how many days has it been since patient 42473 stayed in the careunit tsicu for the last time in this hospital encounter?
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 = 42473 and admissions.dischtime is null ) and transfers.careunit = 'tsicu' order by transfers.intime desc limit 1