Method, apparatus, and system for determining a value of one or more parameters of a respiratory effort of a subject

Abstract

A method, apparatus, and system for determining a value of one or more parameters of a respiratory effort of a subject, including obtaining a thoracic signal (T), the thoracic signal (T) being an indicator of a thoracic component of the respiratory effort, obtaining an abdomen signal (A), the abdomen signal (A) being an indicator of an abdominal component of the respiratory effort, and determining, without directly measuring, the value of the one or more parameters of the respiratory effort by using constraints and/or relationships of components of a model of a respiratory system of the subject, and fitting the components of the model of the respiratory system of the subject with data from the obtained thoracic signal (T) and data from the obtained abdomen signal (A).

What is claimed: 
     
         1 . A method of determining a value of one or more parameters of a respiratory effort of a subject, the method comprising:
 obtaining a thoracic signal (T), the thoracic signal (T) being an indicator of a thoracic component of the respiratory effort;   obtaining an abdomen signal (A), the abdomen signal (A) being an indicator of an abdominal component of the respiratory effort; and   determining, without directly measuring, the value of the one or more parameters of the respiratory effort by
 using constraints and/or relationships of components of a model of a respiratory system of the subject, and 
 fitting the components of the model of the respiratory system of the subject with data from the obtained thoracic signal (T) and data from the obtained abdomen signal (A). 
   
     
     
         2 . The method according to  claim 1 , wherein the thoracic signal (T) is a thoracic respiratory inductive plethysmograph (RIP) signal, and the abdomen signal (A) is an abdomen respiratory inductive plethysmograph (RIP) signal; and
 wherein each of the determined one or more parameters of the respiratory effort is different than each of
 the thoracic component of the respiratory effort, 
 the abdominal component of the respiratory effort, 
 a weighted thoracic component of the respiratory effort, 
 a weighted abdominal component of the respiratory effort, 
 a paradox component of the respiratory effort, and 
 a respiratory movement. 
   
     
     
         3 . The method according to  claim 1 , wherein the one or more parameters include one or a combination of:
 an airway resistance Rr of the subject;   an intercostal muscle drive force FTm;   a diaphragm drive force FAm;   a thorax counterforce FTb based on a force of lifting the chest weight and/or stretching muscle and skin of the chest;   an abdomen counterforce FAb based on a force created by organ hydraulic pressure from the abdomen of the subject;   an intrathoracic pressure PIt;   a ratio of inhalation time over exhalation time;   a ratio of thoracic inhalation time over thoracic exhalation time;   a ratio of abdomen inhalation time over abdomen exhalation time;   a ratio of total inhalation time over total exhalation time;   a body pressure based on differing body positions of the subject;   a sleep stage of the subject;   an abdomen inhalation time;   an abdomen exhalation time Aet;   a thoracic inhalation time;   a thoracic exhalation time Tet;   a thoracic negative pressure force FTp;   an abdomen negative pressure force FAp;   respiratory drive;   changes in respiratory drive;   a thorax contribution to respiration;   changes in the thorax contribution to respiration;   an abdomen exhalation time constant;   changes in the abdomen exhalation time constant;   a thoracic exhalation time constant;   changes in a thoracic exhalation time constant;   intra thoracic pressure;   changes in the intrathoracic pressure;   a comparison of a thoracic exhalation time Tet and an abdomen exhalation time Aet;   a ratio of inhalation time versus exhalation time; or   a thoracic mass component or abdomen mass component of the subject.   
     
     
         4 . The method according to  claim 3 , wherein the one or more parameters includes at least the thoracic negative pressure force FTp. 
     
     
         5 . The method according to  claim 4 , wherein the thoracic negative pressure force FTp is based on an additional force caused by an intrathoracic pressure PIt across a thoracic area (At), such that FTp=PIt*At. 
     
     
         6 . The method according to  claim 3 , wherein the one or more parameters includes at least the abdomen negative pressure force FAp. 
     
     
         7 . The method according to  claim 6 , wherein the abdomen negative pressure force FAp is based on an additional force caused by an intrathoracic pressure PIt across an Abdomen area (Aa), such that FAp=PIt*Aa. 
     
     
         8 . The method according to  claim 7 , wherein
 low airway resistance Rr of the subject results in low thoracic negative pressure force FTp and/or low abdomen negative pressure force FAp, or   high airway resistance Rr of the subject results in high thoracic negative pressure force FTp and/or high abdomen negative pressure force FAp.   
     
     
         9 . The method according to  claim 7 , wherein low airway resistance Rr indicates that an upper airway resistance is low. 
     
