Abstract: A differential Fick technique including a first phase in which baseline breathing parameters may be established and a second phase in which a change in the effective ventilation of a patient is induced. The durations of the first and second phases may be substantially the same and may be abbreviated relative to the durations of comparable phases of previously known differential Fick techniques. The disclosed differential Fick technique also lacks a recovery period in which the respiratory parameters of a patient are permitted to return to “normal” levels.

Abstract: Methods for estimating the volume of the carbon dioxide stores of an individual's respiratory tract include determining a carbon dioxide store volume at which a correlation between corresponding signals of carbon dioxide elimination and an indicator of the content of carbon dioxide in blood of the individual is optimized. The estimate of the volume of carbon dioxide stores, which comprises a model of the respiratory tract, or lungs, of the individual, may be used as a transformation to improve the accuracy of one or both of the carbon dioxide elimination and carbon dioxide content signals. Transformation, or filtering, algorithms are also disclosed, as are systems in which the methods and algorithms may be used. The methods, algorithms, and systems may be used to accurately and noninvasively determine one or both of the pulmonary capillary blood flow and cardiac output of the individual.

Abstract: Methods for estimating the volume of the carbon dioxide stores of an individual's respiratory tract include determining a carbon dioxide store volume at which a correlation between corresponding signals of carbon dioxide elimination and an indicator of the content of carbon dioxide in blood of the individual is optimized. The estimate of the volume of carbon dioxide stores, which comprises a model of the respiratory tract, or lungs, of the individual, may be used as a transformation to improve the accuracy of one or both of the carbon dioxide elimination and carbon dioxide content signals. Transformation, or filtering, algorithms are also disclosed, as are systems in which the methods and algorithms may be used. The methods, algorithms, and systems may be used to accurately and noninvasively determine one or both of the pulmonary capillary blood flow and cardiac output of the individual.

Abstract: A basic life support system (BLSS) includes a processing element and an output element, such as a display screen or an audio output element, for providing an individual with real-time instructions on providing emergency medical care to a patient until paramedics or other healthcare professionals arrive to take over care for the patient. The instructions may be provided as graphics, including animations, as text, audibly, or as a combination of visible and audible elements. The BLSS may be configured for providing emergency medical care to individuals who have suffered from ventricular fibrillation. Accordingly, the BLSS may also include a defibrillation apparatus, an air or oxygen supply, a respiratory interface, one or more sensors, or a combination thereof.

Abstract: Methods for noninvasively evaluating indicators of cardio-pulmonary performance of a subject, such as cardiac output, pulmonary capillary blood flow, and blood carbon dioxide content, include obtaining data of an expiratory carbon dioxide signal and comparing data generated by an algorithmic lung model to the data of the expiratory carbon dioxide signal of a subject. The variables that are input into the algorithmic lung model are adjusted until the data generated thereby reflects that of the measured expiratory carbon dioxide signal with a desired degree of accuracy. Once the algorithmic lung model replicates the data of the measured expiratory carbon dioxide signal with the desired degree of accuracy, one or more of the input values may be used to determine one or more of the cardiac output, pulmonary capillary blood flow, or a blood gas content of the subject from which the expiratory carbon dioxide signal was obtained.

Abstract: Methods for estimating the volume of the carbon dioxide stores of an individual's respiratory tract include determining a carbon dioxide store volume at which a correlation between corresponding signals of carbon dioxide elimination and an indicator of the content of carbon dioxide in blood of the individual is optimized. The estimate of the volume of carbon dioxide stores, which comprises a model of the respiratory tract, or lungs, of the individual, may be used as a transformation to improve the accuracy of one or both of the carbon dioxide elimination and carbon dioxide content signals. Transformation, or filtering, algorithms are also disclosed, as are systems in which the methods and algorithms may be used. The methods, algorithms, and systems may be used to accurately and noninvasively determine one or both of the pulmonary capillary blood flow and cardiac output of the individual.

Abstract: Methods for estimating the volume of the carbon dioxide stores of an individual's respiratory tract include determining a carbon dioxide store volume at which a correlation between corresponding signals of carbon dioxide elimination and an indicator of the content of carbon dioxide in blood of the individual is optimized. The estimate of the volume of carbon dioxide stores, which comprises a model of the respiratory tract, or lungs, of the individual, may be used as a transformation to improve the accuracy of one or both of the carbon dioxide elimination and carbon dioxide content signals. Transformation, or filtering, algorithms are also disclosed, as are systems in which the methods and algorithms may be used. The methods, algorithms, and systems may be used to accurately and noninvasively determine one or both of the pulmonary capillary blood flow and cardiac output of the individual.

Abstract: Methods for noninvasively measuring, or estimating, functional residual capacity or effective lung volume include obtaining carbon dioxide and flow measurements at or near the mouth of a subject. Such measurements are obtained during baseline breathing and during and shortly after inducement of a change in the subject's effective ventilation. The obtained measurements are evaluated to determine the amount of time required for exhaled carbon dioxide levels to return to normal—effectively an evaluation of carbon dioxide “washout” from the subject's lungs. Conversely, carbon dioxide and flow measurements may be evaluated to determine the amount of time it takes carbon dioxide to “wash in,” or reach peak levels within, the lungs of the subject following the change in the subject's effective ventilation. Apparatus for effective such methods are also disclosed.

Abstract: Methods for inducing changes in the effective ventilation of an individual by varying one or more respiratory parameters to derive measurements which may be utilized to calculate measures of hemodynamic performance, e.g., pulmonary capillary blood flow and cardiac output, are provided. The methods of the present invention are used to attain measurements under the wide array of ventilatory modes available with modem ventilation machines to calculate indicators of hemodynamic performance using a differential form of the carbon dioxide Fick equation.

Abstract: Methods for estimating the volume of the carbon dioxide stores of an individual's respiratory tract include determining a carbon dioxide store volume at which a correlation between corresponding signals of carbon dioxide elimination and an indicator of the content of carbon dioxide in blood of the individual is optimized. The estimate of the volume of carbon dioxide stores, which comprises a model of the respiratory tract, or lungs, of the individual, may be used as a transformation to improve the accuracy of one or both of the carbon dioxide elimination and carbon dioxide content signals. Transformation, or filtering, algorithms are also disclosed, as are systems in which the methods and algorithms may be used. The methods, algorithms, and systems may be used to accurately and noninvasively determine one or both of the pulmonary capillary blood flow and cardiac output of the individual.

Abstract: A differential Fick technique including a first phase in which baseline breathing parameters may be established and a second phase in which a change in the effective ventilation of a patient is induced. The durations of the first and second phases may be substantially the same, and may be abbreviated relative to the durations of comparable phases of previously known differential Fick techniques. The disclosed differential Fick technique also lacks a recovery period in which the respiratory parameters of a patient are permitted to return to “normal” levels.