（0.09）、0.44（0.11）、0.53 (0.09)kPa。相应的vdalv值分别为25.5、33.8、35.8、48.9和47.4 ml。除了0.33-0.5和0.75 - 0.97 fio2水平外，每个连续的高氧水平都显示ΔPa−e ' co2显著增加。结论麻醉患者的ΔPa - e 'CO2依赖于fio2。
BackgroundEnd-tidalPCO2(Pe′CO2) is routinely used in the clinical assessment of the adequacy of ventilation because it provides an estimate ofPaCO2. How wellPe′CO2reflectsPaCO2depends on the gradient between them, expressed as ΔPa−e′CO2. The major determinant of ΔPa−e′CO2is alveolar dead space (Vdalv). The fraction of inspired O2(FiO2) is not thought to substantially affect ΔPa−e′CO2in anaesthetized patients. We hypothesized that a highFiO2may indeed increase ΔPa−e′CO2by preferentially vasodilating well-perfused alveoli, resulting in the redistribution of blood flow to these alveoli from poorly perfused alveoli and an increase inVdalv. We therefore investigated the effects of changes inFiO2on ΔPa−e′CO2andVdalv.MethodsWith Institutional Review Board approval and informed consent, we studied 20 ASA I–II supine patients undergoing elective lower abdominal surgery under combined general and epidural anaesthesia. At constant levels of ventilation,FiO2levels of 0.21, 0.33, 0.5, 0.75, and 0.97 were applied in a random order and ΔPa−e′CO2andVdalvwere calculated.ResultsThe ΔPa−e′CO2values were, in order of ascendingFiO2, {mean [standard error of the mean (sem)]} 0.13 (0.04), 0.28 (0.08), 0.29 (0.09), 0.44 (0.11), and 0.53 (0.09) kPa. The corresponding values ofVdalvwere 25.5, 33.8, 35.8, 48.9, and 47.4 ml. Each successive hyperoxic level showed a significant increase in ΔPa−e′CO2except between the 0.33–0.5 and 0.75–0.97FiO2levels.ConclusionsThese data demonstrate that ΔPa−e′CO2, in anaesthetized patients depends onFiO2.