The ionised calcium is a more accurate reflection of calcium status, especially in patients with low serum albumin. Severe hypocalcaemia may appear within an hour of acute ingestion of hydrofluoric acid, fluorides, fluorosilicates or oxalic acid. Paraesthesias, tetany, and convulsions are often present. The electrocardiograph shows a widened or prolonged QT interval and large or peaked T waves. Dysrhythmias and cardiac arrest may occur.
Calcium acts as a chelating agent in the stomach.
Extensive skin contamination by hydrofluoric acid, fluorides, fluorosilicates or oxalic acid may lead to systemic toxicity and severe hypocalcaemia. The required dose of calcium salt may be from 3 g to 20 g on the first day. Serum calcium and ionised calcium concentrations. Some of the causes of hypocalcaemia may also lead to severe hyperkalaemia - measure serum potassium and electrolytes frequently. V. Afanasiev, M. Burger, T. Della Puppa, L. Fruchtengarten, K. Olsen, J. Szajewski.