Validity of the 6 min walk test as a surrogate for the anaerobic threshold in the preoperative assessment clinic

Hdl Handle:
http://hdl.handle.net/10149/95795
Title:
Validity of the 6 min walk test as a surrogate for the anaerobic threshold in the preoperative assessment clinic
Authors:
Sinclair, R. C. F. (Rhona); Goodridge, V.; Batterham, A. M. (Alan); Danjoux, G. R. (Gerry)
Editors:
Webb, S. T. (Stephen); Ghosh. S.
Affiliation:
University of Teesside
Citation:
Sinclair, R. C. F. et al. (2009) 'Validity of the 6 min walk test as a surrogate for the anaerobic threshold in the preoperative assessment clinic', Meeting of the anaesthetic research society, royal College of anaesthetists, London, England, November 20 - 21, 2008 in, Webb, S. T. and Ghosh, S. (eds) British Journal of Anaesthesia, 102 (4), pp.573-573.
Publisher:
Oxford University Press
Journal:
British Journal of Anaesthesia
Conference:
Meeting of the anaesthetic research society, royal College of anaesthetists, London, England, November 20 - 21, 2008
Issue Date:
Apr-2009
URI:
http://hdl.handle.net/10149/95795
Additional Links:
http://bja.oxfordjournals.org/content/vol102/issue4/index.dtl#IN_THIS_ISSUE
Abstract:
Functional assessment of exercise capacity is now widely recognized as a major determinant of preoperative risk prediction before major surgery. Two different techniques are principally used in the UK: cardiopulmonary exercise testing (CPET) and subjective patient-reported assessment of metabolic equivalents (METs). The identification of anaerobic threshold (AT), from CPET, presently represents the UK gold standard; however, reported METs form a cornerstone of the American Heart Association preoperative guidelines. Unpublished data from our institution have demonstrated a poor correlation between patient-reported METs and oxygen consumption (VO2) at AT (r¼0.31). The sensitivity and predictive value of METs to identify objective, CPET-derived exercise capacity was also low (sensitivity 24%). With this in mind, our group felt that where CPET is unavailable, a more robust test of exercise capacity is required to accurately assess the operative risk. We propose that the 6 min walk test (6MWT) may fulfil this requirement. The aim of this study was to examine the validity of the 6MWT against a criterion measure derived from CPET: AT. Fifteen participants, undergoing major non-cardiac surgery, were recruited from our preoperative assessment clinics. CPET was conducted according to our standardized ramped protocol with participants exercising until they attained their AT. AT was derived from the data recorded using the V-slope method. After a short rest period, participants completed two separate 6MWT; the furthest distance walked was recorded. Statistical analysis used an ordinary least-squares linear regression method to derive the validity coefficient (r) and the standard error of the estimate (SEE), providing the typical prediction error associated with the prediction of AT from the results of a 6MWT in an individual patient. All participants completed three tests. Mean age was 69.5 (SD 7.0) yr (12 males and three females). Data from 13 participants were suitable for statistical analysis (two exclusions: one unreadable CPET and one invalid 6MWT from knee injury). The group achieved a mean AT of 10.1 (SD 3.5) ml O2 kg21 min21 and a mean 6MWT distance of 548.1 (SD 74.1) m. The distances walked during two 6MWT demonstrated a mean improvement of 19 m; the 6MWT was a highly reliable test, with an intraclass correlation (3.1) of 0.94. We found a validity coefficient of r¼0.76, with a standard error of prediction of AT from distance walked during 6MWT of +2.4 ml O2 kg21 min21. The 6MWT demonstrates a strong correlation with AT in this pilot study, with good repeatability between tests. It may provide a robust, cheap, accurate alternative for measuring exercise capacity where CPET is unavailable. On the basis of this encouraging exploratory phase correlation, we now plan to undertake a definitive concurrent validity study.
Type:
Article; Meetings and Proceedings
Language:
en
Keywords:
anaerobic threshold; cardiopulmonary exercise testing; preoperative assessment; walk test
ISSN:
0007-0912
Rights:
Subject to restrictions, author can archive post-print (ie final draft post-refereeing). For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 07/04/2010]
Citation Count:
0 [Web of Science, 07/04/2010]

