Exertional dyspnea-related acidotic and sympathetic responses in patients with sequelae of pulmonary tuberculosis.

The objective of this study was to investigate whether exertional dyspnea correlates with exercise responses, especially arterial blood pH and plasma norepinephrine (NE) changes, in patients with sequelae of tuberculosis (TBsq). Cardiopulmonary exercise testings were performed in 49 TBsq patients and 9 controls. Each group had a break point in the dyspnea, plasma lactate, and plasma NE changes during exercise, all of which occurred at a similar exercise point. In TBsq patients in both exercise phases before and after the dyspnea break point, the dyspnea-slope (DeltaBorg scale/Deltaminute ventilation) correlated with the pH-slope (DeltapH/Deltaoxygen uptake) (r = -0.616, p < 0.0001; r = -0.629, p < 0.0001, respectively, before and after the break point) and with the NE-slope (DeltaNE/Deltaoxygen uptake) (r = 0.443, p = 0.0012; r = 0.643, p < 0.0001, respectively, before and after the break point). In TBsq patients during exercise, increases in circulating NE levels and exertional acidosis were correlated with exertional dyspnea.