Hartford C G, Turner M J, van Schalkwyk J M, Rogers G G
Department of Physiology, University of the Witwatersrand Medical School, Johannesburg, South Africa.
Pediatr Pulmonol. 1997 Nov;24(5):353-63. doi: 10.1002/(sici)1099-0496(199711)24:5<353::aid-ppul8>3.0.co;2-j.
Amplitude and phase frequency response characteristics of infant air-balloon catheters (IABC) of differing French gauge (FG) sizes and brands were quantified to determine their suitability for measuring dynamic intra-esophageal pressure (Pes) accurately. Frequency response performances of matching IABC and water-filled catheters (WFC) were also compared using the swept sine wave technique. The maximum respiratory rate within which IABCs could potentially measure Pes within a 5% error limit was calculated (FRR). Frequency responses of IABCs greater than FG size 5 exhibited underdamped resonant properties, while smaller FG size IABCs exhibited near-critical damping or overdamping. IABCs maintained uniform amplitude frequency responses up to 25 Hz, demonstrating the ability to measure Pes potentially up to 148 breaths/min within a 5% error limit. The frequency response performance of FG size 6 IABCs was similar to that of FG size 10 IABCs. Compared with matching WFCs, the frequency response performance of IABCs was significantly superior, the frequency response variability within IABC samples was lower, and IABC correlation between FG size and FRR was advantageously lower than for WFCs. FRR values for differing IABC brands and FG sizes are presented. We conclude that IABCs manufactured to infant-appropriate balloon specifications exhibit significantly superior frequency response characteristics compared with matching WFCs. Measurement accuracy is not improved using IABCs greater than FG size 6. Inexpensive intra-esophageal IABCs are technical suitable for the accurate measurement of dynamic Pes during high-frequency respiratory mechanics encountered during infant artificial ventilation.
对不同法制规格（FG）尺寸和品牌的婴儿气囊导管（IABC）的幅度和相位频率响应特性进行了量化，以确定它们是否适合准确测量动态食管内压力（Pes）。还使用扫频正弦波技术比较了匹配的IABC和充水导管（WFC）的频率响应性能。计算了IABC能够在5%误差范围内测量Pes的最大呼吸频率（FRR）。大于FG尺寸5的IABC的频率响应表现出欠阻尼共振特性，而较小FG尺寸的IABC表现出接近临界阻尼或过阻尼。IABC在高达25Hz的频率范围内保持均匀的幅度频率响应，表明能够在5%误差范围内测量高达148次/分钟的Pes。FG尺寸6的IABC的频率响应性能与FG尺寸10的IABC相似。与匹配的WFC相比，IABC的频率响应性能明显更优，IABC样本内的频率响应变异性更低，且IABC的FG尺寸与FRR之间的相关性比WFC更有利地更低。给出了不同IABC品牌和FG尺寸的FRR值。我们得出结论，按照适合婴儿的气囊规格制造的IABC与匹配的WFC相比，具有明显更优的频率响应特性。使用大于FG尺寸6的IABC并不能提高测量精度。价格低廉的食管内IABC在技术上适用于在婴儿人工通气期间遇到的高频呼吸力学过程中准确测量动态Pes。
