Claure Nelson, D'Ugard Carmen, Bancalari Eduardo
Division of Neonatology, Department of Pediatrics, University of Miami School of Medicine, Miami, Florida 33101, USA.
J Pediatr. 2003 Sep;143(3):315-20. doi: 10.1067/S0022-3476(03)00299-3.
Mainstream airflow sensors used in neonatal ventilators to synchronize mechanical breaths with spontaneous inspiration and measure ventilation increase dead space and may impair carbon dioxide (CO(2)) elimination.
To evaluate a technique consisting of a continuous gas leakage at the endotracheal tube (ETT) adapter to wash out the airflow sensor for synchronization and ventilation monitoring without CO(2) rebreathing in preterm infants.
Minute ventilation (V'(E)) by respiratory inductance plethysmography, end-inspiratory and end-expiratory CO(2) by side-stream microcapnography, and transcutaneous CO(2) tension (TcPCO(2)) were measured in 10 infants (body weight, 835+/-244 g; gestational age, 26+/-2 weeks; age, 19+/-9 days; weight, 856+/-206 g; ventilator rate, 21+/-6 beats/min; PIP, 16+/-1 centimeters of water (cmH(2)O); PEEP, 4.2+/-0.4 cmH(2)O; fraction of inspired oxygen (FIo(2)), 0.26+/-0.6). The measurements were made during four 30-minute periods in random order: IMV (without airflow sensor), IMV+Sensor, SIMV (with airflow sensor), and SIMV+Leak (ETT adapter continuous leakage).
Airflow sensor presence during SIMV and IMV+Sensor periods resulted in higher end-inspiratory and end-expiratory CO(2), Tcpco(2), and spontaneous V'(E) compared with IMV. These effects were not observed during SIMV+Leak.
The significant physiologic effects of airflow sensor dead space during synchronized ventilation in preterm infants can be effectively prevented by the ETT adapter continuous leakage technique.
新生儿呼吸机中用于使机械通气与自主吸气同步并测量通气量的主流气流传感器会增加死腔，可能损害二氧化碳（CO₂）的清除。
评估一种技术，该技术通过气管内导管（ETT）接头处的持续气体泄漏来冲洗气流传感器，以实现同步和通气监测，同时避免早产儿出现CO₂重复吸入。
采用呼吸感应体积描记法测量分钟通气量（V̇(E)），采用旁流微二氧化碳图测量吸气末和呼气末CO₂，以及测量经皮CO₂分压（TcPCO₂），对10例婴儿（体重835±244 g；胎龄26±2周；年龄19±9天；体重856±206 g；呼吸机频率21±6次/分钟；吸气峰压16±1厘米水柱（cmH₂O）；呼气末正压4.2±0.4 cmH₂O；吸入氧分数（FIo₂）0.26±0.6）进行测量。测量在四个30分钟时间段内随机进行：间歇指令通气（IMV，无气流传感器）、IMV+传感器、同步间歇指令通气（SIMV，有气流传感器）和SIMV+泄漏（ETT接头持续泄漏）。
与IMV相比，SIMV和IMV+传感器时间段内气流传感器的存在导致吸气末和呼气末CO₂、TcPCO₂以及自主V̇(E)更高。在SIMV+泄漏期间未观察到这些影响。
通过ETT接头持续泄漏技术可有效预防气流传感器死腔在早产儿同步通气期间产生的显著生理影响。
