Fig. 3. Individual Bayesian estimates (open circles ) of the elimination clearance (Cl¹), distribution clearance (Cl²), and the peripheral volume of distribution (V²), obtained from the model, without covariates, as functions of plasma alfentanil concentration (A ), heart rate (B  and C ), and cardiac output (D  and E ). The linear relation between plasma alfentanil concentration, heart rate, or cardiac output and Cl¹or V²(lines ) were estimated by linear regression (coefficients not presented).