     
         10 . The method according to  claim 1 , wherein the thoracic signal (T) and abdomen signal (A) are obtained by a Respiratory Inductive Plethysmograph (RIP) system, including a first stretchable belt including a first conductor formed therein, the first stretchable belt being arranged at a thoracic region of the subject, and a second stretchable belt including a second conductor formed therein, the second stretchable belt being arranged at an abdomen of the subject, and a processing unit configured to obtain the thoracic signal (T) as a first inductive signal from the first conductor and the processing unit is configured to obtain the abdomen signal (A) as a second inductive signal from the second conductor. 
     
     
         11 . The method according to  claim 1 , wherein any one or more of intercostal muscle drive force FTm, a thorax counterforce FTb, a diaphragm drive force FAm, an abdomen counterforce FAb are determined based on a Respiratory Inductive Plethysmograph (RIP) system, including a first stretchable belt including a first conductor formed therein, the first stretchable belt being arranged at a thoracic region of the subject, and a second stretchable belt including a second conductor formed therein, the second stretchable belt being arranged at an abdomen of the subject, and a processing unit configured to obtain the thoracic signal (T) as a first inductive signal from the first conductor and the processing unit is configured to obtain the abdomen signal (A) as a second inductive signal from the second conductor. 
     
     
         12 . The method according to  claim 1 , wherein any one or more of intercostal muscle drive force FTm, a thorax counterforce FTb, a diaphragm drive force FAm, an abdomen counterforce FAb are determined based on an evaluation of one or more inhalations. 
     
     
         13 . The method according to  claim 1 , wherein any one or more of intercostal muscle drive force FTm, a thorax counterforce FTb, a diaphragm drive force FAm, an abdomen counterforce FAb are determined based on an evaluation of one or more exhalations. 
     
     
         14 . The method according to  claim 1 , wherein any one or more of intercostal muscle drive force FTm, a thorax counterforce FTb, a diaphragm drive force FAm, an abdomen counterforce FAb are determined based on an evaluation of one or more respiration times. 
     
     
         15 . The method according to  claim 1 , wherein any one or more of intercostal muscle drive force FTm, a thorax counterforce FTb, a diaphragm drive force FAm, an abdomen counterforce FAb are determined based on an evaluation of one or more shape deviations between the thorax signal (T) and the abdomen signal (A). 
     
     
         16 . The method according to  claim 1 , wherein any one or more of intercostal muscle drive force FTm, a thorax counterforce FTb, a diaphragm drive force FAm, an abdomen counterforce FAb are determined based on an evaluation of one or more phase shifts between the thorax signal (T) and the abdomen signal (A). 
     
     
         17 . The method according to  claim 1 , wherein the determining of the value of the one or more parameters of the respiratory effort is further based on a ratio of inhalation time versus exhalation time, and
 wherein a determination of intrathoracic pressure is determined based on a ratio of inhalation time versus exhalation time, where it is assumed that PIt becomes more negative the longer it takes to fill a respiratory capacity compared with an exhalation time.   
     
     
         18 . The method according to  claim 1 , wherein determining, without directly measuring the value of the one or more parameters of the respiratory effort includes
 determining, without directly measuring, a weighted sum (S) of the thoracic signal (T) and the abdomen signal (A) that correctly represents the respiratory volume by the relative contribution of the thoracic signal (T) and the abdomen signal (A) to two or more harmonics of the weighted sum (S).   
     
     
         19 . A system for determining a value of one or more parameters of a respiratory effort of a subject, the system comprising:
 a first sensor device configured to obtain a thorax signal (T), the thorax signal (T) being an indicator of a thoracic component of the respiratory effort;   a second sensor device configured to obtain an abdomen signal (A), the abdomen signal (A) being an indicator of an abdominal component of the respiratory effort;   a processor configured to receive the thorax signal (T) and the abdomen signal (A);   wherein the processor further is configured to
 receive the thorax signal (T), 
 receive an abdomen signal (A), and 
 determine, without directly measuring, the value of the one or more parameters of the respiratory effort by
 using constraints and/or relationships of components of a model of a respiratory system of the subject, and 
 fitting the components of the model of the respiratory system of the subject with data from the obtained thoracic signal (T) and data from the obtained abdomen signal (A). 
 
   
     
     
         20 . A hardware storage device having stored thereon computer executable instructions which, when executed by one or more processors, implement a method of determining a value of one or more parameters of a respiratory effort of a subject, the method comprising:
 obtaining a thoracic signal (T), the thoracic signal (T) being an indicator of a thoracic component of the respiratory effort;   obtaining an abdomen signal (A), the abdomen signal (A) being an indicator of an abdominal component of the respiratory effort; and   determining, without directly measuring, the value of the one or more parameters of the respiratory effort by
 using constraints and/or relationships of components of a model of a respiratory system of the subject, and 
 fitting the components of the model of the respiratory system of the subject with data from the obtained thoracic signal (T) and data from the obtained abdomen signal (A).