Gavriely N, Kelly K B, Grotberg J B, Loring S H
J Appl Physiol (1985). 1987 Jun;62(6):2398-403. doi: 10.1152/jappl.1987.62.6.2398.
To study the mechanism of generation of respiratory wheezes we examined the relationships between forced expiratory wheezes (FEW) and flow limitation in the lung. Tracheal lung sounds were measured in six healthy subjects during forced expiration through a flow-limiting valve in series with a high-impedance suction pump. Mouth pressure, esophageal pressure, transpulmonary pressure (Ptp), flow (V), and volume were also measured. For any flow rate, V was constant until the subject became flow limited. The onset of flow limitation was documented by a small change in V and a sudden change in Ptp, which was previously found by Olafsson and Hyatt to correspond to the beginning of the flow plateau of the isovolume pressure-flow curve (J. Clin. Invest. 48: 564-573, 1969). FEW started 107 +/- 45 ml (SD) after the onset of flow limitation. Additional 79 +/- 65 ml were exhaled between the onset of FEW to the final sharp drop in V. The frequency spectra of FEW were the same as those of respiratory wheezes found in obstructive airway diseases. Administration of inhaled bronchodilator (isoproterenol) did not eliminate the FEW, nor did it change their relationship to flow limitation. The sequence of events around the onset of FEW, and the tight correlation with the onset of flow limitation correspond well to recent experimental observations on the onset of flutter in collapsible, thick-walled latex tubes.
为研究呼吸性哮鸣音的产生机制，我们检测了用力呼气时哮鸣音（FEW）与肺内气流受限之间的关系。在六名健康受试者通过与高阻抗吸引泵串联的限流阀进行用力呼气过程中，测量气管呼吸音。同时还测量口腔压力、食管压力、跨肺压（Ptp）、气流（V）和容积。对于任何气流速率，在受试者出现气流受限之前V保持恒定。气流受限的开始通过V的微小变化和Ptp的突然变化记录下来，这一点先前由奥拉夫松和海亚特发现，对应于等容压力 - 流量曲线流量平台的开始（《临床研究杂志》48: 564 - 573, 1969）。FEW在气流受限开始后107±45 ml（标准差）出现。从FEW开始到V最终急剧下降之间又呼出了79±65 ml。FEW的频谱与在阻塞性气道疾病中发现的呼吸性哮鸣音的频谱相同。吸入支气管扩张剂（异丙肾上腺素）并不能消除FEW，也不会改变它们与气流受限的关系。FEW开始前后的事件顺序以及与气流受限开始的紧密相关性与最近关于可塌陷、厚壁乳胶管中颤动开始的实验观察结果非常吻合。
