Vallinis P, Davis G M, Coates A L
Respiratory Medicine Division, McGill University-Montreal, Quebec, Canada.
J Appl Physiol (1985). 1990 Oct;69(4):1542-5. doi: 10.1152/jappl.1990.69.4.1542.
In premature and full-term neonates, technical limitations hamper the measurements of pulmonary mechanics. Current commercially available pneumotachographs (PNT) either increase the dead space, causing hyperventilation, or increase resistance, thus altering the mechanics of breathing. We modified a previously described low dead space PNT for infants to increase the linear range and frequency response. The mean resistance of the new PNT was 2.44 cmH2O.1-1.s compared with 2.65 cmH2O.1-1.s for the Fleisch no. 0 PNT. The added dead space over the standard endotracheal connector was 0.6 ml compared with 4.7 ml for the Fleisch PNT. Like the Fleisch PNT, the flow resistance was linear from 0 to 15 l/min. In response to a sinusoidal waveform, the new PNT had a phase angle of 21 degrees at 5 Hz and 50 degrees at 16 Hz compared with 19 degrees and 43 degrees, respectively, for the Fleisch PNT. The change in attenuation for both systems was zero until 20 Hz. In summary, the new PNT is lightweight and provides accuracy and low resistance with a very small dead space.
在早产儿和足月儿中，技术限制妨碍了肺力学的测量。目前市售的呼吸流速计（PNT）要么增加死腔，导致通气过度，要么增加阻力，从而改变呼吸力学。我们对先前描述的婴儿用低死腔PNT进行了改进，以增加线性范围和频率响应。新PNT的平均阻力为2.44 cmH2O·L-1·s，而Fleisch 0号PNT为2.65 cmH2O·L-1·s。标准气管内连接器上方增加的死腔为0.6 ml，而Fleisch PNT为4.7 ml。与Fleisch PNT一样，流速阻力在0至15 l/min范围内呈线性。对于正弦波形，新PNT在5 Hz时的相角为21度，在16 Hz时为50度，而Fleisch PNT分别为19度和43度。两个系统在20 Hz之前的衰减变化均为零。总之，新PNT重量轻，具有高精度、低阻力和非常小的死腔。
