THE EFFECTS OF TRANSTRACHEAL GAS DELIVERY ON CENTRAL INSPIRATORY NEUROMUSCULAR DRIVE

Previous studies have shown transtracheal delivery of low-flow oxygen (TTO) decreases inspired minute ventilation (VEinsp) and have postulat ed that this would result in a decrease in the work of breathing (WOB) . We hypothesized that a fall in central inspiratory neuromuscular dri ve (CIND) with TTO would reflect a fall in WOB. We measured resting ve ntilatory parameters (RVP) and CIND by the mouth occlusion pressure te chnique (MOP) at different gas flow rates through the catheter in 21 s ubjects (13 men, 8 women; mean age, 60 +/- 10.6 years) with severe COP D with a mature intratracheal oxygen catheter (ITOC). We also construc ted a lung/chest wall analog (LCA) to determine if flow through the ca theter would alter pressure changes during inspiration. Inspiratory ti dal volume (VTinsp) and minute ventilation (VEinsp) decreased proporti onally to the gas flow rate through the catheter. However, with increa sing flow through the catheter, P0.1 increased in the LCA, presumably due to the Bernoulli effect. The lack of a similar change in the subje ct group suggests that CIND does, in fact, fall, and that possibly the re is a decrease in WOB. This effect may be of benefit to patients wit h severe COPD.