From the Guidelines
Elevated lactate levels are a medical emergency that requires immediate attention and treatment, focusing on addressing the underlying cause, such as shock, severe infections, or metabolic dysfunction, with the goal of normalizing lactate levels and improving tissue perfusion and oxygenation. The causes of hyperlactatemia include shock (septic, cardiogenic, or hypovolemic), severe infections, cardiac arrest, seizures, liver dysfunction, certain medications (metformin, nucleoside reverse transcriptase inhibitors), malignancies, and excessive exercise.
Treatment Approach
Treatment primarily focuses on addressing the underlying cause. For shock, this involves:
- Fluid resuscitation with crystalloids (typically 30 ml/kg initially for septic shock) 1
- Vasopressors like norepinephrine (starting at 0.05-0.1 mcg/kg/min) if fluids are insufficient 1
- Antibiotics for infections (within one hour for sepsis) 1
- Oxygen supplementation to maintain adequate tissue oxygenation
- In cases of metformin-associated lactic acidosis, hemodialysis may be necessary
Monitoring and Goals
Serial lactate measurements should be obtained every 2-4 hours to monitor response to treatment, with a goal of normalizing levels (below 2 mmol/L) 1. The pathophysiology involves either increased production from tissue hypoxia causing anaerobic metabolism or decreased clearance due to liver or kidney dysfunction. Persistent hyperlactatemia despite treatment indicates poor prognosis and may require escalation of care, including mechanical ventilation or extracorporeal support in severe cases.
Key Considerations
- Elevated lactate has been shown to correlate with increased mortality in various types of shock 1
- Lactate-guided resuscitation has been consistently shown to be effective 1
- Clinicians should complement haemodynamic targets with other serial markers of systemic and organ perfusion, such as lactate, mixed or central venous oxygen saturations, urine output, skin perfusion, renal and liver function tests, mental status, and other haemodynamic variables 1
From the FDA Drug Label
LEVOPHED should not be given to patients who are hypotensive from blood volume deficits except as an emergency measure to maintain coronary and cerebral artery perfusion until blood volume replacement therapy can be completed If LEVOPHED is continuously administered to maintain blood pressure in the absence of blood volume replacement, the following may occur: severe peripheral and visceral vasoconstriction, decreased renal perfusion and urine output, poor systemic blood flow despite "normal" blood pressure, tissue hypoxia, and lactate acidosis Prolonged administration of any potent vasopressor may result in plasma volume depletion which should be continuously corrected by appropriate fluid and electrolyte replacement therapy If plasma volumes are not corrected, hypotension may recur when LEVOPHED is discontinued, or blood pressure may be maintained at the risk of severe peripheral and visceral vasoconstriction (e.g., decreased renal perfusion) with diminution in blood flow and tissue perfusion with subsequent tissue hypoxia and lactic acidosis and possible ischemic injury
Elevated lactate levels (hyperlactatemia) can be caused by:
- Tissue hypoxia due to severe peripheral and visceral vasoconstriction
- Decreased renal perfusion and urine output
- Poor systemic blood flow despite "normal" blood pressure
- Lactate acidosis as a result of prolonged administration of potent vasopressors like norepinephrine (2) (2)
From the Research
Causes of Elevated Lactate Levels
- Tissue hypoperfusion is considered the most common cause of elevated lactate levels, although many other etiologies or contributing factors exist 3
- Lactic acidosis can occur due to inadequate oxygen delivery, resulting in tissue hypoxia and causing anaerobic glycolysis, but lactate formation during sepsis is not entirely related to tissue hypoxia or reversible by increasing oxygen delivery 4
- Aerobic glycolysis in skeletal muscle secondary to epinephrine-stimulated Na+,K+-ATPase activity can also contribute to increased blood lactate levels, rather than anaerobic glycolysis due to hypoperfusion 5
- Medications, such as epinephrine and albuterol, can induce hyperlactatemia and lactic acidosis, with 59 unique medications identified as potential causes 6
- Other causes of elevated lactic acid levels include Grand Mal seizures, liver failure, hematologic malignancies, congenital enzyme deficiencies, thiamine deficiencies, diabetes mellitus, and alcohol abuse 7
Treatment of Elevated Lactate Levels
- Management strategies for elevated lactate levels are heterogeneous and may include supportive care, exogenous bicarbonate therapy, medication-specific antidotes, and decontamination strategies 6
- Treatment of lactic acidosis and its impact on clinical outcome should be tailored to the underlying cause of elevation 4
- In cases of medication-induced lactate level elevations, medications may be continued without change, permanently discontinued, continued with a dosage reduction, or initially withheld then resumed after lactate level normalization 6
- Unexplained lactate level elevations should prompt clinicians to assess for medication-induced lactate level elevations, and pharmacists can serve as experts in the diagnosis and management of medication-induced lactate level elevations 6