This dialog is invoked by the Agent and Circuit command on the Anesthesia menu. Select the desired anesthetic and circuit type for the simulation in the currently active simulation window. Press 'OK' to confirm your choices and continue; press 'CANCEL' to continue without changing the agent or circuit.
The anesthetic that is changed is either
You can only select or change the agents to administer at the start of a simulation.
See Multiple Agent Simulations for an explanation of how to add multiple agents.