Figure 31-15 A, Move/no move versus serum thiopental concentration for five different clinical stimuli. Each bar indicates the serum thiopental concentration and response to stimuli applied to an individual patient. B, Predicted probability of no movement versus serum thiopental concentrations obtained by using logistic regression of the data indicated in A. The bars indicate the 95% confidence bounds of the estimate of serum thiopental concentration that produces a 50% probability of no movement response. I, laryngoscopy/intubation; L, laryngoscopy; S, trapezius muscle squeeze; T, tetanic nerve stimulation; V, verbal. (From Hung OR, Varvel JR, Shafer SL, et al: Thiopental pharmacodynamics. II. Quantitation of clinical and electroencephalographic depth of anesthesia. Anesthesiology 77:237, 1992.)