Calcium chloride
This chapter is relevant to Section I3(ii) of the 2017 CICM Primary Syllabus, which expects the exam candidates to "describe the function, distribution, regulation and physiological importance of sodium, chloride potassium, magnesium, calcium and phosphate ions". It is only relevant because Question 4 from the first paper of 2011 asked the trainees to compare calcium chloride and calcium gluconate.
Calcium chloride
Each vial contains 1g of calcium chloride, which equates to approximately 6.8 mmol of calcium and 13.6 mmol of chloride. Thus, it contains 3 times as much calcium as the same ampoule of calcium gluconate, because each calcium ion is partnered up with two relatively lightweight chloride ions, instead of two huge gluconate ions.
Its various uses outside of medicine include prevention of leaching calcium ions from swimming pool concrete, and providing ionized calcium to the invertebrates of a salt-water aquarium, so better to build their shells with.
References
From MIMS online, via CIAP; and directly from the manufacturer propaganda.
Lin, Chi-Ying, et al. "Skin necrosis after intravenous calcium chloride administration as a complication of parathyroidectomy for secondary hyperparathyroidism: report of four cases." Surgery today 37.9 (2007): 778-781.