Fujino Y, Kacmarek R M, Hess D R
Massachusetts General Hospital, Boston 02114, USA.
Respir Care. 2000 Sep;45(9):1097-104.
Inhaled nitric oxide (NO) is used increasingly in the care of infants with hypoxemic respiratory failure and is frequently combined with high-frequency oscillation (HFO). The aim of this study was to evaluate delivery of NO during HFO using titration into the ventilator circuit or using the INOvent Delivery System.
NO was delivered into the HFO circuit at three sites (pre-humidifier, post-humidifier, and after the bellows) by continuous titration using a rotameter. The target NO concentration ([NO]) was initially adjusted using a rapid-response chemiluminescence NO analyzer without oscillation at 5, 10, and 20 parts per million (ppm). During the study, gas was sampled 5 cm from the bellows (proximal), 35 cm from the bellows (middle), and at the distal end of the circuit (distal). The ventilator was set at frequencies of 5, 10, and 15 Hz, mean airway pressures of 15, 20, and 25 cm H(2)O, and amplitudes of 20, 30, and 40 cm H(2)O. Soft and hard circuits were evaluated. The fraction of inspired oxygen was 0. 90, the inspiratory time fraction was 33%, and the bias flow was 20 L/min throughout the study. An INOvent Delivery System was also evaluated with the same HFO settings.
The fluctuation of [NO] was minimal with continuous titration pre-humidifier at all HFO settings. [NO] fluctuated with titration post-humidifier and after the bellows, especially at the proximal sampling site. At the lung model, however, fluctuation of [NO] was always < 1.5 ppm and usually < 1 ppm. Delivered [NO] was lower than target [NO] with injection after the bellows (> 5%). The soft circuit showed better mixing of NO than the hard circuit. The INOvent Delivery System delivered a stable and accurate [NO] at all settings. [NO(2)] was < 1 ppm at all settings.
Mixing of NO during HFO was acceptable at all the injection sites evaluated, although injection pre-humidifier was preferable because of small fluctuations of [NO]. The INOvent Delivery System was simple to use and delivered an accurate and precise [NO] during HFO.
吸入一氧化氮（NO）在低氧性呼吸衰竭婴儿的护理中应用越来越广泛，且常与高频振荡（HFO）联合使用。本研究的目的是评估在HFO期间通过滴定到呼吸机回路或使用INOvent输送系统来输送NO的情况。
通过使用转子流量计连续滴定，在三个部位（加湿器前、加湿器后和波纹管后）将NO输送到HFO回路中。最初使用快速响应化学发光NO分析仪在5、10和20百万分之一（ppm）的浓度下，在无振荡的情况下调整目标NO浓度（[NO]）。在研究过程中，在距离波纹管5厘米（近端）、35厘米（中间）和回路远端（远端）采集气体样本。呼吸机设置为频率5、10和15赫兹，平均气道压力15、20和25厘米水柱，振幅20、30和40厘米水柱。对软回路和硬回路进行了评估。在整个研究过程中，吸入氧分数为0.90，吸气时间分数为33%，偏流为20升/分钟。还在相同的HFO设置下对INOvent输送系统进行了评估。
在所有HFO设置下，加湿器前连续滴定的[NO]波动最小。加湿器后和波纹管后滴定的[NO]会波动，尤其是在近端采样部位。然而，在肺模型中，[NO]的波动始终<1.5 ppm，通常<1 ppm。波纹管后注射时输送的[NO]低于目标[NO]（>5%）。软回路显示出比硬回路更好的NO混合效果。INOvent输送系统在所有设置下都能输送稳定且准确的[NO]。在所有设置下，[NO₂]<1 ppm。
在评估的所有注射部位，HFO期间NO的混合情况均可接受，不过由于[NO]波动较小，加湿器前注射更为可取。INOvent输送系统使用简单，在HFO期间能输送准确且精确的[NO]。
