PREDICTIVE VALUE OF SERUM IONIZED BUT NOT TOTAL MAGNESIUM LEVELS IN HEAD-INJURIES

Despite a wealth of recent literature and research on traumatic brain injury, very little has been applicable to diagnosing and treating thi s syndrome at a tissue level. Part of this problem is the inability to assess rapidly and early in the syndrome the degree or progression of brain injury at a tissue level using simple biochemical analytes. Wit h this in mind, we designed a study in 66 human subjects, who presente d with acute blunt head trauma, to determine whether free, ionized ser um magnesium (IMg2+) and/or free, ionized serum calcium (ICa2+) levels correlated with the severity of head trauma (HT) and whether any pred ictive reliable patterns emerge. By using a new ion-selective electrod e (ISE) for IMg2+, we have been able to determine IMg2+ and ICa2+ with in minutes after sampling in the serum of patients early (1-8 h) after HT. These studies reveal that acute HT is associated with graded defi cits (up to 62%, mean=25%) in serum IMg2+, but not in total serum Mg, which are related to severity of injury based on CT scans and other di agnostic parameters. The greater the degree of injury, the greater the ICa2+/IMg2+ ratio. These ionic findings are compatible with the idea that early ischaemia after head trauma may be important in determining neurological outcome. Our findings provide the first evidence for div alent cation changes in blood after traumatic brain injury, which coul d be of both diagnostic and prognostic value in patients with traumati c brain injury.