The Six Minute Walk Test

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68 AARC Tmes February 2000

S

C l i n i c a l P e r s p e c t i v e s

The

Six-MinuteWalk Testby Janet C. Sclafani, RRT, RPFT

PULMONARY FUNCTION TESTING:

ince the introduction ofthe 12-minute walk test by C.R.

McGavin and colleagues in 1976,time-distance walk testing hasbecome widely used as an indica-tor of functional capacity. In1982, J.A. Butland furtherdefined the test into two- andsix-minute increments. Whilethe two-minute version of thetest is less discriminatory and the12-minute test too long for mostchronic obstructive pulmonarydisease patients, the six-minute

test has proven to offer the bestresults in terms of objectivityand clinical indications.1

This test has become a stan-dard evaluation tool at the startof a rehabilitation program toassess the patients exercisecapacity and set the exercise pre-scription. Exercise testing with

gas analysis generally precedesthe use of the six-minute walk as

the most comprehensive evalua-tion tool. At the conclusion of

the rehabilitative process, thesix-minute walk may be used todetermine the outcome of thephysical conditioning compo-nent of the program. The test hasbeen used as part of the selectioncriteria of when to place patientson the lung transplantation list.

The six-minute walk test is aval ued as se ss me nt to ol byNational Emphysema Treat-ment Trial (NETT) centers dur-

ing the pre-surgical and post-sur-gical rehab ilitati on progress.Even patients themselves haverealized their own success withthe results of the six-minute test.Patients who have achievedapproximately 170 feet increasein distance have rated them-selves as doing a little better onevaluation tools assessing theirperception of disability.2 Cer-

tainly, clinicians can use this dataas proof of a successful rehabili-

tation program when competingfor health care reimbursementfor their patients.

Testing environment andperformance issues

A measured walking distanceof at least 100 feet is required forperforming this test. The walk-ing path should be as unob-structed as possible, with mini-mal traffic and no stairwell or

elevator exits into the walkway.The path should have rest areas

where the patient can either sitor stand with support.

Blood pressure, heart rate, res-piratory rate, and resting bloodsaturation by pulse oximetryshould be obtained prior to test-ing. The patient, after beingfamiliarized with the 10-pointBorg Dyspnea Index Scale,


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AARC Tmes February 2000 69


should rate their perception of thelevel of shortness of breath at rest.

If patients are using supple-

mental oxygen, it is best to testthem on the system that theycurrently use. Supportive de-

vices such as canes and walkersmay also be used if needed. Reststops are permitted as often asnecessary, and the timer contin-ues to run during rest stops.

According to the AmericanThoracic Society (ATS) recom-

mendations for evaluation ofdesaturation, SpO2 (oxygen satu-ration as measured by pulse

oximetry), heart rate, and dis-tance should be recorded everyminute. A recovery saturationreading after the walk should benoted. The test should be per-formed two times, with a mini-mum of 15 minutes of restbetween trials. Though notessential, testing on separatedays is the most ideal.

Clinicians role

Staff supervising the walk testshould instruct the patient aboutthe walking path and test guide-

lines. They should also carry thepatients oxygen, if needed, and

walk slightly behind them sothey do not pace the walkingspeed. The patient may use anymedication needed prior to thetest and use their prescribed literflow of oxygen for activity.Words of encouragement duringthe test have a positive effect onthe results.3 The patient shouldfollow instructions to walk the

path and cover as much distanceas possible in the six-minute timeframe. The patient should nottalk while walking. At the con-clusion of the test, patientsshould again be rated on theirlevel of shortness of breath.Instructions to the patient arenecessary to place them at ease

with the test.

The patient should be familiar-ized with both the walking pathand the Borg scale prior to test-

ing. The less apprehensive thepatient is during the test, the bet-ter the results. Assurances shouldbe given that they can stop thetest at any time, medications maybe used, and they will be per-forming two tests with a restperiod in between each one.

Guidelines fordesaturat ion

The ATS Pulmonary FunctionLaboratory Management andProcedure Manual provides guid-ance for oxygen titration at restand with exercise.4 Each depart-ment should have a well-definedpolicy for oxygen titration. At ourfacility, we have successfully usedthe following procedure. Forpatients who desaturate to lessthan 88 percent on room air dur-ing a six-minute walk test, it is rec-ommended to titrate the adminis-tration of oxygen until the desired

SpO2 is achieved. This should befollowed with an arterial blood gasmeasurement after 20 minutes onthe new liter flow. If the results areacceptable, the test is thenrepeated on 2 L/min. Arrange-ments may then be made for thepatient to use the new liter flowduring activity.

Patients who desaturate to lessthan 88 percent on their pre-scribed liter flow should have their

liter flow increased by 1 L/min. for20 minutes. The test is repeated atthe increased liter flow, the physi-cian is contacted, and adjustmentsare made to the prescribed literflow with exercise. These changescan then be discussed with thepatient before they leave. Patientspresenting with a saturation levelless than 88 percent on room air

The six-minute walk test is a valued

assessment tool by NETT centers during

the pre-surgical and post-surgical

rehabilitation progress.


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are not tested. The physicianshould be contacted for furtherinstructions and testing criteria.

