Miles J F, Bright P, Ayres J G, Cayton R M, Miller M R
Chest Research Institute, Heartlands Hospital, Birmingham, U.K.
Respir Med. 1995 Oct;89(9):603-5. doi: 10.1016/0954-6111(95)90227-9.
The accuracy of 84 new and 35 old Mini Wright peak flow meters were tested using a servo-controlled pump system. The 95% confidence limits for flow measurement across the range of the new meters was between +/- 151 min-1 at the lower end of the range and +/- 28 l min-1 at the top of the range. The readings for 22 (63%) of the old meters (age range 1-13 yr) were within these 95% confidence limits. For the remaining 13 old meters (age range 1-13 yr) whose readings were not within these limits, there were 11 meters with readings falling below and two meters with readings above these limits. Twelve of these old meters were washed and retested and there was no significant change in their readings. Twenty of the new meters were retested after 1 yr of continuous use and their readings were significantly higher with a median value of 5 l min-1 across the range, although only two of these 20 meters had readings outside the 95% confidence limits set from the 84 new meters. It is concluded that whilst Mini Wright meters aged up to 14 yr can give readings which are as good as new meters, some meters demonstrate significant changes in readings after only 1 yr and washing did not correct this change. It is recommended that clinicians prescribing peak expiratory flow (PEF) meters should be responsible for checking the patient's meter as well as their PEF readings at clinic visits.
使用伺服控制泵系统对84台新的和35台旧的Mini Wright峰值流量计的准确性进行了测试。新流量计整个量程范围内流量测量的95%置信区间在量程下限为±15 l/min，量程上限为±28 l/min之间。22台（63%）旧流量计（年龄范围1 - 13岁）的读数在这些95%置信区间内。对于其余13台读数不在这些区间内的旧流量计（年龄范围1 - 13岁），有11台读数低于区间，2台读数高于区间。其中12台旧流量计经过清洗后重新测试，读数没有显著变化。20台新流量计连续使用1年后重新测试，其读数显著升高，整个量程的中位数为5 l/min，尽管这20台流量计中只有2台的读数超出了由84台新流量计设定的95%置信区间。结论是，虽然年龄达14岁的Mini Wright流量计读数可能与新流量计一样好，但一些流量计仅使用1年后读数就出现显著变化，且清洗并不能纠正这种变化。建议开具峰值呼气流量（PEF）计的临床医生在门诊就诊时负责检查患者的流量计及其PEF读数。
