Apparatus and method for measuring an induced perturbation to determine a physiological parameter

A monitor for determining a physiological parameter of a patient comprising:

• a calibration device configured to provide a calibration signal representative of one of the patient's physiological parameters;
• an exciter adapted to be positioned over a blood vessel of the patient and configured to induce a transmitted exciter waveform into the patient;
• a noninvasive sensor adapted to be positioned over said blood vessel and configured to sense a hemoparameter and to generate a noninvasive sensor signal representative of said hemoparameter containing a component of a received exciter waveform;
• a processor configured to determine a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• wherein said processor includes a filter configured to separate a component of said noninvasive sensor signal having a phase that varies with blood pressure from at least one other component of said noninvasive sensor signal having a phase that does not so vary;
• and
• wherein said processor is connected to receive said calibration signal and said noninvasive sensor signal and is configured to determine said physiological parameter based at least in part on said calibration signal, said component having a phase that varies with blood pressure, and said relationship.

A monitor for determining a physiological parameter of a patient, comprising:

• a calibration device configured to provide a calibration signal representative of one of the patient's physiological parameters;
• an exciter adapted to be positioned over a blood vessel of the patient and configured to induce a transmitted exciter waveform into the patient;
• a noninvasive sensor adapted to be positioned over said blood vessel and configured to sense a hemoparameter and to generate a noninvasive sensor signal representative of said hemoparameter containing a component of a received exciter waveform;
• a processor configured to determine a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• and
• wherein said processor is connected to receive said calibration signal and said noninvasive sensor signal and is configured to determine said physiological parameter based at least in part on said calibration signal, said noninvasive sensor signal and said relationship;
• wherein said exciter is further configured to induce a second transmitted exciter waveform into the patient;
• and
• wherein said processor includes a filter configured to separate from said noninvasive sensor signal a component of one of the group consisting of said physiological parameter waveform, said received exciter waveform, a second received exciter waveform, a signal exciter waveform, second signal exciter waveform and a noise waveform.

A processor for determining a physiological parameter of a patient with an apparatus having a calibration device configured to provide a calibration signal representative of one of the patient's physiological parameters, an exciter adapted to be positioned over a blood vessel of the patient and configured to induce a transmitted exciter waveform into the patient, and a noninvasive sensor adapted to be positioned over said blood vessel and configured to sense a hemoparameter and to generate a noninvasive sensor signal representative of said hemoparameter, said processor comprising:

• a first input configured to receive said calibration signal;
• a second input configured to receive said noninvasive sensor signal;
• a filter configured to from said noninvasive sensor signal a component representing a received exciter waveform;
• a relationship routine configured to determine a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• wherein said filter is configured to separate a component of said noninvasive sensor signal having a phase that varies with blood pressure from at least one other component of said noninvasive sensor signal having a phase that does not so vary;
• and
• a determination routine to determine said physiological parameter based at least in part on said calibration signal, said component having a phase that varies with blood pressure, and said relationship.

A method for determining a physiological parameter of a patient comprising:

• providing a calibration signal representative of one of the patient's physiological parameters and storing the calibration signal;
• inducing a transmitted exciter waveform into the patient;
• noninvasively sensing a hemoparameter and generating a noninvasive sensor signal representative of said hemoparameter containing a component of a received exciter waveform;
• and
• processing said noninvasive sensor signal including the steps of:
• (a) determining a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• (b) separating a signal exciter waveform component of said noninvasive sensor signal from at least one other component of said noninvasive sensor signal;
• and
• (c) determining said physiological parameter based at least in part on said calibration signal, said signal exciter waveform component, and said relationship.

A method for determining a physiological parameter of a patient comprising:

• providing a calibration signal representative of one of the patient's physiological parameters and storing the calibration signal;
• inducing a transmitted exciter waveform into the patient;
• noninvasively sensing a hemoparameter and generating a noninvasive sensor signal representative of said hemoparameter containing a component of a received exciter waveform;
• and
• processing said noninvasive sensor signal including the steps of:
• (a) determining a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• (b) separating a signal exciter waveform a component of said noninvasive sensor signal having a phase that varies with blood pressure from at least one other component of said noninvasive sensor signal having a phase that does not so vary;
• and
• (c) determining said physiological parameter based at least in part on said calibration signal, said component having a phase that varies with blood pressure, and said relationship.

A of determining a physiological parameter of a patient, comprising the steps of:

• providing a calibration signal representative of one of the patient's physiological parameters and storing the calibration signal;
• inducing a transmitted exciter waveform into the patient;
• noninvasively sensing a hemoparameter and generating a noninvasive sensor signal representative of said hemoparameter containing a component of a received exciter waveform;
• processing said noninvasive sensor signal including the steps of:
• (a) determining a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• and
• (b) determining said physiological parameter based at least in part on said calibration signal, said noninvasive sensor signal and said relationship;
• inducing a second transmitted exciter waveform into the patient;
• and
• wherein said processing step includes a filtering step of separating from said noninvasive sensor signal a component of one of the group consisting of said physiological parameter waveform, said received exciter waveform, a second received exciter waveform, a signal exciter waveform, a second signal exciter waveform and a noise waveform.

