Hyperlactatemia in Critically Ill Children: Modeling Early Recovery Kinetics After Initiation of Extracorporeal Membrane Oxygenation
Bibliographic record
Abstract
OBJECTIVES: Blood lactate concentration ([Lac] b ) reflects the balance among production, clearance (C l[Lac] ), and volume of distribution. We have observed dramatic improvement in [Lac] b in critically ill patients after starting support with extracorporeal membrane oxygenation (ECMO) and discontinuing vasopressors. Here, we evaluated such [Lac] b profiles to develop a mathematical model of recovery kinetics. We then examined the interrelationships between maximum [Lac] b and model-derived parameters of lactate production, endogenous lactate transfer, and C l[Lac] . DESIGN: Mathematical modeling using a convenience sample. SETTING: Quaternary U.S. academic children's hospital. PARTICIPANTS: A retrospective sample of 25 ECMO patients (from birth to < 18 yr) with serial [Lac] b measurements during the first 30 hours after initiation of ECMO. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: The median (interquartile range [IQR]) age of ptients was 17 days (IQR 3-152 d), and the median weight was 3.3 kg (IQR 2.7-4.7 kg). At the initiation of ECMO, the mean peak [Lac] b was 16.7 mmol/L (95% CI, 14.3-20.0 mmol/L). Recovery in [Lac] b could be described using a one-compartment, bi-exponential, open model of kinetics. Solving the model equation showed starting lactate load was 17.7 mmol/kg (95% CI, 14.6-20.7 mmol/kg) and C l[Lac] was 19.7 mL/min (95% CI, 3.0-36.4 mL/min). The interrelationship between maximum [Lac] b and model-derived parameters in children requiring ECMO at the limits of cardiopulmonary survival showed: 1) lactate production ranged from 2.3 to 6.4 µmol/kg/min (95% CI), 2) initial endogenous lactate transfer velocity, 82.5-1301.0 µmol/kg/min, 3) high initial [Lac] b levels suggested severely impaired C l[Lac] , 4) a strong correlation was observed between model-derived velocity and transfer parameters (rho 0.75; p < 0.0001), at levels exceeding those seen in high-intensity endurance exercise, and 5) upon achieving steady state, lactate production and C l[Lac] were balanced. CONCLUSIONS: At the time of maximal cardiopulmonary instability requiring ECMO initiation, our model of [Lac] b recovery indicated that high initial [Lac] b reflected severely impaired and reduced C l[Lac] . This modeling approach may also be applicable to assessing changes in lactate kinetics in other forms of critical illness.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".