Monitoring system and probe

Abstract

A probe for use in performing impedance measurements on a biological subject is described. The probe can include a housing configured to be held by an operator in use, a conductive contact surface for contacting the subject and a connector for connecting the contact surface to a measuring device. The probe can be configured to act as an electrode that can be moved over the subject when performing an impedance measurement procedure.

1 ) A probe for use in performing impedance measurements on a biological subject, the probe including:
 a) a housing configured to be held by an operator in use;   b) a conductive contact surface for contacting the subject; and,   c) a connector for connecting the contact surface to a measuring device, wherein the probe is configured to act as an electrode that can be moved over the subject when performing an impedance measurement procedure.   
     
     
         2 ) A probe according to  claim 1 , wherein the probe includes a position sensor configured to determine a position of the probe relative to the subject. 
     
     
         3 ) A probe according to  claim 1 , wherein the housing is an elongate housing made from an insulating material. 
     
     
         4 ) A probe according to  claim 1 , wherein the contact surface includes a moving member for moving relative to the subject and wherein the moving member is one of:
 a) a roller ball, the housing including a shaped mounting for receiving the roller ball; and,   b) a cylindrical roller mounted on an axle.   
     
     
         5 ) A probe according to  claim 4 , wherein the probe includes a contact for electrically connecting the moving member to the connecter. 
     
     
         6 ) A probe according to  claim 4 , wherein the probe includes a sensor for sensing movement of the moving member. 
     
     
         7 ) A probe according to  claim 6 , wherein the sensor includes at least one of:
 a) an optical sensor; and,   b) moving elements in contact with the moving member.   
     
     
         8 ) A probe according to  claim 1 , wherein the probe is configured to be moved along a segment of the subject to thereby allow an impedance profile representing variations in impedance along the segment to be determined. 
     
     
         9 ) A system for use in performing impedance measurements on a biological subject, the system including:
 a) a probe including:
 i) a housing configured to be held by an operator in use; 
 ii) a conductive contact surface for contacting the subject; and, 
 iii) a connector for connecting the contact surface to a measuring device, wherein the probe is configured to be moved over the subject when performing an impedance measurement procedure; and, 
   b) a measuring device including:
 i) a signal generator configured to apply one or more electrical signals to the subject using first electrodes; 
 ii) a sensor configured to measure electrical signals across second electrodes, the second electrodes including the probe; and, 
 iii) a processing system configured to: 
   (1) cause at least one electrical signal to be applied to the subject via the first electrodes;   (2) determine an indication of at least one second electrical signal measured by the sensor via the second electrodes; and,   (3) determine at least one impedance value using the indication of the at least one second electrical signal.   
     
     
         10 ) A system according to  claim 9 , wherein the probe includes a position sensor and wherein the processing system is configured to:
 a) determine impedance values measured as the probe is moved along a segment of the subject;   b) determine positional information from the position sensor as the impedance values are measured; and,   c) determine an impedance profile using the sequence of impedance values and the positional information.   
     
     
         11 ) A system according to  claim 10 , wherein the processing system is configured to display a representation of the impedance profile. 
     
     
         12 ) A system according to  claim 9 , wherein the method includes, in the processing system:
 a) determining one or more impedance parameter values from measured impedance values, the impedance parameter values including at least one of:
 i) an impedance at infinite applied frequency (R ∞ ); 
 ii) an impedance at zero applied frequency (R 0 ); and, 
 iii) an impedance at a characteristic frequency (Z c ); and, 
   b) determining the impedance profile using the impedance parameter values.   
     
     
         13 ) A system according to  claim 11 , wherein the representation includes at least one of:
 a) a baseline impedance profile for the segment;   b) a reference impedance profile derived from a normal population; and,   c) an impedance profile for a contra-lateral segment.   
     
     
         14 ) A system according to  claim 13 , wherein the processing system is configured to:
 a) determine one or more subject details, the subject details including at least one of:
 i) limb dominance; 
 ii) ethnicity; 
 iii) age; 
 iv) sex; 
 v) weight; and, 
 vi) height; and, 
   b) select a reference impedance profile at least partially in accordance with the subject details.   
     
     
         15 ) A system according to  claim 11 , wherein the impedance profile is indicative of a presence, absence, degree or location of oedema in the subject. 
     
     
         16 ) A method of performing impedance measurements on a subject using a probe, the probe including a housing configured to be held by an operator in use, a contact surface for contacting the subject and a connector for connecting the contact surface to a measuring device, the method including:
 a) positioning the probe in contact with a segment of the subject;   b) causing the measuring device to perform a sequence of impedance measurements; and,   c) moving the probe along the segment during the sequence of impedance measurements so that the measuring device determines impedance measurements along the segment.   
     
     
         17 ) A method according to  claim 16 , wherein the method includes, in the measuring device:
 a) causing a sequence of first electrical signals to be applied to the subject via first electrodes provided on the subject;   b) determining an indication of a sequence of second electrical signals measured via second electrodes positioned on the subject, the second electrodes including the probe; and,   c) using the indication of the sequence of second electrical signals to determine a sequence of impedance values.   
     
     
         18 ) A method according to  claim 16 , wherein the method includes, in the measuring device:
 a) using the impedance measurements to determine an impedance profile representing variations in measured impedance along the segment; and,   b) displaying a representation of the impedance profile.   
     
     
         19 ) A method according to  claim 18 , wherein the method includes, in the measuring device:
 a) determining positional information from a position sensor of the probe as the impedance values are measured; and,   b) determining the impedance profile using the positional information.   
     
     
         20 ) A method according to  claim 18 , wherein the method includes using the impedance profile to determine a presence, absence, degree or location of oedema in the subject.