Hay I F, Woolman P S, Wood A, Higenbottam T W
Respiratory Physiology Department, Addenbrooke's Hospital, Cambridge, U.K.
Clin Phys Physiol Meas. 1988 Nov;9(4):331-7. doi: 10.1088/0143-0815/9/4/004.
Rapid and accurate measurement of air temperature is needed to determine both heat and water losses from the respiratory tract during breathing. We have designed, constructed and validated a low dead-space, two-channel valve/mouthpiece which prevents mixing of inspired and expired air outside the body. The effects of airflow on the thermocouple response time and of thermocouple position within the airstream on the temperature measured were assessed. The 63% thermocouple response time fell from 159 to 78.8 ms as airflow rose from 23.7 to 297 1 min-1, a range including the peak flows observed while breathing at rest and during exercise. Measurement of temperature profiles across the valve/mouthpiece at different flows indicated that thermocouples were best positioned at the centre of the airstream, though small deviations did not adversely affect accuracy.
为了确定呼吸过程中呼吸道的热量和水分损失，需要快速准确地测量气温。我们设计、制造并验证了一种低死腔双通道阀门/口罩，可防止体外吸入和呼出的空气混合。评估了气流对热电偶响应时间的影响以及气流中热电偶位置对所测温度的影响。随着气流从23.7升至297升/分钟（该范围包括静息呼吸和运动时观察到的峰值流量），热电偶63%的响应时间从159毫秒降至78.8毫秒。在不同流量下对阀门/口罩的温度分布进行测量表明，热电偶最好放置在气流中心，不过小的偏差不会对准确性产生不利影响。
