Control of muscle relaxation during anesthesia: a novel approach for clinical routine.
During general anesthesia drugs are administered to provide hypnosis, ensure analgesia, and skeletal muscle relaxation. In this paper, the main components of a newly developed controller for skeletal muscle relaxation are described. Muscle relaxation is controlled by administration of neuromuscular blocking agents. The degree of relaxation is assessed by supramaximal train-of-four stimulation of the ulnar nerve and measuring the electromyogram response of the adductor pollicis muscle. For closed-loop control purposes, a physiologically based pharmacokinetic and pharmacodynamic model of the neuromuscular blocking agent mivacurium is derived. The model is used to design an observer-based state feedback controller. Contrary to similar automatic systems described in the literature this controller makes use of two different measures obtained in the train-of-four measurement to maintain the desired level of relaxation. The controller is validated in a clinical study comparing the performance of the controller to the performance of the anesthesiologist. As presented, the controller was able to maintain a preselected degree of muscle relaxation with excellent precision while minimizing drug administration. The controller performed at least equally well as the anesthesiologist.
Stadler
Konrad S
KS
Automatic Control Laboratory, Swiss Federal Institute of Technology (ETH), Physikstrasse 3. CH-8092 Zurich, Switzerland. kss@ieee.org
Schumacher
Peter M
PM
Hirter
Sibylle
S
Leibundgut
Daniel
D
Bouillon
Thomas W
TW
Glattfelder
Adolf H
AH
Zbinden
Alex M
AM
D018681:Anesthetics, General / Q000008:administration & dosage*; D003198:Computer Simulation; D004338:Drug Combinations; D004360:Drug Therapy, Computer-Assisted / Q000379:methods*; D006801:Humans; D008954:Models, Biological; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology*; D009126:Muscle Relaxation / Q000187:drug effects* / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D009465:Neuromuscular Agents / Q000008:administration & dosage*
D018681:Anesthetics, General; D004338:Drug Combinations; D009465:Neuromuscular Agents