Method and apparatus for automatically controlling the level of
Contents
1. 560 1 460 186 MODIFY PCA ROUTINE PATIENT INITIATED REQUEST 188 QUERY PATIENT PCA TIMER EXPIRED 190 OBTAIN HISTORICAL DATA PROCESS DATA MODIFY PCA 194 Fig 5 U S Patent May 15 2001 Sheet 6 of 7 US 6 231 560 1 PAIN INTENSITY SCALES SIMPLE DESCRIPTIVE PAIN INTENSITY SCALE Fig 6 MILD MODERATE SEVERE VERY WORST PAIN PAIN PAIN PAIN SEVERE X POSSIBLE PAIN PAIN 0 10 NUMERIC PAIN INTENSITY SCALE MODERATE PAIN PAIN POSSIBLE PAIN poo EUM eed NO PAIN AS BAD PAIN AS IT COULD POSSIBLE BE USED AS A GRAPHIC RATING SCALE 10 CM BASELINE IS RECOMMENDED 2A10 CM BASELINE IS RECOMMENDED FOR VAS SCALES SOURCE ACUTE PAIN MANAGEMENT GUIDELINE PANEL 1992 436 SELECT PCA PROFILE PROGRAM PATIENT PCA ALGORITHM SET INITIAL BASAL RATE 702 704 Fig 7 706 SET INITIAL BOLUS AMOUNT 714 716 U S Patent May 15 2001 Sheet 7 of 7 US 6 231 560 1 530 N OFF CONTROL 532 NO OFF KEY PRESSED OK FOR POWER OFF NO INTERMITTENT MODE MORE DOSES YES TURN POWER OFF 540 STEALTH MODE Fig 8 US 6 231 560 B1 1 METHOD AND APPARATUS FOR AUTOMATICALLY CONTROLLING THE LEVEL OF MEDICATION BACKGROUND OF THE INVENTION The present invention is directed to a method and appa ratus for automatically adjus2. Ash et al 73 861 05 OTHER PUBLICATIONS 5 002 055 3 1991 Merki et al VM 5 038 800 8 1991 128 904 Literature of I Flow Corporation advertising its Vivus 4000 5 069 668 12 1991 Boydman Infusion System 5 078 683 1 1992 Sancoff et al 604 67 One page article by Jerry Hirsch entitled Portable IV Frees 5 100 380 3 1992 Epstein et al 5 109 849 5 1992 Goodman et al 5 115 133 5 1992 Knudson A 5116312 5 1992 Blankenship et al 604 66 Bedder et al Cost Analysis of Two Implantable Narcotic 5 137 023 8 1992 Mendelson et al 128 633 Delivery Systems Journal of Pain and Symptom Manage 5 152 296 10 1992 Simons anan 128 670 ment vol 6 No 6 Aug 1991 pp 368 373 5 153 827 10 1992 Coutr et al 364 413 02 Peter Lord Hossein Allami Mark Davis Raul Dias Patrice 5 155 603 10 1992 Altmayer et al 364 550 Heck and Robert Fischell 66 71 from book chapter 5 165 874 11 1992 Sancoff et al 417 474 entitled MiniMed Technologies Programmable Implantable 5 167 235 12 1992 Seacord eal i sene 128 664 Infusion System describing clinical trials from Nov 1986 5 191 891 3 1993 Righter 128 710 IMED Status Infusion Management System 6 page 5 207 642 5 1993 Orkin et al 604 65 2 5 213 099 5 1993 Tripp Jr 128 633 brochure IMED Corporation San Diego CA no date listed 5 226 425 7 993 Rig
3. a liquid medicant in accordance with the infusion mode selected at one of steps 418 422 426 430 434 and the infusion parameters entered at one of steps 420 424 428 432 436 The pump 10 remains in the run mode 460 until the hold key is pressed as determined at step 462 Upon the occurrence of an alarm condition an alarm is reported at step 464 At step 462 if the hold key is pressed the infusion is stopped at step 466 and the pump 10 waits for the run key to be pressed at step 468 or the on off switch to be turned off at step 470 10 15 20 25 30 35 40 45 50 55 60 65 8 Summarizing the operation described above if the pump is to be utilized in lockout mode a caregiver turns the pump on programs the desired infusion mode at one of steps 420 424 428 432 436 and then turns the pump off The programmed infusion parameters will be retained in the nonvolatile memory 208 The caregiver would then turn the pump back on press the No key in response to the Programmable prompt at step 414 enter the lockout information at step 416 and then turn the pump off again When the patient subsequently turned on the pump to perform the infusion after a cassette 12 is primed with the liquid to be infused and inserted into the pump the program would proceed from step 412 directly to the ready to run step 410 which would prevent the patient from altering the infusion parameters If the lockout mo
4. and the backlight 220 Both the RAM 208 and the real time clock 210 are connected to a battery 214 which supplies power to them only in the absence of system power generated by a second battery 282 Since it is always powered the RAM 208 is a non volatile memory The controller 200 which may be a conventional micro controller such as an 80C196KB commercially available from Intel Corporation controls an audible alarm generator 230 via a line 232 the LED s 20 via a line 234 and a pump motor signal amplifier circuit 236 via a line 238 The pump motor signal amplifier circuit 236 is connected to drive the pump motor 51 which drives the rotary pump wheel During normal operation the controller 200 also sends a periodic signal to a conventional watchdog timer 250 via a line 252 If the controller 200 should fail to transmit the periodic signal to the watchdog timer 250 which would indicate failure or malfunction of the controller 200 the watchdog timer 250 transmits a signal via a line 260 to cause the alarm 230 to sound transmits a signal via a line 262 to cause the red LED to be illuminated and transmits a signal via a line 264 to the amplifier circuit 236 to cause the pump motor 51 to stop The pump 10 has a number of sensors which sense various conditions relating to the operation of the pump These sensors include an input pressure sensor 270 for detecting the liquid pressure within the flexible tube 40 at a point upstream of the rot
