1. Volume 150, Issue 1, Pages e23-e27 (July 2016)
A 56-Year-Old, Otherwise Healthy Woman Presenting With Light-headedness and Progressive Shortness of Breath 
J. Alberto Neder, MD, Daniel M. Hirai, PhD, Joshua H. Jones, BSc, Joel T. Zelt, BSc, Danilo C. Berton, MD, Denis E. O’Donnell, MD 
CHEST 
Volume 150, Issue 1, Pages e23-e27 (July 2016)
DOI: /j.chest
Copyright © 2016 American College of Chest Physicians Terms and Conditions

2. Figure 1
Key cardiopulmonary exercise testing data. A and B, Note preexercise bursts of increased ventilation and increasing dyspnea scores (A), which were out of proportion to metabolic demand (B). C, Changes in ventilation were associated with erratic variations in breathing pattern. D, End-tidal and arterialized Pco2 (Partco2) decreased in parallel. Start of exercise was associated with a decrease in dyspnea (A) and sudden recoupling of ventilation to metabolism (B), which led to a progressive increase in Pco2 (D). The patient increased ventilation near the end of exercise in order to compensate for ongoing metabolic acidosis (“respiratory compensation point”). Rec = recovery.
CHEST  , e23-e27DOI: ( /j.chest )
Copyright © 2016 American College of Chest Physicians Terms and Conditions

3. Figure 2
Near-infrared spectroscopic measurements of cerebral oxygenation as related to prevailing end-tidal Pco2 levels. Note progressive impairment in preexercise cerebral oxygenation (proportional to cerebral perfusion in nonhypoxemic patients) with accompanying neurological symptoms as end-tidal Pco2 decreased. Cerebral oxygenation subsequently improved (and the symptoms subsided) as end-tidal Pco2 increased during exercise.
CHEST  , e23-e27DOI: ( /j.chest )
Copyright © 2016 American College of Chest Physicians Terms and Conditions