The Annals of thoracic surgery
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The effects of oxygen and 60% nitrous oxide and oxygen on the pressure and volume of Portex low-pressure (LP) and high-pressure (HP) endotracheal tube cuffs were determined in 120 intubated patients undergoing thoracic surgical procedures. Cuffs were filled with either room air or a sample of the inspired gases. ⋯ Cuff gas analysis revealed that cuff volume changes were due to diffusion of oxygen and nitrous oxide into the cuff and failure of nitrogen to diffuse out. These findings suggest that cuff overexpansion during anesthesia or prolonged ventilation may be an important cause of tracheal trauma.
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Pulmonary mechanics and oxygenation were measured in 24 consecutive patients with posttraumatic flail chest requiring continuous mechanical ventilation. The mean duration of mechanical ventilation was fourteen days. Mortality was 38% for all patients, 29% if deaths from head injury are excluded. ⋯ Vital capacity and maximal inspiratory force measurements were useful in assessing chest wall stabilization. Total lung compliance correlated negatively with fatal outcome from respiratory failure. The alveolar-arterial oxygen gradient was not useful in assessing chest wall stabilization.
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Applying subdiaphragmatic compression has been successful in saving victims of food-choking and drowning by expelling the asphyxiating bolus or aspirated water. Sudden elevation of the diaphragm compresses the lungs, which explosively forces air out through the trachea, ejecting the obstructing object. The flow rate, pressure, and volume of air expelled were determined in 10 subjects and found to be substantial, providing confirmation of the effectiveness of the procedure.