Bi-directional partial re-breathing method
AssigneeNTC Technology, Inc.
InventorsKai Kück, Joseph A. Orr, Michael B. Jaffe, Dinesh G. Haryadi
Life of this patent
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Abstract
A re-breathing method for determining pulmonary capillary blood flow that accounts for changes in the carbon dioxide content of a patient. The carbon dioxide elimination and partial pressure of end tidal carbon dioxide of the patient are measured prior to re-breathing, during re-breathing, and after re-breathing. A rate of change of carbon dioxide content of the venous blood of the patient is then calculated. The rate of change is then employed in calculating the pulmonary capillary blood flow of the patient.
Claims59
A method of non-invasively determining pulmonary capillary blood flow of a patient, comprising:
- measuring a before re-breathing carbon dioxide elimination and a before re-breathing partial pressure of end tidal carbon dioxide prior to a re-breathing phase;
- measuring a during re-breathing carbon dioxide elimination and a during re-breathing partial pressure of end tidal carbon dioxide during said re-breathing phase;
- and
- measuring an after re-breathing carbon dioxide elimination and an after re-breathing partial pressure of end tidal carbon dioxide after said re-breathing phase.
A method of non-invasively determining a pulmonary capillary blood flow of a patient, comprising:
- determining a before re-breathing carbon dioxide elimination (VCO2B) of the patient, a before re-breathing alveolar partial pressure of carbon dioxide (PACO2B) of the patient, and a before time (tB);
- re-breathing to determine a during re-breathing carbon dioxide elimination (VCO2D) of the patient, a during re-breathing alveolar partial pressure of carbon dioxide (PACO2D) of the patient, and a during time (tD);
- determining an after re-breathing carbon dioxide elimination (VCO2A) of the patient, an after re-breathing alveolar partial pressure of carbon dioxide (PACO2A) of the patient, and an after time (tA);
- and
- calculating a rate of change (k) of a carbon dioxide content of venous blood of the patient.
A method of non-invasively determining a pulmonary capillary blood flow of a patient, comprising:
- measuring a carbon dioxide elimination (VCO2) of the patient before, during and after a re-breathing process;
- and
- determining an alveolar partial pressure of carbon dioxide (PACO2) of the patient before, during and after said re-breathing process.
A method of determining a rate of change in carbon dioxide content of venous blood of a patient, comprising:
- measuring a carbon dioxide elimination (VCO2) of the patient before (B), during (D) and after (A) a re-breathing process;
- and
- determining an alveolar partial pressure of carbon dioxide (PACO2) of the patient before, during and after said re-breathing process.
A method of determining a change in carbon dioxide content of venous blood of a patient, comprising:
- measuring a carbon dioxide elimination (VCO2) of the patient before (B), during (D) and after (A) a re-breathing process;
- and
- determining an alveolar partial pressure of carbon dioxide (PACO2) of the patient before, during and after said re-breathing process.
A method of non-invasively determining pulmonary capillary blood flow of a patient, comprising:
- measuring a before carbon dioxide elimination and a before partial pressure of end tidal carbon dioxide prior to a change in effective ventilation;
- measuring a during carbon dioxide elimination and a during partial pressure of end tidal carbon dioxide during said change in effective ventilation;
- and
- measuring an after carbon dioxide elimination and an after partial pressure of end tidal carbon dioxide after said change in effective ventilation.
Dependencies are inferred from the claim text.