The Principles of Total Intravenous Anesthesia (TIVA)

Abstract

This review will provide the reader with a rational basis for the administration of intravenous anesthetics. This will be based on our increasing understanding of the pharmacological processes that provide anesthesia. The goal of any anesthetic drug is to rapidly render the patient unconscious, maintain adequate anesthesia (irrespective of any surgical intervention), and then allow a rapid recovery to the awake state. To achieve this the drug needs to provide a rapid onset/offset and have a delivery system that can readily alter the effective concentration of the drug. Over the past 30 years we have gained a greater appreciation of the pharmacokinetic principles that determine onset and offset of intravenous drugs. Classically, intravenous anesthetics have been given either as a large single dose or by multiple smaller intermittent doses for induction and maintenance of anesthesia. Recent studies indicate that intravenous anesthetics given by variable rate continuous infusions provide several advantages over intermittent bolus administration. These include: a) greater hemodynamic stability; b) fewer incidences of hemodynamic breakthrough and other signs of patient responsiveness; c) reduced need for supplemental anesthetics or vasoactive drugs; d) more rapid awakening; e) decreased incidence of requirements for naloxone or need for post-operative ventilatory support; f) decreased incidence of side effects; and g) lower total dose of drug given (1).