[Monitoring respiratory and circulatory parameters in comparing various jet ventilation procedures]

Reported is a system of apparatures to control characteristic changes of cardiorespiratory function during different methods of endoscopic ventilation. The aim of the study is to measure and record simultaneously and continuously ECG, thoracic movement, tracheal pressure, pulmonary artery pressure and arterial oxygen pressure using transcutaneous technique. Measurements of arterial blood pressure and blood gas analysis (PaO2, PaCO2, BE, HCO3-, pH) are carried out in intervals. Four different methods of injector-ventilation are compared with the conventional laryngoscopic ventilation on the basis of a test program. Laryngoscopic ventilation as well as injectorventilation by CARDEN-Tubus make it possible to achieve a hyperoxaemic situation by normofrequent ventilation. Despite of hyperventilation it is not possible in every case to achieve an increased capillary oxygen pressure of 200 to 300 mm Hg by injector-ventilation with Venturi effect because of a smaller oxygen proportion. In jet-ventilation with N2O/O2-mixture (3:1) there is no appreciable hyperoxia, but a small reduction of systemic arterial blood pressure. With all techniques of mechanical respiration usual middle intratracheal pressure of respiration was not exceeded. Traumatic pressure of jets was only indirectly shown in steep rises of pressure by the applied technique of measurement.