高频振荡通气治疗小儿重度肺源性急性呼吸窘迫综合征的疗效分析

Efficacy of high frequency oscillation ventilation in pediatric patients with severe pulmonary acute respiratory distress syndrome

目的评估高频振荡通气(HFOV)治疗小儿重度肺源性急性呼吸窘迫综合征(ARDSp)的临床疗效。方法选择河北省儿童医院2015年1月至2018年7月收治的ARDSp患儿28例,在采用常频机械通气(CMV)失败后行HFOV治疗。参数设置:初始设置平均气道压较CMV时高2~3 cmH2O(1 cmH2O≈0.098 kPa),吸入氧浓度(FiO2)0.6~1.0,维持经皮脉搏血氧饱和度(SpO2)0.89以上;振幅以观察到胸壁振荡延续到患儿腹股沟处为限,振荡频率为9~12 Hz,偏置气流25~30 L/min;吸气时间百分比初始设置为33%,根据血气水平调整呼吸机参数:动脉血二氧化碳分压(PaCO2)增高时提高振幅,降低频率,反之亦反。观察治疗前及治疗后12、24、48、72 h通气-氧合指标、循环指标的变化以及患儿预后。结果与治疗前比较,HFOV治疗后12、24、48、72 h患儿通气-氧合指标均有明显改善,PaCO2明显降低〔mmHg(1 mmHg≈0.133 kPa):45.7±13.2、41.4±11.7、43.5±12.8、42.4±10.7比52.3±16.1,均P<0.05〕,氧合指数(OI)也明显降低(24.5±2.3、23.7±2.4、22.7±2.5、21.6±1.7比29.7±2.8,均P<0.01),动脉血氧分压和吸入氧浓度比值(PaO2/FiO2)均明显升高(mmHg:115.5±12.2、120.7±14.2、151.8±10.5、113.8±12.6比69.3±11.2,均P<0.01)。随时间延长,HFOV治疗后患儿心率较治疗前逐渐降低并趋向于正常(次/min:147.0±9.4、139.1±11.5、124.1±10.3、125.3±11.6比172.1±9.5,均P<0.01),治疗前后各时间点平均动脉压(MAP)无明显变化(mmHg:50.2±7.6、51.5±8.6、50.6±8.5、51.2±6.3比52.6±7.8,均P>0.05)。本组患儿存活18例,死亡10例(病死率为35.7%)。结论对CMV治疗无效的ARDSp患儿,尽早实施HFOV治疗可有效改善肺部氧合及通气,对血流动力学无不良影响。HFOV可作为ARDSp患儿的重要抢救措施。

Objective To evaluate the clinical effectiveness of high frequency oscillation ventilation(HFOV)in treatment of pediatric patients with severe pulmonary acute respiratory distress syndrome(ARDSp).Methods Twenty-eight pediatric patients in Hebei Children's Hospital during January 2015 to July 2018 treated with HFOV after therapeutic failure by conventional mechanical ventilation(CMV)were enrolled.The ventilation parameters were set as follows:the initial mean airway pressure of HFOV was 2-3 cmH2O(1 cmH2O≈0.098 kPa)higher than that of CMV,inspired oxygen concentration(FiO2)was 0.6-1.0 to maintain percutaneous pulse blood oxygen saturation degree(SpO2)above 0.89;when the fluctuation from the chest wall continuing to groin was observed,that was the limit of amplitude,the fluctuating frequency of HFOV being 9-12 Hz and bias airflow 25-30 L/min;the initial inspiration time ratio was set at 33%and according to the levels of blood gas,ventilation parameters were adjusted;for example,when the partial pressure of carbon dioxide(PaCO2)was elevated,the amplitude was up-regulated and the frequency was down-regulated,and vice versa.The changes of ventilation-oxygenation and circulatory indexes before and after treatment at 12,24,48 and 72 hours,and patients'prognosis were observed and compared.Results Compared with those before treatment,after HFOV treatment at 12,24,48 and 72 hours,the ventilation-oxygenation indexes improved significantly and PaCO2 decreased obviously[mmHg(1 mmHg≈0.133 kPa):45.7±13.2,41.4±11.7,43.5±12.8,42.4±10.7 vs.52.3±16.1,all P<0.05]and oxygenation index(OI)also decreased significantly(24.5±2.3,23.7±2.4,22.7±2.5,21.6±1.7 vs.29.7±2.8,all P<0.01),while the ratio of arterial partial pressure of oxygen to inspiratory oxygen concentration(PaO2/FiO2)increased markedly(mmHg:115.5±12.2,120.7±14.2,151.8±10.5,113.8±12.6 vs.69.3±11.2,all P<0.01).After HFOV treatment,with the extension of time,the heart rate(HR)gradually decreased to normal(bpm:147.0±9.4,139.1±11.5,124.1±10.3,125.3±11.6 vs.172.1±9.5,all P<0.05).No obvious changes were observed in mean arterial pressure(MAP)before and after treatment at various time points(mmHg:50.2±7.6,51.5±8.6,50.6±8.5,51.2±6.3 vs.52.6±7.8,all P>0.05).In this group of patients with ARDSp,18 were survived and 10 died(mortality of 35.7%).Conclusions When the conventional mechanical ventilation has no effect for treatment of pediatric patients with ARDSp,using HFOV as soon as possible can beneficially improve the pulmonary oxygen delivery and ventilation without any adverse effect on hemodynamics.Thus,HFOV could be used as an important rescue treatment for children with ARDSp.