Method for estimating leaks from ventilator circuits

A device for estimating gas leakage from the ventilator circuit and patient interface that relies on breath-by-breath or time-to-time variability in the pattern of pressure delivery by the ventilator, which comprises:

• computer for storing and processing data corresponding to pressure (PCIRCUIT) and flow rate (Flow) in the ventilator circuit, with said processing comprising:
• algorithm(s) for integrating Flow (Integrated Flow),
• algorithm(s) for measuring the change in Integrated Flow (ΔV) over an INTERVAL extending from a selected point in the expiratory phase of a ventilator cycle to a selected point during the expiratory phase of a nearby ventilator cycle,
• repeating said measurement of ΔV in at least two said INTERVALs,
• algorithm(s) for processing PCIRCUIT to produce an index or indices that reflect(s) the pattern of pressure delivery by the ventilator during each of said INTERVALs,
• applying statistical methods to determine the relation between the differences in ΔV among INTERVALs and the corresponding differences in said index or indices of PCIRCUIT,
• establishing from said relation the leak rate at specified PCIRCUIT values.

A computer readable medium having a computer program stored thereon for estimating gas leakage from the ventilator circuit and patient interface that relies on breath-by-breath or time-to-time variability in the pattern of pressure delivery by the ventilator, the computer program comprising:

• program code for receiving signals that correspond to pressure (PCIRCUIT) and flow rate (Flow) in the ventilator circuit,
• program code for integrating Flow (Integrated Flow),
• program code for measuring the change in Integrated Flow (ΔV) over an INTERVAL extending from a selected point in the expiratory phase of a ventilator cycle to a selected point during the expiratory phase of a nearby ventilator cycle,
• program code for repeating said measurement of ΔV in at least two said INTERVALs,
• program code for, based on PCIRCUIT , producing an index or indices that reflect(s) the pattern of pressure delivery by the ventilator during each of said INTERVALs,
• program code for applying statistical methods to determine the relation between the differences in ΔV among INTERVALs and the corresponding differences in said index or indices of PCIRCUIT,
• program code for establishing from said relation the leak rate at specified PCIRCUIT values.