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Anesthesia Advisory Display (AAD): Real time guidance through the pharmacokinetic and interaction pharmacodynamic relationship during simultaneous administration of multiple drugs.

Author(s):

P.M. Schumacher, T. Bouillon, D. Leibundgut, V. Sartori, A.M. Zbinden
Conference/Journal:

ASA - American Society of Anesthesiologists Annual Meeting, Las Vegas, Nevada, Abstract
Abstract:

Background: Pharmacokinetic and (interaction) pharmacodynamic characterizations of drugs used in anesthesia are available or can be obtained by extrapolation of potency ratios, enabling scientists to predict optimal drug concentration ratios for analgosedation and anesthesia. These predictions are static and probabilistic. They are based on the definition of an isobole for the desired effect, definition of an isobole for recovery of consciousness and spontaneous respiration and determining the points of least distance in the time domain (=fastest wakeup time) on these isoboles. Vuyk et al. introduced this kind of analysis in 1997 (1). However, anesthesia takes place in a dynamic environment and neither predicted drug concentrations and effects nor online calculations of corresponding recovery times for optimization of drug concentration ratios are routinely available during clinical anesthesia. We propose an advisory system which leaves the anesthesiologist in complete control of dosing but enables him to obtain real time information about the predicted drug concentrations, predicted combined effect and predicted wakeup time resulting from his actions as well as displaying the optimal drug concentration ratio for a given effect in the typical patient in an intuitively appealing format. Methods: The authors postulated a minimal requirements specification for the display and identified the following issues: i) implementation with minimal regulatory involvement (the device should provide information, which is not accessible otherwise, but not actively alter the state of the patient), ii) general applicability (the display should be usable for any combination of a volatile agent/propofol and opioid and easily modifiable (incorporation of new drug combinations and/or new interaction models), iii) maximal synthesis of information (comparable to using a primary flight display instead of the classical 6 flight instruments in aviation), iv) intuitive understandability/minimal training requirements. They then implemented a prototype of the device for simultaneous administration of propofol, remifentanil and fentanyl using MATLAB. Results: The prototype display will be available at the session. A target oriented infusion approach was chosen. The anesthesiologist directly manipulates the infusion pumps, the display reads the dosing information from the pumps. It consists of a 2 dimensional effect map in the concentration domain, showing colour coded areas bounded by isoboles for probability of tolerating noxious stimuli, similar to displaying contour lines and color coded terrain altitudes on a map. A marker referring to the predicted effect compartment concentrations of the drugs displays the current position on the map.The predicted ideal concentration ratio, the predicted concentrations 5 and 15 minutes into the future when maintaining the same infusion rates and the currently predicted wake-up time are also displayed. These predictions are dynamically updated depending on the dosing history and duration of anesthesia. Conclusions: The authors introduce a tool which will not require the same stringent approval procedure as a TCI and provide information far beyond that implemented in e.g. the Diprifusor. Suggested uses are training (a simulation mode is provided) and online use in the OR. References: Anesthesiology (1997) 87: 1549-62

Year:

2004
Type of Publication:

(01)Article
Supervisor:

A.M. Zbinden

No Files for download available.
% Autogenerated BibTeX entry
@InProceedings { SchEtal:2004:IFA_1858,
    author={P.M. Schumacher and T. Bouillon and D. Leibundgut and V. Sartori and A.M. Zbinden},
    title={{Anesthesia Advisory Display (AAD): Real time guidance
	  through the pharmacokinetic and interaction pharmacodynamic
	  relationship during simultaneous administration of multiple
	  drugs.}},
    booktitle={ASA - American Society of Anesthesiologists Annual Meeting},
    pages={},
    year={2004},
    address={Las Vegas, Nevada},
    month=oct,
    url={http://control.ee.ethz.ch/index.cgi?page=publications;action=details;id=1858}
}
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