Volume guarantee ventilation, interrupted expiration, and expiratory braking
Volume guarantee ventilation, interrupted expiration, and expiratory braking
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DOI：
10.1136/adc.2004.061390
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发表时间：
2005-08-01
影响因子：
5.2
通讯作者：
Morley, CJ
中科院分区：
文献类型：
--
作者：
McCallion, N;Lau, R;Morley, CJ
背景资料：在使用Drager Babylog 8000呼吸机的容量保证通气中，监测吸气和呼气流量，并在每次充气后计算呼气潮气量。修改下一次充气的压力，以确保呼气潮气量接近设定值。目的：研究自主呼吸、机械通气的婴儿在容量保证通气期间观察到的呼气中断。方法：在容量保证下通气的自主呼吸婴儿记录了气体流量、呼吸机压力、潮气量波形、血氧饱和度、心率，和经皮氧和二氧化碳在10分钟的recording.Results：共6540充气分析10名婴儿，62%被触发。发现两种不同的模式：（1）正常容量保证模式，97%触发性充盈和91%非触发性充盈。其呼气曲线正常，平均呼气潮气量在设定容量的3%以内，但由于婴儿的呼吸，变化很大。(2)由于呼气期间少量吸气（类似于1.3 ml/kg），在3%充气后出现呼气流量中断的模式。这导致呼吸机计算出不适当的总呼气潮气量的膨胀和增加的压力为下一个inflation.Conclusions：约3%的充气后，与体积保证通气，中断的呼气会导致增加的压力为下一个充气的类似4.9厘米H2O，与正常的体积保证充气。中断的呼气很可能是由于自动刹车。
Background: In volume guarantee ventilation with the Drager Babylog 8000 ventilator, inspiratory and expiratory flows are monitored and the expiratory tidal volume calculated following each inflation. The pressure for the next inflation is modified to ensure the expired tidal volume is close to the set value.Aim: To investigate interrupted expiration observed during volume guarantee ventilation of spontaneously breathing, ventilated infants.Methods: Spontaneously breathing infants, ventilated with volume guarantee, had recordings of gas flow, ventilator pressures, tidal volume waveforms, oximetry, heart rate, and transcutaneous oxygen and carbon dioxide during 10 minute recordings.Results: A total of 6540 inflations were analysed from 10 infants; 62% were triggered. Two different patterns were found: (1) Normal volume guarantee pattern with 97% of triggered and 91% untriggered inflations. It had a normal expiratory curve and a mean expired tidal volume within 3% of the set volume, but a large variation due to the babies' breathing. (2) A pattern of interrupted expiratory flow after,3% of inflations due to a small inspiration (similar to 1.3 ml/kg) during expiration. This led the ventilator to calculate an inappropriate total expired tidal volume for that inflation and an increase in the pressure for the next inflation.Conclusions: After about 3% of inflations, with volume guarantee ventilation, interruption of the expiration causes an increased pressure for the next inflation of similar to 4.9 cm H2O, compared with normal volume guarantee inflation. The interrupted expiration is most likely to be due to diaphragmatic braking.