To the Editor.—
Halpren et al in their recent article "Interstitial Fibrosis and Chronic Renal Failure Following Methoxyflurane Anesthesia" (223:1239, 1973) presented two cases. They reviewed the literature and argued that the progressive interstitial fibrosis, which they had noted in one patient, was due to fluoride, a metabolite1 of methoxyflurane (Penthrane).We report two additional cases of chronic renal failure following methoxyflurane anesthesia, one of which recovered sufficiently in five weeks to be discharged. In the other patient renal failure began only after a second, higher dose of the anesthetic. This may indicate a dose-dependent rather than a hypersensitivity reaction. Phagocytosis of the intratubular crystalline oxalate deposits by foreign-body giant cells in one case could represent a defense mechanism that might lead to improvement of renal function.
Report of Cases.—Case 1.—
A 77-year-old woman received methoxyflurane and nitrous oxide for two hours and fifteen minutes during choledocholithotomy.