Apparatus and method for non-invasively monitoring a subjects arterial blood pressure

An apparatus for monitoring the pressure within a subject's blood vessel, comprising:

• a pressure transducer that produces a pressure signal indicative of the pressure applied against it;
• a coupling device comprising;
• a base configured to provide reaction forces for urging the pressure transducer into compressive association with the tissue overlying the subject's blood vessel, thereby compressing the vessel such that the pressure variations within the vessel are coupled through the tissue to the pressure transducer;
• a first variable positioning device configured to controllably adjust the nominal location toward the target location;
• a second variable positioning device configured to modulate the pressure transducer toward and away from the subject's blood vessel, about the nominal location;
• and
• a lever arm connected to the pressure transducer;
• wherein the first variable positioning device is configured to controllably adjust the nominal location relative to the target location by actuating a first portion of the lever arm, and the second variable positioning device is configured to modulate the pressure transducer by actuating a second portion of the lever arm, the second portion of the lever arm being different from the first portion of the lever arm;
• and
• a controller configured to control the coupling device so as to controllably modulate the pressure transducer toward and away from the subject's blood vessel, about a nominal location;
• wherein the controller is configured to monitor the effect of the modulation on the pressure signal and to produce an error signal indicative of the deviation of the nominal location from a target location at which the vessel is compressed according to a prescribed requirement, and controllably adjust the nominal location toward the target location using the coupling device.

An apparatus for monitoring the pressure within a subject's blood vessel, comprising:

• a pressure transducer that produces a pressure signal indicative of the pressure applied against it;
• a coupling device comprising;
• a base configured to provide reaction forces for urging the pressure transducer into compressive association with the tissue overlying the subject's blood vessel, thereby compressing the vessel such that the pressure variations within the vessel are coupled through the tissue to the pressure transducer;
• a first variable positioning device configured to controllably adjust the nominal location toward the target location;
• and
• a second variable positioning device configured to modulate the pressure transducer toward and away from the subject's blood vessel, about the nominal location;
• wherein the first and second variable positioning devices and the pressure transducer are configured to be removable from the base by way of a quick-release attachment;
• and
• a controller configured to control the coupling device so as to controllably modulate the pressure transducer toward and away from the subject's blood vessel, about a nominal location;
• wherein the controller is configured to monitor the effect of the modulation on the pressure signal and to produce an error signal indicative of the deviation of the nominal location from a target location at which the vessel is compressed according to a prescribed requirement, and controllably adjust the nominal location toward the target location using the coupling device.

An apparatus for monitoring the pressure within a subject's blood vessel, comprising:

• a pressure transducer that produces a pressure signal indicative of the pressure applied against it;
• a coupling device configured to urge the pressure transducer into compressive association with tissue overlying a subject's blood vessel, to compress the vessel such that the pressure variations within the vessel are coupled through the tissue to the pressure transducer;
• a sensor housing connected to the coupling device, the sensor housing defining a chamber;
• a plug disposed at least partly within the sensor housing's chamber, wherein the sensor housing and the plug are configured such that the plug provides the compressive association between the pressure transducer and the tissue overlying the subject's blood vessel;
• and
• a controller configured to control the coupling device so as to controllably modulate the pressure transducer toward and away from the subject's blood vessel, about a nominal location;
• wherein the controller is configured to monitor the effect of the modulation on the pressure signal and to produce an error signal indicative of the deviation of the nominal location from a target location at which the vessel is compressed according to a prescribed requirement.

An apparatus for monitoring the pressure within a subject's blood vessel comprising:

• a pressure transducer that produces a pressure signal indicative of the pressure applied against it;
• a sampler configured to periodically sample the pressure transducer's pressure signal;
• a processor configured to process the sampled pressure signal to produce a plurality of pressure waveforms, each waveform representing the blood vessel pressure at a compression level associated with a specific transmural pressure;
• a coupling device configured to urge the pressure transducer into compressive association with tissue overlying a subject's blood vessel, to compress the vessel such that the pressure variations within the vessel are coupled through the tissue to the pressure transducer;
• and
• a controller configured to control the coupling device so as to controllably modulate the pressure transducer toward and away from the subject's blood vessel, about a nominal location;
• wherein the controller is configured to monitor the effect of the modulation on the pressure signal and to produce an error signal indicative of the deviation of the nominal location from a target location at which the vessel is compressed according to a prescribed requirement.

A method for monitoring the pressure within a subject's blood vessel, comprising:

• providing a pressure transducer configured to produce a signal indicating a pressure applied to the pressure transducer, the pressure transducer being connected to a lever arm having a first portion and a second portion;
• locating the pressure transducer at a nominal location relative to the subject such that the pressure transducer is in compressive association with tissue overlying a subject's blood vessel, thereby compressing the vessel such that the pressure variations within the vessel are coupled through the tissue to the pressure transducer;
• modulating the pressure transducer toward and away from the subject's blood vessel, about the nominal location, by oscillating the second portion of the lever arm, thereby varying the blood vessels transmural pressure and causing variations in the signal produced by the pressure transducer;
• monitoring the effect of the pressure transducer's modulation on the pressure signal;
• producing an error signal indicative of the relative position of the nominal location from a target location such that the vessel would be compressed according to a prescribed requirement;
• and
• adjusting the nominal location toward the target location in response to the error signal, the act of adjusting comprising changing the position of the first portion of the lever arm.

A method for monitoring the pressure within a subject's blood vessel, comprising:

• providing a pressure transducer configured to produce a signal indicating a pressure applied to the pressure transducer;
• locating the pressure transducer at a nominal location relative to the subject such that the pressure transducer is in compressive association with tissue overlying a subject's blood vessel, thereby compressing the vessel such that the pressure variations within the vessel are coupled through the tissue to the pressure transducer;
• linearly oscillating the pressure transducer toward and away from the subject's blood vessel, about the nominal location, to vary the blood vessel's transmural pressure, and thereby cause variations in the signal produced by the pressure transducer;
• monitoring the effect of the pressure transducer's modulation on the pressure signal;
• and
• producing an error signal indicative of the relative position of the nominal location from a target location such that the vessel would be compressed according to a prescribed requirement.