Flow therapy

Abstract

A method of estimating a parameter indicative of respiratory flow of a patient being administered flow therapy, comprising: optionally administering a gas at a flow rate to the patient using a flow therapy apparatus with a patient interface, determin—-ing a terminal pressure in, at or proximate the outlet of the patient interface or in, at or proximate the nares of the patient, determin -ing nasal RTF, determining a nasal flow parameter being or indicative of nasal flow based on the pressure and a nasal RTF, and optionally outputting the nasal flow parameter or parameter derived therefrom.

1 - 25 . (canceled) 
     
     
         26 . A method of promoting gas exchange in a patient’s airway, the method comprising:
 receiving a gas; and 
 varying the gas to provide to the patient a gas flow with a non-random unidirectional varying flow rate; 
 controlling a base flow rate to meet or exceed an inspiratory demand of the patient; and 
 providing the gas flow to the patient’s airway via a non-sealing patient interface. 
 
     
     
         27 . The method according to  claim 26 , wherein the non-random unidirectional varying flow rate includes two or more frequency components. 
     
     
         28 . The method according to  claim 26  further comprising heating the gas. 
     
     
         29 . The method according to  claim 26  further comprising humidifying the gas. 
     
     
         30 . The method according to  claim 26 , wherein the gas flow provides a net positive flow to the patient. 
     
     
         31 . The method according to  claim 26 , wherein the non-random unidirectional varying flow rate has a given frequency. 
     
     
         32 . The method according to  claim 26  further comprising specifying, through a user interface, at least one of:
 an amplitude of one or more frequencies of the non-random unidirectional varying flow rate, 
 a frequency of the one or more frequencies of the non-random unidirectional varying flow rate, or 
 the base flow rate of the gas flow. 
 
     
     
         33 . The method according to  claim 26 , wherein the non-random unidirectional varying flow rate includes a frequency higher than a breathing frequency of the patient. 
     
     
         34 . The method according to  claim 26 , wherein the non-random unidirectional varying flow rate includes at least one frequency that promotes CO 2  washout of the patient’s airway of the patient and/or increases O 2  in the patient’s airway of the patient. 
     
     
         35 . The method according to  claim 26 , wherein the non-random unidirectional varying flow rate includes at least one frequency based on a resonant frequency of the patient’s airway. 
     
     
         36 . The method according to  claim 26 , further comprising generating the base flow rate by a flow generator. 
     
     
         37 . The method according to  claim 26 , wherein the base flow rate is:
 offset from zero, and/or   constant.   
     
     
         38 . The method according to  claim 26 , wherein the base flow rate is in a range of 20-90 litres per minute. 
     
     
         39 . The method according to  claim 26 , wherein varying the gas comprises modulating the base flow rate to provide the gas flow with the varying flow rate. 
     
     
         40 . The method according to  claim 26 , wherein receiving the gas comprises receiving a first gas flow at a first flow rate having a first frequency component and receiving a second gas flow at a second flow rate having a second frequency component. 
     
     
         41 . The method according to  claim 40 , wherein varying the gas comprises superimposing the first gas flow and the second gas flow. 
     
     
         42 . The method according to  claim 40 , wherein the first gas flow is:
 provided at a constant rate;   varied during a therapy session; and/or   in response to expiratory and inspiratory transitions.   
     
     
         43 . The method according to  claim 26 , wherein varying the gas comprises operating a flow generator at varying speeds. 
     
     
         44 . The method according to  claim 26 , wherein the gas flow is supplied to the non-sealing patient interface via a heated inspiratory conduit.