what was the last dose of sodium chloride during their current hospital encounter given to patient 82132?
select prescriptions.dose_val_rx from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 82132 and admissions.dischtime is null ) and prescriptions.drug = 'sodium chloride' order by prescriptions.startdate desc limit 1