J Trauma
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Passive leg raising is widely used to treat hypotension associated with hypovolemia. Presumably gravity causes a central translocation of leg venous blood and an increase in filling pressure, cardiac output, and arterial pressure. Ten healthy volunteers, 25 to 35 years old, had measurements of heart rate, blood pressure, and cardiac output in the supine position after 20 sec and 7 min of 60 degrees passive leg elevation. ⋯ After 45 min supine, leg raising had no effect on stroke volume or cardiac output but increased blood pressure (4 mm Hg) by increasing peripheral resistance (15%). Thus, leg raising, like application of the MAST trousers, fails to produce any sustained increase in cardiac output or stroke volume. Small venous leg volumes and time-dependent changes in the distribution of venous volume and compliance may explain the absence of any sustained 'autotransfusion' effect.
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Using computerized gamma scintigraphy, 10-cm H2O PEEP did not alter the rate of capillary protein leakage in dogs following pulmonary microvascular injury with 0.01 to 0.2 ml/kg oleic acid. A rising lung:heart radioactivity ratio, or 'slope of injury,' was seen during PEEP which paralleled the 'slope of injury' had PEEP not been used. A sudden decrease in lung and heart count activity (p less than 0.001) and decreased lung:heart radioactivity ratio (p less than 0.001) occurred with PEEP at all doses of oleic acid studied. ⋯ When all vessels leading to and from the heart and lungs were ligated, PEEP produced a 60% fall in count activity over the lung without any change in cardiac radioactivity. The apparent radiographic improvement and 2/3 of the fall in lung radioactivity with PEEP were due to an increased pulmonary air volume and 1/3 due to a decreased pulmonary blood volume. The decreased cardiac output with PEEP must be secondary to decreased ventricular filling rather than decreased ventricular function.
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Superior dislocation of the patella with interlocking osteophytes was only once found roentgenologically documented. Such a dislocation occurs without tendon rupture, and can occur with a hyperextension force. ⋯ Full active motion is present post-reduction. This entity should not be confused with vertical dislocations of the patella.
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While the technique of early excision and grafting has many advantages in the treatment of thermal injuries, it is not without significant complications. Hemorrhage accompanying burn wound excision can be deceptively great, as can the metabolic stress of large surgical procedures performed in the postburn period. In an effort to minimize these complications, we have developed a two-stage technique for excision and grafting of burn wounds. ⋯ Temperature decrease during surgery was also great, with significant hypothermia occurring in 51% of procedures exceeding 2 hours in length. We conclude that performing excision and grafting in two stages limits hemorrhage and heat loss from each individual surgery, thereby permitting the performance of larger procedures. Nonetheless, continued awareness of the magnitude of these complications remains an essential of successful excisional therapy.