TABLE 2.

Final piperacillin model and bootstrap analysis^a

Parameter	Final model				Bootstrap analysis (n = 1,000)
	Point estimate	RSE (%)	95% CI	Shrinkage (%)	2.5th percentile	Median	97.5th percentile
Typical value
CL (liters/h)	3.92	17.4	2.58 to 5.26		2.74	3.72	5.35
Vc (liters)	4.87	27.2	2.28 to 7.46		2.47	4.35	8.24
Q (liters/h)	0.25	86.2	−0.17 to 0.68		0.05	0.21	1.24
Vp (liters)	0.49	47.9	0.03 to 0.95		0.19	0.66	8.46
Covariate effect
WT on CL and Q (exponent)	1.40	13.2	1.03 to 1.76		0.95	1.36	1.78
Furosemide on CL	−0.28	97.7	−0.83 to 0.26		−0.64	−0.29	−0.06
WT on Vc and Vp (exponent)	1.26	23.4	0.68 to 1.84		0.32	1.16	1.95
Variance model
IIV (CL)	0.44	17.6	0.29 to 0.59	4.8	0.27	0.42	0.57
IIV (Vc)
IIV (Q)
IIV (Vp)
Proportional error	0.46	10.5	0.37 to 0.56	15	0.36	0.45	0.53

^aCI, confidence interval; CL, clearance; IIV, interindividual variability; Q, intercompartmental clearance; RSE, residual standard error; V_c, volume of distribution of the central compartment; V_p, volume of distribution of the peripheral compartment; WT, body weight.