PTH and Hypocalcemia: Whilst the exact mechanism of hypocalcaemia in trauma is yet to be elucidated, various sources suggest potential mechanisms other than citrate chelation, such as dilution [43, 48, 49], colloid binding [50], lactate binding [21], acidosis [9, 51], ischaemic reperfusion [52–55], and impaired parathyroid hormone secretion or action [56–59].