BACKGROUNDA study was undertaken to evaluate the use of a biological quality control programme for a computer controlled, breath-by-breath exercise test system over a 2.5 year period.
METHODSOne healthy volunteer performed a regular progressive treadmill test with breath-by-breath measurements of oxygen uptake (O₂), carbon dioxide output (CO₂), ventilation (E), and the ECG heart rate (HR). Following a familiarisation period, five consecutive tests were performed and the measurements at peak exercise were averaged to give baseline values. All tests were compared with these values.
RESULTSA total of 35 tests were recorded. The within subject standard deviation for measurements at peak exercise were 52 ml/min for O₂, 74 ml/min for CO₂, 3.1 l/min for E, and 3 beats/min for HR. The mean (SE) percentage variation in measurements at peak exercise compared with the baseline values was +0.37 (0.30)% for O₂, -0.10 (0.39)% for CO₂, -0.88 (0.52)% for E, and +1.2 (0.26)% for HR. The variability present in measurements made during high and moderate intensity exercise (73% O₂peak) was not significantly different (p>0.05). During the study period the quality control detected a fault on the oxygen analyser which was not apparent from the automatic calibration.
CONCLUSIONSRegular quality control using a healthy volunteer allows all components of the breath-by-breath system to be checked simultaneously and in a manner which is consistent with its clinical use. This practice can highlight faults not detected by automatic calibration.


Keywords: quality control; exercise testing; breath-by-breath system