Chest
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The patient had classic ECG changes of hypothermia (sinus bradycardia, prolonged PR interval, prolonged QT interval, and Osborn waves). These changes occurred in hypothermia resulting from sepsis, without exposure being a factor. Documentation of Osborn waves in this clinical setting supports the theory that they result as a direct consequence of myocardial cooling.
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The relationship between changes in cardiac output and intrapulmonary shunt associated with mechanical ventilation was evaluated in 20 patients with the adult respiratory distress syndrome (ARDS). The distribution of ventilation-perfusion (VA/Q) ratios and the level of intrapulmonary shunt was determined by the multiple inert gas technique. Pulmonary blood flow was distributed predominantly to either effective gas-exchanging units or shunt units. ⋯ Changes in shunt and cardiac output were quantitatively and qualitatively silimar and a strong correlation was found between changes in shunt and cardiac output with both PEEP and high tidal volumes (r = 0.76). Cardiac output depression associated with tese modes of ventilation appears to be a mechanism of shunt reduction in ARDS. Interpretation of improvements in gas exchange in ARDS must take into account concomitant hemodynamic changes.
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A 25-year-old paraplegic woman suffered cardiopulmonary arrest due to a major pulmonary embolism during intravenous mannitol therapy. Although it is possible that the mannitol caused an acute episode of hemagglutination, we postulate that rapid administration of mannitol caused dilation of her venous system, causing a preexisting clot to break loose.