PTH and Hypocalcemia: Mechanisms by which hypocalcemia has been hypothesized to be associated with mortality include APE with a high risk of causing proinflammatory cytokine release, inhibiting parathyroid hormone release, causing cellular redistribution of calcium, and consequently precipitating hypocalcemia [15]; hypocalcemia is associated with cardiac dysfunction and hypotension [25]; and vitamin D deficiency is considered to be one of the most common causes of hypocalcemia and contributes to poor prognosis in patients with cardiopulmonary disease [26, 27].