Abstract:
A drug identification and security apparatus usable in conjunction with an electronic drug delivery system having at least one drug channel therein, the apparatus providing a first interlock mechanism between a locking member of the apparatus and the drug delivery system to lock the upper and lower doors of the drug channel and to disengage the drug delivery system and prevent removal of a drug container/cassette assembly when the locking member is in a locked position. A second interlock mechanism is interposed between a bar code reading device usable with the drug delivery apparatus and a sensor provided on the drug delivery system, the sensor assuring the placement of a cassette assembly in a drug channel with a scanner activating a switch to enable the scanner to read identifying indicia provided on a drug container of a cassette assembly installed in the drug channel, and both cassette sensor and scanner switch must be activated to enable a scan of a drug container installed in the drug channel, to enable the drug delivery system to deliver the drug in the container through the drug channel to the patient receiving a drug dosage in a controlled amount and at a controlled delivery rate.

Description:
RELATED APPLICATIONS 
     This document is a continuation-in-part of prior U S. patent application Ser. No. 811,516 filed on Dec. 20, 1991, (now abandoned). The benefit of the filing date of the prior application is hereby claimed under 35 U.S.C. § 120. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to drug identification and security apparatus generally and in particular to a drug channel drug identification and security apparatus useful in a drug delivery system to prevent the dispensing of drugs when the system is locked and further to assure that the drug container from which the drug is dispensed is disposed in the drug delivery system. 
     BACKGROUND OF THE INVENTION 
     It is known to provide a locking enclosure for a drug delivery device such as a programmable infusion pump to permit the pump to be used as a patient-controlled analgesia (PCA) device. For example, depicted in U.S. Pat. No. 4,627,839 entitled &#34;Patient Controlled Analgesia Conversion&#34;, is a pump which infuses a drug into the patient at a dosage set by the doctor but at a rate controlled by the patient. To prevent the patient from accessing the pump to obtain more drug than prescribed, safety interlocks are provided to disable the keyboard once dosage requirements have been set and the pump is operative. However, under certain circumstances it might be necessary to disable the mechanism itself, as in a drug delivery situation where the physician needs to be present during the time of drug delivery and needs to prevent the delivery of drugs in his absence. An accommodation as described above is not available in the aforementioned device. Another form of locking member associated with a patient controlled analgesia device is shown in U.S. Pat. No. 5,009,641 entitled &#34;Patient-Controlled Analgesia Security Attachment For A Medication Infusion System&#34;. The subject patent discloses both a compartment for securely storing a medication supply and means for preventing either a cassette associated therewith or a fluid line between a storage compartment and a cassette from being removed or tampered with. However, such an attachment offers no advantage to the programming of multiple infusion devices and further does not permit the disablement of such devices subsequent to programming and prior to use so as to prevent unauthorized activation of the device when the physician programming the device is not present. 
     While it may be possible to provide within a single drug delivery apparatus a bar code reader fixedly mounted on the device, such as shown in U.S. Pat. No. 4,978,335 entitled &#34;Infusion Pump Of Bar Code Input To Computer&#34;, such a scheme is not suitable for all drug delivery applications. For example, a hand-held reader may be preferable to a built-in reader for certain applications. In such applications it would be desirable to know that the vial being read is properly installed inside the device. Further, such consideration would also apply to a multi-channel drug delivery apparatus using but a single hand-held bar code reader. 
     Accordingly, in a drug delivery system having multiple drug channels which uses a single bar code reader, it may be necessary to provide a bar code reader which is hand-held and moveable to scan each drug channel of the system and further to provide a drug identification and security apparatus with interlock means to assure that a drug container is disposed within its respective drug delivery channel of the drug delivery system and further means to assure that the bar code scanner reads the bar code on the drug container installed within its respective drug delivery channel in the drug delivery system. Moreover, in such a proposed apparatus it is clearly necessary that the apparatus prevent the scanner from reading the bar code of a drug container not installed in the apparatus or a drug container not properly positioned for reading within the drug delivery system. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a multi-channel drug delivery system includes a drug identification and security apparatus to insure proper placement of a drug container within a discrete channel of the system, and further to provide that a simple turn of a key will electronically disengage the system to prevent its operation in the absence of the physician attending the system, as well as to prevent the removal of the drug container. 
