A chest wall restrictor to study effects on pulmonary function and exercise - 1. Development and validation

Chest wall-restrictive loading reduces a person's ability to expand the che st wall during inhalation and results in decrements in lung capacities, res ting pulmonary function, and ultimately, exercise performance. Chest walt r estriction is observed in some forms of skeletal and pulmonary diseases (e. g., scoliosis) as well as in occupational situations (e.g., bulletproof ves ts). We have designed a constant-pressure chest wall-restrictive device tha t provides a quantifiable and reproducible load on the chest. This paper de scribes the device and the initial pulmonary function tests conducted. Ten subjects participated in this study. Subjects wore the restrictive device w hile performing pulmonary function tests at four externally added restricti ve loads on three separate occasions. A two-way repeated-measures multivari ate analysis of variance revealed significant decreases in forced expirator y vital capacity (FVC) and forced expiratory volume in 1 s (FEV1.0) at each load white the ratio of FEV1.0 to FVC (FEV1.0%) was maintained. No signifi cant differences in any Variable were found across time or between the seat ed and standing position. These results indicate that this chest wall-restr ictive device provides a quantifiable added inspiratory load in the breathi ng cycle that results in reproducible decrements in pulmonary function repr esentative of those seen in some restrictive pulmonary disease and occupati onal situations.