神经调节辅助通气在婴幼儿先天性心脏病术后的应用

Application of neurally adjusted ventilatory assist in infants who underwent cardiac surgery for congenital heart disease

目的该研究旨在验证神经调节辅助通气(neurally adjusted ventilatory assist,NAVA)这一新的辅助通气模式在先天性心脏病术后应用的血流动力学安全性,并比较NAVA和传统的压力支持通气(pressure support ventilation,PSV)在氧合功能和气体交换能力上的差异。方法21例先天性心脏病纠治手术后患儿平均年龄(2.9±2.1)月,平均体重(4.2±1.4)kg,分别先后随机接受PSV和NAVA辅助通气60min,比较两种模式通气时的血流动力学指标、呼吸力学指标和氧合功能。结果21例患儿中3例因双侧膈肌麻痹,无膈肌电活动(EAdi)信号不能转换为NAVA模式而退出研究,另外18例PSV和NAVA模式的血流动力学指标差异无显著性意义,NAVA模式时PaO2/FiO2比值略高于PSV,但差异尚无显著性意义(P>0.05),PaCO2在二种模式中无明显差别,但NAVA模式此时的PIP和EAdi却低于PSV模式(P<0.05)。拔管后需要再次插管或无创通气的患儿EAdi信号明显高于顺利脱机者(30.0±8.4μVvs11.1±3.6μV;P<0.01)。结论该研究是国内最早关于NAVA通气模式在婴幼儿中应用的研究,NAVA与传统PSV相比在血流动力学上具有同样的安全性,且能够以较PSV更低的气道压力实现与PSV同样的气体交换,可以减少肺损伤的发生,拔管后EAdi信号的监测可以作为再插管或无创通气的预警指标。

OBJECTIVE： Neurally adjusted ventilatory assist （NAVA） is a new mode of mechanical ventilation that delivers ventilatory assist in proportion to neural effort. This study aimed to compare the hemodynamic safety, oxygenation and gas exchange effects ventilated with NAVA and with pressure support ventilation （PSV） in infants who underwent open-heart surgery. METHODS： Twenty-one infants who underwent open-heart surgery for congenital heart disease （mean age 2.9±2.1 months and mean weight 4.2±1.4 kg） were enrolled. They were ventilated with PSV and NAVA for 60 minutes respectively in a randomized order. The hemodynamic, oxygenation and gas exchange effects produced by the two ventilation modes were compared. RESULTS： Three cases failed to shift to NAVA because of the bilateral diaphragmatic paralysis after operation. In the other 18 cases, there were no significant differences in the heart rate （HR）, systolic blood pressure （BPs） and central venous pressure （CVP） in the two ventilation modes. The PaO2/FiO2 （P/F） ratio in NAVA was slightly higher than in PSV, but there was no statistical difference. PaCO2 did not show significant differences in the two modes. The peak inspiratory pressure （PIP） and electrical activity of the diaphragm （EAdi） in NAVA were significantly lower than in PSV. The EAdi signal after extubation was higher in infants who needed reintubation or intervention of noninvasive mechanical ventilation than in those who were extubated successfully （30.0±8.4 μV vs 11.1±3.6 μV; P〈0.01）. CONCLUSIONS： As the first study of application of NAVA in infants in China, this study shows that NAVA has the same homodynamic effects as PSV. However the PIP for maintaining the same level of PaCO2 in NAVA is significantly lower than that in the traditional PSV. Monitoring the EAdi signal after extubation may show the risks of reintubation or intervention of noninvasive mechanical ventilation.