[So-called pocket-sized spirometry versus respiratory function tests: a comparative study of vital capacity, forced...

A simplified preoperative respiratory assessment was carried out in order to assess the reliability of a pocket-sized spirometer. 30 patients were each tested using two methods: 1) the traditional extensive laboratory lung function tests and 2) a bedside test using a pocket-sized spirometer, which measured the vital capacity (VC), the forced expiratory volume in 1 second (FEV1), the peak flow (PEF) and the ratio of FEV1 to VC. The correlation between the two series of VC and FEV1 measurements was highly significant (p less than 0.001). Therefore, these two parameters could be considered as reliable when testing was performed at the bedside. However, the sensitivity of the FEV1/VC ratio was decreased; in three of the patients, the significance of this third parameter was not the same with the two methods. Measurements of peak flow were only collected at the bedside, and a statistical comparison was not established. Analysis of this last parameter always allowed us to confirm or not an obstructive syndrome when the values of FEV1 or FEV1/VC were in disagreement. The pocket-sized spirometer would seem to be a simple and reliable means of diagnosing respiratory insufficiency, its type (obstructive or restrictive) and its seriousness.