持续气道正压通气、T管及压力支持通气等条件下患者呼吸功的比较性研究

Comparison of work of breathing among continuous positive airway pressure ventilation,T tube and pressure support ventilation in patients

目的：探讨从呼吸功角度评价呼吸机脱机方式优劣的可能性及其意义。方法：通过ＢｉｃｏｒｅＣＰ１００呼吸监测仪测定２２例患者在压力支持通气（ＰＳＶ）、持续气道内正压（ＣＰＡＰ）通气、Ｔ管及拔管后２小时等条件下的呼吸功的变化。结果：ＣＰＡＰ０．４９ｋＰａ（１ｋＰａ＝１０．２０ｃｍＨ２Ｏ）、Ｔ管、ＰＳＶ０．４９ｋＰａ时，患者呼吸功依次逐渐降低。ＣＰＡＰ０．４９ｋＰａ时呼吸功（９．９８Ｊ／ｍｉｎ）比ＰＳＶ０．４９ｋＰａ时高２３．７％（Ｐ＜０．００１），比拔管后２小时高４８．５％（Ｐ＜０．０１），与Ｔ管时比较无显著性差异。Ｔ管时呼吸功（９．３１Ｊ／ｍｉｎ）比ＰＳＶ０．４９ｋＰａ时高１５．４％（Ｐ＜０．０５），比拔管后２小时高３８．５％（Ｐ＜０．０１）。结论：患者呼吸功因脱机方式不同而显著不同，ＰＳＶ０．４９ｋＰａ比ＣＰＡＰ０．４９ｋＰａ和Ｔ管更有利于脱机。

Objective:To evaluate the application of work of breathing in assessment of weaning from mechanical ventilation and its mechanism.Methods:Using Bicore CP100 respiratory function monitor,changes in work of breathing were measured in 22 patients during continuous positive airway pressure (CPAP),T tube,pressure support ventilation (PSV),and at 2 hours after tube extraction.Results:Under the ventilative conditions of CPAP 0 49 kPa (1 kPa=10 20 cmH 2O),T tube as well as PSV 0 49 kPa,work of breathing was reduced successively.The work of breathing in patients with CPAP 0 49 kPa was 9 98 J/min,which was significantly higher than those with PSV 0 49 kPa(23 7%), P <0 001,and with 2 hours after tube extraction (48 5%), P <0 01.It was no obviously difference compared to the condition of T tube.However,in patients with T tube,the work of breathing was high by 15 4% compared with PSV 0 49 kPa( P <0 05),and by 38 5% compared with 2 hours after tube extraction ( P <0 01).Conclusions:Our data suggest that the work of breathing appears to be markedly different according to various models of weaning from mechanical ventilation.PSV 0 49 kPa is superior to both CPAP 0 49 kPa and T tube for weaning from mechanical ventilation.