instruction: what is in the current hospital encounter maximum vancomycin value of patient 57050?
response: SELECT MAX(labevents.valuenum) FROM labevents WHERE labevents.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 57050 AND admissions.dischtime IS NULL) AND labevents.itemid IN (SELECT d_labitems.itemid FROM d_labitems WHERE d_labitems.label = 'vancomycin')