     In particular, the proposed drug identification and security apparatus provides a first interlock to ensure that a drug container installed in a preferred embodiment of the drug delivery system is properly installed within a drug delivery channel of the system for reading by a scanner device. A second interlock maintains the system in a closed configuration once the drug container has been installed in the system and further electronically inactivates the system to insure that the drug contained in the container installed therein cannot be dispensed in the absence of the attending physician. 
     In accordance with the present invention, a drug identification and security apparatus is usable in conjunction with an electronic drug delivery system, the drug delivery system comprising a multi-channel device wherein each drug delivery channel includes a pump mechanism, a pump cassette installed in the mechanism, a drug container connected to the cassette via a container adapter, and a drug channel enclosure enclosing each drug delivery channel of the device. The drug identification and security apparatus includes a locking member in engagement with the drug channel and movable between separable lock and unlock positions. A position sensor interposed between the locking member and the drug delivery system electronically disengages said system when the locking member is in the lock position. 
     Provided in association therewith is a drug identification apparatus which includes a scanning device for reading identifying indicia, such as a bar code, provided on the drug container. An interlock mechanism includes means interposed between the scanning device and the drug channel enclosure to assure the presence of the drug container in a drug channel of the enclosure at a designated position within such enclosure, to enable the drug delivery system to activate a drug container scan, to identify the drug in the drug channel, to permit the entry of selected drug parameters, to deliver the drug in the container through the system to a patient receiving a drug dosage in a controlled amount and at a controlled delivery rate as specified. 
     The proposed drug identification and security apparatus offers multiple levels of protection to the user of the automated electronic drug delivery system used in conjunction with the present invention. First the proposed drug identification interlock assures that the drug container is placed within the system before use and that the apparatus is identifying the drug container placed in the system and not a drug container disposed remotely from the apparatus. In a multi-channel drug delivery system the drug identification and security apparatus can identify drug containers disposed in respective drug channels and enable the user to program a drug channel once its drug container has been installed therein and identified by an appropriate scanning device. 
     Moreover, once a drug container has been installed in its respective drug delivery channel and the channel has been programmed per the requirements of the attending physician, the drug identification and security apparatus provides additional security to the attending physician by first locking the drug container within the drug delivery system, and second, providing means to electronically disable that drug delivery system in the absence of the attending physician. 
     Further objects and advantages of the present invention will become apparent upon a reading of the detailed description of the preferred embodiment as set forth below, particularly when such detailed description is considered in conjunction with the accompanying drawings briefly described below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top right perspective view of a multi-channel electronic drug delivery system which employs the drug identification and security apparatus of the present invention; 
     FIG. 2 is a top right perspective view of the right-hand drug channel of FIG. 1, with a protective hood enclosure open, to expose the drug vial therein; 
     FIG. 3 is a front elevation of the drug channel of FIG. 2, having a drug vial disposed therein; 
     FIG. 4 is a side elevation of the drug channel of FIG. 2, showing the alignment of the drug channel with a bar code scanner; 
     FIG. 5 is a perspective view of the bar code scanner of FIG. 4; 
     FIG. 6 is a block diagram showing the interaction of a drug channel interlock with the microprocessor; FIGS. 6a and 6b are timing diagrams plotting both the bar code scanner signal and the channel door sensor signal versus time; 
     FIG. 7 is a front elevational view of the drug channel of FIG. 2 with the cover and certain other portions of said channel removed for clarity; 
     FIG. 8a is a view taken generally along lines 8a--8a of FIG. 7 with a cassette assembly including the drug container in place in the drug channel and both the lower door and the hood fully closed; 
     FIG. 8b is a view similar to FIG. 8a with the hood partially raised; 
     FIG. 8c is a view similar to FIG. 8a with the hood fully raised and the lower door open; 
     FIG. 8d is a view similar to FIG. 8a in which the hood is removed and a spring release enables the lower door to fully rotate about a lower pivot point; 
     FIG. 8e is a view taken generally along the lines 8e--8e of FIG. 7; 
     FIG. 8f is a view taken generally along the lines 8f--8f of FIG. 7; and 
     FIG. 9 is a view taken along lines 9--9 of FIG. 8a. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Shown in FIG. 1 is a multi-channel electronic drug delivery system 10. Such system includes three substantially equivalent drug delivery channels 12a, 12b, and 12c. The system also includes a fluid delivery channel 14 adjacent the drug delivery channels. Drug delivery parameters are displayed on a touch screen 16. Drug delivery parameters are entered via a touch screen segment 16a, 16b, or 16c for respective drug channels 12a, 12b, or 12c, and fluid delivery parameters for fluid channel 14 are entered via a key pad 18. A base enclosure 20 of the electronic drug delivery system 10 encloses a host computer 21 (FIG. 6) for driving the system 10. Key lock 22 is disposed on one side of the drug channel 12c and engages a security interlock 24 (FIGS. 7,8) discussed in detail below. A bar code reader 39 is electronically connected to the system 10 as by a cord 39a. 
