How do you treat elevated lactate?

Treatment of Elevated Lactic Acid

The primary treatment of elevated lactate is identifying and aggressively treating the underlying cause—restore tissue perfusion through immediate fluid resuscitation (30 mL/kg crystalloid within 3 hours) and hemodynamic support (norepinephrine to maintain MAP ≥65 mmHg), while avoiding sodium bicarbonate therapy for pH ≥7.15. 1

Immediate Risk Stratification Based on Lactate Level

Your treatment approach depends critically on the lactate threshold:

• Lactate ≥4 mmol/L: This is a medical emergency with 46.1% mortality requiring immediate protocolized resuscitation without delay 1, 2
• Lactate 2-4 mmol/L: Indicates moderate tissue hypoperfusion with ~30% mortality, warranting aggressive intervention 1
• Lactate >2 mmol/L: Any elevation above 2 mmol/L signals potential tissue hypoperfusion requiring investigation 1

Initial Resuscitation Protocol (First 3-6 Hours)

For Lactate ≥4 mmol/L (Critical Threshold)

Initiate protocolized quantitative resuscitation immediately with these specific targets within the first 6 hours: 1, 2

• Fluid resuscitation: Administer at least 30 mL/kg IV crystalloid within first 3 hours 3, 1
• Mean arterial pressure: Maintain MAP ≥65 mmHg 3, 1
• Central venous pressure: Target CVP 8-12 mmHg 1
• Urine output: Achieve ≥0.5 mL/kg/hour 3, 1
• Central venous oxygen saturation: Target ScvO₂ ≥70% 1

Fluid Administration Technique

Deliver crystalloid boluses of 250-500 mL over 15 minutes, titrating to clinical endpoints including MAP, urine output, and signs of fluid responsiveness 3. Continue fluid administration if the patient remains fluid-responsive, but monitor carefully for signs of fluid overload (increased jugular venous pressure, pulmonary crackles) 3.

Vasopressor Therapy

When to Initiate

Start vasopressors when MAP remains <65 mmHg despite initial fluid resuscitation 3, 1. Do not wait for a specific fluid volume threshold in most cases, though WHO guidelines suggest considering pressors after 60 mL/kg within the first 2 hours 3.

Choice of Vasopressor

Norepinephrine is the preferred first-line vasopressor 3, 1. Administer via central venous line using a syringe or infusion pump when available 3. Target MAP ≥65 mmHg, with consideration of higher targets in patients with chronic pre-existing hypertension 3.

Serial Lactate Monitoring Strategy

Measurement Frequency

• During acute resuscitation: Measure lactate every 2-6 hours 1
• Target clearance rate: Achieve lactate clearance of at least 10% every 2 hours during the first 8 hours 1
• Prognostic milestone: Normalization to <2 mmol/L within 24 hours is associated with 100% survival in trauma patients 1, 2

Prognostic Implications of Clearance Time

The timing of lactate normalization has profound survival implications: 1, 2

• Within 24 hours: 100% survival
• Within 48 hours: 77.8% survival
• Beyond 48 hours: Only 13.6% survival

Identifying the Underlying Cause

While resuscitating, simultaneously investigate the specific etiology:

Tissue Hypoperfusion States (Most Common)

Look for clinical signs of inadequate perfusion: 1

• Cold, sweaty extremities (peripheral vasoconstriction)
• Prolonged capillary refill (>2 seconds indicates persistent hypoperfusion) 1
• Oliguria (<0.5 mL/kg/hour signals inadequate renal perfusion)
• Altered mental status (reflects cerebral hypoperfusion)
• Narrow pulse pressure (suggests reduced cardiac output)

Common causes include: 1, 4

• Sepsis/septic shock: Most common cause, requiring immediate broad-spectrum antibiotics within 1 hour 1
• Hemorrhagic shock: Requires surgical or interventional hemostasis and blood product transfusion 1
• Cardiogenic shock: May require inotropic support 1
• Mesenteric ischemia: Suspect with abdominal pain + lactate >2 mmol/L; proceed urgently to CT angiography 1

