instruction: what is the difference between arterial bp mean last measured on the first icu visit compared to the second to last value measured on the first icu visit for patient 3663?
response: SELECT (SELECT chartevents.valuenum FROM chartevents WHERE chartevents.icustay_id IN (SELECT icustays.icustay_id FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 3663) AND NOT icustays.outtime IS NULL ORDER BY icustays.intime LIMIT 1) AND chartevents.itemid IN (SELECT d_items.itemid FROM d_items WHERE d_items.label = 'arterial bp mean' AND d_items.linksto = 'chartevents') ORDER BY chartevents.charttime DESC LIMIT 1) - (SELECT chartevents.valuenum FROM chartevents WHERE chartevents.icustay_id IN (SELECT icustays.icustay_id FROM icustays WHERE icustays.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 3663) AND NOT icustays.outtime IS NULL ORDER BY icustays.intime LIMIT 1) AND chartevents.itemid IN (SELECT d_items.itemid FROM d_items WHERE d_items.label = 'arterial bp mean' AND d_items.linksto = 'chartevents') ORDER BY chartevents.charttime DESC LIMIT 1 OFFSET 1)