Monitoring system

Abstract

Apparatus for performing impedance measurements on a subject. The apparatus includes a first processing system for determining an impedance measurement procedure and determining instructions corresponding to the measurement procedure. A second processing system is provided for receiving the instructions, using the instructions to generate control signals, with the control signals being used to apply one or more signals to the subject. The second processing system then receives first data indicative of the one or more signals applied to the subject, second data indicative of one or more signals measured across the subject and performs at least preliminary processing of the first and second data to thereby allow impedance values to be determined.

1 ) A method of performing impedance measurements on a subject, the method including, in a processing system:
 a) determining an encoded value associated with at least one electrode lead; and,   b) causing at least one impedance measurement to be performed using the encoded value.   
     
     
         2 ) A method according to  claim 1 , wherein the encoded value is used for calibration. 
     
     
         3 ) A method according to  claim 1 , wherein the encoded value is determined from a resistance value. 
     
     
         4 ) A method according to  claim 1 , wherein the encoded value is indicative of an identity of the lead. 
     
     
         5 ) A method according to  claim 1 , wherein the method includes, in the processing system, controlling the current applied to the subject using the encoded value. 
     
     
         6 ) A method according to  claim 1 , wherein the encoded value is a lead identifier, and wherein the method includes, in the processing system:
 a) determining, using the lead identifier, an impedance measurement procedure; and,   b) causing the determined impedance measurement procedure to be performed.   
     
     
         7 ) A method according to  claim 6 , wherein the method includes, in the processing system:
 a) comparing the determined identifier to one or more predetermined identities; and,   b) determining the impedance of the subject in response to a successful comparison.   
     
     
         8 ) A method according to  claim 6 , wherein the method includes, in the processing system:
 a) determining the lead identifier associated with the at least one electrode lead;   b) determining, using the lead identifier, a lead usage;   c) comparing the lead usage to a threshold; and,   d) in accordance with the results of the comparison, at least one of:
 i) generating an alert; 
 ii) terminating an impedance measurement procedure; and, 
 iii) performing an impedance measurement procedure. 
   
     
     
         9 ) A method according to  claim 1 , wherein the method includes, in the processing system, at least one of:
 a) processing electrical signals measured from the subject to thereby determine one or more impedance values; and,   b) processing determined impedance values.   
     
     
         10 ) A method according to  claim 1 , wherein the encoded value is stored in a store. 
     
     
         11 ) A method according to  claim 1 , wherein the impedance measurement is performed using at least four electrodes, each having a respective identifier, and wherein the method includes, in the processing system:
 a) determining an electrode identifier for each electrode;   b) determining, using each electrode identifier, an electrode position for each electrode; and,   c) performing at least one impedance measurement using the electrode positions by:
 i) causing signals to be applied to at least two of the electrodes in accordance with the determined electrode positions; and, 
 ii) causing signals to be measured from at least two of the electrodes in accordance with the determined electrode positions. 
   
     
     
         12 ) A method according to  claim 11 , wherein the method includes, in the processing system, determining the electrode identifier for an electrode by selectively measuring the conductivity between one or more contacts provided on the electrode. 
     
     
         13 ) A method according to  claim 1 , wherein the processing system is coupled to a signal generator and a sensor, and wherein the method includes, in the processing system controlling a multiplexer to:
 a) selectively interconnect the signal generator and at least two electrode leads, to thereby allow signals to be applied to the subject; and,   b) selectively interconnect the sensor at least two electrode leads to thereby allow a signal to be measured from the subject.   
     
     
         14 ) A method according to  claim 1 , wherein the at least one electrode includes visual indicia indicative of the position of the at least one electrode on the subject. 
     
     
         15 ) Apparatus for performing impedance measurements on a subject, the apparatus including:
 a) at least one lead for connecting to electrodes coupled to the subject, the at least one lead including an encoded value; and,   b) a processing system coupled to the at least one lead for:
 i) determining the encoded value; and, 
 ii) causing at least one impedance measurement to be performed using the encoded value. 
   
     
     
         16 ) A method of performing impedance measurements on a subject, the method including, in a processing system:
 a) determining an electrode identifier associated with at least one electrode provided on the subject;   b) determining, using the electrode identifier, an electrode position indicative of the position of the at least one electrode on the subject; and,   c) causing at least one impedance measurement to be performed using the electrode position.   
     
     
         17 ) A method according to  claim 16 , wherein the impedance measurement is performed using at least four electrodes, each having a respective identifier, and wherein the method includes, in the processing system:
 a) determining an electrode identifier for each electrode;   b) determining, using each electrode identifier, an electrode position for each electrode; and,   c) performing at least one impedance measurement using the electrode positions.   
     
     
         18 ) A method according to  claim 16 , wherein the method includes, in the processing system:
 a) causing signals to be applied to at least two of the electrodes in accordance with the determined electrode positions; and,   b) causing signals to be measured from at least two of the electrodes in accordance with the determined electrode positions.   
     
     
         19 ) A method according to  claim 16 , wherein the method includes, in the processing system, determining the electrode identifier for an electrode by selectively measuring the conductivity between one or more contacts provided on the electrode. 
     
     
         20 ) A method according to  claim 16 , wherein the processing system is coupled to a signal generator and a sensor, and wherein the method includes, in the processing system:
 a) selectively interconnecting the signal generator and at least two electrode leads, to thereby allow signals to be applied to the subject; and,   b) selectively interconnecting the sensor at least two electrode leads to thereby allow a signal to be measured from the subject.   
     
     
         21 ) A method according to  claim 20 , wherein the method includes, in the processing system controlling a multiplexer to thereby selectively interconnect the leads and at least one of the signal generator and the sensor. 
     
     
         22 ) A method according to  claim 16 , wherein the at least one electrode includes visual indicia indicative of the position of the at least one electrode on the subject.