允许性高碳酸血症在先天性重症膈疝中的作用

目的 探讨允许性高碳酸血症这一通气策略在先天性重症膈疝治疗中的意义.方法 回顾本院1985年1月到2007年5月的33例重症膈疝患儿,按通气方法分两个阶段,第一阶段14例,平均气道峰压PIP≥30cm H2O,尽可能保证较低二氧化碳分压(PaCO2)及较高的pH值.第二阶段19例,术前患儿采用允许性高碳酸血症的通气策略:控制PIP≤22cm H2O,保证导管前SaO2≥80%,PaCO2≤60mmHg,对导管后氧饱和度放宽标准,如果患儿导管前SaO2<80%或PaCO2>60mmHg,则应用高频通气,以出院患儿生存情况作为评价指标.结果 两个阶段患儿胎龄、体重、疾病的严重程度差异无统计学意义(P>0.05),第一阶段患儿生存率50%,第二阶段为84.2%;气道峰压,第二阶段较第一阶段明显降低,两者差异有统计学意义(P<0.05);第一阶段术前有2例发生气胸,术后患儿死亡,第二阶段则无类似气道损伤发生.延期手术/急诊手术组生存率为77.2%/65.4%(P>0.05).11例患儿进行了高频通气.8例患儿吸入NO,仅短时提高SaO2,但肺动脉高压未缓解.结论 允许性高碳酸血症配合低压高频通气可以明显减少医源性气道损伤,提高重症膈疝存活率.

Congenital diaphragmatic hernia in infants treated with permissive hypercapnea

Objective To evaluate the impact of permissive hypercapnea strategy on the survival of patients with congenital diaphragmatic hernia (CDH). Methods From January 1985 through May 2007, infants with CDH, symptomatic in the first 6 hours of life, were reviewed. Thirty-three patients were divided into two periods. In period 1, treatment consisted of paralysis, hyperventilation, and alkalization for pulmonary hypertension. However, in period 2, hyperventilation and alkalization were abandoned. Patients were lightly sedated and ventilated with the lowest pressure providing adequate chest movement, and the rate was set to patient comfort, with the goals of maintaining postductal PaCO2 at 40 to 60 mmHg, keeping preductal saturations remain≥80%, and the perfusion is satisfactory. High frequency ventilation and nitric oxide were reserved for the life- threatening situation. Results The disease severity and incidence of associated anomalies did not differ between groups. Overall, 16 of 19(84.2%) patients in study period 2 survived compared with 7 of 14(50%) in the hyperventilation period (P<0.05). Peak inspiratory pressure and arterial PH were lower and PaCO2 was higher (P<0. 05) in period 2 than in the period 1. Two patients died because of pneumothorax in period 1. There was no mortality in period 2. Delayed surgery was performed in several patients, but it showed no survival benefit. Although NO were used in 8 patients, this did not appeared to contribute to our improved results. Conclusions The majority of infants with life-threatening CDH treated with permissive hypercapnea and high frequency ventilation lead to significantly improved survival rates, and decreased incidence of barotraumas.