System and method for measuring the mechanical impedance of the respiratory system

A method for measuring the mechanical impedance of a patient's respiratory system during a spontaneous breath, comprising the step of recording air pressure and air flow measurements of the patient;

• said recording step comprising stages of varying the rotational speed of a fan positioned within a cavity for controlling a pressure within the cavity such as to force an air flow into said cavity to generate, in proximity to an airway opening of said cavity, pressure oscillations of maximum amplitude less than or equal to 3 cmH2O and frequencies greater than 2 Hz;
• enabling said patient to breathe spontaneously through said cavity, containing said fan;
• said cavity having a maximum impedance equal to 1 cm H2O/L/s, measured at normal breathing frequencies within the range of 0-1 Hz;
• and measuring the air pressure and air flow within said cavity in proximity to the patient's airways.

A portable system for self-assessment of the mechanical impedance of a patient's respiratory system during a spontaneous breath, comprising a fan;

• a motor which operates said fan;
• said motor and said fan being positioned within a cavity and a speed of the fan controlling a pressure within the cavity;
• said cavity comprising an initial end and a final end, both providing access to an outside of the cavity;
• said cavity having a length between said initial end and said final end equal to or less than 25 cm;
• said cavity, including said motor and said fan, comprising an impedance between said initial end and said final end of less than 1 cm H2O/L/s, measured at normal breathing frequencies within the range of 0-1 Hz;
• said fan having a total area not exceeding three-fourths of the area of a cross-section of the cavity;
• said fan withdrawing air from said final end and providing pressure variations, with maximum peak-peak amplitude equal to or less than 3 cmH2O and frequency greater than 2 Hz, to said initial end;
• said initial end comprising an air pressure and an air flow measurement sensor and a connection configured to be directly connected to an airway opening of the patient, and including a nozzle adapted for reducing the motion of the patient's cheeks.