A 38-year-old female patient with a history of hepatic cirrhosis (Child-Pugh Class B) is scheduled for emergency repair of a perforated peptic ulcer. The anesthesiologist is selecting an inhalational agent for maintenance anesthesia and is concerned about hepatic metabolism and fluoride ion accumulation. The patient's baseline serum creatinine is 1.2 mg/dL (normal). Which inhalational agent would be the safest choice, and what is the primary reason based on its metabolic profile?