Management of Lactic Acidosis in Acute Liver Failure and Critical Illness

Diagnostic Work‑up for Acute Liver Failure (ALF)

Impaired hepatic lactate clearance in ALF is a primary mechanism for severe lactic acidosis. 1, 2
Initial evaluation should include acetaminophen level, hepatitis A IgM, hepatitis B surface antigen and anti‑HBc IgM, toxicology screen (amphetamines, cocaine), hepatic Doppler ultrasound, and transthoracic echocardiography. 1, 3
Baseline coagulation (PT/INR, factor V), arterial blood gas with lactate, arterial ammonia, and glucose are essential laboratory studies. 1, 2

Administer intravenous N‑acetylcysteine immediately, irrespective of the presumed etiology of ALF. 1, 2
Early notification of a liver transplant center is recommended. 1, 2
If herpes simplex virus infection is clinically suspected (e.g., fever), start empiric acyclovir. 1, 2
Perform rapid assessment of encephalopathy, hemodynamic status, and renal function. 1

Metformin is contraindicated in patients with advanced renal insufficiency or impaired hepatic function because of a heightened risk of lactic acidosis. 4, 5
Discontinuation of metformin should be immediate in the setting of liver disease. 4, 5

Sodium bicarbonate should not be used for lactic acidosis when arterial pH is ≥ 7.15, as it offers no hemodynamic benefit and may cause harm. 6, 7, 8
Evidence shows bicarbonate does not improve vasopressor requirements or tissue perfusion in hypoperfusion‑related lactic acidosis. 7, 8
Potential adverse effects of bicarbonate therapy include sodium/fluid overload, increased lactate and PaCO₂, and reduced ionized calcium. 7, 8
Bicarbonate may be considered only when pH falls below 7.15; however, supporting data are limited. 7, 8

Apply a lung‑protective ventilatory strategy if endotracheal intubation is required. 3, 2
Systematically evaluate volume status, cardiac output, and right‑ and left‑sided cardiac function. 3, 2
Crystalloid fluids are the first‑line choice for volume expansion. 3, 2
Initiate norepinephrine infusion for refractory hypotension. 3, 2

Indications for RRT are limited to definitive clinical needs such as severe hyper‑kalemia, uremia, or refractory volume overload. 6, 7, 8
RRT should not be employed solely to treat lactic acidosis or an isolated rise in creatinine without other indications. 7, 8
Continuous RRT modalities are preferred when fluid balance management is required in hemodynamically unstable patients. 6, 7

Frequent neurologic monitoring; intubate if the Glasgow Coma Scale falls below 8. 3, 2
Maintain serum sodium within 140–145 mmol/L. 3, 2
Check blood glucose at least every 2 hours. 3, 2
Initiate empirical broad‑spectrum antibiotics when encephalopathy worsens or systemic inflammatory response syndrome develops. 3, 2
Do not use lactulose or rifaximin to lower ammonia levels in ALF. 3
Routine correction of coagulopathy is unnecessary unless active bleeding is present. 3
Avoid nephrotoxic agents, including non‑steroidal anti‑inflammatory drugs. 3

Lactate concentrations > 9 mmol/L are linked to extremely poor outcomes and may serve as a contraindication to liver transplantation. 9
Lactate levels > 4 mmol/L are associated with adverse post‑transplant outcomes. 9
Additional poor‑prognosis markers include PaO₂/FiO₂ < 150, escalating vasopressor support, and dependence on mechanical ventilation. 9, 10