instruction: what is patient 035-4312's maximum paco2 on their current hospital encounter?
response: SELECT MAX(lab.labresult) FROM lab WHERE lab.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '035-4312' AND patient.hospitaldischargetime IS NULL)) AND lab.labname = 'paco2'