Normative Reference Equations for Breathlessness Intensity During Incremental Cardiopulmonary Cycle Exercise Testing

Figures

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  Figure 1.. Participant flowchart in the CanCOLD development sample. BMI = body mass index; CanCOLD = Canadian Cohort Obstructive Lung Disease; COPD = chronic obstructive pulmonary disease; CPET = cardiopulmonary exercise testing; DlCO = diffusing capacity of the lungs for carbon monoxide; ECG = electrocardiogram; FEV1 = forced expiratory volume in 1 second; FVC = forced vital capacity; LLN = lower limit of normal; TLC = total lung capacity; ULN = upper limit of normal; V˙o2 = oxygen uptake.

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  Figure 2.. (A–F) Observed and expected breathlessness intensity and the ULN during incremental cycle cardiopulmonary exercise testing in men and women, plotted using penalized B-spline by (A) power output (watts), (B) oxygen uptake (V˙o2), (C) minute ventilation (V˙e), (D) W % Predmax, (E) V˙o2 % Predmax, and (F) V˙e % Predmax. The expected breathlessness intensity is an anticipated average breathlessness intensity, calculated as the sum of all possible Borg scores, each multiplied by its predicted probability. CR10 = Borg 0–10 category ratio; ULN = upper limit of normal; V˙e % Predmax = V˙e expressed as a percentage of the predicted maximal value; V˙o2 % Predmax = V˙o2 expressed as a percentage of the predicted maximal value; W % Predmax = power output expressed as a percentage of the predicted maximal value.

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  Figure 3.. (A and B) Example of the predicted normal breathlessness response to incremental cycle cardiopulmonary exercise testing in terms of (A) probability of normality (defined as the probability of having an equal or greater score among healthy people) for each possible Borg 0–10 category ratio (CR10) score at a power output (watts) of 75% predmax for the individual and (B) the ULN for breathlessness (CR10) intensity at different power outputs. Blue lines are values for a man (age 50 years, body mass 80 kg, height 180 cm) and red lines for a woman (age 75 years, body mass 60 kg, height 170 cm). Both reported a breathlessness intensity of 6 of 10 at power output 75% predmax. That breathlessness intensity had a probability of normality of 8.9% for the man and 0.9% for the woman (A), which was within normal predicted ranges (less than or equal to the ULN) for the man but abnormal (greater than the ULN) for the woman (B). CR = category ratio; % predmax = percentage of the predicted maximal value. ULN = upper limit of normal.