Capnotracking of cardiac output or effective pulmonary blood flow during mechanical ventilation
AssigneeMaquet Critical Care AB
InventorMagnus Hallbäck
Life of this patent
Estimating the term…
Abstract
A capnotracking method for continuous determination of cardiac output or EPBF of a mechanically ventilated subject includes the steps of measuring expiratory CO2 of the subject and determining a first value of cardiac output or EPBF of the subject at a first point in time; controlling the mechanical ventilation of the subject to keep a level of venous CO2 of the subject substantially constant between the first point in time and a second point in time; determining from the expiratory CO2 measurements a change in alveolar CO2 of the subject between the first and second points in time; and determining a second and updated value of cardiac output or EPBF of the subject based on the first value and the change in alveolar CO2.
Claims11
A method for controlling a breathing apparatus and determining a cardiac output or an Effective Pulmonary Blood Flow (“EPBF”) of a mechanically ventilated subject, comprising:
- determining, at a first point in time, a first value of cardiac output or EPBF of the subject by a control unit of the breathing apparatus;
- measuring, at the first point in time, a first expiratory CO2 content of the subject, wherein the first expiratory CO2 content is measured by at least one CO2 sensor;
- controlling a mechanical ventilation of the subject by the control unit adjusting one or more settings of the breathing apparatus so as to keep a level of venous CO2 of the subject substantially constant between the first point in time and a second point in time;
- measuring, at the second point in time, a second expiratory CO2 content of the subject, wherein the second expiratory CO2 content is measured by the at least one CO2 sensor;
- determining a change in alveolar CO2 content of the subject between the first and second points in time by the control unit based on the first expiratory CO2 content and the second expiratory CO2 content measured by the at least one CO2 sensor, and
- determining a second value for the cardiac output or the EPBF of the subject by the control unit based on the first value and the change in alveolar CO2 content between the first and second points in time.
A non-transitory, computer readable data storage medium with an executable program stored thereon, wherein the program instructs a processing unit of a breathing apparatus to perform operations for controlling the breathing apparatus and determining a cardiac output or an Effective Pulmonary Blood Flow (“EPBF”) of a mechanically ventilated subject, when executed by the processing unit, the operations comprising steps to:
- determine, at a first point in time, a first value of cardiac output or EPBF of the subject;
- receive a measure of a first expiratory CO2 content of the subject, measured at the first point in time;
- control a mechanical ventilation of the subject by adjusting one or more settings of the breathing apparatus so as to keep a level of venous CO2 of the subject substantially constant between the first point in time and a second point in time;
- receive a measure of a second expiratory CO2 content of the subject, measured at the second point in time;
- determine a change in alveolar CO2 content of the subject between the first and second points in time based on the first expiratory CO2 content and the second expiratory CO2 content, and
- determine a second value for the cardiac output or the EPBF of the subject based on the first value and the change in alveolar CO2 content between the first and second points in time.
A breathing apparatus configured to provide mechanical ventilation to a subject and to determine a cardiac output or an Effective Pulmonary Blood Flow (“EPBF”) of the mechanically ventilated subject, comprising a control unit configured to:
- determine, at a first point in time, a first value of cardiac output or EPBF of the subject;
- receive a measure of a first expiratory CO2 content of the subject, measured by at least one CO2 sensor at the first point in time;
- control the mechanical ventilation of the subject to keep a level of venous CO2, of the subject substantially constant between the first point in time and a second point in time;
- receive a measure of a second expiratory CO2 content of the subject, measured by the at least one CO2 sensor at the second point in time;
- determine a change in alveolar CO2 of the subject between the first and second points in time based on the first expiratory CO2 content and the second expiratory CO2 content measured by the at least one CO2 sensor, and
- determine a second value for the cardiac output or the EPBF of the subject based on the first value and the change in alveolar CO2 content between the first and second points in time.
Dependencies are inferred from the claim text.