EFFECTS OF HYPERBARISM ON CENTRAL RESPIRATORY DRIVE AND RESPIRATORY PATTERN IN HUMANS

The aim of our study was to evaluate the effects of increasing pressure (from 1 to 3 and 6 atm abs) on respiratory drive, respiratory pattern, and inspiratory impedance of the respiratory system. Seven healthy volunteers were studied during a dry compression to 6 atm abs in a hyperbaric multiplace chamber. We observed a significant increase in tidal volume, P-0.1 (the pressure generated in the airway after 100 ms of inspiration against a closed inspiratory line), T-tot, and T-i, and a significant respiratory rate reduction with increasing pressure from 1 to 3 atm.abs; P-0.1 also increased significantly when comparing 3 and 6 atm abs measurement with 1 atm abs. The P > 0.01 and P-0.1/(VT/T-i) showed a significant progressive increase compared with 1 atm abs. In conclusion, the passage from 1 to 3 and 6 atm abs causes, in healthy subjects at rest, an increase in the central respiratory drive activity, evaluated with P-0.1 measurement. The response to the respiration system is an increase in tidal volume and T-i with a decrease in respiratory rate.