###HUMAN: what is the variation of patient 006-181433's weight second measured on the current hospital visit compared to the first value measured on the current hospital visit?, ###ASSISTANT: SELECT (SELECT patient.admissionweight FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '006-181433' AND patient.hospitaldischargetime IS NULL) AND NOT patient.admissionweight IS NULL ORDER BY patient.unitadmittime LIMIT 1 OFFSET 1) - (SELECT patient.admissionweight FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '006-181433' AND patient.hospitaldischargetime IS NULL) AND NOT patient.admissionweight IS NULL ORDER BY patient.unitadmittime LIMIT 1)