Alterations of acid-base balance, electrolyte concentrations, and osmolality caused by nonionic hyperosmolar contrast medium during pediatric cardiac catheterization.

ABSTRACT

OBJECTIVE: This prospective clinical observational study was conducted to investigate the effects of contrast medium on acid-base balance, electrolyte concentrations, and osmolality in children. BACKGROUND: For pediatric cardiac catheterization, high doses of nonionic hyperosmolar contrast medium are widely used. METHODS: Forty pediatric patients (age 0-16 years) undergoing cardiac angiography with more than 3 ml·kg(-1) of nonionic hyperosmolar contrast medium (Iomeprol) were enrolled, and the total amount of the contrast agent given was documented. Before and after contrast medium administration, a blood sample was collected to analyze electrolytes, acid-base parameters, osmolality, hemoglobin, and hematocrit. RESULTS: After cardiac catheterization, pH, hemoglobin, hematocrit, bicarbonate, base excess, sodium, chloride, calcium, anion gap and strong ion difference decreased, whereas osmolality increased significantly (base excess -1.8 ± 1.8 vs -3.4 ± 2.3, sodium 138 ± 2.9 vs 132 ± 4.1 mm, osmolality 284 ± 5.7 vs 294 ± 7.6 mosmol·kg(-1), P < 0.01). Seventy-eight percent of the children developed hyponatremia (sodium <135 mm). No changes were seen in pCO(2) , lactate, and potassium levels. CONCLUSIONS: Regarding the differential diagnosis of metabolic disturbances after pediatric cardiac catheterization, low-anion gap metabolic acidosis and hyponatremia should be considered as a possible side effect of the administered contrast medium.