when did patient 18841 get admitted to the hospital for the first time the last year via emergency room admitting?
select admissions.admittime from admissions where admissions.subject_id = 18841 and admissions.admission_location = 'emergency room admit' and datetime(admissions.admittime,'start of year') = datetime(current_time,'start of year','-1 year') order by admissions.admittime asc limit 1