Safety issues in adaptive control systems for automatic administration of vasoactive drugs

Automatic administration of drugs to control cardiovascular function during and after surgery has received considerable attention. Although the potential benefits associated with such a technology remain unquestioned, the several adaptive control strategies proposed thus far have had very limited success in practice. In developing robust adaptive control methodologies for drug dosing in cardiovascular applications, we have analysed a well-known multiple-model adaptive control strategy for blood pressure control. The results reveal that no guarantee of protection against actually inserting a destabilising controller into the closed-loop is given and one cannot even put a global upper bound on the time during which the destabilising controller is attached.We advocate caution towards issues which in the past may have been either disregarded or not subjected to a systematic analysis as instability could be fatal in the context of a clinical application.