Transtracheal ventilation with oscillatory pressure for complete upper airway obstruction

Another study documented that percutaneous transtracheal ventilation with a special 3.5-mm I.D. cannula was possible in experimental complete upper airway obstruction (CAO) using Ambu-assisted ventilation. The effects of ventilation during CAO by occlusion of the endotracheal tube was evaluated by use of a portable oscillatory pressure device (POPD) attached to a 10-g (I.D. mm) angiocath catheter inserted through the tracheal wall. Eight pigs were anesthetized and ventilated with the POPD for 15 minutes after CAO with a mean peak airway pressure of 14 cm H ₂ O and continuous positive airway pressure of 5—7 cm H20, tidal volume below 100 ml, and a rate below 5 Hz. A Venturi delivered an FIO ₂ of 0.68—0.92. All eight showed markedly stable blood gases and cardiovascular parameters (heart rate and systemic and pulmonary arterial pressures). A similar trend was obtained in a separate group of four pigs ventilated with an Ambu bag for 30 minutes; however, the PO ₂ was lower. In the control group, asphyxia after CAO produced cardiorespiratory failure in every animal in less than 6 minutes. Low- frequency ventilation with a POPD for CAO ensures adequate gas exchange using a standard transtracheal catheter of only 2.4 mm I.D.