Pulse oximetry devices

When using a pulse oximetrydevice, the limitations and valid-ity of the results must be consid-ered. The patient should beassessed for low perfusion andhistory of abnormal hemoglobinthat may alter the results. Nailpolish should not be worn. Thestability of the readings andmotion artifact should be con-sidered when reporting results.

The clinician needs to assessthe agreement between the pal-pitated heart rate and the read-ing on the device, along with theclinical appearance of thepatient. The two determine theaccuracy of the displayed results.The condition and placement ofthe probe is of particular consid-eration. The fit of the probeshould not allow for exposure toambient light conditions. Newer

technology in pulse oximetrynow affords the identification of

ve no us bl oo d si gnal s. Th evenous signal can be canceled,allowing the arterial signal to bemeasured. Signal ExtractionTechnology (SET) lo okspromising in relation to usingpulse oximetry during move-ment and by decreasing thenumber of false alarms gener-ated. Certainly this technology

will afford the respiratory thera-pist a more accurate reflection ofthe saturation by eliminatingmotion artifact.5 If the issuesregarding motion artifact can beresolved in the equipment, theclinician can make decisionsregarding the patients medicalcare with greater confidence inthe device used to measure thesaturation.

Oxygen devices

Continuous flow or pulsedelivery systems may be usedduring testing. It is recom-mended that patients use theirpersonal system to assess theiroxygen needs during activity.Patients who desaturate with apulse delivery system may

require continuous flow duringactivity.

There is no preference foroxygen delivery devices. As

with the oxyg en system, thepatients usual delivery device isused. The method of deliveryshould be noted on the report as

well as whether the device wascarried by the therapist orpatient.

Reporting results

Reporting formats vary frominstitution to institution; however,

vital information must be includeduniformly. Heart rate, blood pres-sure, respiratory rate, and a restingdyspnea index are basic evalua-tions that clinicians will look forinitially on the report. A list of

medications, current symptomsthe patient may be experiencing,and limitations of the patientshould also be included. The use ofsupportive devices, such as canes,

walkers, or wheelchairs, should bedocumented.

Reporting formats includedistance walked in feet, the aver-age saturation, dyspnea index at

references

1. Butland, R.J., Pang, J., Gross,

E.R., et al. (1982). Two-, six-, and12-minute walking tests in respi-

ratory disease. British Medical

Journal, 284(6329), 1607-1608.

2. Redelmeier, D.A., Bayoumi,

A.M., Goldstein, R.S., & Guyatt,

G.H. (1997). Interpreting small

differences in functional status:

The six minute walk test in

chronic lung disease patients.

American Journal of Respiratory

Critical Care Medicine, 155(4),

1278-1282.

3. Guyatt, G.H., Pugsley, S.O.,Sullivan, M.J., et al. (1984). Effect

of encouragement on walking

test performance. Thorax,

39(11), 818-822.

4. American Thoracic Society.

(1998). Pulmonary function labo-

ratory management and proce-

dure manual. New York: Ameri-

can Thoracic Society.

5. Harrington, S., Henderson, D.,

& Burton, G.G. (1999). Reliable

pulse oximetry during exercise

testing [Abstract]. Respiratory

Care, 44(10), 1226.

additionalreadingAmerican Association

for Respiratory

Care. (1991).

AARC clinical

practice guideline: Pulse

oximetry. Respiratory Care,

36(12), 1406-1409.

Connors, G. (1999, March). NETT

seminar. Presented by the American

College of Chest Physicians in

Orlando, FL.

Kadikar, A., Maurer, J., & Kesten, S.

(1997). The six-minute walk test: A

guide to assessment for lung trans-

plantation. The Journal of Heart and

Lung Transplantation, 16(3), 313-319.

McGavin, C.R., Gupta, S.P., &

McHardy, G.J. (1976). Twelve-minute

walking test for assessing disability in

chronic bronchitis. British Medical

Journal, 1(6013), 822-823.

(continued on page 108)


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the very conclusion of the walk,and a recovery saturation read-ing. A notation should indicate

whether the test was on room airor with supplemental oxygen andthe amount of oxygen used. Rea-sons for the termination of thetest should be clearly docu-mented and may include ele-

vated heart rate, pain, desatura-tion, or patient request to stop.

Documented oxygen desatura-tion treated with the applicationof oxygen and any subsequentarterial blood gases should be doc-umented. Information gatheredfrom the second walk test shouldbe the same as in the first and alsobe included in the report.

Tests that are not performedsecondary to low saturationsshould document physician noti-fication of such and any actiontaken.

Uti l i ty of results

Used appropriately, the six-minute walk test can supply crit-

ical information for the patientand the clinician. It can serve asan assessment for oxygenrequirements, efficacy of therehabilitative process, and as apart of the selection criteria forsurgery. The test is simple to per-form and the results easily appre-ciated by patients, providingthem with positive feedbackafter an exercise program.

Janet C. Sclafani is coordinator of pul-monary rehabilitation at Sarasota

Memorial Hospital in Sarasota, FL, and

serves on the Executive Board of Direc-

tors of the American Lung Association

of Gulfcoast Florida.

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The Six Minute Walk Test