A dose-response model can return an estimate beyond the doses used in an experiment. The confidence interval and observed data help show how much support that estimate has.
One hundred patients were randomized to five single intravenous doses between 0.2 and 0.6 mg/kg. For the endpoint BIS at or below 60, the fitted model estimated an ED90 of 1.172 mg/kg, with a 95% confidence interval from 0.704 to 13.959 mg/kg. Responses tended to plateau in the upper part of the tested range.
The ED90 was outside the tested range, and its very wide interval shows uncertainty in the fit. It does not establish that this dose reliably reaches the endpoint or has acceptable clinical effects. The authors also explored a different BIS threshold after the fact, which answers a different endpoint question.
Chen et al., Drug Design, Development and Therapy ยท Full text