J Trauma
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When dehydration, infection, and mechanical trauma are prevented, procedures (such as cooling and/or oral antithromboxane) designed to diminish ischemia in experimental zone-of-stasis burns have been associated with no or only minor improvement in wound healing. To test the hypothesis that ongoing skin damage occurring postburn (PB) may in part be due to release of oxygen-derived free radicals during the 16-hour through 4-day PB period of reperfusion in such burns, beginning immediately and for a period of 5 days PB, equal numbers of guinea pigs received: allopurinol 150 mg/kg PO q 6 h vs. placebo, dimethylsulfoxide (DMSO) 75% applied topically q 12 h vs. placebo, or yeast-derived superoxide dismutase coupled with polyethylene glycol (PEG-SOD, Pharmacia) 10,000 U (Fridovich) given IV q 8 h producing a concentration of 16 U/cc of plasma 8 hr after injection vs. placebo. Gross and histologic examination of wounds by a 'blinded' investigator at 1 week and 3 weeks PB revealed no difference between treatment and control groups when rates of re-epithelialization and frequencies of hair-follicle retention were compared. Using the dosages, routes, and model described, treatment of a zone-of-stasis burn with PO allopurinol (a xanthine oxidase inhibitor), topical DMSO (a scavenger of the hydroxyl radical), or IV PEG-SOD (a scavenger of the superoxide radical) during the first 5 days PB was associated with no increase in the rate of re-epithelialization or frequency of hair follicle retention at 1 and 3 weeks PB when compared with controls.
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Numerous formulas have been used to estimate the calorie requirements of hypermetabolic burned patients. With the recent development of instrumentation for indirect calorimetric measurements, questions have been raised concerning the validity and accuracy of the early equations. Because metabolic rate decreases during the course of wound healing, we attempted to determine the magnitude of hypermetabolism and the accuracy of the Curreri formula in patients with various wound sizes. ⋯ The measured REE was 27, 35, and 50% greater than the BEE in Groups 1, 2, and 3, respectively (p less than 0.001). The ACEE underestimated REE by 7% in Group 1, and overestimated REE by 13 and 35% in Groups 2 and 3, respectively (p less than 0.001). Resting energy expenditure should be measured at regular intervals in individuals with open burn wounds greater than 10% BSA in order to adjust nutritional support appropriately.
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The purpose of this study was to determine whether or not thromboxane A2 (TXA2) was necessary or sufficient for the development of end-organ pathology during graded bacteremia. Pulmonary artery catheters were placed in 21 adult male pigs under pentobarbital anesthesia and breathing room air. After a control period, animals were studied in four groups: Group 1, anesthesia only; Group 2, infusion of 1 X 10(9) ml Aeromonas hydrophila which was gradually increased from 0.2 ml/kg/hr to 4.0 ml/kg/hr over 4 hours; Group 3, pretreatment with SQ 29,548 (TXA2 antagonist) then Aeromonas h. infusion; Group 4, infusion of U46619 (TXA2 agonist) to pulmonary artery pressures measured in Group 2. ⋯ The results indicated that physiologic thromboxane A2 agonist (Group 4) was sufficient alone to cause pulmonary inflammation. Thromboxane A2 was neither necessary nor sufficient for significant renal, hepatic, pulmonary, or splenic pathology to occur in graded bacteremia, manifested in similar microanatomic abnormalities in these organs in Groups 2 and 3 and in Groups 1 and 4. Pulmonary leukocyte infiltration was significantly increased in Group 3 compared to all other groups, suggesting that TXA2 impairs inflammatory responses.
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Comparative Study
Effects of resuscitation from hemorrhagic shock on cerebral hemodynamics in the presence of an intracranial mass.
This study compares intracranial pressure, cerebral blood flow, and cerebral oxygen transport during hemorrhagic shock and following fluid resuscitation with crystalloid or colloid solution in a canine model with an epidural mass lesion. After placement of an epidural balloon, intracranial pressure was increased to 30 mm Hg for 5 minutes and then permitted to vary without further manipulation. Hemorrhagic shock was produced by the rapid removal of blood to achieve a mean arterial pressure of 55 mm Hg for 30 minutes. ⋯ Intracranial pressure was significantly lower immediately after resuscitation in the hetastarch group; it then gradually increased so that the difference was much less 1 hour later. Cerebral blood flow decreased during shock and was not restored by either fluid; cerebral oxygen transport fell further with resuscitation in both groups due to hemodilutional reductions in hemoglobin. Although colloid resuscitation improved systemic hemodynamics and maintained lower intracranial pressure, it failed, as did crystalloid resuscitation, to restore cerebral oxygen transport to prehemorrhagic shock levels.
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Comparative Study
Natural course of the human bite wound: incidence of infection and complications in 434 bites and 803 lacerations in the same group of patients.
Human bites and common lacerations are frequent in certain residential groups in institutions for the care of developmentally disabled individuals. We screened the records of such an institution and studied the course and outcome of 434 human bite wounds and 803 lacerations in the same group of clients. Infection developed in 13.4% of the lacerations, and 17.7% of the bite wounds (chi 2 = 3.474; p greater than 0.06). ⋯ No patient with a bite wound required debridement, initial or subsequent surgical intervention other than wound closure, admission to hospital, or intravenous antibiotics. There is no recorded instance of a bite wound complication other than immediate loss of tissue. These data substantiate a higher incidence of infection in human bite wounds, but they are scant support for admonition that such wounds are indication for routine antimicrobial prophylaxis or aggressive surgical intervention.