Schibler A, Henning R
Paediatric Intensive Care Unit, Royal Children's Hospital Melbourne, Parkville 3052, Victoria, Australia.
Pediatr Res. 2001 Apr;49(4):581-8. doi: 10.1203/00006450-200104000-00022.
A sulfur hexafluoride (SF(6)) washin/washout technique was developed using an ultrasonic flowmeter to measure functional residual capacity (FRC) during mechanical ventilation. The ultrasonic flowmeter measures simultaneously flow and molar mass of the mainstream gas. Ventilation distribution was studied using moment ratios analysis (alveolar-based mean dilution number). Accuracy and precision of the measurement technique were tested in a mechanical lung model, and the method's sensitivity to changes of FRC was assessed in seven ventilated rabbits and six children. In the mechanical lung model with a volume range from 10 to 60 mL, the mean error of FRC measurement was 0.096 +/- 0.9 mL (range, 0-2 mL). In seven rabbits (mean body weight, 3.6 kg), measurements of FRC and alveolar-based mean dilution number were made at positive end-expiratory pressures (PEEP) of 0, 3, and 6 cm H(2)O. The mean coefficient of variation of 66 FRC-measurements was 5.5% (range, 0-15.3%). As the applied PEEP increased, mean FRC per kilogram body weight increased from 13.3 +/- 3.4 mL/kg (PEEP of 0 cm H(2)O) to 16.7 +/- 3.6 mL/kg (PEEP of 3 cm H(2)O) and to 20.8 +/- 4.3 mL/kg (PEEP of 6 cm H(2)O). Alveolar-based mean dilution number decreased accordingly from 1.94 +/- 0.42 (PEEP = 0; mean +/- SD), to 1.91 +/- 0.45 (PEEP = 3) and to 1.59 +/- 0.35 (PEEP = 6). In the six children, as applied PEEP increased, mean FRC per kilogram increased from 21.1 +/- 4.51 mL/kg (PEEP = 0), to 22.4 +/- 1.8 mL/kg (PEEP = 5) and 27.2 +/- 3.4 mL/kg (PEEP = 10). FRC measurement using the ultrasonic flowmeter is accurate and simple to use in ventilated and spontaneously breathing children.
开发了一种六氟化硫（SF₆）冲洗/洗脱技术，使用超声波流量计在机械通气期间测量功能残气量（FRC）。超声波流量计可同时测量主流气体的流量和摩尔质量。使用矩比分析（基于肺泡的平均稀释数）研究通气分布。在机械肺模型中测试了测量技术的准确性和精密度，并在7只通气的兔子和6名儿童中评估了该方法对FRC变化的敏感性。在体积范围为10至60 mL的机械肺模型中，FRC测量的平均误差为0.096±0.9 mL（范围为0至2 mL）。在7只兔子（平均体重3.6 kg）中，在呼气末正压（PEEP）为0、3和6 cm H₂O时测量FRC和基于肺泡的平均稀释数。66次FRC测量的平均变异系数为5.5%（范围为0至15.3%）。随着应用的PEEP增加，每千克体重的平均FRC从13.3±3.4 mL/kg（PEEP为0 cm H₂O）增加到16.7±3.6 mL/kg（PEEP为3 cm H₂O），再增加到20.8±4.3 mL/kg（PEEP为6 cm H₂O）。基于肺泡的平均稀释数相应地从1.94±0.42（PEEP = 0；平均值±标准差）降至1.91±0.45（PEEP = 3）和1.59±0.35（PEEP = 6）。在6名儿童中，随着应用的PEEP增加，每千克的平均FRC从21.1±4.51 mL/kg（PEEP = 0）增加到22.4±1.8 mL/kg（PEEP = 5）和27.2±3.4 mL/kg（PEEP = 10）。使用超声波流量计测量FRC在通气和自主呼吸的儿童中准确且易于使用。
