Carnitine is essential for the transport of fatty acids into the mitochondria and energy production in different muscles, including the myocardium. It is also needed to protect myocyte cell membranes from oxidative damage by removing excess acyl carnitine groups. Patients receiving chronic intermittent hemodialysis (HD) are known to be at increased risk for carnitine deficiency as a result of its removal during the dialysis procedure, lack of endogenous synthesis by the kidney, and inadequate dietary intake. The carnitine status of children undergoing continuous renal replacement therapy (CRRT) has not been studied. Children undergoing CRRT in the intensive care unit (ICU) setting may be at increased risk for carnitine deficiency due to its continuous removal, lack of carnitine production by the kidney, and absence of carnitine intake (as majority of these children can not eat and there is no carnitine added to total parenteral nutrition (TPN). Carnitine deficiency may increase the risk of cardiac dysfunction in critically ill children. This is the first study to examine carnitine status in children undergoing CRRT. Standard echo as well as more sensitive speckle tracking echo will be used to evaluate the effect of carnitine deficiency on myocardial function.

Study Design:The research design consists of a prospective study group that would be compared to two control groups (a prospective control groups and a retrospective control group). The study group will consist of critically ill children receiving CRRT and IV carnitine supplementation (added in the TPN). The prospective control group will consist of critically ill children not receiving CRRT or carnitine Retrospective control group will consist of critically ill children who received CRRT but did not receive carnitine supplementation. . Subjects for the prospective study and control groups will be recruited from the pediatric intensive care unit (PICU) and the cardiac intensive care unit (CICU) at Children's National. Informed consent will be obtained from participants enrolled in the prospective study and control groups. Data for the retrospective control group will be obtained from the medical record.

Patients

CRRT Study Group (n=10) Inclusion Criteria

1. age 1-21 years
2. Receiving CRRT in the PICU or CICU
3. NPO or TPN-dependent Exclusion Criteria

1. Children on chronic dialysis 4. Children on carnitine supplementation for a metabolic disorder 5. Children on CRRT for less than 1 week

Prospective Control Group (n=10) Inclusion Criteria 1. age 1-21years 2. Receiving care in the PICU or CICU, but not requiring CRRT 3. NPO or TPN-dependent Exclusion Criteria

1. Children on chronic dialysis
2. Children on carnitine supplementation for a metabolic disorder

Retrospective CRRT Control Group (n=10) Inclusion Criteria

1. 1-21years of age
2. Received CRRT between 2011-2015
3. Had total and free carnitine level checked while on CRRT (2 values>1 week apart)
4. Had echocardiogram (2 studies >1 week apart) Exclusion Criteria

1. Receiving supplemental carnitine at time of carnitine level and/or echocardiogram 2. Congenital or acute heart disease 3. On ECMO

Children and young adults, age 1-21 years Critically ill, receiving care in intensive care unit