Pursed-lip Breathing

Excerpt

The major drive for respiration originates in the central and peripheral chemoreceptors. The central chemoreceptors are located anterior medulla in the brainstem and predominantly responds to a decrease in pH from the accumulation of carbon dioxide in the cerebral spinal fluid. The blood-brain barrier protects the central nervous system from external stimuli. Carbon dioxide is lipid-soluble, which allows it to quickly diffuse across the protective barrier and influence the respiratory drive.