Location-dependent effects of trauma on oxidative stress in humans

Though circulating antioxidant capacity in plasma is homeostatically regulated, it is not known whether acute stressors (i.e. trauma) affecting different anatomical locations could have quantitatively different impacts. For this reason, we evaluated the relationship between the anatomical location of trauma and plasma total antioxidant capacity (TAC) in a prospective study, where the anatomical locations of trauma in polytraumatic patients (n = 66) were categorized as primary affecting the brain -traumatic brain injury (TBI)-, thorax, abdomen and pelvis or extremities. We measured the following: plasma TAC by 2 independent methods, the contribution of selected antioxidant molecules (uric acid, bilirubin and albumin) to these values and changes after 1 week of progression. Surprisingly, TBI lowered TAC (919 ± 335 μM Trolox equivalents (TE)) in comparison with other groups (thoracic trauma 1187 ± 270 μM TE; extremities 1025 ± 276 μM TE; p = 0.004). The latter 2 presented higher hypoxia (PaO₂/FiO₂ 272 ± 87 mmHg) and hemodynamic instability (inotrope use required in 54.5%) as well. Temporal changes in TAC are also dependent on anatomical location, as thoracic and extremity trauma patients’ TAC values decreased (1187 ± 270 to 1045 ± 263 μM TE; 1025 ± 276 to 918 ± 331 μM TE) after 1 week (p < 0.01), while in TBI these values increased (919 ± 335 to 961 ± 465 μM TE). Our results show that the response of plasma antioxidant capacity in trauma patients is strongly dependent on time after trauma and location, with TBI failing to induce such a response.

[Risk factors of the hepatic dysfunction associated with parenteral nutrition]

BACKGROUND AND OBJECTIVE

The objective of this study is to describe the incidence of hepatic dysfunction (HD) in our hospital and evaluate the possible risk factors associated with HD development as an improvement of the caring process received by patients treated with parenteral nutrition (PN).

PATIENTS AND METHOD

A prospective study of patients (n=994) who required PN during the period 2000-2004. HD is the identification of an increase above 1,5 of the top reference value of alkaline phosphatase (40-450U/l) and gamma glutamyl transpeptidase (11-49U/l) associated with an increase of transaminases (5-32U/l) and a total bilirrubin higher than 1,2mg/dl.

RESULTS

The incidence of HD was 4,9% (n=49). Days with PN were significantly higher in the HD group: median (interquartile range): 30 (20-59) vs 15 (8-25) days (p<0.001). In the univariated HD analysis, the variables that reached significant odds ratio were: the critical patient condition, the PN duration, the total calorie contribution higher than 25kcal/kg, to exceed 3g of carbohydrates/kg, to administer more than 0.8g/kg of lipids and to exceed 0.16g of nitrogen/kg. In the multivariated analysis, the variables selected as independent risk factors were: to exceed 3 weeks of PN, to be a critical patient and a contribution over 0.16g of nitrogen/kg.

CONCLUSIONS

The present profiles of the patients who will develop HD are those with prolonged PN. These patients undergo processes and critical therapy, where the specialists must monitor, not only calorie contribution, carbohydrates or lipids, but proteins as well.