Amount of elemental calcium in calcium solutions

I read with interest the review article ‘Calcium and the anaesthetist’ (Aguilera & Vaughan. Anaesthesia 2000; 55: 779–90). Most anaesthetists infrequently use intravenous calcium and appropriate doses can be difficult to remember as the amount of elemental calcium in most preparations is an odd amount of milligrams or millimoles. Unfortunately, the authors of this paper have fallen victim to this confusion, as they have misquoted the amount of elemental calcium in calcium chloride and calcium gluconate solutions. The correct amounts are: Calcium gluconate 10%: 1 ml (not 10 ml) = 9 mg of elemental calcium = 0.22 mmol elemental calcium. Calcium chloride 10%: l ml (not 10 ml) = 27 mg = 0.68 mmol of elemental calcium. Calcium chloride is also available as a l mmol.ml−1 elemental calcium solution, which makes the calculations a little easier.