Nomogram to estimate age-related MAC

Area of Science:

• Anesthesiology
• Pharmacology
• Clinical Anesthesia

Background:

• Accurate estimation of anesthetic depth is crucial in clinical practice.
• Calculating age-corrected Minimum Alveolar Concentration (MAC) and required end-expired agent concentrations can be challenging.
• Existing methods for determining anesthetic requirements are often time-consuming.

Purpose of the Study:

• To develop a simplified tool for estimating anesthetic requirements.
• To provide a rapid method for calculating age-corrected MAC multiples.
• To determine the precise end-expired volatile agent concentration for a target MAC multiple.

Main Methods:

• Developed a single nomogram using standard nomogram techniques.
• The nomogram covers a wide range of patient ages (1-100 years) and MAC values (0.1-1.8).
• Included common volatile anesthetics (halothane, enflurane, isoflurane, sevoflurane, desflurane) and nitrous oxide.

Main Results:

• The nomogram allows for rapid estimation of anesthetic requirements with simple graphical methods.
• Demonstrated specific examples of achieving target MAC multiples across different ages and agent combinations.
• Showcased the nomogram's utility in both calculating MAC from concentrations and determining concentrations for a desired MAC.

Conclusions:

• The developed nomogram provides accurate and easily obtainable results for anesthetic management.
• The nomogram is user-friendly, requiring only the drawing of two straight lines.
• The nomogram's design is adaptable for other anesthetic agents, such as xenon.