What is the management approach for pediatric patients on Veno-Arterial (VA) Extracorporeal Membrane Oxygenation (ECMO) with elevated lactate levels and receiving unwashed blood?

Management of Pediatric Patients on VA-ECMO with Elevated Lactate and Unwashed Blood

In pediatric patients on VA-ECMO with elevated lactate, aggressive lactate clearance monitoring every 2-6 hours is critical, with target clearance >10% every 2 hours during the first 12 hours, as lactate clearance at 3,9, and 12 hours post-ECMO initiation significantly predicts mortality. 1

Lactate Monitoring Strategy

Serial lactate measurements are the cornerstone of management in pediatric VA-ECMO patients:

• Measure lactate at ECMO initiation, then at 3,6,9, and 12 hours post-cannulation, as these time points have proven predictive value for mortality 1
• Target lactate clearance cut-offs: ≥3.8% at 3 hours, ≥51% at 9 hours, and ≥56% at 12 hours post-ECMO start 1
• Lactate values at 12-24 hours post-ECMO are independent predictors of unfavorable outcomes, with values >48.6 mg/dL (5.4 mmol/L) associated with 100% specificity for poor outcomes 2
• Pre-ECMO lactate levels >11.7 mmol/L are associated with significantly increased mortality compared to survivors (6.0 mmol/L) 3

Optimizing ECMO Flow Rates

High ECMO flow rates are essential for reversing shock and improving survival in pediatric septic shock:

• Target ECMO flows >150 mL/kg/min at 4 hours after ECMO institution, as this strategy is associated with significantly higher survival compared to standard flows 4
• Central (atrioaortic) ECMO cannulation should be considered to achieve higher blood flow rates, with reported survival rates of 74% versus historical <50% with conventional approaches 3
• Monitor for adequate reversal of shock using multiple parameters: capillary refill ≤2 seconds, urine output >0.5 mL/kg/hr, normal mental status, and cardiac index >3.3 L/min/m² 4

Fluid and Blood Product Management

For pediatric ECMO patients with elevated lactate receiving unwashed blood:

• Use balanced crystalloid solutions (Plasmalyte) as first-line IV fluid rather than normal saline, as saline worsens hyperchloremic acidosis in patients with existing lactic acidosis 5
• Target hemoglobin ≥10 g/dL during resuscitation of low superior vena cava oxygen saturation shock (<70%), then consider lower target <7.0 g/dL after stabilization 4
• Maintain platelet count >100,000/mm³, fibrinogen >200 mg/dL, and antithrombin III >1 U/mL to minimize bleeding complications 4
• Unwashed blood transfusions contain higher potassium and lactate loads—monitor electrolytes closely and consider these contributions when interpreting lactate trends 5

Anticoagulation Management

Pediatric ECMO anticoagulation requires meticulous monitoring:

• Administer 100 U/kg heparin before cannulation (may forego loading dose if transitioning from CPB) and maintain continuous infusion targeting ACT 180-220 seconds 4
• Check anti-factor Xa levels, PT, PTT, fibrinogen, platelet count, and antithrombin III at least daily, with PTT target 1.5-2.5 times control and anti-Xa 0.3-0.7 U/mL 4
• Transfuse fresh-frozen plasma or supplement antithrombin III when deficient, particularly in patients <1 year of age who are at highest risk 4

Hemodynamic Targets

Achieve the following targets during the first 6-12 hours of ECMO support:

• Mean arterial pressure ≥65 mmHg (age-appropriate targets for younger children) 4
• Central venous pressure 8-12 mmHg 4
• Urine output ≥0.5 mL/kg/hr 4
• Central venous oxygen saturation ≥70% 4
• Lactate clearance ≥10% every 2 hours 1

Metabolic Support

Optimize oxygen delivery and glucose metabolism:

• Ensure adequate glucose delivery with D10%-containing isotonic IV solution at maintenance rate, titrating insulin to maintain glucose 80-150 mg/dL while avoiding hypoglycemia 5
• Target cardiac index >3.3 L/min/m² and <6.0 L/min/m² using volume loading and inotrope/vasodilator support when needed 5
• Monitor for adequate tissue perfusion using capillary refill ≤2 seconds, warm extremities, and normal mental status 4

Critical Decision Points

Poor lactate clearance indicates need for intervention escalation:

• If lactate clearance <10% at 2-hour intervals or lactate remains >5.4 mmol/L at 12-24 hours, consider: increasing ECMO flow rates, optimizing cardiac output with inotropes/vasodilators, ensuring adequate hemoglobin and oxygen delivery, and evaluating for ongoing bleeding or inadequate source control 1, 2
• Failure to achieve lactate normalization within 24 hours is associated with dramatically reduced survival (77.8% if normalized by 48 hours, only 13.6% if elevated beyond 48 hours) 6

Common Pitfalls

Avoid these critical errors in pediatric VA-ECMO management:

• Don't rely solely on blood pressure or central venous oxygen saturation—up to 23% of septic patients have elevated lactate despite ScvO₂ >70% due to impaired oxygen extraction 6
• Don't use sodium bicarbonate for pH ≥7.15, as it does not improve outcomes and may cause harm 6, 5
• Don't ignore the lactate contribution from unwashed blood products—each unit can add significant lactate load that confounds interpretation 5
• Don't accept standard ECMO flows—survival is significantly better with high flows >150 mL/kg/min 4
• Don't delay surgical control of bleeding—ongoing hemorrhage despite ECMO support is associated with poor survival 4