Can a Dr. see signs of meths withdrawals when surgery was only done 3 days prior??

after aortic aneurysom surgery a Dr. has said he seen withdrawals from meth on this person. I would like to know how when this person has not even woke up yet.he has high blood pressure and has had for many years. yes meth was found in his system supposably but when you are not even awake yet how can that be?
the kind of withdraws i am saying is not of the blood samples but of the persons actions after the aorta surgery

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