Lactate Acidosis in Postoperative Hearts

Completed

Brief Summary: This is a single-center, observational study. Investigators aim to characterize the metabolism of lactate in children over the first forty-eight hours following cardiac surgery. Blood samples will be obtained up to 12 timepoints. Samples will be analyzed for concentration of pyruvate. Results will be compared to standard of care laboratory results for lactate and other direct and indirect measures of cardiac output.

Detailed Description: Investigators will characterize the etiologies of hyperlactatemia predominantly present at serial postoperative timepoints in children recovering from cardiac surgery by following lactate levels and the lactate-to-pyruvate ratio over the first 48 post-operative hours and correlating them with cardiac output as determined by conventional markers and physical exam. Investigators expect to validate the assumption that in children recovering from heart surgery whose cardiac output is apparently normal, hyperlactatemia (if seen) is predominantly due to impaired lactate clearance or metabolism, while in those whose cardiac output is low, it is predominantly due to inadequate oxygen delivery. Blood samples will be obtained up to 12 timepoints (arrival at the intensive care unit postoperatively, hour 1, hour 2, hour 3, hour 4, hour 6, hour 8, hour 10, hour 12, hour 24, hour 36 and hour 48 postoperative) or only at up to 6 time points (approximately Hour 0, 2, 4, 6, 8, and 12) for infants under 10 kg as described below. . Samples will be analyzed for concentration of pyruvate. Results will be compared to standard of care laboratory results for lactate and other direct and indirect measures of cardiac output.

Recruitment & Eligibility

Inclusion Criteria

All immediately post-operative cardiac patients admitted to the pediatric cardiac intensive care unit (PCICU)

Exclusion Criteria

Lack of parental or patient consent, or patient assent when applicable, including non-English speakers and wards of the state
Dosing weight less than 4 kg*
Cardiac catheterization being the only operative procedure
Severe hepatic dysfunction at any time during the hospital course
Seizures during the study period
Sepsis during the study period
Need for extracorporeal membrane oxygenation or continuous renal replacement therapy
Known congenital myopathy, ataxia, polyneuropathies or inborn errors of metabolism including congenital lactic acidosis and other mitochondrial disorders
Primary hypoventilation
Malignancies
Fanconi syndrome
Wernicke encephalopathy

Arm && Interventions

Group	Intervention	Description
Pediatric post-cardiac surgery	Pyruvate levels	All immediately post-operative pediatric cardiac patients will be enrolled. Standard of care laboratory analysis will be performed based on current clinical protocols. Results for lactate, blood gases, liver enzymes, creatinine, glucose, hemoglobin, hematocrit and other direct and indirect measure of cardiac output will be collected. Investigators will also measure pyruvate levels at specific time points, which is not part of standard of care. To measure pyruvate, an additional 1 ml of arterial blood will be drawn at each routine postoperative blood draw. The lactate/pyruvate ratio will be calculated and compared to direct and indirect measure of cardiac output described above.

Primary Outcome Measures

Name	Time	Method
Lactate/pyruvate ratio	Hourly, assessed up to 48 hours

Secondary Outcome Measures

Name	Time	Method

Locations (1): University of Florida Shands Children's Hospital
🇺🇸
Gainesville, Florida, United States

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