     The right hand drug delivery channel 12c is in the perspective view of FIG. 1. Single drug delivery channel 12c is discussed in detail since the drug delivery channels 12a, 12b, and 12c are identical. 
     Referring now to FIGS. 2 and 3, it should be noted that the drug delivery channel 12c includes a drug delivery system similar to that described in U.S. Pat. No. 4,842,584 entitled Disposable Fluid Infusion Pumping Chamber Cassette and Drive Mechanism thereof, issued Jun. 27, 1989, to the assignee of the subject application. To enable the reader to fully understand the structure of the drug infusion pump associated with the drug delivery channel of the present invention, such U.S. Patent is herein incorporated by reference. 
     As best seen in FIGS. 2 and 3, the drug delivery channel 12c includes an enclosure member 23 including a pivotable lower door 27 operable in conjunction with a pivotable hood 28. As best seen in FIGS. 8a--8e, the lower door 27 pivots around pivot point 27a to permit a cassette assembly 32 to be inserted into the drug channel 12c. 
     When the door 27 pivots to a closed position as shown in FIG. 3, the cassette assembly 32 is disposed in active position therein. The cassette assembly 32 comprises a cassette 32a connected to a container adapter 31, which is then connected to a drug container 30 of the cassette assembly 32 through a container cover 33. The upper enclosure or hood 28 overlies the drug container 30 when the door 27 is closed. When the hood 28 is closed, with a cassette assembly 32 in place, an open drug identification window 36 is disposed at a forward upper end of the drug channel 12c between the door 27 and the hood 28 to provide scanner access to the drug container 30 and bar code identifying indicia 37 provided on the drug container. Further, the cassette 32a engages a channel door sensor 29a mounted on a wall 29b of drug channel 12c when the door 27 and hood 28 are conjointly closed to provide sensor input to the microprocessor 21. The sensor 29a is not activated and there is no input to the microprocessor 21 when a cassette assembly 32 is not installed in the door 27 and the door 27 and hood 28 are closed. 
     As seen in FIGS. 4 and 5, the bar code 37 provided on the drug vial 30 is read by a bar code scanner 39 electronically connected to the system 10, as by a cable 39a. Other connections are possible, including a wireless connection. An active reading area 40 is provided at a forward end of the bar code scanner 39. An essential element of the present invention is a magnetic safety latch 41 provided at a forward end of the scanner 39. When the scanner 39 is driven to a position within the drug identification window 36 sufficient to enable the scanner to read the bar code 37 provided on the drug vial 30, a magnet of the latch 41 on the scanner activates a reed switch 43 mounted adjacent window 36 on a fixed arm 44 of the drug channel 12c. 
