Techniques of Ventilation Using Constant Flow
The traditional concept of gas exchange in the lung during spontaneous breathing or conventional mechanical ventilation (MV) predicts that to achieve adequate gas exchange, the tidal volume (VT) must exceed the dead space (VD). This model is based on the concept that gas transport in the lung takes place in two distinct zones: the conducting airways where gas transport occurs by convection, and the alveolar zone where transport occurs by molecular diffusion. This concept forms the basis for the design of most mechanical ventilators that have been used very successfully over the last fifty years . However, because VT must be relatively large to exceed VD, relatively large pressures are produced in the lung and this is associated with a number of complications including pulmonary barotrauma and hemodynamic compromise.
KeywordsHeart Rate Response Alveolar Ventilation Ventilatory Failure Left Heart Bypass Apneic Oxygenation
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