Measurement of CO₂ in chronic fatigue syndrome patients

This study has two goals: One, to compare the resting end-tidal pCO₂ (PetCO₂) and heart rate (HR) of chronic fatigue syndrome patients (CFS) with controls; two, to examine the effects of a mouthpiece and noseclips upon measurements of PetCO₂ and HR. Patients from the CFS Center came to the University Hospital pulmonary function laboratory for one testing session. Arterial (PaCO₂), PetCO₂, end-nasal (PenCO₂) and HR were measured twice; both with and again without the subject breathing through the mouthpiece. We found that PenCO₂ was greater and HR lower for both CFS and non-CFS groups when subjects were not confined by the mouthpiece. We conclude that there is no abnormality in the regulation of respiration in CFS patients. Changes in HR accompany changes in PetCO₂ in this study. Most likely, both result from anxiety associated with mouthpiece breathing.