Clinical pulmonary function tests as predictors of work performance during respirator wear

The Occupational Safety and Health Administration (OSHA) mandate requiring medical information for respirator users provides the physician with little or no guidance as to what objective criteria may be valuable in assessing the worker's ability to use a respirator safely. Therefore, the purpose of this study is to use the results of clinical pulmonary function testing to predict performance time on maximal- and endurance-type exercise tests. Respirator mask wear reduced clinical pulmonary function measures from 7%-15% from mouthpiece controls. The resistances of the mask reduced forced vital capacity by an average of 11.6% (0.65 L); forced expiratory volume in 1 sec by 7.3% (0.33 L); and maximum voluntary ventilation in 15 sec by 7.4% (12.4 L/min). Stepwise linear regression analysis was used to determine the clinical pulmonary function measures that were the best predictors of work performance. The MVV.25 with the respirator was determined to be the best predictor of maximal exercise performance both with and without the respirator. The difference in peak inspired flow with and without the respirator was the best predictor of performance time with the respirator during the endurance walk to exhaustion. Recommendations are made to the physician for procedures for determining a worker's pulmonary capacity and calculating the effect of the respirator in reducing that capacity. This information then will allow the physician to determine safe levels of ventilation for a particular work task.