Figure 3. (Left) Effect of a step increase in end-tidal isoflurane tension (PETiso) from 0 to approximately 0.9 mmHg on sustained hypoxia-driven minute ventilation (V with dotE) in subject 415 at min 17 of isocapnic hypoxia. (Right) Mean effect of exposure to isoflurane on sustained hypoxia-driven V with dotE. Data points are means plus/minus SE (n = 11) of PETisoand V with dotE(percentage of prehypoxic normoxic V with dotE). The last expiration without isoflurane was indexed at time 0. The lines through the data points were drawn by hand. *P < 0.05 versus hypoxia awake (circles).