Isofluran – Ableitung eines BAT-Wertes

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area re-evaluated isoflurane [26675-46-7] and a maximum concentration at the workplace (MAK value) of 2 ml/m3 has been set for isoflurane. The substance is used as a volatile anaesthetic, and absorption of isoflurane at the workplace is by inhalation. Human studies are not available to derive a quantitative relationship between the internal dose and the critical toxic effects of isoflurane (neurotoxicity and liver toxicity, effects on reproductive organs). Three studies on surgical employees show a linear correlation between the concentration of isoflurane in the air and urine concentration. In correlation to the MAK value of 2 ml/m3, a biological tolerance value (BAT value) of 4 µg isoflurane/l urine was established. Sampling time is at the end of exposure or end of shift. There are no studies in neonatal or juvenile animals at non-anaesthetic concentrations to derive a no observed adverse effect concentration (NOAEC) for developmental neurotoxic effects of isoflurane. Therefore, isoflurane was assigned to Pregnancy Risk Group D. Since the BAT value was derived in correlation to the MAK value, Pregnancy Risk Group D also applies to the BAT value.