- 期刊
Breathing Near to Residual Volume with Positive and Expiratory Pressure
接近肺餘容積外加正壓呼氣(PEEP)的呼吸所引起的生理效應
摘要
二十五位健康受試者，在接近肺餘容積(RV)的呼吸方式下呼吸，用ear oximeter監測血氧飽和度(Oxygen Saturation)，發現有血氧飽和度下降現象(Oxygen desaturation)。此種血缺氧症(hypoxaemia)係由於肺底部小氣道閉鎖(Closure of dependent airways)的關係。本實驗以增加呼氣壓力(Positve End Expiratory Pressure-PEEP)，受試者同樣用接近肺餘容積的呼吸方式下呼吸，來探討血缺氧症，是否會減輕。研究結果，發現血缺氧症，不但未獲改善，反而加劇。分析呼出氣成份，證明肺內通氣血流比値(Ventilation-perfusion ratio)，在此呼吸方式下，已有改變。促使血缺氧症惡化的原因，係由於肺內通氣血流比値降低的範圍及升高的範圍，皆有增加。 由此一研究結果，司瞭解肺內局部控制，以及調節肺內通氣血流比値的機制之重要性。
關鍵字
無資料並列摘要
Normal subjects breathing near to residual volume exhibit arterial desaturation and this has been monitored with an ear oximeter. The hypoxaemia has been attributed to closure of dependent airways and the present series of experiments examines the effect of raising expiratory pressure on this phenomenon, whilst inspiring at ambient pressure. The general results showed a greater degree of hypoxaemis rather than its mitigation which was the expected result. In order to understand the changes in ventilation-perfusion ratio expired gas analysis was undertaken and this suggested that expiring against pressure increassed the volume of lung with a low ventilation-perfusion ratio, and also increased the volume with a high ratio. There was also an unexplained increase in breathing rate. These results are significant in the understanding of local control over ventilation-perfusion ratios.