Humidification and airway pressures during high-frequency jet ventilation delivered through the suction-biopsy channel of a flexible bronchofiberscope

The suction-biopsy channel (SBC) of a flexible bronchofiberscope was used to deliver gas into the trachea during high-frequency jet ventilation (HFJV) at a rate of 95 cycle/min and a tidal volume (VT) of 95 ml. A Portex epidural catheter inserted into the SBC was used to entrain water for humidifica...

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Published inCritical care medicine Vol. 12; no. 9; p. 820
Main Authors Ramanathan, S, Sinha, K, Arismendy, J, Chalon, J, Turndorf, H
Format Journal Article
LanguageEnglish
Published United States 01.09.1984
Subjects
Adult
Animals
Bronchoscopes
Carbon Dioxide - blood
Cardiac Output
Dogs
Fiber Optic Technology
Humans
Humidity
Hydrogen-Ion Concentration
Larynx - physiology
Oxygen - blood
Pressure
Pulmonary Gas Exchange
Respiration, Artificial - instrumentation
Respiration, Artificial - methods
Trachea - physiology
Ventilators, Mechanical
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Summary:The suction-biopsy channel (SBC) of a flexible bronchofiberscope was used to deliver gas into the trachea during high-frequency jet ventilation (HFJV) at a rate of 95 cycle/min and a tidal volume (VT) of 95 ml. A Portex epidural catheter inserted into the SBC was used to entrain water for humidification by the injector principle. Inspired humidity (IH) was regulated by adjusting the distance (D) between the injector and jet portals. Airway pressures, pulmonary gas exchange and IH levels were measured in 11 dogs. In addition, tracheal cytology scores (TCS, a sensitive index of tracheal epithelial damage caused by breathing dry gases) were assessed in 12 patients. The system maintained adequate pulmonary gas exchange in both dogs and humans. In dogs the mean tracheal pressure was 2.8 +/- 0.5 (SD) torr with a peak pressure of 3.8 +/- 0.5 torr. The upper-airway pressure was subatmospheric (-2 +/- 0.2 torr) during the first half of jet inspiration, but peaked synchronously with tracheal pressures during the second half. Both the upper airway and the trachea had a positive end-expiratory pressure (PEEP) of 1.8 +/- 0.2 torr. When D was 0.3 cm, the system delivered gas with an IH of 44 mg H2O/L (almost saturated at 37 degrees C). Human TCS did not change significantly after 2 h of humidified HFJV, suggesting efficient humidification.
ISSN:0090-3493
DOI:10.1097/00003246-198409000-00032