Non-invasively monitoring blood parameters

Abstract

An apparatus for monitoring vital sign parameters in a biological entity is disclosed. In an embodiment, the apparatus includes at least one light source for transmitting light through the biological entity and at least one photodetector for receiving light transmitted through the biological entity. At least one light source and at least one photodetector are configured to be positioned proximate the biological entity in a manner that does not significantly impede blood flow through the biological entity. A signal is generated in response to the transmittance or reflectance of light through the biological entity. The signal corresponds to at least one characteristic of the generally unimpeded blood flow through the biological entity. The apparatus also includes a control system configured to analyze the signal to determine vital sign parameters in the biological entity. A method for monitoring vital sign parameters in a biological entity is also provided.

1 - 79 . (canceled) 
     
     
         80 . A system comprising:
 a processor;   a first sensor, configured to be placed proximate to a biological entity and to be in communication with the processor; and   a memory storing instructions executable by the processor for acquiring a response from the first sensor, analyzing the response, and determining a set of characteristics of the biological entity, wherein the set of characteristics includes at least one of a blood parameter and a physiological marker, and wherein analyzing the response includes calculating the upward slope of the response and determining Myocardial Contractility based on the calculated slope.   
     
     
         81 . The system of  claim 80 , the memory further storing instructions for determining blood oxygen saturation from the response of the first sensor. 
     
     
         82 . The system of  claim 81 , the memory further storing instructions for determining respiration rate in the biological entity by detecting rhythmic changes in blood oxygen saturation. 
     
     
         83 . The system of  claim 80 , the memory further storing instructions for acquiring the response from the first sensor periodically, and developing a reference envelope having a lower limit band and an upper limit band, wherein the envelope is developed around a sequence of acquired sensor responses. 
     
     
         84 . The system of  claim 83 , further comprising an alarm, the memory further storing instructions for employing the reference envelope to monitor subsequent responses from the first sensor, and activating the alarm when a subsequent response crosses the upper or lower envelope limit. 
     
     
         85 . The system of  claim 83 , the memory further storing instructions for comparing a response from the first sensor to the envelope and determining the performance of the cardiovascular and pulmonary systems of the biological entity. 
     
     
         86 . The system of  claim 80 , the memory further storing instructions for creating at least one database containing envelopes that correspond to least one of the biological entity and a representative population, wherein the population is categorized by at least one of age, gender, height, weight, race, geographic residence, medical history, medical condition, education, military service, and occupation. 
     
     
         87 . The system of  claim 86 , the memory further storing instructions for comparing a response from the first sensor to at least one of the envelopes in the database and activating the alarm when the response crosses a limit of the at least one envelope. 
     
     
         88 . The system of  claim 80 , further comprising a second sensor, configured to be proximate to the biological entity and in communication with the processor, the memory further storing instructions for comparing a response from the first sensor and a response from the second sensor, and identifying changes in at least one of a blood parameter or a physiological marker. 
     
     
         89 . The system of  claim 80 , the memory further storing instructions for creating a Myocardial Contractility Index based on multiple Myocardial Contractility measurements. 
     
     
         90 . The system of  claim 80 , wherein analyzing the response includes calculating the area under a portion of a curve of the response, determining at least one of Tissue Perfusion and Vascular Elasticity, and creating at least one of a Tissue Perfusion Index based on multiple Tissue Perfusion measurements and a Vascular Elasticity Index based on multiple Vascular Elasticity measurements. 
     
     
         91 . The system of  claim 80 , further comprising an electrocardiograph, the memory further storing instructions for comparing the acquired electrocardiograph signals with a sensor response and identifying a heart condition of electromechanical disassociation by determining when the electrocardiograph signal represents electrical activity in the heart and the sensor response represents the absence of pumping action in the heart. 
     