     The reed switch 43 is a known device which can be held either normally open or normally closed in the presence of a magnetic device. The switch 43 is activated to a respective closed position by the presence of the magnet in the latch 41, and open when the latch 41 moves away from the switch 43. The closed switch 43 generates a scanner presence signal to the microprocessor 21. When the channel door sensor 29a is activated and the latch 41 activates the reed switch 43, the combined input to the microprocessor 21 activates the scanner 39 to read the bar code 37 on the vial 30 in drug channel 12c. 
     Drug channel 12c is so configured that drug identification cannot be initiated until a cassette assembly 32 placed in the door 27 activates the door sensor 29a with the closing of the door and hood, and the latch 41 activates the reed switch 43. The system 10 will not display drug type for user confirmation until the drug channel 12c is activated and the drug installed therein is identified by the system. Thus, the drug identification and security apparatus of the present invention will not permit a reading taken from a drug container 30 to be displayed on the touch screen 16c of the drug delivery channel 12c unless the cassette door 28 is closed and the scanner 39 is placed in window 36 to latch the reed switch 43 mounted adjacent the window 36 and generate a scanner presence signal to the microprocessor 21. Moreover, the reed switch 43 is inactivated when the scanner 39 is removed from window 36, to terminate the scanner presence signal and to prevent the scanner from reading a drug container 30 installed in another drug channel or disposed remotely from the system. 
     Each drug channel 12a, 12b, an 12c has its own reed switch 43 and its own channel door sensor 29a and once a cassette assembly 32 is installed in a drug channel and the door 27 is closed to enable the cassette to activate the door sensor, drug identification can occur in any desired order, i.e., with a respective drug channel door closed, and a cassette assembly 32 in place and with a sensor 29a activated for each of drug channels 12a, 12b and 12c, the bar code scanner 39 can enter the drug channels in any order to enable the scanner&#39;s latch 41 to activate the reed switch associated with the selected channel and then read the drug container 30 installed therein. 
     FIG. 6 shows that both scanner input and channel door sensor input to microprocessor 21 is required to initiate a valid scan process. 
     As shown in FIGS. 6a and 6b, whenever an activation of cassette position sensor 29a generates a container position signal (such as the Channel ID pattern) or start of a drug container identity data (such as a bar code) is generated by switch 43 in an attempt to identify a drug in a designated position, the relative timing of these two events is compared by the microprocessor 21. Given bar code data starting at time t, the change in Channel ID pattern must occur after a time t 1 , where t-t 1  ≦X. The value X is chosen as an interval too small to allow the repositioning of the bar code scanner outside the designated Channel after the detection of the Channel ID pattern. 
     When the change in Channel ID pattern occurs after the start of the bar code data, it must occur before a time t 2 , where t 2  -t≦Y. The value Y is chosen to be an interval too small to allow the repositioning of the bar code scanner outside the designated Channel before the detection of the Channel ID pattern. 
     If the relative timing between the container position signal and the drug container identity data falls within the boundaries described above, this positively identifies the drug and drug position. 
     In FIGS. 7 and 8a-8f, the security interlock 24 associated with the drug delivery channel 12c is shown in the full range of motion associated with the opening and closing of the door 27 and the hood 28 conjointly. The interlock 24 comprises a pivotable over-center member 46 that is roughly T-shaped, which rotates around a central pivot point 47. As seen in FIG. 8f, leg 48 of the T-shaped member 46 carries a longitudinal cam track 48a on an inner surface thereof which receives cam follower 50 carried on the door 27. 
     In the closed position of the lower door 27 (FIG. 8a) cam follower 50 is disposed at an upper end of cam track 48a, and places the member 46 in an over-center position which effectively prevents the door 27 from being opened by direct lateral forces applied to it. In the open position of the door 27 (FIG. 8c) the cam follower 50 is disposed at a lower end of cam 48a. 
