Evaluation of an electronic hand-held spirometer in patients with asthma

In this pilot study we assessed patient compliance and acceptability of data recorded in the home environment by asthmatics using a Vitalograph 2110 spirometer which measures peak expiratory flow rate (PEFR) and forced expiratory volume in 1 s (FEV1). This meter automatically time and date stamps all measurements and can also assess the technical acceptability of results. Data are uploaded to a personal computer for review and analysis. We recruited 30 patients (10 male and 20 female, age range 21-72 years) from the chest clinic at Guy's Hospital (n = 20) and from a GP clinic (n = 10). Patients were asked to record spirometry data using the meter at set times (8.00 a.m. and 8.00 p.m.) for 2 weeks. The spirometer incorporated an alarm to remind patients to take measurements. All patients completed the study. Mean (SD) compliance with spirometer use was 100.8% (49.9%). Nineteen patients had a compliance rate of between 80% and 120% of expected use. Timing of recordings was compared with the scheduled times of 8.00 a.m. and 8.00 p.m. Values recorded with +/- 2 h were judged as acceptable. For morning recordings 67.4% of all values and for evening recordings 71.7% of all values met this criterion. Technical acceptability of spirometry data was also assessed by using quality assurance criteria recorded by the spirometer. Valid tests were performed for 75.2% of all recordings. Twenty-two patients performed valid tests for 80-100% of the time. We suggest that the use of an electronic meter in the home environment is practical and is likely to generate more accurate and reliable data.