Companion web site to

Eric Nikkelen, MSEE 1, Willem L. van Meurs, PhD 1,2,3, and Maria A.K. Öhrn, MD 1:

Hydraulic analog for simultaneous representation of pharmacokinetics and pharmacodynamics: Application to vecuronium


Journal of Clinical Monitoring and Computing, J Clin Monit Comput. 1998 Jul;14(5):329-37.

1Department of Anesthesiology, University of Florida College of Medicine; 2Department of Electrical and Computer Engineering, University of Florida College of Engineering; 3University of Florida Brain Institute.

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Copyright © 1998, University of Florida

Click on one of the dosing buttons to inject drug. EDxx: Effective dose of vecuronium, resulting in xx % single twitch force depression. IR50: infusion rate of vecuronium, resulting in 50% twitch force depression. The simulation can be accelerated by clicking on the buttons at the bottom of the hydraulic analog.

Fluid delivered into the central reservoir is equivalent to drug infusion. The heights of the fluid columns in the central and peripheral reservoirs are equivalent to the drug concentrations in the corresponding pharmacologic compartments. The height of the fluid column in the "effect reservoir" is equivalent to the apparent effect site concentration in a simultaneous pharmacokinetic-pharmacodynamic model. The non-linear scale on the effect reservoir represents the relationship between the effect site concentration and the clinical effect. 5, 50, and 95 % twitch force depression are indicated.