[rscho]

MAC is the alveolar concentration (so strictly speaking defined only for anesthetic gases) at which half of people show no motor reaction on surgical incision. I understand your interpretation about paralysis, but we know the measurement endpoint is not paralysis in practice. Gases are hypnotics, and although they do cause some amount of muscle relaxation they do not induce paralysis. Hence the need for other drugs when we need paralysis. BTW, there is evidence that EEG prevents awareness under anesthesia, but it's not a guarantee either. Fortunately, awareness is extremely rare even in the select cases where it occurs more often (emergency C-section and cardiac surgery, especially in seniors).