Article Title



Austin Gooch, Marc A. Augenreich, Jonathon L. Stickford. Appalachian State University, Boone, NC.

Background: Electronic cigarette (EC) use has been shown to increase airway resistance, which may lead to alterations in thoracic gas compression volume during maximal expiratory maneuvers. Furthermore, changes to gas compression volume could potentially confound the measurement of forced expiratory volume in one second (FEV1). Purpose: To investigate the acute effects of EC use on three separate indicators of thoracic gas compression volume. Methods: Ten (N=10) male adults participated in all testing procedures over the course of two laboratory visits. Participants inhaled from an EC with (EC+) or without (EC-) the nicotine cartridge in a randomized order. After each use of the EC (EC+ or EC-) participants completed pulmonary function testing. The area under the curve (AUC) between the maximal expiratory flow-lung volume loop and the maximal expiratory flow-mouth volume loop was quantified in each condition. The differences (Δ) in forced expiratory flow at 25% (FEF25%), 50% (FEF50%), and 75% (FEF75%) of forced vital capacity (FVC) between the lung volume and mouth volume loops were measured. Additionally, the Δ in volume between the maximal expiratory flow-lung volume loop and the maximal expiratory flow-mouth volume loop at peak expiratory flow (PEF), FEF25%, FEF50%, and FEF75%were also evaluated for both conditions. All values are expressed as mean ± SD. Results: The AUC between the lung volume and mouth volume loops was not different between conditions (EC+: 3.68 ± 1.42 L2·s; EC-: 3.47 ± 1.44 L2·s; P > 0.05). There were no significant differences in ΔFEF25%, FEF50%, and FEF75% between the two conditions (all P > 0.05). However, the ΔFEF decreased alongside lung volume, independent of condition (P < 0.05). Additionally, there was a reduction in the volume difference at FEF50% and FEF75% compared with PEF and FEF25% (P < 0.05) but no differences were detected between conditions (P > 0.05). Conclusion: We observed no change in the volume of thoracic gas compression during the maximal expiratory maneuver following acute EC use. We interpret this to mean the thoracic gas compression volume does not change spirometry measurements (in particular, FEV1) in relation to pulmonary function testing immediately after acute EC use. Funding provided by the Appalachian State University Office of Student Research and the University Research Council.

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