     A sheet spring member 80 mounted on the outside of member 46 conforms generally to a triangular shape and is somewhat larger than member 46 to overlie an outer face thereof. The spring 80 is a stainless steel sheet mounted to member 46 at an inner end by screws 81 and 82. The outer end 80a of spring 80 is bent (FIG. 9) to engage and retain cam follower 50 in track 48 when the door 27 is in the open position of FIG. 8c, but can be moved out of the way to fully rotate door 27 about its lower pivot point 27a, as shown in FIG. 8d, to permit full access to the interior of drug channel 12c for cleaning, repairs, etc. Connecting lever 51 is provided between the lower door 27 and the hood 28. The lever 51 is somewhat S-shaped, with a lower leg 51a pinned at its outer end to the over center member 46 at a pivot point 52. Mid leg portion 51b is integral to the first outer leg 51a at one end and to upper leg portion 51c at its opposite end. Upper leg portion 51c is connected to the hood 28 at pivot point 53. A latch opening 51d is provided at an outer or rear edge of upper leg 51c at a mid-portion thereof and is described in detail below. Hood 28 pivots about a pivot point 54. 
     Link 56 is pivotally connected to the over center member 46 at pivot point 57. At its opposite end link 56 carries a cam track 58 which both rotates and translates about a pivot point 60 carried on an outer face of side frame 61 of the drug channel 12c. A tension spring 62 is connected at one end to the fixed pivot point 60 and at an opposite end to a fixed point 64 disposed on the member 56 near the mid-point thereof. The spring 62 has a generally semi-circular shape and is under increased tension when the drug channel door 27 is open since the distance between the pins 60 and 64 is reduced with the door opened and the pin 60 at or near the inner end of the track 58. 
     Because of the over center configuration of the member 46, the cassette door 27 can only be opened by upward movement of the hood 28, with the interconnection of the member 51 between the over-center member 46 and the hood 28 enabling opening both the door and hood as follows. 
     As the hood 28 is raised, there is some initial movement of the link 51 about its lower pivot point 52 (FIG. 8b). However, because there is no movement of over-center member 46, there is no movement of lower door 27. Once the member 51 is extended to the position of FIG. 8b, further upward movement of the hood 28 causes the member 51 to rotate over-center member 46 about the central pivot 47 and open the lower door 27. Also, link 56 traverses outwardly along its cam track 58 under the force of the upward movement of the hood 28 and against the inward force of spring 62 as the over-center member 46 rotates about its pivot point 47 and the member 51 is translated upward to the open position of the hood 28. At the same time cam follower 50 moves along the cam track 48a in leg 48 to rotate the door outwardly to the open position of FIG. 8c. 
     Interlock 24 prevents opening of the door 27 and hood 28 of the associated drug channel 12c as follows. A locking member 70 comprises an elongated bale having a closed end 70a, a mid-leg portion 70b, and a hook portion 70c, and which extends the length of drug channels 12a, 12b and 12c. Longitudinal pin 73 extends through the closed end 70a of bale 70 to rest at one end in a bearing 73a disposed in a first frame opening 71 provided in the side frame 61 of the drug channel 12c and at an opposite end in a similar bearing (not shown) disposed in a complementary opening provided an outer side frame (not shown) of the drug channel 12a. The hook portion 70c of bale 70 is biased by a tension spring 75 which is connected at one end to the mid-leg 70b of the bale 70 and at an opposite end to a fixed point 75a provided in the side frame 61 of drug channel 12c. The spring 75 drives the hook portion 70c into latch opening 51d provided in the upper leg 51c of the S-shaped member 51 to latch door 27 and hood 28 in a closed and locked position (FIG. 8a) which prevents movement of member 51 when the bale hook 70c is held in place in the opening 51d by the bias of the tension spring 75. 
     A rotatable cam 22a (FIGS. 7, 8e) associated with the key lock 22 can be rotated by a key (not shown) inserted into key lock 22. The cam 22a engages the flat mid-leg portion 70b of the bale 70 to move and hold the bale hook portion 70c at a position out of engagement with the latch opening 51d in the connecting member 51 and against the bias of the spring 75 to permit upward movement of the member 51 to open the hood 28 and the door 27 of the drug channel 12c. 
