Effect of hypercapnia on laryngeal airway resistance in normal adult humans.
Effect of hypercapnia on laryngeal airway resistance in normal adult humans.
复制标题
高碳酸血症对正常成年人喉部气道阻力的影响。
DOI：
10.1152/jappl.1994.77.6.2797
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Updegrove,JD
中科院分区：
文献类型：
--
作者：
Kuna,ST;Vanoye,CR;Griffin,JR;Updegrove,JD
在进行性高氧高碳酸血症过程中，测量了8名正常成人的喉气道阻力（Rlar）。在大多数受试者中，经喉压力-流量关系在碳酸正常条件下呈线性。在高碳酸血症期间，吸气和呼气的压力-流量关系是曲线的，随着经喉压力的增加，流量的增量逐渐变小。通过对整个吸气和呼气过程中的数据进行最小二乘线性回归，在其共同的流量范围内比较了不同CO2水平下的经喉压力-流量关系。在正常碳酸血症期间，平均斜率，即，平均Rlar为0.50 +/- 0.21（SD）cmH2O.l-1.s。潮气末CO2浓度为9%时，Rlar中度显著降低（P = 0.08）。在一个单独的系列实验中，受试者通过连接到呼吸速度计的面罩呼吸氧气和氦气混合气体。在正常碳酸血症期间存在的流量范围内的数据分析显示，鼻呼吸和口呼吸之间的Rlar没有差异，并且在高碳酸血症条件下使用基于氧气和氦气的气体混合物的Rlar类似降低。在常见但相对较低的流量范围内发现从正常碳酸血症到高碳酸血症的Rlar降低，这预示着在声门孔径不增加的情况下，在高流速下会发生Rlar的更大增加。
Laryngeal airway resistance (Rlar) was measured in eight normal adult humans during progressive hyperoxic hypercapnia. In most subjects, the translaryngeal pressure-flow relationship appeared linear under normocapnic conditions. During hypercapnia, the pressure-flow relationship on inspiration and expiration was curvilinear with increasing translaryngeal pressure associated with progressively smaller increments in flow. Translaryngeal pressure-flow relationships at different CO2 levels were compared over their common flow ranges by performing a least-squares linear regression on data throughout inspiration and expiration. During normocapnia, the mean slope, i.e., mean Rlar, was 0.50 +/- 0.21 (SD) cmH2O.l-1.s. A moderately significant decrease in Rlar was present at 9% end-tidal CO2 (P = 0.08). In a separate series of experiments, subjects breathed oxygen- and helium-based gas mixtures through a face mask attached to a pneumotachograph. Data analysis over the flow range present during normocapnia revealed no difference in Rlar between nose and mouth breathing and similar decreases in Rlar under hypercapnic conditions with the oxygen- and helium-based gas mixtures. The decrease in Rlar from normocapnic to hypercapnic conditions found over common, but relatively low, ranges of flow predicts that even greater increases in Rlar would occur at high flow rates in the absence of increasing glottic aperture.