高频通气时传导气道在气体交换中的作用——一项临床与理论分析。

The role of conducting airways in gas exchange during high-frequency ventilation--a clinical and theoretical analysis.

作者信息

Eriksson I

出版信息

Anesth Analg. 1982 Jun;61(6):483-9.

Abstract

Observed values for lung clearance index and mixing ratio appeared to be better than the calculated ideal values in seven of nine patients during high-frequency positive-pressure ventilation (HFPPV). The presence of substantial amounts of N2 (9.2% to 22.5%) in the initial expired gas suggests that these findings are explained by amplified mixing of tidal gas with residual gas in the conducting airways secondary to the high gas flow velocity during inspiration. There was a moderate positive correlation (r = 0.59) between the amount of residual gas (N2) present in the initial part of the expirate and the efficiency of nitrogen washout. A "functional" dead space for N2 can be calculated. During HFPPV this was 125 +/- 71 ml and during spontaneous breathing 354 +/- 121 ml (p less than 0.001), giving a VD/VT for N2 of 0.38 +/- 0.06 as compared with 0.84 +/- 0.21 (p less than 0.001) during spontaneous breathing. It also implies a more efficient washout of N2 than of CO2 (VD/VT approximately 0.75) during HFPPV.

摘要

在高频正压通气（HFPPV）期间，9名患者中有7名患者的肺清除指数和混合比的观测值似乎优于计算出的理想值。初始呼出气体中存在大量的N2（9.2%至22.5%），这表明这些发现可以用吸气期间高气流速度导致的潮气量与传导气道中残气量的混合增强来解释。呼出气体初始部分中存在的残气量（N2）与氮清除效率之间存在中度正相关（r = 0.59）。可以计算出N2的“功能性”死腔。在HFPPV期间，其为125±71 ml，在自主呼吸期间为354±121 ml（p<0.001），N2的VD/VT为0.38±0.06，而在自主呼吸期间为0.84±0.21（p<0.001）。这也意味着在HFPPV期间，N2的清除比CO2（VD/VT约为0.75）更有效。