J Trauma
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Shock increases mortality from brain injuries, but the mechanism is poorly understood. We hypothesized that brain injury followed by shock and resuscitation leads to a secondary reperfusion injury mediated in part by polymorphonuclear leukocytes (PMNs). To validate this hypothesis, we studied cerebral perfusion pressure (CPP), intracranial pressure (ICP), cerebral blood flow (CBF), cortical water content (CWC), and hemodynamic variables in a porcine model of focal cryogenic brain injury and hemorrhagic shock. ⋯ The CPMN in both hemispheres in group 3 was significantly greater than in either group 2 or group 4. There was a significant positive correlation between CPMN and both ICP and CWC, and a significant negative correlation between CPMN and CBF. These data suggest an association between CPMN accumulation and secondary brain injury.
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Comparative Study
Hypertonic saline (7.5%) versus mannitol: a comparison for treatment of acute head injuries.
Hypertonic saline (7.5% NaCl = HS) was compared with 20% mannitol (MAN), for the treatment of increased intracranial pressure (ICP), in a large animal model of head injury. Sheep were instrumented for hemodynamic and ICP monitoring and fluid administration. Elevated ICP (20-25 mm Hg) was produced by inflating an epidural balloon for 1 hour. ⋯ Brain water contents were also similar (HS = 3.68 +/- 0.09 mL H2O/g dry wt; MAN = 3.83 +/- 0.08 mL H2O/g dry wt). The 7.5% NaCl was equally effective in treating elevated ICP caused by a space-occupying lesion when compared with 20% mannitol. Hypertonic saline has the additional benefit of rapid cardiovascular resuscitation of associated hemorrhagic shock with small-volume infusion.
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We measured plasma levels of interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), and interleukin-6 (IL-6) following thermal injury. Cytokine levels in the plasma of 27 burned patients were serially screened by ELISA and compared with cytokine levels in 16 healthy laboratory employees. The relationships between cytokine concentrations and patient mortality, burn size, and time postburn were examined. ⋯ The IL-1 beta concentrations were positively correlated with burn size. These findings suggest that IL-1 beta and IL-6 may influence metabolic and immunologic responses in the first few weeks following thermal injury. Tumor necrosis factor alpha was transiently elevated in a small subpopulation of burned patients with no obvious relationship to burn size or time postburn.
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Recent studies have concluded that pelvic fractures in children, unlike those in adults, are not a source of life-threatening hemorrhage. Our study hypothesis was that major bleeding occurs in children with pelvic fractures, and fracture geometry allows early identification of patients at risk for severe hemorrhage. Fifty-seven (5.5%) of 1044 pediatric trauma patients sustained pelvic fractures. ⋯ Age, sex, Injury Severity Score, Revised Trauma Score, mechanism of injury, and pelvic fracture geometry were evaluated as risk factors predictive of hemorrhage employing multiple logistic regression. Only pelvic fracture geometry independently identified patients at increased risk of major bleeding. We conclude that pelvic fracture geometry identifies a subset of pediatric trauma patients at high risk for life-threatening hemorrhage and urge a prompt multispecialty approach to these patients.
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The hypothesis that alveolar fluid clearance depends on factors other than the alveolar-capillary oncotic gradient was tested by comparing lung clearance rates of three different colloid solutions and isotonic saline. The solutions (4 mL/kg) were instilled into the lower lobes of New Zealand rabbits. Colloid solutions were diluted to produce a fixed gradient of 8 mm Hg for each experiment. ⋯ These data suggest that fluid clearance from the airspaces is primarily dependent on factors other than simple colloid-capillary osmotic gradient. Alveolar PMN migration was not a major determinant of fluid clearance. The association between surfactant inhibition and decreased fluid clearance rate observed with homologous plasma suggests that protein interference with the surfactant monolayer may play a role in reducing alveolar fluid clearance.(ABSTRACT TRUNCATED AT 250 WORDS)