title: Six-minute walk test: observed adverse events and oxygen desaturation in a large cohort of patients with chronic lung disease.
abstract: BACKGROUND
  The 6-min walk test (6MWT) is widely used to assess patients with chronic lung disease (CLD). Anecdotal reports and studies in small numbers of patients with CLD suggest that complications associated with the 6MWT are rare. This study reports the incidence of observed adverse events during the 6MWT in patients referred to an outpatient pulmonary rehabilitation service.
  
  
  METHODS
  Seven hundred and forty-one patients with stable CLD (chronic obstructive pulmonary disease (COPD), n= 572) completed the 6MWT in accordance with a standardized protocol that included continuous monitoring of oxygen saturation (SpO(2)) and heart rate (Polar).
  
  
  RESULTS
  Adverse events occurred in 43 tests (6%). One 6MWT was terminated by the tester because of chest pain and one patient developed persistent tachycardia and irregular pulse immediately following the test. In 35 tests, the tester instructed the patient to stop walking because of profound oxygen desaturation (SpO(2) < 80%). Six patients prematurely terminated the 6MWT because of symptoms. Forty-seven per cent (n= 345) of patients exhibited significant oxygen desaturation (≥4% fall in SpO(2) to <90%). Pre-exercise SpO(2) was a significant predictor of desaturation in the COPD (1.79, 1.54-2.08, adjusted odds ratio (OR), 95% confidence intervals) and ILD (OR 1.40, 1.11-1.77) cohorts with FEV(1) (forced expiratory volume in 1 s) also a predictor in COPD (OR 3.02, 1.77-5.15).
  
  
  CONCLUSIONS
  Profound oxygen desaturation is the most common adverse event observed during the 6MWT in patients with stable ILD and COPD. We propose that the American Thoracic Society 6MWT guidelines are revised to recommend continuous monitoring of SpO(2) during the 6MWT in patients with ILD and COPD.
authors.affiliation: Physiotherapy Department, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia. s.jenkins@curtin.edu.au
authors.forename: S
authors.initials: S
authors.lastname: Jenkins
authors.forename: N
authors.initials: N
authors.lastname: Čečins
mesh_terms: D000368:Aged; D002637:Chest Pain / Q000209:etiology; D002908:Chronic Disease; D015897:Comorbidity; D004417:Dyspnea / Q000209:etiology; D005080:Exercise Test / Q000009:adverse effects*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000209:etiology*; D008171:Lung Diseases / Q000097:blood / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010313:Partial Pressure; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000503:physiopathology; D012189:Retrospective Studies; D013610:Tachycardia / Q000209:etiology; D016138:Walking
chemical_list: D010100:Oxygen