Performance Evaluation of a Closed-Loop Sodium Nitroprusside Delivery Device during Hypotensive Anesthesia in Mongrel Dogs

  • N. Ty Smith
  • James F. Martin
  • Michael L. Quinn
  • Tom S. Scanlon
  • Gregory I. Voss
Conference paper


Although many closed-loop drug delivery systems have been proposed for automatic regulation of blood pressure with sodium nitroprusside (SNP) [1-11], the only commercially available device is the IVAC TITRATOR™ System [12]. The TITRATOR System contains a self-tuning, nonlinear proportional-plus-integral-plus-derivative (PID) regulator. It continuously estimates and adjusts to patient sensitivity, baseline pressure, and control horizon. To provide increased patient safety, it has an integrated supervisor that constrains estimation, limits SNP infusion rates, responds aggressively to rapidly changing pressures, and rejects artifactual pressure measurements. The current FDA approved indications for use of the TITRATOR System are limited to the postoperative control of hypertension following cardiovascular surgery. Recent enhancements have been made to the system’s control algorithm in an attempt to widen the range of applications. The objective of this study was to determine, using an animal model, the performance of the TITRATOR System’s enhanced algorithm in inducing and maintaining deliberate hypotension during various challenges to blood pressure homeostasis.


Mean Arterial Pressure Sodium Nitroprusside Model Reference Adaptive Control Baseline Pressure Titrator System 
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Copyright information

© Springer-Verlag Tokyo 1992

Authors and Affiliations

  • N. Ty Smith
    • 1
  • James F. Martin
    • 2
  • Michael L. Quinn
    • 1
  • Tom S. Scanlon
    • 3
  • Gregory I. Voss
    • 2
  1. 1.Department of AnesthesiologyUCSD and USVA Medical CenterSan DiegoUSA
  2. 2.Department of Cardiovascular Systems and Control IVAC CorporationSan DiegoUSA
  3. 3.Department of AnesthesiologyNaval HospitalSan DiegoUSA

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