The development of renal insufficiency (RI) following cardiac surgery can lead to a prolonged stay in the intensive care unit and has been linked with increased mortality. This study was undertaken to evaluate the incidence of RI after cardiac surgery and the routine administration of nephrotoxic drugs. A retrospective review of the EMR of patients <2years-old admitted to the CICU after undergoing cardiac surgery from 3/1/07 until 9/30/08 was conducted with IRB approval. Patients receiving intravenous furosemide (+/- additional diuretics) and ACE inhibition in the form of captopril or enalapril/enalaprilat were included.
322 patients <2 were admitted to the CICU during the review period. Of those patients, 176 (54%) received both furosemide and ACE inhibitors following surgery. RI (defined as a creatinine as >0.8mg/dl and a BUN of >20mg/dl) occurred in less than 10% of this population (25 patients had 26 episodes). Peak creatinine occurred from 32 days prior to 8 days after the initiation of ACE inhibitors with 17/26 episodes occurring prior to initiation of ACE inhibition. Elevated creatinine correlated more closely with diuretic use (6 days prior to 12 days following peak furosemide administration) with all patients receiving loop diuretic therapy during the period of RI. Peak BUN also related more closely to diuretic use than to initiation or up-titration of ACE inhibition.
RI occurred in <10% of patients in our study and appears to be more closely correlated with aggressive diuretic use and the patient’s peri-operative hemodynamics rather than renal toxicity from the use of ACE inhibitors.