FDA approval for a drug product suggests safety and efficacy. The same approval for medical devices does not. Approval for a device only says the manufacturing method is reliable and that the device is similar to another on the market.

The Vest Airway Clearance System falls in this category. Its a high frequency chest-wall appliance for chest physical therapy, available since 1988. Doctors sometimes prescribe it for a range of pulmonary problems that include asthma, cystic fibrosis, bronchiectasis, chronic obstructive pulmonary disease (COPD) and others.

Most studies of the vest involve cystic fibrosis because daily physical chest therapy is an accepted, medically necessary treatment. Patients with cystic fibrosis have abnormal sputum and frequent pulmonary infections that progressively lessen their pulmonary systems effectiveness. Physical chest therapy provides patients with some relief.

To date, there are no randomized, multiple center, controlled, long-term outcome clinical trials documenting the safety or efficacy of the vest for any disease. The studies show no documented superiority of the vest over routine chest physical therapy in any disease where the result of the clinical trial is a significant outcome. That is where the outcome showed fewer hospitalizations for pulmonary infections, decreased length of hospital stay or a lessening of the progression of pulmonary disease. Even short-term studies present no documentation of superiority over conventional chest physical therapy.

Faced with a lack of fact-based medical evidence, manufacturers often turn to anecdotal information to market their devices. As an example, the vest manufacturer markets its $16,000 appliance by providing doctors with vest prescriptions and free trials for patients. Usually both a physician and patient testimonial follow the trial. The testimonials argue the device is FDA approved and useful to the patient.

As compelling as such anecdotal evidence may be, testimonials do not trump medical evidence. They are not a substitute for randomized, controlled, clinical trials to prove a devices efficacy and safety for a disease.

The lack of fact-based evidence means that the vest is a convenience. While it provides no advantage over conventional physical chest therapy, it can be useful in situations where multiple patients need physical chest therapy from a single caregiver.