High frequency jet ventilation: the influence of gas flow, inspiration time and ventilatory frequency on gas transport in healthy anaesthetized dogs.
High frequency jet ventilation (HFJV) experiments were performed in healthy anaesthetized mongrel dogs via a multilumen tracheal jet tube to examine the influence of gas flow, ventilatory frequency and inspiration time (as a percentage of the total ventilatory cycle) on gas exchange. We compared arterial PO2, PCO2 and cardiac output during periods of adequate intermittent positive pressure ventilation (IPPV) and periods of HFJV. Reducing gas flow by decreasing the number of activated valves and increasing the frequency to greater than 4 Hz resulted in less than optimal arterial PO2 and PCO2 compared with IPPV. This indicates that convection during HFJV is probably essential for efficient gas exchange. Inspiration time proved to be important in determining efficacy of ventilation for a fixed ventilator minute volume. Cardiac output during all HFJV settings was equal to or greater than cardiac output during IPPV, even as those HFJV settings that resulted in a positive end-expiratory pressure.
D000818:Animals; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D004285:Dogs; D006611:High-Frequency Jet Ventilation; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011659:Pulmonary Gas Exchange; D012119:Respiration; D013997:Time Factors
D002245:Carbon Dioxide; D010100:Oxygen