System for providing flow-targeted ventilation synchronized to a patient's breathing cycle

An apparatus for delivering a flow of oxygen-containing gas to the airway of a spontaneously-breathing patient, said apparatus comprising:

• a tube delivering a flow of oxygen-containing gas into a patient's airway without interfering with a patient's spontaneous respiration;
• a gas source having a housing and delivering a variable flow of gas through the tube combining oxygen from an oxygen source and air from an air source;
• a sensor detecting a physical property of a patient's respiratory cycle;
• and
• a processor monitoring the sensor and controlling the gas source to deliver a flow of oxygen-containing gas through the tube to augment the patient's spontaneous respiration, said flow varying over each inspiratory and expiratory phase of the respiratory cycle in a predetermined non-constant flow waveform synchronized with the respiratory cycle, said waveform including:
• (a) a positive flow accelerating at the onset of the patient's inspiratory phase at a flow rate sufficient to significantly mitigate the airway pressure the patient must generate during spontaneous breathing and thereby reduce the patient's work of breathing;
• and
• (b) a positive flow during at least the early portion of the patient's expiratory phase at a flow rate sufficient to significantly mitigate the airway pressure the patient must generate during spontaneous breathing and thereby reduce the patient's work of breathing, and to wash carbon dioxide from the patient's airway.