[Collecting end-expiratory air for capnography in high-frequency jet ventilation]

By means of an ejector attachment to the endotracheal tube a negative intratracheal pressure of approx. -1 mmHg is created during an interruption of HFJV. Within 4 to 10 sec. this suction supplies alveolar air to the distal end of the endotracheal tube where capnographic analysis is possible in the mainstream or bystream. The end-tidal pCO2 differs by 0.1 mmHg (mean) from the arterial carbon dioxide partial pressure with a highly positive correlation (R = 0.98).