Variable ventilation as a diagnostic tool for assessing lung mechanical function
View Patent ↗Systems and methods for determining lung recruitment/derecruitment dynamics of an individual are disclosed. The disclosed embodiments advantageously use variable ventilation of the individual to determine lung dynamics without necessitating additional, potentially harmful ventilation maneuvers.
1. A method for measuring lung function of an individual being mechanically ventilated with a ventilator, comprising the steps of:
supplying, using the ventilator, a plurality of breath cycles to the individual, the breath cycles having varying tidal volumes such that at least one of the breath cycles does not have a same tidal volume as at least one of the other breath cycles;
measuring airway pressure and airway flow during the breath cycles; and
determining lung derecruitability from the airway pressure measurements and airway flow measurements.
2. The method of claim 1 , wherein a mean tidal volume of the plurality of breath cycles is Vt Mean .
3. The method of claim 2 , wherein the tidal volumes of the plurality of breath cycles vary from 0.7 Vt Mean to 2.25 Vt Mean .
4. The method of claim 2 , wherein the tidal volumes of the plurality of breath cycles vary from 0.7 Vt Mean to 3.5 Vt Mean.
5. The method of claim 4 , where the tidal volumes are distributed according to a specified probability distribution function.
6. The method of claim 3 , where the tidal volumes are distributed according to a specified probability distribution function.
7. The method of claim 6 , where the tidal volumes are distributed according to a Gaussian function.
8. An apparatus for determining a lung function of individual being ventilated by a ventilator, the ventilator configured to provide variable ventilation to the individual through an airway, the apparatus comprising:
a processor; and
an airway meter in communication with the processor, the airway meter configured to measure a pressure and flow of the airway;
wherein the processor is programmed to:
receive a plurality of measurements of airway pressures and airway flows from the airway meter, wherein the plurality of measurements correspond to a plurality of breath cycles having varying tidal volume and/or breathing frequency; and
determine lung derecruitability from the airway pressure measurements and airway flow measurements.
9. The apparatus of claim 8 , further comprising an interface in communication with the processor, the interface configured to communicate with the ventilator.
10. The apparatus of claim 9 , wherein the processor is further programmed to utilize data received from the ventilator in determining lung derecruitability.
11. An apparatus for determining a lung function of an individual, comprising:
a ventilator, the ventilator configured to provide variable ventilation to the individual through an airway;
an airway meter configured to measure a pressure and flow of the airway; and
a processor;
wherein the processor is programmed to:
receive a plurality of measurements of the airway pressures and airway flows from the airway meter;
receive data from the ventilator; and
determine lung derecruitability from the airway pressure measurements, airway flow measurements, and ventilator data.