Medication-Induced Causes

Consider these specific drugs: 1

• Metformin: Causes lactic acidosis in patients with eGFR <30 mL/min/1.73 m², liver failure, or conditions causing anaerobic metabolism (sepsis, hypoxia). Discontinue immediately and consider hemodialysis if lactate >5 mmol/L 1
• Epinephrine: Can elevate lactate through beta-2-adrenergic receptor stimulation independent of tissue perfusion 1
• NRTIs (antiretrovirals): Monitor closely for lactate 2-5 mmol/L; consider switching regimens if symptomatic 1

Type B Lactic Acidosis (Non-Hypoperfusion)

When lactate remains elevated despite adequate perfusion markers (normal MAP, good urine output, warm extremities, normal ScvO₂), consider: 1, 5, 6

• Malignancy: Particularly hematologic malignancies like acute lymphoblastic leukemia 5
• Liver dysfunction: Impairs lactate clearance even with adequate perfusion 1
• Accelerated aerobic glycolysis: Driven by excess beta-adrenergic stimulation, can increase lactate without tissue hypoxia 1, 6

Complementary Monitoring Parameters

Base Deficit

Measure base deficit from arterial blood gas—it provides independent information about global tissue acidosis that doesn't strictly correlate with lactate 1. Assess both parameters separately rather than assuming they move together.

Clinical Perfusion Markers

Monitor these alongside lactate: 1

• Capillary refill time (target ≤2 seconds)
• Extremity temperature (warm vs. cold)
• Mental status (alert vs. confused)
• Urine output (≥0.5 mL/kg/hour)

What NOT to Do

Avoid Sodium Bicarbonate

The Surviving Sepsis Campaign explicitly recommends AGAINST sodium bicarbonate for hypoperfusion-induced lactic acidemia with pH ≥7.15, as it does not improve outcomes and may cause harm 1. Only consider bicarbonate for severe acidemia (pH <7.15) in consultation with critical care specialists.

Don't Ignore "Cryptic Shock"

Up to 23% of septic patients have lactate ≥2 mmol/L with ScvO₂ >70%, representing "cryptic shock" 1. Normal or high ScvO₂ does not rule out persistent tissue hypoxia in septic patients due to impaired oxygen extraction 1. Continue aggressive resuscitation based on lactate clearance, not ScvO₂ alone.

Don't Delay ICU Admission

Patients with lactate ≥4 mmol/L require ICU-level care for protocolized resuscitation and close monitoring 2. Do not delay ICU admission pending further workup—begin resuscitation immediately 2.

Special Clinical Scenarios

Mesenteric Ischemia

When lactate >2 mmol/L with abdominal pain: 1

• Proceed urgently to CT angiography without delay
• D-dimer >0.9 mg/L has 82% specificity for intestinal ischemia
• Emergency revascularization (endovascular preferred) is required if diagnosed
• Do not wait for lactate trends or additional labs in unstable patients

Post-Operative/Trauma Patients

Serial lactate measurements are particularly valuable as they correlate directly with mortality 1. Consider: 1

• Ongoing bleeding requiring surgical hemostasis
• Alcohol consumption may confound lactate interpretation; base deficit may be more reliable
• Altered liver perfusion can prolong lactate clearance

Dehydration

Dehydration causes intravascular volume depletion leading to tissue hypoperfusion and lactate elevation 1. However, if lactate remains elevated after adequate fluid resuscitation, investigate for complications like peritonitis or bowel ischemia 1.

Algorithm Summary

1. Measure lactate in any patient with suspected sepsis, shock, trauma, or unexplained metabolic acidosis 1
2. Risk stratify based on level (≥4 mmol/L = emergency; 2-4 mmol/L = urgent; >2 mmol/L = investigate) 1, 2
3. Initiate immediate resuscitation with 30 mL/kg crystalloid and target MAP ≥65 mmHg 3, 1
4. Start norepinephrine if MAP <65 mmHg despite fluids 3, 1
5. Remeasure lactate every 2-6 hours targeting ≥10% clearance every 2 hours 1
6. Identify and treat underlying cause (sepsis, hemorrhage, ischemia, medications) 1
7. Admit to ICU if lactate ≥4 mmol/L 2
8. Target normalization within 24 hours for optimal survival 1, 2