Figure 2: Distribution of BIS values according to MAC categories. Note: Twenty percent of patients received high MAC values. Amongst them, 70% had deep and 30% adequate BIS levels. Seventy-eight percent of the patients received normal MAC values, and among these patients, 49% exhibited deep and 51% adequate BIS values. All patients that received low MAC values had deep BIS levels. MAC: Mean alveolar concentration; BIS: bispectral index.