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Abstract
BACKGROUND A 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.
METHODS One healthy volunteer performed a regular progressive treadmill test with breath-by-breath measurements of oxygen uptake (V˙o 2), carbon dioxide output (V˙co 2), ventilation (V˙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.
RESULTS A total of 35 tests were recorded. The within subject standard deviation for measurements at peak exercise were 52 ml/min forV˙o 2, 74 ml/min forV˙co 2, 3.1 l/min forV˙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 V˙o 2, –0.10 (0.39)% for V˙co 2, –0.88 (0.52)% forV˙e, and +1.2 (0.26)% for HR. The variability present in measurements made during high and moderate intensity exercise (73%V˙o 2peak) 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.
CONCLUSIONS Regular 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.
- quality control
- exercise testing
- breath-by-breath system