System and method for non-invasive ventilation
Systems and methods for non-invasive ventilation are provided. The systems may include a gas source that provides breathing gases to a patient through one or more of a primary flow path (PFP) and a flushing flow path (FFP). The system may include a control assembly configured to open and restrict gas flow through the PFP. When the PFP is open, a significant portion of the gas flows through the PFP while the remaining gas flows through the FFP. When the PFP is restricted, a significant portion of the gas flows through the FFP. Increased flow through the FFP may have a high velocity (especially relative to the flow through the PFP). Gas delivered through the FFP may be used to flush dead space. One or both flow paths may contribute to inspiratory positive airway pressure (IPAP), expiratory positive airway pressure (EPAP), and/or positive end expiratory pressure (PEEP).
1 . A method for providing non-invasive ventilation to a patient, the method comprising:
providing positive pressure breathing gases to a patient through a patient interface apparatus comprising a sealing mask forming a seal with a mouth and a nose of the patient, an inlet that receives the positive pressure breathing gases from a pressurized gas flow source, and a gas outlet;
wherein:
during patient inhalation, the flow of gas is provided to the patient through one or more of the mouth and the nose of the patient; and
during patient exhalation, a flow restrictor of the patient interface apparatus is configured to increase a portion of the positive pressure breathing gases along a flow path that provides anatomical dead space flushing through a nasal cavity of the patient and out through the gas outlet.
2 . The method of claim 1 , wherein the flow restrictor causes the increase in the portion of the positive pressure breathing gases along the flow path that provides anatomical dead space flushing based at least in part on an increase of pressure within the patient interface apparatus.
3 . The method of claim 2 , wherein the increase in pressure within the patient interface apparatus is further caused by exhalation of the patient.
4 . The method of claim 2 , wherein the flow path that provides anatomical dead space flushing comprises flow through a non-sealing cannula comprising two prongs positioned within a chamber that seals about the mouth and nose of the patient.
5 . The method of claim 1 , wherein the flow restrictor is configured to cause the increase in the portion of the positive pressure breathing gases along the flow path that provides anatomical dead space flushing during patient exhalation and to a start of patient inhalation.
6 . The method of claim 1 , wherein the flow path that provides anatomical dead space flushing comprises flow in through the nose of the patient, out through the mouth of the patient or out through the nose of the patient, and out through the gas outlet.
7 . The method of claim 1 , wherein the sealing mask comprises a non-sealing cannula comprising two prongs positioned within a chamber that seals about the mouth and nose of the patient.
8 . The method of claim 7 , wherein each of the two prongs is configured in size and shape to direct and/or accelerate at least a portion of the positive pressure breathing gases into nares of the patient.
9 . The method of claim 1 , wherein the gas outlet comprises a bias vent.
10 . The method of claim 1 , wherein the gas outlet is configured to connect to an expiratory limb.
11 . The method of claim 1 , wherein the positive pressure breathing gases are provided continuously.