instruction: when was first time the respiration of patient 016-29754 was greater than 20.0 on the last icu visit?
response: SELECT vitalperiodic.observationtime FROM vitalperiodic WHERE vitalperiodic.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '016-29754') AND NOT patient.unitdischargetime IS NULL ORDER BY patient.unitadmittime DESC LIMIT 1) AND vitalperiodic.respiration > 20.0 AND NOT vitalperiodic.respiration IS NULL ORDER BY vitalperiodic.observationtime LIMIT 1