Metformin内服患者における開心術後乳酸アシドーシスに対し持続的腎代替療法を行った1例

Lactic Acidosis after Cardiac Surgery Treated by Continuous Renal Replacement Therapy in a Patient on Metformin；Report of a Case

はじめに　乳酸アシドーシスは開心術後にしばしば経験する病態であるが，その要因はさまざまであり，時に原因特定に難渋する．しかし，的確に原因を診断して治療を行わなければ致死的となりうる．一方，乳酸アシドーシスはmetformin内服によるまれな副作用としても知られており，過剰摂取による乳酸アシドーシスでは，持続的腎代替療法（CRRT）が有効であったとの報告がある．われわれは，metformin内服による開心術後の乳酸アシドーシスに対し，CRRTが奏効した1例を経験したので報告する．

Lactic acidosis is a common condition observed in a patient after cardiac surgery. It is important to identify the pathogenesis of lactic acidosis since the delay of an appropriate treatment leads to high mortality. Metformin overdose has been known as a risk of lactic acidosis, and previous reports have demonstrated that continuous renal replacement therapy （CRRT） is effective. However, it has yet to be known if metformin-related lactic acidosis after cardiac surgery is treatable with CRRT. We, herein, report a case of 64-year-old diabetic male who had been on metformin treatment until 1 day before surgery. He presented lactic acidosis postoperatively and was successfully treated with CRRT. This case suggests that it is necessary to discontinue metformin no later than 2 days before surgery and that CRRT is of use for perioperative lactic acidosis in a patient on metformin.