A monitor for determining a patient's blood pressure comprising:

• an inflatable cuff adapted to be positioned on an extremity of the patient and configured to provide a calibration signal representative of one of the patient's physiological parameters;
• an exciter adapted to be positioned over a blood vessel of the patient and configured to induce a transmitted exciter waveform into the patient;
• a noninvasive sensor adapted to be positioned over said blood vessel at a distance from said exciter and configured to sense a hemoparameter and to generate a noninvasive sensor signal representative of said hemoparameter containing a component of a received exciter waveform;
• a processor configured to determine a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• wherein said processor is connected to receive said calibration signal and said noninvasive sensor signal;
• wherein said processor includes a filter configured to separate a component of said noninvasive sensor signal having a phase that varies with blood pressure from at least one other component of said noninvasive sensor signal having a phase that does not so vary;
• and
• wherein said processor is configured to determine said blood pressure based at least in part on said calibration signal, said component having a phase that varies with blood pressure, and said relationship.

A method of obtaining data of blood pressure of a patient, comprising:

• noninvasively inducing into an artery of the patient a repetitive pressure wave;
• noninvasively monitoring a characteristic of the repetitive wave upon modification by the artery;
• determining a relationship between magnitudes of the monitored wave characteristic and blood pressure;
• using the monitored wave characteristic and said relationship in a manner to provide the blood pressure of the patient;
• and
• noninvasively monitoring relative values of the blood pressure in the artery of the patient, and wherein using the monitored wave characteristic and said relationship includes scaling the monitored relative values of the blood pressure by the monitored wave characteristic and said relationship in a manner to provide absolute values of said blood pressure.

A method of obtaining data of blood pressure of a patient, comprising:

• noninvasively inducing into an artery of the patient a repetitive wave upon modification by the artery;
• determining a relationship between magnitudes of the monitored wave characteristic and blood pressure;
• using the monitored wave characteristic and said relationship in a manner to provide the blood pressure of the patient;
• and
• wherein using the monitored wave characteristic and said relationship includes processing the monitored characteristic of the pressure wave after modification by the artery in a manner to separate a component that varies with a period of the blood pressure from other, components that do not so vary, thereby to filter out a desired component of the monitored characteristic.

A method of obtaining data of blood pressure of a patient, comprising:

• noninvasively inducing into an artery of the patient a repetitive pressure wave,
• noninvasively monitoring a characteristic of the pressure wave between two spaced apart locations along a length of the artery,
• processing the monitored characteristic of the pressure wave by separating a component that varies with a period of the blood pressure from other components that do not so vary, thereby to filter out a desired component of the monitored characteristic that is related to blood pressure, and
• determining the blood pressure from the filtered component.

A monitor for determining a physiological parameter of a patient comprising:

• an exciter adapted to be positioned over a blood vessel of the patient and configured to induce a transmitted exciter waveform into the patient;
• a noninvasive sensor adapted to be positioned over said blood vessel and configured to sense a hemoparameter and to generate a noninvasive sensor signal representative of said hemoparameter containing a received exciter waveform component and a physiological waveform component;
• a processor configured to utilize a relationship between a property of said received exciter waveform component and a property of said physiological parameter;
• wherein said processor is configured to scale said noninvasive sensor signal including said physiological waveform component by use of said relationship to generate a scaled waveform;
• and
• wherein said processor is connected to receive said sensor signal and is configured to determine said physiological parameter based at least in part on said scaled waveform.

A monitor for determining a physiological parameter of a patient comprising:

• an exciter adapted to be positioned over a blood vessel of the patient and configured to induce a transmitted exciter waveform into the patient;
• a noninvasive sensor adapted to be positioned over said blood vessel and configured to sense a hemoparameter and to generate a noninvasive sensor signal representative of said hemoparameter containing a received exciter waveform component and a physiological waveform component;
• a processor configured to utilize a relationship between a property of said received exciter waveform component and a property of said physiological parameter;
• wherein said processor is connected to receive said sensor signal and is configured to determine said physiological parameter based at least in part on said sensor signal and said relationship;
• and
• means in addition to said sensor for noninvasively monitoring relative values of the physiological parameter of the patient, and wherein said processor is additionally configured for scaling the monitored relative values of the physiological parameter by the sensor signal and said relationship in a manner to provide absolute values of said physiological parameter.

A monitor for determining a physiological parameter of a patient comprising:

• an exciter adapted to be positioned over a blood vessel of the patient and configured to induce transmitted exciter waveform into the patient;
• a noninvasive sensor adapted to be positioned over said blood vessel and configured to sense a hemoparameter and to generate a noninvasive sensor signal representative of said hemoparameter containing a component of a received exciter waveform;
• a processor configured to utilize a relationship between a property of said received exciter waveform and a property of said physiological parameter;
• wherein said processor is connected to receive said sensor signal and is configured to determine said physiological parameter based at least in part on said sensor signal and said relationship;
• and
• wherein said processor is additionally configured for processing the sensor signal in a manner to separate a component that varies with a period of blood pressure variations in the artery from other components that do not so vary, thereby to filter out a desired component of the sensor signal.

A method for determining a physiological parameter of a patient comprising:

• noninvasively positioning over a blood vessel of the patient an exciter that induces an exciter waveform into the blood vessel;
• noninvasively positioning a sensor over the blood vessel of the patient at a location spaced a distance apart from the exciter along the blood vessel in order to detect a sensor signal of the exciter waveform at said spaced apart location that contains a component representative of a hemoparameter of the patient;
• providing a relationship between a property of said sensor signal and a property of said physiological parameter;
• separating a component of said noninvasive sensor signal having a phase that varies with blood pressure from at least one other component of said noninvasive sensor signal having a phase that does not so vary;
• and
• determining the physiological parameter from at least said component having a phase that varies with blood pressure, and said relationship.