Anesthesiology Gases and Vapors - MAC Part 1 [History of MAC]

Description: 00:06 Introduction 02:20 The Prehistory of MAC 04:52 1963 - The Development of MAC 06:07 Saidman and Eger's Landmark Paper 10:31 "Minimum Alveolar Concentration" 1965 12:04 MAC is the EC50 for Movement to surgical incision - Nothing More 13:32 MAC changes with Age 1969 14:35 1996 Mapleson Clarifies the relationship between MAC and age and sets to defining MAC values for Volatile Anesthetics 16:50 MAC age response curves (Mapleson) 18:46 MAC is Additive 21:10 What MAC is not 23:52 Review and Preview ‪@or2icu‬ ​ This is the first of 3 tutorials on the MAC - minimum alveolar concentration. In this tutorial, we explore the origins and true meaning of Minimal Alveolar Concentration (MAC), the cornerstone of inhalational anesthesia practice. Beginning in the 1950s, anesthetic depth lacked a reliable, quantitative framework until the development of end-tidal gas analysis enabled a link between anesthetic concentration and a measurable biological endpoint: movement. We follow the pioneering work of Ted Eger and colleagues, from early animal studies to the landmark 1964 human trials that established MAC as the concentration preventing movement in 50% of patients. This tutorial clarifies that MAC is not a measure of unconsciousness, but rather the EC50 for immobility in response to surgical stimulus. We also examine the key modifier of MAC: age . I highlight the critical concept that MAC is a population median—not an individual property. Understanding these principles is essential for applying MAC safely and intelligently in clinical practice.