Methods of non-invasively estimating intrapulmonary shunt fraction and measuring cardiac output
First Claim
1. A method of estimating a cardiac output of a patient, comprising:
- determining an oxygen saturation of arterial blood of the patient;
determining a fraction of inspired oxygen of the patient;
determining a pulmonary capillary blood flow of the patient; and
determining an intrapulmonary shunt fraction from said oxygen saturation and said fraction of inspired oxygen.
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Abstract
A method of non-invasively estimating the intrapulmonary shunt in a patient. The method includes non-invasively measuring respiratory flow, respiratory carbon dioxide content, and arterial blood oxygen content. A re-breathing process is employed to facilitate an estimate of the patient'"'"'s pulmonary capillary blood flow. Any inaccuracies of the arterial blood oxygen content are corrected to provide a substantially accurate arterial blood oxygen content measurement. The respiratory flow, carbon dioxide content and arterial blood oxygen content measurements, and the pulmonary capillary blood flow estimate are employed to estimate an intrapulmonary shunt of the patient. The invention also includes a method of determining the total cardiac output of the patient which considers the estimated intrapulmonary shunt.
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Citations
43 Claims
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1. A method of estimating a cardiac output of a patient, comprising:
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determining an oxygen saturation of arterial blood of the patient;
determining a fraction of inspired oxygen of the patient;
determining a pulmonary capillary blood flow of the patient; and
determining an intrapulmonary shunt fraction from said oxygen saturation and said fraction of inspired oxygen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method of determining a cardiac output of a patient, comprising:
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determining a respiratory flow and a respiratory carbon dioxide content of gas mixtures inhaled and exhaled by the patient;
calculating a first carbon dioxide elimination and a first alveolar carbon dioxide content of the patient;
conducting a re-breathing process on the patient'"'"'s breathing;
calculating a second carbon dioxide elimination and a second alveolar carbon dioxide content of the patient during said conducting;
estimating a pulmonary capillary blood flow of the patient;
non-invasively determining an arterial blood oxygen content of the patient;
estimating an intrapulmonary shunt of the patient; and
calculating the cardiac output from said estimated intrapulmonary shunt and said estimated pulmonary capillary blood flow. - View Dependent Claims (28)
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29. A method of estimating an intrapulmonary shunt fraction of a cardiac output of a patient, comprising:
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determining an oxygen saturation of arterial blood of the patient;
determining a fraction of inspired oxygen of the patient;
determining a pulmonary capillary blood flow of the patient; and
employing said oxygen saturation of arterial blood and said fraction of inspired oxygen to determine the intrapulmonary shunt fraction of said pulmonary capillary blood flow. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification