A clinical comparison of the six minute walk test to a six minute step test protocol for prescribing ambulatory oxygen.

Brief Name: Ambulatory Oxygen assessments: the Six Minute Walk Test (6MWT) (Arm 1) and a Step Test protocol (Arm 2). What: Arm 1 - Materials for the 6MWT: 30 meter flat walking track (with marks every 1m), two seats, marker cones, High-Vis vests (for patient and tester), cylinder oxygen (c-size, in cylinder trolley as approved by the hospital biomedical engineering department), Oxygen Conserving Device (OCD) set at pulse 4, nasal cannula, stop watch, Oximeter, Modified Borg Scale (10 point) for rating perception of breathlessness and leg fatigue, scripted test instructions (international standards ATS 2005 and 2014 update). Arm 2 - Materials for the Step Test: 2-level step apparatus with hand rails (1 meter squared footprint), seat, oxygen delivery cart comprising of a c-size oxygen cylinder and c-size medical air cylinder attached to an oxygen titration device (set at 4 pulsed), nasal cannula, stop watch, Oximeter, Modified Borg Scale (10 point) for rating perception of breathlessness and leg fatigue. Materials for patient: Patient Information Sheet (approved by local HREC), patient consent form (approved by local HREC), patient “Questionnaire” (approved by local HREC). Who provided: Pulmonary Function (PFT) Laboratory staff (ie. the Clinical Medical Scientists) working in the Queen Elizabeth Hospital (TQEH) PFT Lab conduct the patient testing, recruit the patients, and record the patient data as per routine clinical testing protocol for TQEH PFT Laboratory. Each lab staff has a minimum of 3 years undergraduate tertiary education in a relevant science applicable to respiratory medicine, and a minimum of 2 years employment in the TQEH PFT lab. How: All testing is conducted face-to-face with the Medical Scientist and patient, in an individual one-on-one testing context. Arm 1 - 6MWT protocol: 1. The patient is seated for 10 minutes at the 30m-track start line, with the pulse oximeter attached. Oxygen saturations (SpO2), Borg Scale ratings for breathlessness and leg fatigue (resting values, “pre-exercise”) are recorded. 2. Test instructions are given (as per ATS 2005 and 2014-update guidelines). Patient instructed to stand, and stop watch set to 0:00. 3. Patient instructed to begin walking. Test instruction instructions are given at each minute mark (as per ATS 2005 and 2014 guidelines). 4. End of Test: At 6 minutes patient instructed to stop, SpO2 and Borg Scale ratings for breathlessness and leg fatigue (peak exercise values, “post-exercise”) are recorded. (NOTE: patient may stop walking and restart during the 6 minutes exercise period, as many times as they like and for any time duration. Number of stops are recorded.) 5. Patient instructed to sit, resting for 10 minutes minimum (at the 30m-track start line) connected to supplemental oxygen cylinder (nasal cannula, OCD at pulse setting 4). 6. Walk test repeated as above (steps 1-4), with supplemental oxygen (delivered via nasal cannula with OCD on pulse setting 4) in place also, while walking. (Walking aides are permitted as per the patient’s capacity/choice. Specific aides must be recorded and must be used in both repeats of the 6MWT.) Arm 2 - Step Test protocol: 1. The patient is seated for 10 minutes in front of the Step setup, with the pulse oximeter attached and connected to medical air cylinder (nasal cannula, OCD at pulse setting 4). Oxygen saturations (SpO2), Borg Scale ratings for breathlessness and leg fatigue (resting values, “pre-exercise”) are recorded. 2. Test instructions are given (as per TQEH Laboratory Procedures Manual). Patient instructed to stand, and stop watch set to 0:00. 3. Patient instructed to begin stepping. 4. End of Test: At 6 minutes or as soon as the patient wishes to stop/pause stepping (ie. before 6 minutes has passed), the patient is instructed to be seated. Stop time, SpO2 and Borg Scale ratings for breathlessness and leg fatigue (peak exercise values, “post-exercise”) are recorded. Recovery time for SpO2 is recorded (ie. minutes/seconds taken for SpO2 to return to pre-test SpO2 %). 5. Patient instructed to remain seated, resting for 10 minutes minimum (in front of the Step setup) connected to supplemental oxygen cylinder (nasal cannula, OCD at pulse setting 4). 6. Step test repeated as above (steps 1-4), with supplemental oxygen (delivered via nasal cannula with OCD on pulse setting 4) in place also, while stepping and during the recovery (resting) time after stepping has ceased. Where: All testing is conducted within the Pulmonary Function Laboratory at TQEH, on the designated 6MW track (30 meters) and in the designated Exercise Laboratory room (where the stepping apparatus and Oxygen delivery cart are permanently set up). See methods for 6MWT and Step Test for infrastructure outline. When and How much: The 6MWT is conducted as per International Standards (ATS 2005 and 2014 update) on room air (ie no cylinder gases), and then repeated with cylinder oxygen (as described below). There is a 10-30 minutes resting period between repeats. The Step Test is conducted on the placebo gas (cylinder medical air), and repeated on cylinder oxygen, also with a 10-30 minutes resting period between repeats. The 2 ambulatory oxygen assessment tests (6MWT and Step Test) are conducted as either two 30 minute sessions with a week in between (1 session for the 6MWTs and 1 session for the Step Test), or in one longer session (of 60-90 minutes, where both test protocols are performed (as above) on the same day with a minimum of 30 minutes between the 6MWTs and Step Test), as the patient prefers. In both tests, the oxygen is delivered via nasal cannula with a pulsed flow rate set on 4. In the step test, the medical air (placebo) is also delivered via nasal cannula with pulsed flow rate set on 4.