What causes lactic acidosis? is it from metformin? how to avoid lactic acidosis?

Lactic acidosis: Most cases of type a lactic acidosis are due to marked tissue hypoperfusion in shock or during cardiopulmonary arrest. In type b lactic acidosis, systemic tissue hypoperfusion is not apparent. Metformin therapy for type ii diabetes can cause it, although the likelihood of this is relatively low. Risk factors for this include impaired kidney function and liver disease or concurrent alcohol abuse.