Background-A study was undertaken to evaluate the use of a biological quali
ty control programme for a computer controlled, breath-by-breath exercise t
est system over a 2.5 year period,
Methods-One healthy volunteer performed a regular progressive treadmill tes
t with breath-by-breath measurements of oxygen uptake ((V)O-2), carbon diox
ide output ((V)over dot CO2), ventilation ((V)over dot E), and the ECG hear
t rate (HR). Following a familiarisation period, five consecutive tests wer
e performed and the measurements at peak exercise were averaged to give bas
eline values. All tests were compared with these values.
Results-A total of 35 tests were recorded. The within subject standard devi
ation for measurements at peak exercise were 52 ml/min for (V)over dot O-2,
74 ml/min for (V)over dot CO2, 3.1 1/min for (V)over dot E, and 3 beats/mi
n for HR. The mean (SE) percentage variation in measurements at peak exerci
se compared with the baseline values was +0.37 (0.30)% for (V)over dot O-2,
-0.10 (0.39)% for (V)over dot CO2, -0.88 (0.52)% for (V)over dot E, and +1
.2 (0.26)% for HR. The variability present in measurements made during high
and moderate intensity exercise (73% (V)over dot O(2)peak) was not signifi
cantly different (p > 0.05). During the study period the quality control de
tected a fault on the oxygen analyser which was not apparent from the autom
atic calibration.
Conclusions-Regular quality control using a healthy volunteer allows all co
mponents of the breath-by-breath system to be checked simultaneously and in
a manner which is consistent with its clinical use. This practice can high
light faults not detected by automatic calibration.