     
         92 . A system comprising:
 a processor;   a sensor, configured to be placed proximate a biological entity, in communication with the processor;   a device configured to selectively obstruct blood flow through the biological entity; and   a memory storing instructions executable by the processor for causing the device to progressively obstruct blood flow through the biological entity, acquiring a sequence of responses from the sensor during the progressive blood flow obstruction, analyzing the sensor response, determining blood pressure, developing an envelope having a lower limit band and upper limit band wherein the envelope is developed around the sequence of acquired sensor responses, calculating the upward slope of a steady state portion of the response, and determining Myocardial Contractility based on the slope.   
     
     
         93 . The system of  claim 92 , wherein the blood flow obstruction device is at least one of an inflatable bladder and a blood pressure cuff. 
     
     
         94 . The system of  claim 92 , wherein analyzing the response includes identifying characteristics of oscillations in the response that correspond to mean arterial blood pressure, identified as A m , diastolic blood pressure, identified as A d , and systolic blood pressure, identified as A s , calculating mean arterial blood pressure, diastolic blood pressure, and systolic blood pressure, and relating diastolic blood pressure and systolic blood pressure to mean arterial blood pressure, such that A d /A m =X and A s /A m =Y, where X and Y are empirically determined constants. 
     
     
         95 . The system of  claim 92 , wherein progressively obstructing blood flow through the biological entity includes applying pressure to the biological entity, maintaining a predetermined pressure sufficient to substantially obstruct the flow of blood through the biological entity for a predetermined period of time, and relieving the pressure on the biological entity. 
     
     
         96 . The system of  claim 95 , wherein analyzing the response includes determining a first mean arterial blood pressure while the pressure is being applied to the biological entity, determining a second mean arterial blood pressure while the pressure is being relieved and averaging the first mean arterial blood pressure and the second mean arterial blood pressure to determine a final mean arterial blood pressure. 
     
     
         97 . The system of  claim 92 , wherein determining blood pressure includes comparing a response from the sensor to a reference envelope and determining when the response crosses the upper or lower band limit. 
     
     
         98 . The system of  claim 92 , wherein determining blood pressure in the biological entity includes continuously or near-continuously analyzing the sensor response to provide a continuous or near-continuous determination of blood pressure. 
     
     
         99 . The system of  claim 92 , the memory further storing instructions for creating a Myocardial Contractility Index based on multiple Myocardial Contractility measurements. 
     
     
         100 . The system of  claim 92 , wherein analyzing the response includes calculating the area under a steady state portion of the curve of the response, determining at least one of Tissue Perfusion and Vascular Elasticity, and creating at least one of a Tissue Perfusion Index based on multiple Tissue Perfusion measurements and a Vascular Elasticity Index based on multiple Vascular Elasticity measurements. 
     
     
         101 . The system of  claim 92 , wherein analyzing the response includes analyzing the reference envelope to identify a peak amplitude that is equal to mean arterial pressure, calculating the area under a first portion and a second portion of the curve in a steady state portion of the response, determining Tissue Perfusion and Vascular Elasticity, comparing mean arterial blood pressure, Myocardial Contractility, Tissue Perfusion, and Vascular Elasticity, and evaluating the pulmonary system based on the comparison. 
     
     
         102 . A system comprising:
 a processor;   a sensor, configured to be placed proximate a biological entity, in communication with the processor;   a memory storing instructions executable by the processor for analyzing a response from the sensor corresponding to at least one characteristic of blood flow through the biological entity, sampling the response at periodic times, developing a reference envelope having a lower limit band and an upper limit band, employing the reference envelope to monitor subsequent responses, and determining when the response crosses the envelope upper or lower limit.   
     
     
         103 . A system comprising:
 a processor;   a sensor, configured to be placed proximate a biological entity, in communication with the processor;   a memory storing instructions executable by the processor for sampling the response of the sensor at periodic times to develop a reference envelope having a lower limit band and an upper limit band, and creating at least one database containing envelopes that correspond at least one of the biological entity and a representative population categorized by at least one of age, gender, height, weight, race, geographic residence, medical history, medical condition, education, military service, and occupation.   
     
     
         104 . The system of  claim 103 , the memory further storing instructions for comparing a response from the sensor with the envelopes contained in the database. 
     
