Accuracy of Handheld Spirometry as a Comparable Diagnostic Tool to Pulmonary Function Testing

Abstract

Background Assessment of patients with pulmonary illnesses requires objective measurement. However not all areas have standard spirometry. Portable electronic spirometers have been developed, but need further evaluation. The objective of this study is to evaluate the handheld spirometer as a diagnostic tool in comparison to standard pulmonary function testing. Methodology A cross-sectional study conducted at the Philippine Heart Center. Patients 19 years old and above, who underwent standard pulmonary function testing were requested to undergo handheld spirometry upon return. Results were interpreted independently. Results A total of 395 subjects were included. There was a significant difference in the values of the FVC, FEV1 and FEV1/FVC between handheld spirometer and standard PFT (p 0.0001). However, there was good agreement between the two devices as to diagnosis of normal, obstructive and restrictive lung disease (kappa 0.984, p 0.008). There was also good agreement between the two devices as to classification of mild, moderate and severe for both obstructive (kappa 0.839 + 0.044) and restrictive lung disease (kappa 0.898 + 0.028). The handheld spirometer was noted to be accurate in diagnosing obstructive lung disease (kappa 1.0, sensitivity 100%, specificity 100%, PPV 100%, NPV 100%), but slightly less accurate in diagnosing restrictive lung disease (0.968, sensitivity 97.9%, specificity 100%, PPV 100%, NPV 95.9%). Conclusion The values of FVC, FEV1 and FEV1/FVC obtained using the handheld spirometer may vary significantly from standard PFT, but the handheld spirometer can diagnose normal, restrictive and obstructive lung disease, and classify disease severity as to mild moderate and severe, with good agreement with standard PFT. The handheld spirometer was found to be accurate in diagnosing obstructive lung disease and slightly less accurate in diagnosing restrictive lung disease. It may substitute the use of standard spirometry in areas lacking standard PFT and for patients with difficulty ambulating.