MEGX disposition in critically-ill trauma patients: subsequent assessments during the first week following trauma

The objective of this study was to evaluate MEGX disposition as a surrogate marker in assessing the influence that injury may exert on liver function during the first week after the traumatic event in young vs. elderly patients. The MEGX exposure over time was assessed at 0.25, 0.5, 1, 2, 4 and 6 h after the intravenous administration of a 1 mg/kg lidocaine test dose in 12 young and 7 elderly trauma patients on days 1, 4 and 7 after a severe injury (Apache II score > 10). MEGX plasma concentration-time profiles were consistently different on day 1 in the elderly vs. young, consistent with a statistically significant lower rate of both lidocaine clearance and MEGX formation, and with a considerably longer MEGX elimination in the elderly than in the young. This suggests an impairment of liver blood flow as a result of splanchnic vasoconstriction occurring mainly in elderly trauma patients. A significant improvement in MEGX disposition occurred on days 4 and 7 vs. the day of trauma in most elderly, whereas minor changes were observed in the young. Multiple factors may account for these major changes in the elderly: the more severe status, the major sensitivity to the pathophysiologic changes induced by trauma, and also at least partially the ageing processes. Although referring to a limited number of observations, our findings on MEGX disposition suggest that liver function may be affected by the severity of injury, even if the influence of age should not be underestimated in these patients.