Chest
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Comparative Study
Does hypoxia or hypercarbia independently affect resuscitation from cardiac arrest?
In a previous cardiopulmonary resuscitation (CPR) study in swine, ventilation was associated with improved rate of return of spontaneous circulation (ROSC) compared with nonventilated animals, which had greater hypoxia and hypercarbic acidosis. We used the same model to determine the independent effect of hypoxia and hypercarbic acidosis on ROSC after cardiac arrest. ⋯ Both hypoxia and hypercarbia independently had an adverse effect on resuscitation from cardiac arrest. In this model with a prolonged interval of untreated cardiac arrest, adequate ventilation was important for resuscitation.
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Comparative Study
CPAP reduces inspiratory work more than dyspnea during hyperinflation with intrinsic PEEP.
Hyperinflation with intrinsic positive end-expiratory pressure (PEEPi) loads the respiratory muscles and causes dyspnea in obstructive lung disease. Continuous positive airway pressure (CPAP) has shown some efficacy in reducing inspiratory work and dyspnea. However, in obstructive lung disease, inspiratory work and dyspnea may be increased by additional factors that may not be affected by CPAP. ⋯ We conclude that CPAP can substantially ameliorate the respiratory work load induced by hyperinflation with intrinsic PEEP. However, the effects of CPAP on dyspnea and endurance are more limited. This suggests that the limits to breathing at high lung volumes are related to factors in addition to respiratory muscle work, and that CPAP may be of more value in reducing the work than in relieving the distress of obstructive lung disease.
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Endoscopic guidance during percutaneous dilational tracheostomy reduces the risk of paratracheal insertion of the tracheostomy tube but may impair ventilation and does not eliminate the possibility of premature endotracheal extubation. Use of a small-caliber, hollow endotracheal tube exchanger during stomal dilation in lieu of a fiberoptic bronchoscope allows for better ventilation and more secure airway control.