how many time did patient 14154 get a calculated total co2 test since 10/2103?
select count(*) from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'calculated total co2' ) and labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 14154 ) and strftime('%y-%m',labevents.charttime) >= '2103-10'