Table 1. Remifentanil Concentrations for the Ventilatory Depression Study
After having obtained baseline values in absence of drug, each concentration step was maintained for 15 min before switching to the next one (exception: volunteers 1 and 2, 20 min). The first concentration indicated refers to the highest concentration achieved (maintained spontaneous ventilation at free-floating Pco2. The concentration ranges were determined by the tolerance of the respective volunteer to the ventilatory depressant effect of remifentanil.
* Volunteer 1 was excluded because of a spuriously low baseline (Paco2), in volunteer 16 we were unable to get a carbon dioxide response because of equipment failure.