When using a balanced anaesthetic technique, specific agents are utilized to produce the desired clinical effects, notably sedation-hypnosis, amnesia, analgesia and muscle relaxation. TIVA follows naturally from this concept, when all of these components are produced by intravenously administered drugs. Delivery of drug directly into the intravascular space permits a rapid onset of effects and optimal titration to the desired end-point, while at the same time avoiding the problem of airborne pollution and freeing the airway for the sole purposes of delivering oxygen and removing carbon dioxide. The intravenous anaesthetic agents eliminate many of the undesirable pharmacological properties of the volatile agents. Further, they can be employed in situations where inhaled agents cannot be used. Newer intravenous agents are capable of producing more specific pharmacodynamic effects, have a faster onset of effect and more rapid elimination and, thereby, permit more precise 'fine tuning' of the anaesthetic depth. In addition to providing general anaesthesia, application of the same principles of improved control with reduced dosages of the same sedative-hypnotic agents can provide sedation to supplement regional or local anaesthetics as well as for critically ill patients. Future developments will probably include the discovery of rapid-acting drugs with even more precisely defined effects and shorter half-lives. In addition, improvements in intravenous drug delivery systems and better monitoring of the intravenous anaesthetic state will produce even greater safety and reliability. © 1991 Baillière Tindall.
