ACHIEVING CONTROL OF ANESTHETIC ADMINISTRATION: The Infusion Pump Versus The Vaporizer

Despite the recent introduction of several drugs into our practice, the search for the "ideal agent" continues. Titratability is a desirable property of potential new agents. The quest for increased anesthetic control is evident in the search for volatile agents with decreasing blood and tissue solubility and for more evanescent intravenous agents. At the same time, much scholarly activity is being devoted to improving our understanding of the pharmacologic properties of the agents that are currently available. The concepts developed from this body of work are clinically applicable and can facilitate a more rational approach to the everyday administration of inhaled and intravenous anesthetics than has been heretofore possible. In this way, many of the shortcomings of the currently available agents may be minimized. Control of anesthesia entails controlling the depth of the anesthetic and controlling the components of the anesthetic. The intuitive simplicity of the calibrated anesthetic vaporizer makes inhalational anesthesia difficult to match in terms of control of anesthetic depth. On the other hand, the capacity to tailor an intravenous anesthetic technique to provide the specific individual components of hypnosis, amnesia, analgesia, autonomic reflex suppression, and muscle relaxation is not readily achieved with a pure inhalational technique. It is becoming apparent that anesthetic techniques dependent upon single agents have significant limitations. It is appropriate therefore to develop an anesthetic technique that utilizes combinations of drugs, thus providing the ability to control the depth of anesthesia in a manner analogous to using a vaporizer with the ability to control the components of anesthesia by using intravenous agents. This article explores strategies designed to achieve these goals.