Extracorporeal membrane oxygenation with continuous renal replacement therapy to treat metformin-associated lactic acidosis A case report

Rationale: Metformin-associated lactic acidosis (MALA) is rarely encountered, but has a high mortality rate, Conventional treatments include hemodialysis or continuous renal replacement therapy (CRRT); however, when the disease progresses to end-stage, cardiac function is significantly inhibited, circulation cannot be maintained, CRRT cannot be tolerated, V-A extracorporeal membrane oxygenation (ECMO) may be the last treatment. Patient concerns: The study report a rare case of MALA in an elderly female patient at the age of 72 who was admitted to hospital because of nausea for 2 days, complicated with systemic fatigue. Diagnosis: MALA was cofirmed because of patient have increased lactic acid levels, blood pH <7.2, and a history of oral metformin intake. Interventions: Venoarterial ECMO (V-A ECMO) combined with CRRT was initiated when circulation was still not hold after intravenous fluids and 5% sodium bicarbonate were prescribed. Outcomes: V-A ECMO was then terminated after 48 hours when circulation was perserved, CRRT was discontinued when PH and lactic acid level were normal limited. etformin-associated lactic acidosis did not recur during 6 months follow-up. Lessons: The incidence of MALA is low, but mortality is very high. Intermittent hemodialysis or CRRT should be performed if the lactic acid level is persistently elevated. When severe circulatory dysfunction occurs and cardiac function is inhibited, V-A ECMO support should be performed immediately to maintain circulation, followed by CRRT, which may be the final measure to treat refractory MALA.