     
         105 . A system comprising:
 a processor;   a sensor, configured to be placed proximate a biological entity, in communication with the processor;   a memory storing instructions executable by the processor for analyzing a response from the sensor corresponding to at least one characteristic of blood flow through the biological entity, wherein analyzing the response includes calculating the area under a portion of the curve of the response, and determining at least one of Tissue Perfusion and Vascular Elasticity.   
     
     
         106 . The system of  claim 105 , the memory further storing instructions for creating at least one of a Tissue Perfusion Index based on multiple Tissue Perfusion measurements and a Vascular Elasticity Index based on multiple Vascular Elasticity measurements. 
     
     
         107 . A system comprising:
 a processor;   a sensor, configured to be placed proximate a biological entity, in communication with the processor;   a device configured to selectively obstruct blood flow through the biological entity; and   a memory storing instructions executable by the processor for causing the device to progressively obstruct blood flow through the biological entity, acquiring a sequence of responses from the sensor during the progressive blood flow obstruction, analyzing the sensor responses, determining blood pressure, developing an envelope having a lower limit band and upper limit band wherein the envelope is developed around the sequence of acquired sensor responses, determining when a sensor response crosses the upper or lower limit of the envelope.   
     
     
         108 . The system of  claim 107 , wherein the blood flow obstruction device is at least one of an inflatable bladder and a blood pressure cuff. 
     
     
         109 . The system of  claim 107 , further comprising an alarm, the memory further storing instructions for activating the alarm when the sensor response crosses the upper or lower limit of the envelope. 
     
     
         110 . A system comprising:
 a processor;   a first sensor, configured to be placed proximate a biological entity, in communication with the processor;   a memory storing instructions executable by the processor for acquiring a response from the first sensor, analyzing the sensor response, comparing the sensor response to a signal representing the electrical activity of the heart, and determining a condition of electromechanical disassociation when the signal represents electrical activity in the heart and the sensor response represents the absence of pumping action in the heart.   
     
     
         111 . The system of  claim 110 , the memory further storing instructions for sampling the sensor response at periodic times to develop a reference envelope having a lower limit band and an upper limit band, employing the reference envelope to monitor subsequent sensor responses, and determining when a sensor response crosses the upper or lower limit. 
     
     
         112 . The system of  claim 110 , the memory further storing instructions for creating at least one database containing envelopes that correspond to at least one of the biological entity and a representative population categorized by at least one of age, gender, height, weight, race, geographic residence, medical history, medical condition, education, military service, and occupation. 
     
     
         113 . The system of  claim 112 , the memory further storing instructions for comparing the sensor response with envelopes contained in the database. 
     
     
         114 . The system of  claim 110 , the memory further storing instructions for determining blood oxygen saturation from the sensor response. 
     
     
         115 . The system of  claim 114 , the memory further storing instructions for determining respiration rate in the biological entity by detecting rhythmic changes in blood oxygen saturation. 
     
     
         116 . The system of  claim 110 , the memory further storing instructions for sampling the response of the first sensor at periodic times to develop a reference envelope having a lower limit band and an upper limit band, comparing a sensor response to the envelope, and determining the performance of the cardiovascular and pulmonary systems in the biological entity based on the comparison. 
     
     
         117 . The system of  claim 110 , wherein analyzing the response includes determining at least one of Myocardial Contractility, Tissue Perfusion and Vascular Elasticity. 
     
     
         118 . The system of  claim 117 , wherein analyzing the response includes creating at least one of a Myocardial Contractility Index based on multiple Myocardial Contractility measurements, a Tissue Perfusion Index based on multiple Tissue Perfusion measurements and a Vascular Elasticity Index based on multiple Vascular Elasticity measurements. 
     
     
         119 . The system of  claim 110 , further comprising a second sensor, configured to be proximate to the biological entity and in communication with the processor, the memory further storing instructions for comparing a response from the first sensor and a response from the second sensor, and identifying changes in at least one of a blood parameter or a physiological marker.