Potassium chloride (KCl) supplementation is common among critically ill 
children. Intravenous (IV) KCl supplementation for pediatric patients is poorly 
characterized. This study aimed to examine the efficacy and safety of IV KCL and 
to determine factors affecting patient responses to IV KCL in the pediatric 
cardiac intensive care unit (CICU). A retrospective review of 211 children (794 
KCl doses) undergoing cardiac surgery or a hospital stay for heart failure in 
the CICU of a tertiary care teaching and referral children's hospital in 2011 
was performed. Demographic data, weight, height, creatinine, and concomitant 
medications during each KCl dose were recorded and analyzed. Body surface area 
(BSA), creatinine clearance, and change in [K(+)] were calculated. The median 
age of the children was 4 months (range, 10 days-18 years). In this study, 151 
KCl doses were administered to neonates (19 %), 307 doses (39 %) to females, and 
510 doses (64 %) to patients with a BSA smaller than 0.33 m(2) (a group with 
relative renal insufficiency). The mean KCl dose was 0.97 ± 0.006 mEq/kg. No 
adverse events were associated with IV KCl administration. Blood/plasma [K(+)] 
increased 0.8 ± 0.02 mEq/L. The responses to KCl did not differ significantly 
between males and females, between neonates and children, or between patients 
with a BSA smaller than 0.33 m(2) and those with a BSA of 0.33 m(2) or larger. 
The responses to IV KCl were attenuated by concomitant furosemide (p = 0.01), 
amphotericin B (p < 0.01), and KCl in parenteral nutrition (p < 0.01). The 
responses were augmented by concomitant enalapril (p = 0.03), ethacrynic acid (p 
< 0.001), and hemodialysis (p < 0.01). Intravenous KCl can be administered 
safely for CICU patients. Responses to KCl are altered when it is given with 
certain medications. Intravenous KCl should be used cautiously in children 
receiving angiotensin-converting enzyme inhibitors. Future studies are needed 
for further characterization of factors affecting responses to IV KCl in 
children.