how many days has it been since the last time patient 72909 stayed during their current hospital visit in the careunit ccu?
select 1 * ( 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 = 72909 and admissions.dischtime is null ) and transfers.careunit = 'ccu' order by transfers.intime desc limit 1