MAC-BAR

MAC-BAR (Blockade of Autonomic Responses) is the MAC that blocks changes in heart rate, blood pressure, pupil diameter

and/or plasma catecholamine concentrations in 50% of subjects when a supramaximal noxious stimulus is applied (Roizenet al.

1981). 

The ratio of MAC-BAR/MAC for isoflurane in goats is approximately 2.8 (Antognini & Berg 1995) and for halothane in humans is approximately 1.45 (Roizenet al. 1981)