what is the daily maximum amount of calculated total co2 patient 31854 has in 2105?
select max(labevents.valuenum) from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 31854 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'calculated total co2' ) and strftime('%y',labevents.charttime) = '2105' group by strftime('%y-%m-%d',labevents.charttime)