Obstruction With No Significant Bronchodilator Response
Mrs. Rivera is a 52-year-old Hispanic woman who works in a school kitchen. She has never smoked, has no known asthma, and reports 2 years of progressive exertional dyspnea. Her height is 158 cm and weight 82 kg. Pre-bronchodilator spirometry: FEV1 1.85 L (78% of predicted), FVC 2.75 L (88% of predicted), FEV1/FVC 0.67. The laboratory's reference values give a lower limit of normal (LLN) for FEV1/FVC of 0.72 and for FEV1 of 80% predicted. Post-bronchodilator (400 mcg salbutamol via spacer, 15 minutes): FEV1 1.98 L, FVC 2.85 L, FEV1/FVC 0.695. Predicted post FEV1 is unchanged. She feels well during the test. The employer's safety officer asks for 'the numbers and a pass/fail' for a respirator program; the worker asks what the results mean and whether she can keep working. The clinic uses electronic records and has a policy to release results only to the worker and, with authorization, to the employer.
1. Interpret the spirometry pattern and bronchodilator response. Is the post-bronchodilator change significant?
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Pre-bronchodilator FEV1/FVC 0.67 is below the LLN of 0.72, so the pattern is obstructive. Post-bronchodilator ratio 0.695 remains below the LLN, so obstruction persists. FEV1 at 78% predicted is below the LLN of 80% and in the mild range by the usual FEV1 severity cut-point (≥70% predicted), but severity should be based on the post-bronchodilator FEV1 and the reference set used. The FEV1 change is 1.98 − 1.85 = 0.13 L, or 7.0%, which does not meet the usual significant bronchodilator response criterion of at least 12% and 200 mL in FEV1 or FVC. The FVC change is 0.10 L (3.6%). So there is no significant reversibility, but spirometry alone does not establish a diagnosis; clinical correlation and further evaluation are needed.
2. What should be communicated to the worker and to the employer, and how should the record be handled?
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Tell Mrs. Rivera in plain language that her breathing test shows airflow obstruction, not a normal result, and that she should discuss it with her clinician; the test does not by itself diagnose asthma or COPD. Avoid giving her a 'pass/fail' label for respirator use-that is a medical fitness determination, not a spirometry result. With her written authorization, send the employer only the information the respirator program needs, such as whether she is cleared for respirator use and any restrictions, not the raw numbers or diagnosis. If the employer requests records, follow your release policy and applicable access rules. Document the interpretation, the communication, and the authorization in the EHR, and give her a copy of her results.