1997 OPEN FORUM Abstracts
The Six-minute Walk is Nothing When Compared to a Complete Exercise Evaluation
Gretchen Lawrence, Tuesday, December 8, 1997.
Differentiating the diagnosis when the patient presents with shortness of breath (SOB) out of proportion to the activity performed can be challenging - and expensive. But beginning the evaluation using the simplest and most cost-effective test, the six-minute walk, may eliminate the need to do a much more expensive and anxiety-creating test, the metabolic (met) cart. For the patient, just getting instructions prior to a met cart test (using nose clips and putting a very large rubber thing in your mouth) may evoke physiological responses much like those seen during the test itself - rapid and irregular heart rate, rapid breathing, and oxygen desaturation.
The supply costs for the six-minute walk test do not exceed sixty cents per test. The only equipment needed is a hallway and a technician to walk with the patient and record data. The patient is instructed to walk at his own pace, stop to rest as needed, and resume walking as soon as possible. The distance covered in six minutes is recorded, along with heart rate, respiratory rate, oxygen saturation and patient's perception of dyspnea (using the Borg scale or similar instrument) every minute throughout the test. This data is then used to develop a safe exercise prescription for the patient. Performing a test that is equivalent to daily experience can go a long way in reassuring the patient as he works to increase exercise tolerance in the face of increasing SOB.
For the patient with COPD, the six-minute walk test is reliable, valid, safe, and inexpensive and can be adapted to any age and either sex. Instructions to the patient are easy to understand and follow, meaning that this test is useful in testing patients with low literacy. G.H. Guyatt, a well known researcher in the area of patient motivation, reports that results of this testing method yield objective and reproducible results. Granted, the met cart test reports oxygen consumption, carbon dioxide production, minute ventilation and other data to measure work of breathing, but do all those bells and whistles from the mitochondria really change the exercise prescription for the COPD patient who is short of breath with exertion and may need supplemental oxygen to maintain saturation during rest and/or exercise?
AARC 50th Anniversary, December 6 - 9, 1997, New Orleans, Louisiana.