when was the last time until 38 months ago that patient 88558 had the minimum red blood cells value?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 88558 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'red blood cells' ) and datetime(labevents.charttime) <= datetime(current_time,'-38 month') order by labevents.valuenum asc, labevents.charttime desc limit 1