Systems and methods for optical access disconnection

Abstract

An access disconnection system includes: a material capable of absorbing blood from a patient, a light emitter positioned to emit light onto a first portion of the material, the first portion spaced at least a threshold distance from a second portion of the material, the second portion located so as to cover arterial line and venous line access points to the patient, the threshold distance including a distance from the access points to provide for an allowable amount of blood seepage from either access point due to a needle stick, a receiver positioned adjacent to the light emitter to receive light reflected off of the first portion of the material, and circuitry coupled to the light emitter and receiver and configured to provide an output (i) when light received by the receiver reaches a particular level or (ii) indicative of an amount of light received by the receiver.

The invention is claimed as follows: 
     
         1 . An access disconnection system comprising:
 a material capable of absorbing blood from a patient;   a light emitter positioned to emit light onto a first portion of the material, the first portion spaced at least a threshold distance from a second portion of the material, the second portion located so as to cover arterial line and venous line access points to the patient, the threshold distance including a distance from the access points to provide for an allowable amount of blood seepage from either access point due to a needle stick;   a light receiver positioned adjacent to the light emitter to receive light reflected off of the first portion of the material; and   electronic circuitry operably coupled to at least one of the light emitter and receiver, the circuitry configured to provide an output (i) when light received by the light receiver reaches a particular level or (ii) indicative of an amount of light received by the light receiver.   
     
     
         2 . The access disconnection system of  claim 1 , wherein the threshold distance is between approximately one inch (2.54 cm) and three inches (7.62 cm). 
     
     
         3 . The access disconnection system of  claim 1 , wherein the threshold distance corresponds to a distance from the access points such that blood from either access point reaching the first portion of the material is indicative of a line disconnection. 
     
     
         4 . The access disconnection system of  claim 1 , wherein the light emitter and the light receiver are a first light emitter and a first light receiver, and which includes:
 a second light emitter positioned to emit light onto a third portion of the material that is at least the threshold distance from the second portion of the material; and   a second light receiver positioned adjacent to the second light emitter to receive light reflected off of the third portion of the material.   
     
     
         5 . The access disconnection system of  claim 4 , wherein the electronic circuitry is operably coupled to at least one of the second light emitter and second light receiver, the circuitry configured to provide the output (i) when light received by at least one of the first light receiver or the second light receiver reaches the particular level or (ii) indicative of the amount of light received by the first light receiver and the second light receiver. 
     
     
         6 . The access disconnection system of  claim 4 , wherein the electronic circuitry is configured to provide the output when light received by both the first light receiver and the second light receiver reaches the particular level. 
     
     
         7 . The access disconnection system of  claim 4 , wherein the third portion of the material is located on an opposite side of the access points from the first portion of the material. 
     
     
         8 . The access disconnection system of  claim 4 , wherein the second light emitter is positioned to be closer to the access points than the first light emitter. 
     
     
         9 . The access disconnection system of  claim 1 , which includes an attachment mechanism operable to attach the material to an arm of the patient. 
     
     
         10 . The access disconnection system of  claim 1 , wherein the light emitter emits light having a wavelength causing the light to be absorbed by blood. 
     
     
         11 . The access disconnection system of  claim 1 , which includes at least one of: (i) the material being gauze; (ii) the light emitter being a light emitting diode; and (iii) the light receiver being a photocell or phototransistor. 
     
     
         12 . The access disconnection system of  claim 1 , which includes a film positioned between the material and the light emitter/receiver, the material selected to allow light to pass through the material. 
     
     
         13 . The access disconnection system of  claim 1 , wherein the electronic circuitry is configured to provide the output when light received by the receiver falls below the particular level. 
     
     
         14 . The access disconnection system of  claim 1 , wherein the particular level is an at least substantially no-light received level. 
     
     
         15 . The access disconnection system of  claim 1 , wherein the output is of a type selected from the group consisting of: an electrical output and a radio frequency output. 
     
     
         16 . The access disconnection system of  claim 1 , which includes a blood treatment unit, the output sent to the blood treatment unit. 
     
     
         17 . The access disconnection system of  claim 16 , wherein the blood treatment unit performs at least one of: (i) determines if the amount of light received warrants an access disconnection condition; (ii) alarms the patient upon receiving the output; and (iii) shuts down at least one of a blood pump and a dialysate pump upon receiving the output. 
     
     
         18 . The access disconnection system of  claim 1 , which includes at least one of: (i) a plurality of light emitters; (ii) a plurality of light receivers; and (iii) a battery supply to at least one of the light emitter(s) and light receiver(s). 
     
     
         19 . The access disconnection system of  claim 1 , which is a redundant system that combines one of: (i) an electrical impedance access disconnection detector, (ii) an ultrasound access disconnection detector, (iii) an acoustic access disconnection detector and (iv) a bioimpedance access disconnection detector with the light emitter, light receiver and electronic circuitry. 
     
     
         20 . An access disconnection system comprising:
 a material capable of absorbing blood from a patient;   a plurality of light emitters positioned to emit light onto respective portions of the material, each portion spaced at least a threshold distance from an access portion of the material, the access portion located so as to cover arterial and venous line access points to the patient, the threshold distance being defined as a distance from the access points that provides for an allowable amount of blood seepage from either of the access points due to a needle stick;   a plurality of light receivers positioned adjacent to the respective light emitters to receive light reflected off of the respective portions of the material; and   electronic circuitry operably coupled to at least one of the plurality light emitters and light receivers, the circuitry configured to provide an output (i) when light received by at least one of the light receivers reaches a particular level or (ii) indicative of an amount of light received by at least one of the light receivers.   
     
     
         21 . The access disconnection system of  claim 20 , wherein the electronic circuitry is configured to provide the access disconnection output when light received by the at least one of the light receivers falls below the particular level. 
     
     
         22 . The access disconnection system of  claim 20 , wherein the threshold distance corresponds to a distance from the access points such that blood from the access points reaching one of the emitter portions of the material is indicative of a line disconnection. 
     
     
         23 . The access disconnection system of  claim 20 , wherein the plurality of light emitters are located different distances from the access points. 
     
     
         24 . The access disconnection system of  claim 23 , wherein the electronic circuitry is configured to calculate a rate of blood loss based upon when the light received by each of the light receivers reaches the particular level. 
     
     
         25 . The access disconnection system of  claim 24 , wherein the electronic circuitry is configured to transmit an output to trigger an alarm if the rate of blood loss is greater than a predetermined threshold. 
     
     
         26 . The access disconnection system of  claim 20 , wherein the threshold distance is at least approximately one inch (2.54 cm). 
     
     
         27 . An access disconnection detection method comprising:
 positioning a light emitter to emit light onto a first portion of a material capable of absorbing blood from a patient, the first portion being spaced at least a threshold distance from a second portion of the material, the second portion located so as to cover arterial line and venous line access points to the patient, the threshold distance including a distance from the access points to provide for an allowable amount of blood seepage from either access point due to a needle stick;   positioning a light receiver adjacent to the light emitter to receive light reflected off of the first portion of the material; and   providing an output (i) when light received by the light receiver reaches a particular level or (ii) indicative of an amount of light received by the light receiver.