自主呼吸状态下气道压力释放通气联合持续气道吹气对急性肺损伤犬心肺功能影响的研究

The Efficacy of Combination of Continous Tracheal Gas Insufflation and Airway Pressure Release Ventilation on Cardiopulmonary Function in Spontaneously Breathing Canine Model of Acute Lung Injury.

目的比较压力限制控制通气和气道压力释放通气这两种保护性通气策略,以及联合持续气道内吹气对急性肺损伤(ALI)犬心肺功能的影响,探寻出一种更有效而且不良反应小的治疗急性肺损伤的通气方法。方法将24只健康杂种犬,麻醉后仰卧位固定经右心房缓慢注入油酸(0.1 mL/kg)制成急性肺损伤模型后,随机平均分为压力限制控制通气组(A 组)、压力限制控制通气联合持续气道内吹气组(B 组),气道压力释放通气组(C 组)和气道压力释放通气联合持续气道内吹气组(D 组)。A 组和 B 组吸气压调至潮气量达6～8 mL/kg,吸呼比1:2,呼气末正压(PEEP)为8 cmH_2O(1 cmH_2O=0.098 kPa),呼吸频率(RR)20/min;C 和 D 组保留自主呼吸,低压水平(Plow)为8 cmH_2O,高压水平(Phigh)调定方法同上,高压持续时间(Thigh)2 s,低压持续时间(Tlow)1 s,释放频率20/min,吸氧浓度(FiO_2)均为100%,;CTGI 的流量为10 L/min 的纯氧行气管内吹气。各组分别记录分析 ALI 时以及通气后每隔1 h 时的氧和、呼吸动力学、血流动力学指标;于通气4 h 实验结束时处死,开胸取肺部组织置入10%甲醛溶液中待行肺损伤评分。结果通气后各组氧合指数(OI)均显著高于 ALI 时(P<0.05);各组第3 h、4 h,明显高于1 h;D 组4 h 高于2 h(P<0.05);C 和 D 组分别高于 A、B 组(P<0.05)。动脉血二氧化碳分压(PCO_2),A 和 C 组于通气后进行性升高,各时点之间差异均有显著性意义(P<0.05);B 组第2 h、3h、4 h 时高于 ALI 时,3h 和4h 时分别高于1 h(P<0.05);D 组无显著改变;通气过程 A 组显著高于其他组(P<0.05),C 组高于 B 和 D 组(P<0.05),B 和 D 两组之间差异无显著性意义(P>0.05)。动静脉分流(Qs/QT)各组通气后均显著低于 ALI 时(P<0.05),4 h 明显低于1 h(P<0.05);C 和 D 组分别低于 A 和 B 组(P<0.05)。通气最后,A 和 B 组的呼吸系统静态顺应性(CRS,sta)显著高于通气前(P<0.05),C 和 D 组于通气2 h 和4 h 时高于 ALI 时(P<0.05);最终,C 和 D 组分别高于 A 和 B 组(P<0.05)。气道峰压(PIP),B 组高于其它各组(P<0.05),其余各组之间差异无显著性意义(P>0.05)。心搏量(CO)A 组和 B 组通气后显著降低(P<0.05),D 组于通气结束时显著高于 A 组(P<0.05)。通气后 A 组平均肺动脉压(mPAP)上升幅度最大,C 组次之。肺损伤评分C和 D 组分别低于 A 和 B 组,但差异无统计学意义(P>0.05)。结论与压力限制控制通气相比,气道压力释放通气联合持续气道内吹气是治疗急性肺损伤更为有效的措施。

Objective To explore a more effective ventilatory method with less adverse effect to treat acute lung injury (ALI) through comparison of the effects on cardiopulnonary function in ALI canine between pressure limited controlled ventilation(PLCV) and airway pressure release ventilation (APRV),and both of them combined with continous tracheal gas insufflation(CTGI).Methods 24 hybrid healthy dogs after being anesthetized and intubated were placed in supine position,ALl were induced by injection of 0.1 mL/kg purified oleic acid into the right atrial catheter slowly,and then, were randomized into four groups to receive pressure limited controlled ventilation (group A),pressure limited controlled ventilation combined with continous tracheal gas insufflation (groupB),airway pressure release ventilation(group C)and airway pressure release ventilation combined with continous tracheal gas insufflation (group D) respectively.There were six dogs in each group.Positive end expiratory pressure (PEEP) was set at 8cmH2O,inspiratory airway pressure was adjusted to the value that produced a tidal volume of 6-8 mL/kg,the inspiratory to expiratory time ratio was set at 1:2 and the ventilator rate was maintained at 20Bpm,in group A and B; Dogs in group C and D were maintained spontaneous breathing,the low pressure(Plow)was set at 8 cmH_2O,the duration of Plow (Tlow) was set for 2 second,the method of setting high pressure level (Phigh) was similar to previous approach,the duration of high pressure was set for 1 second,the total release rate were 20 Bpm,the fraction of inspiratory oxygen(FiO2) was 100%;Flow rate of CTGI was set at 10L/min of pure oxgen.The condition of oxygenation,respiratory mechanics and hemodynamics were measured during experiment.Results During ventilation,oxygenation index (OI) were significantly higher than thoseof ALI(P<0.05),and which were greater after 3 and 4 hour of ventilation than those of 1 hour in each group;At the end of ventilation,OI in group C and group D were significantly increased than those of 2 hour(P<0.05); Among groups,OI in group C and group D were higher than those of group A and grou B respectively (P<0.05).Arterial partial pressure of carbon dioxide (PCO2) in group A and group C increased persistently during ventilation,there were markedly change among different phrases(P<0.05);In group B,PCO_2 were greater from 2 hour to 4 hour than those of ALI(P<0.05),which were substantially higher at 3 hour and 4 hour than 1 hour.There were no significant change in group D.;Among groups,group A was the highest;There were no significant difference between group B and group D(P >0.05).The ratio of shunted blood to total perfusion(Qs/QT) declined greatly after ventilation,which was evidently low- er at the end of ventilation than those of 1 hour in groups(P<0.05);Both group C and group D were significantly lower than group A and group B respectively (P<0.05).Finally,static compliance of respiratory system (CRS,sta) were higher than those of ALI in group A and group B(P<0.05),which in group C and group D were greater at post-ventilation of 2 hour and 4 hour than those of ALl(P<0.05);In group C and group D,CBS,sta were markedly greater than those of group A and group B respectively(P<0.05).Peak airway pressure(PIP) in group B were higher than any other groups(P <0.05),which have no significant difference among other groups.Cardic output (CO) decreased markedly after ventila- tion in group A and B compared with ALI(P<0.05),which substantially greater in group D than those of group A(P< 0.05)at last.During ventilation,the ascended amplitude of mean pulmonary arterial pressure(re_PAP)in group A was the greatest,group C were only inferior to group A;Lung injury score were higher in group A and group B than those of group C and group D,but without statistical significance.Conclusion Compared with PLCV,APRV combined with CTGI is a more effective method for treatment of ALI.