     When the bale 70 is biased to a lock position by the springs 75 of the drug channels 12a, 12b, 12c and the cam 22a, and the hood 28 of one or more drug channels is raised, any closed drug channel can be reopened because the bale hook 70c is co-extensive with the pin 73 across all drug channels and the member 51 associated with the raised hood 28 is translated upwardly to place a flat rear or outer edge of leg portion 51c below the latch opening 51d into engagement with the hook 70c and bias hook 70c out of engagement with latch portions 51d of members 51 of other drug channels. When the hook 70c is biased out of engagement with one latch opening 51d as described above, the hook is biased out of engagement with latch openings 51d associated with the closed drug channels, and they can be reopened, i.e., if the bale hook 70c is disengaged from the latch opening 51d of any drug channel, all drug channels can be reopened until the last drug channel is closed. This is true even though hook 70c is not biased as far outwardly from the latchopenings 51d as when the cam 22a is activated to move the hook 70c out of latches 51d. Thus, if a drug channel is open, any closed drug channels can be reopened by upward movement of their respective hood 28. Once all the drug channels are closed, the bale 70 is biased into all latches 51d and all the drug channels 12a, 12b and 12c are closed and cannot be reopened without the use of the key lock 22 and associated cam 22a. The key lock 22 must rotate its associated cam 22a against the bale 70 and against the bias of the spring 75 to rotate the hook 70c out of the latch opening 51d of the lever 51 to enable the interaction of hood 28, door 27, lever 51, and the over-center member 46 to open the door and hood of all drug channels. 
     A secondary feature of the interlock 45 is the interaction of the bale 70 with a microswitch 76. An actuating arm 76a of the microswitch 76 is disengaged when the bale 70 is biased into a locking position by the spring 75. In the locking position, the bale 70 is biased away from the arm 76a and the microswitch 76 is normally open, to direct a signal to the microprocessor 21 which the microprocessor interprets as a signal to interrupt drug flow from the system to the patient. When the bale 70 is biased to an unlocked position, it engages arm 76a to close microswitch 76 to direct a signal to the microprocessor 21, which the microprocessor interprets as a signal to resume drug flow from the system to the patient. 
     Thus, a user can install a drug vial 30 in a respective drug delivery channel 12a, 12b or 12c, program each channel of the-drug delivery apparatus 10 and lock up the apparatus through the key lock 22 which causes the bale 70 to engage the levers 51 to lock the door 27 and the hood 28 closed and also to interrupt drug flow from the system 10 to the patient through the micro switch 76 which is normally open when the bale engages the levers 51. 
     When the bale 70 is released, the bale engages the micro switch 76 to a closed position which activates the drug delivery apparatus 10 to enable the attending physician to begin the infusion of the patient through one or more programmed drug delivery channels 12a, 12b, 12c of the system 10. As noted above, the drug channel 12c is not automatically locked when its hood 28 is open and the bale 70 is turned to a lock position. The attending physician can turn the bale 70 to a lock position and then complete his installation of a drug vial 30 in the open drug delivery channel 12c. When the bale 70 is in the lock position, if one or more hoods 28 are in the open position, all closed hoods 28 are not locked. Note, however that a known bale, more complex than bale 70, would enable independent locking of drug channels 12a, 12b and 12c. Note also that the normally open/normally closed dichotomy for the microswitch 76 is the configuration for the preferred embodiment and the alternative configuration is possible. 
     Note also that there is no interconnection between scanner interlock 41 and hood interlock 24. The attending physician may simply lock each drug vial 30 in its respective drug delivery channel 12a, 12b or 12c and scan each drug vial to program the apparatus 10 just prior to infusing the patient. 
     Thus, the present drug identification and security apparatus provides multiple safeguards for both the patient and the attending physician to ensure that the drug container is properly installed in the device and to insure that the device can be easily electronically disengaged by the attending physician when he moves away from the apparatus. A further desirable feature of the present invention is that the drug container is locked in the drug delivery system 10 when the system is disengaged, to prevent removal of the drug container from the system when the attending physician is not present. 
     Having described the preferred embodiment of the invention, it is believed that the specific description set forth herein should not be limiting, but rather that the present invention shall be limited by the claims appended hereto.