Gerald C Ihra1, Ching-Ju Tsai, Oliver Kimberger. 1. Department of Anesthesia, Intensive Care Medicine and Pain Therapy, Medical University Vienna, Waehringer Guertel 18-20, AKH 9i, A-1090 Vienna, Austria. gerald.ihra@meduniwien.ac.a
Abstract
BACKGROUND: Supraglottic jet ventilation (JV(S)) with injectors above airway stenoses may result in inadvertent high lung pressures. We designed this study to investigate intrinsic positive end-expiratory pressure (PEEP(i)) during jet ventilation via a distant injector in a model of dynamic upper airway obstruction. METHODS: Respiratory pressure-time curves were recorded during JV(S) in a tracheal lung model using a pig's trachea and an embolectomy catheter's air-filled balloon to simulate 60 and 80% airway obstruction. JV(S) was performed at various jet frequencies (F(jet) 30 min(-1), 60 min(-1), and 100 min(-1)) and driving pressures (1 bar and 2 bar). RESULTS: JV(S) was associated with generation of PEEP(i), which depended on driving pressure, the degree of obstruction, and on ventilatory frequency. CONCLUSIONS: In the presence of a dynamic upper airway obstruction, JV(S) via a distant injector may result in PEEP(i), which cannot be detected when airway pressure is measured in front of the obstruction.
BACKGROUND: Supraglottic jet ventilation (JV(S)) with injectors above airway stenoses may result in inadvertent high lung pressures. We designed this study to investigate intrinsic positive end-expiratory pressure (PEEP(i)) during jet ventilation via a distant injector in a model of dynamic upper airway obstruction. METHODS: Respiratory pressure-time curves were recorded during JV(S) in a tracheal lung model using a pig's trachea and an embolectomy catheter's air-filled balloon to simulate 60 and 80% airway obstruction. JV(S) was performed at various jet frequencies (F(jet) 30 min(-1), 60 min(-1), and 100 min(-1)) and driving pressures (1 bar and 2 bar). RESULTS: JV(S) was associated with generation of PEEP(i), which depended on driving pressure, the degree of obstruction, and on ventilatory frequency. CONCLUSIONS: In the presence of a dynamic upper airway obstruction, JV(S) via a distant injector may result in PEEP(i), which cannot be detected when airway pressure is measured in front of the obstruction.