Validation of a Novel Compact System for the Measurement of Lung Volumes

Abstract

Background: Current techniques for measuring absolute lung volumes rely on bulky and expensive equipment and are complicated to use for the operator and the patient. A novel method for measurement of absolute lung volumes, the MiniBox method, is presented.

Research question: Across a population of patients and healthy participants, do values for total lung capacity (TLC) determined by the novel compact device (MiniBox, PulmOne Advanced Medical Devices, Ltd.) compare favorably with measurements determined by traditional whole body plethysmography?

Study design and methods: A total of 266 participants (130 men) and respiratory patients were recruited from five global centers (three in Europe and two in the United States). The study population comprised individuals with obstructive (n = 197) and restrictive (n = 33) disorders as well as healthy participants (n = 36). TLC measured by conventional plethysmography (TLC_Pleth) was compared with TLC measured by the MiniBox (TLC_MB).

Results: TLC values ranged between 2.7 and 10.9 L. The normalized root mean square difference (NSD) between TLC_Pleth and TLC_MB was 7.0% in healthy participants. In obstructed patients, the NSD was 7.9% in mild obstruction and 9.1% in severe obstruction. In restricted patients, the NSD was 7.8% in mild restriction and 13.9% in moderate and severe restriction. No significant differences were found between TLC values obtained by the two measurement techniques. Also no significant differences were found in results obtained among the five centers.

Interpretation: TLC as measured by the novel MiniBox system is not significantly different from TLC measured by conventional whole body plethysmography, thus validating the MiniBox method as a reliable method to measure absolute lung volumes.

Keywords: novel measurement; physiology; plethysmograph; pulmonary function test; total lung capacity.