 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. 