重症哮喘的容许性高碳酸血症机械通气治疗

Mechanical ventilation therapy with permissive hypercapnia in severe asthma

目的：探索重症哮喘患者容许性高碳酸血症（ＰＨＶ）机械通气治疗的效果。方法：观察８例重症哮喘患者，应用低潮气量〔ＶＴ，（５．７２±０．６２）ｍｌ／ｋｇ〕通气，容许一定限度的高碳酸血症〔动脉血二氧化碳分压（ＰａＣＯ２）＜１０．６ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ），ｐＨ＞７．１５〕。动态监测气道峰压（ＰＩＰ）、动脉血气、心率和血压。结果：８例患者ＰＨＶ治疗前均有呼吸衰竭伴意识障碍，ＰａＣＯ２为（１１．８±３．５）ｋＰａ，ｐＨ为７．１５±０．０７，动脉血氧分压（ＰａＯ２）／吸氧浓度（ＦｉＯ２）为（２４．５±６．３）ｋＰａ。采用ＰＨＶ治疗（１０．６±７．１）日，ＰＨＶ治疗２小时后ＰａＯ２／ＦｉＯ２明显提高〔（３６．９±１６．１）ｋＰａ，Ｐ＜０．０５〕，１２小时后ＰａＣＯ２和ｐＨ开始改善〔ＰａＣＯ２（８．３±１．６）ｋＰａ，ｐＨ７．２６±０．１０；Ｐ均＜０．０５）〕。ＰａＣＯ２＞６．０ｋＰａ机械通气时间为（５．６±３．１）日，而ｐＨ＜７．３５机械通气时间为（２．６±１．４）日。患者意识转清时间平均为５．４日。在ＰＨＶ治疗期间ＰＩＰ为（４．４３±１．５６）ｋＰａ，心率为（１１６．２±９．３）次／ｍｉｎ，血压为（１５．３±?

Objective:To study the mechanical ventilation (MV) therapy in severe asthma.Methods:Eight cases of severe asthma were included in the present study.Low tidal volume V T,(5 72±0 62)ml/kg was used and certain extent of hypercapnia PaCO 2<10 6 kPa(1 kPa=7 5 mmHg),pH>7 15 was permitted.Airway peak inspiratory pressure (PIP),arterial blood gas analysis,heart rate (HR),and blood pressure (BP) were monitored at various intervals.Results:Before MV,all the eight cases had respiratory failure with disturbance in consciousness,PaCO 2,pH,and oxygenation index (PaO 2/FiO 2) were (11 8±3 5) kPa,7 15±0 07,and (24 5±6 3)kPa,respectively.Permissive hypercapnia ventilation (PHV) was applied in treatment for (10 6±7 1)days.PaO 2/FiO 2 was increased significantly at 2 hours following PHV treatment (36 9±16 1)kPa, P <0 05 ,PaCO 2 and pH were improved 12 hours later (8 3±1 6)kPa and 7 26±0 10,both P <0 05 .The duration of PHV to keep PaCO 2>6 0 kPa was (5 6±3 1)days,pH<7 35 was 2 6±1 4 days,and patients became conscious in about 5 4 days.Also,PIP,HR and BP were respectively (4 43±1 56)kPa,(116 2±9 3)beats/min,and (15 3±2 2)kPa/(9 9±1 4)kPa during treatment with PHV.Conclusions:With appropriate low volume support (half of conventional V T) and sufficient oxygen support,PHV might improve arterial oxygenation rapidly,then gradually decrease PaCO 2 and increase pH.It suggested that PHV is a safe and effective MV therapy of severe asthma.