on the current intensive care unit visit, when patient 20898 got d5w for the first time?
select inputevents_cv.charttime from inputevents_cv where inputevents_cv.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 20898 ) and icustays.outtime is null ) and inputevents_cv.itemid in ( select d_items.itemid from d_items where d_items.label = 'd5w' and d_items.linksto = 'inputevents_cv' ) order by inputevents_cv.charttime asc limit 1