Bourgain J L, Benayoun L, Baguenard P, Haré G, Puizillout J M, Billard V
Service d'anesthésie, institut Gustave-Roussy, France.
Ann Fr Anesth Reanim. 1997;16(8):940-4. doi: 10.1016/s0750-7658(97)82141-7.
To assess whether the pressure gauges at the downstream part of pressure regulators are accurate enough to ensure that pressure in O2 pipeline is always higher than in Air pipeline and that pressure in the latter is higher than pressure in N2O pipeline. A pressure difference of at least 0.4 bar between two medical gas supply systems is recommended to avoid the reflow of either N2O or Air into the O2 pipeline, through a faulty mixer or proportioning device.
Prospective technical comparative study.
Readings of 32 Bourdon gauges were compared with data obtained with a calibrated reference transducer. Two sets of measurements were performed at a one month interval.
Pressure differences between Bourdon gauges and reference transducer were 8% (0.28 bar) in average for a theoretical maximal error less than 2.5%. During the first set of measurements, Air pressure was higher than O2 pressure in one place and N2O pressure higher than Air pressure in another. After an increase in the O2 pipeline pressure and careful setting of pressure regulators, this problem was not observed at the second set of measurements.
Actual accuracy of Bourdon gauges was not convenient enough to ensure that O2 pressure was always above Air pressure. Regular controls of these pressure gauges are therefore essential. Replacement of the faulty Bourdon gauges by more accurate transducers should be considered. As an alternative, the increase in pressure difference between O2 and Air pipelines to at least 0.6 bar is recommended.
评估压力调节器下游部分的压力表是否足够精确，以确保氧气管道中的压力始终高于空气管道中的压力，且空气管道中的压力高于氧化亚氮管道中的压力。建议两个医用气体供应系统之间的压力差至少为0.4巴，以避免氧化亚氮或空气通过有故障的混合器或配比装置回流到氧气管道中。
前瞻性技术对比研究。
将32个波登管压力计的读数与用校准过的参考传感器获得的数据进行比较。每隔一个月进行两组测量。
波登管压力计与参考传感器之间的压力差平均为8%（0.28巴），理论最大误差小于2.5%。在第一组测量中，在一个地方空气压力高于氧气压力，在另一个地方氧化亚氮压力高于空气压力。在提高氧气管道压力并仔细设置压力调节器后，在第二组测量中未观察到该问题。
波登管压力计的实际精度不足以确保氧气压力始终高于空气压力。因此，定期检查这些压力计至关重要。应考虑用更精确的传感器替换有故障的波登管压力计。作为一种替代方法，建议将氧气和空气管道之间的压力差提高到至少0.6巴。
