Accuracy of the piko-1 pocket spirometer

Good asthma control is the main goal of long-term asthma treatment. According to the Global Initiative for Asthma (GINA) guidelines (www.ginasthma.com), medical professionals assess asthma control based on specific questions regarding asthma symptoms and by spirometry measuring forced expiratory volume in 1 second (FEV(1)). Patients trained in early self-detection of asthma exacerbations use a symptom-based questionnaire, such as the Asthma Control Test (ACT) [Nathan RA, Sorkness CA, Kosinski M, et al. Development of the Asthma Control Test. A survey for assessing asthma control. J Allergy Clin Immunol 2004; 113:59-64]. However, some patients may prefer harder indicators, like peak flow values, when considering how to act within their regular asthma self-management plan.

Monitoring of FEV(1) at home could be an even more valuable alternative to recording peak flow values. The inexpensive handheld pocket spirometer "Piko-1®" offers the opportunity to monitor and store consecutive FEV(1) values. This study assesses the accuracy of the Piko-1 device.

Twenty volunteers tested 20 Piko-1 devices over five consecutive days. All results were compared to daily FEV(1) values, as measured by a calibrated reference spirometer.

Overall, the accuracy was acceptable, although Piko-1 tended to underestimate FEV(1) in the lower range. Moreover, there was no evidence of major heterogeneity between Piko-1 devices.

The Piko-1 FEV(1) measurements are sufficiently accurate to start a clinical trial to compare the detection of asthma exacerbations with this device and based on asthma symptoms alone.