Pulmonary Medicine Service, Landstuhl Regional Medical Center, CMR 402, Box 307, APO AE 09180, Landstuhl, Germany.
Respir Care. 2010 Jun;55(6):734-40.
High-frequency percussive ventilation (HFPV) is an increasingly used mode of mechanical ventilation, for which there is no proven real-time means of measuring delivered tidal volume (V(T)).
To validate a pneumotachograph for HFPV and then exploit flow-sensor data to describe the behavior of both low-frequency and high-frequency breaths.
Sensor performance was gauged during changes in high-frequency (4-12 Hz) and low-frequency rate and ratio, mean airway pressure, oxygen concentration, heated or heated-humidified gas flow, and endotracheal tube diameter. Glass bottle (adiabatic V(T)) and test lung (adiabatically derived low-frequency V(T)) based adiabatic conditions provided both an initial source for analog-signal calibration and an accepted standard comparator to flow-sensor measurement of high-frequency and low-frequency (flow-sensor-derived) V(T)), respectively.
Pneumotachography proved accurate and precise over an array of tested settings and conditions when analyzing both high-frequency (difference between mean +/- SD high-frequency V(T) and adiabatic V(T) was -0.2 +/- 1.8%, 95% confidence interval -0.5 to 0.9%) and low-frequency breaths (mean +/- SD difference between flow-sensor-derived low-frequency V(T) and adiabatically derived low-frequency V(T) was 0.6 +/- 2.4%, 95% confidence interval 0.1-1.1%). High-frequency V(T) and frequency exhibited an exponential relationship. During HFPV, flow-sensor-derived low-frequency V(T) had a mean +/- SD of 1,337 +/- 700 mL, 95% confidence interval 1,175-1,499 mL.
Readily available pneumotachography provided accurate measurements of low-frequency and high-frequency V(T) during HFPV. In the setting of acute lung injury, typical HFPV settings may deliver injurious V(T).
高频喷射通气（HFPV）是一种越来越常用的机械通气模式，但目前尚无经过验证的实时测量输送潮气量（V（T））的方法。
验证一种用于 HFPV 的气流计，并利用流量传感器数据来描述低频和高频呼吸的特征。
在高频（4-12Hz）和低频呼吸频率和比率、平均气道压力、氧浓度、加热或加热加湿气体流量以及气管内导管直径变化时，评估传感器性能。玻璃瓶（绝热 V（T））和测试肺（绝热衍生的低频 V（T））提供了初始模拟信号校准源，并作为流量传感器测量高频和低频（流量传感器衍生的 V（T））的接受标准比较器。
气流计在分析高频（高频 V（T）和绝热 V（T）的平均值 +/- SD 之间的差异为-0.2 +/- 1.8%，95%置信区间为-0.5 至 0.9%）和低频呼吸时，在一系列测试设置和条件下均表现出准确和精确的性能（流量传感器衍生的低频 V（T）和绝热衍生的低频 V（T）的平均值 +/- SD 之间的差异为 0.6 +/- 2.4%，95%置信区间为 0.1-1.1%）。高频 V（T）和频率呈指数关系。在 HFPV 期间，流量传感器衍生的低频 V（T）的平均值 +/- SD 为 1,337 +/- 700 mL，95%置信区间为 1,175-1,499 mL。
现成的气流计可在 HFPV 期间准确测量低频和高频 V（T）。在急性肺损伤的情况下，典型的 HFPV 设置可能会输送有害的 V（T）。