Full metadata record

DC FieldValue Language
dc.contributor.authorSinclair, R. C. F. (Rhona)en
dc.contributor.authorGoodridge, V.en
dc.contributor.authorBatterham, A. M. (Alan)en
dc.contributor.authorDanjoux, G. R. (Gerry)en
dc.contributor.editorWebb, S. T. (Stephen)-
dc.contributor.editorGhosh. S.-
dc.date.accessioned2010-04-07T07:52:59Z-
dc.date.available2010-04-07T07:52:59Z-
dc.date.issued2009-04-
dc.identifier.citationBritish Journal of Anaesthesia; 102 (4): 573-573en
dc.identifier.issn0007-0912-
dc.identifier.urihttp://hdl.handle.net/10149/95795-
dc.description.abstractFunctional assessment of exercise capacity is now widely recognized as a major determinant of preoperative risk prediction before major surgery. Two different techniques are principally used in the UK: cardiopulmonary exercise testing (CPET) and subjective patient-reported assessment of metabolic equivalents (METs). The identification of anaerobic threshold (AT), from CPET, presently represents the UK gold standard; however, reported METs form a cornerstone of the American Heart Association preoperative guidelines. Unpublished data from our institution have demonstrated a poor correlation between patient-reported METs and oxygen consumption (VO2) at AT (r¼0.31). The sensitivity and predictive value of METs to identify objective, CPET-derived exercise capacity was also low (sensitivity 24%). With this in mind, our group felt that where CPET is unavailable, a more robust test of exercise capacity is required to accurately assess the operative risk. We propose that the 6 min walk test (6MWT) may fulfil this requirement. The aim of this study was to examine the validity of the 6MWT against a criterion measure derived from CPET: AT. Fifteen participants, undergoing major non-cardiac surgery, were recruited from our preoperative assessment clinics. CPET was conducted according to our standardized ramped protocol with participants exercising until they attained their AT. AT was derived from the data recorded using the V-slope method. After a short rest period, participants completed two separate 6MWT; the furthest distance walked was recorded. Statistical analysis used an ordinary least-squares linear regression method to derive the validity coefficient (r) and the standard error of the estimate (SEE), providing the typical prediction error associated with the prediction of AT from the results of a 6MWT in an individual patient. All participants completed three tests. Mean age was 69.5 (SD 7.0) yr (12 males and three females). Data from 13 participants were suitable for statistical analysis (two exclusions: one unreadable CPET and one invalid 6MWT from knee injury). The group achieved a mean AT of 10.1 (SD 3.5) ml O2 kg21 min21 and a mean 6MWT distance of 548.1 (SD 74.1) m. The distances walked during two 6MWT demonstrated a mean improvement of 19 m; the 6MWT was a highly reliable test, with an intraclass correlation (3.1) of 0.94. We found a validity coefficient of r¼0.76, with a standard error of prediction of AT from distance walked during 6MWT of +2.4 ml O2 kg21 min21. The 6MWT demonstrates a strong correlation with AT in this pilot study, with good repeatability between tests. It may provide a robust, cheap, accurate alternative for measuring exercise capacity where CPET is unavailable. On the basis of this encouraging exploratory phase correlation, we now plan to undertake a definitive concurrent validity study.en
dc.language.isoenen
dc.publisherOxford University Pressen
dc.relation.urlhttp://bja.oxfordjournals.org/content/vol102/issue4/index.dtl#IN_THIS_ISSUEen
dc.rightsSubject to restrictions, author can archive post-print (ie final draft post-refereeing). For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 07/04/2010]en
dc.subjectanaerobic thresholden
dc.subjectcardiopulmonary exercise testingen
dc.subjectpreoperative assessmenten
dc.subjectwalk testen
dc.titleValidity of the 6 min walk test as a surrogate for the anaerobic threshold in the preoperative assessment clinicen
dc.typeArticleen
dc.typeMeetings and Proceedingsen
dc.contributor.departmentUniversity of Teessideen
dc.identifier.journalBritish Journal of Anaesthesiaen
dc.identifier.conferenceMeeting of the anaesthetic research society, royal College of anaesthetists, London, England, November 20 - 21, 2008en
ref.citationcount0 [Web of Science, 07/04/2010]en
or.citation.harvardSinclair, R. C. F. et al. (2009) 'Validity of the 6 min walk test as a surrogate for the anaerobic threshold in the preoperative assessment clinic', Meeting of the anaesthetic research society, royal College of anaesthetists, London, England, November 20 - 21, 2008 in, Webb, S. T. and Ghosh, S. (eds) British Journal of Anaesthesia, 102 (4), pp.573-573.-
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