Pulmonary function measurement using flow time monitor

A flow time monitor (FTM) was developed to measure an individual´s pulmonary function based on air flow and time displacement during the forced maximal expiration through a special tubular mouthpiece. Spirometry parameters are arbitrary and relatively imprecise depending on absolute maximum effort maintained over each forced expiratory maneuver. A typical spirometer is expensive and the mouthpiece is relatively large for small pediatric patients. The FTM was designed to overcome the shortcomings of forced expiratory maneuver required for both the peak flow meter and spirometer. The FTM data acquisition system involves triggering 3 preset pressure transducers when the air flow through the special tubular mouthpiece exceeds or falls below flow rates of 0.56, 1.21 and 2.13 litre per second (1/sec). A C⁺⁺ object oriented program (OOP) was written to acquire the computer´s internal clock time (in 10000^th second) whenever a PCMCIA Slot II card received each pressure transducer signal. Thus 6 time readings are obtained from sequentially turning the 3 pressure transducers `on´ and `off´. FTM was tested on 66 control subjects, age 18 to 40, and 44 Cystic Fibrosis patients, age 14 to 50. They all have performed standard Spirometry test follows by FTM. Results show that the data acquisition system and the C⁺⁺ OOP work successfully with reproducible tests. Data show strong separation of CF from normal subjects. The majority of the CF data fall outside the 95% confidence limits of the normal range. This separation is not as pronounced when using standard spirometrics parameter