how many hours have passed since first time on the current hospital visit patient 14671 stayed in the careunit micu?
select 24 * ( strftime('%j',current_time) - strftime('%j',transfers.intime) ) from transfers where transfers.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 14671 and admissions.dischtime is null ) and transfers.careunit = 'micu' order by transfers.intime asc limit 1