5. page Primary Examiner John D Yasko 74 Attorney Agent or Firm NWallenstein amp Wagner Ltd 57 ABSTRACT A method and apparatus which captures relevant informa tion pertaining to a patient s physiological conditions auto matically adjusts the amount of medication to optimize the treatment of pain and improve the patient s quality of life is described 18 Claims 7 Drawing Sheets US 6 231 560 1 Page 2 U S PATENT DOCUMENTS 5 317 506 5 1994 Coutr et al sse 364 413 5 338 157 8 1994 Blomquist 417 2 3 910 257 10 1975 Fletcher et al 128 21 5 361 758 11 1994 Hall et al 128 633 4 173 971 11 1979 KAZ eter 128 702 5 368 562 11 1994 Blomquist et 604 65 4 392 849 7 1983 Petre et al 5 376 070 12 1994 Purvis et al sse 604 31 4 413 314 11 1983 Slater et 364 188 5 378 231 1 1995 Johnson et al ee 604 67 4 449 538 5 1984 Corbitt et al 128 760 5 395 321 3 1995 Kawahara et 604 67 4 531 527 7 1985 Reinhold Jr et al 128 696 5 395 329 3 1995 Fleitschhackor et al 604 95 4 551 133 11 1985 Zegeers de Bey et al 5 400 246 3 1995 Wilson et al 364 146 4 561 443 12 1985 Hogrefe et al 128 419 PG 5 412 400 5 1995 Takahara et al 345 119 4 586 260 5 1986 Baxter
6. pain level side effects and function impairment Pain level can be determined using either of two methods or by a combination of the two methods In a first method the programmable infusion pump stores the number of bolus requests by the patient and whether or not they resulted in delivery of a bolus over a prescribed period of time If the patient makes a significant number of bolus requests over the maximum permitted in a short period of time this is used as an indication that the patient s pain level is high Asecond method of determining pain level is to query the patient directly and evaluate the patient s responses A combination of both methods can also be used Side effect information can be determined in either of two ways or by using a combination of the two In the first method the patient is asked various questions about specific side effects In a second method if the patient is in a hospital or other facility with a caregiver the caregiver records the patient s responses to inquiries about side effects on the patient s chart The caregiver may also record his observa tions about the patient s side effects onto the patient s chart Data recorded on the patient s chart can later be input to the programmable infusion pump A combination of both meth ods can also be used Similarly information regarding impairment of patient functionality can be input by the patient in response to specific queries prompted by th
7. pertaining to the amount of medication administered to the patient over a predetermined period of time 3 The method of claim 1 wherein the controlling admin istration of the patient s medication includes modification of a basal delivery rate a bolus dose and a number of bolus allowed within a certain time frame 4 The method of claim 1 wherein the step of obtaining information pertaining to the patient s condition further comprises storing the number of bolus requests made by the patient which exceed the maximum number of permitted boluses 5 The method of claim 1 wherein the obtaining infor mation pertaining to the patient s condition further comprise the steps of querying the patient regarding the patient s pain level side effects and impairment of functionalities 6 The method of claim 1 wherein the step of obtaining information pertaining to the patient s condition further comprises the step of providing an evaluation of the patient s side effects 7 The method of claim 1 wherein the step of obtaining information pertaining to the patient s condition further comprises the step of providing an evaluation of the patient s impairment of functionalities 8 A routine for operating an infusion pump to automati cally control the level of a patient s medication the infusion pump comprising a controller for executing the routine and a memory for storing the routine responsive to a request for an evaluation of
8. the pump is in the run mode at step 460 While in the run mode the pump controller 200 periodically checks to see if the patient has initiated a request through bolus cord 15 and bolus button 17 applied to bolus request switch 332 at step 180 If the answer is no the pump controller 200 checks if a PCA time has expired The pump may be programmed to check to see if the PCA programmed values should be modified on a periodic basis say every hour at step 182 If the answer is no the routine loops back to step 460 If the answer to step 180 or step 182 is yes the routine branches to block 186 the PCA modification routine In this preferred routine the patient is queried at a step 188 on pain level side effects and function impairment Data is stored for use by the patient algorithm in evaluating whether or not the PCA programmed values should be changed At step 190 the routine also checks stored historical values such as number of successful bolus requests over time At step 192 the routine processes the data according the patient algorithm and at step 194 modifies the PCA programmed values and returns to the Run Mode The invention allows the pump to automatically adjust basal rate and or bolus rate to alleviate patient pain in the absence of the caregiver s intervention The invention also adjusts the basal rate and quantity of boluses to reduce side effects and restore patient functionalities improving the patient s overall quali
9. The time at which the infusion data is recorded which is determined by the real time clock 210 is also stored along with the infusion data EVENT Power On Program Run Hold Restart Rate Changes Alarms Infusion Complete Malfunctions Resume Maintenance Date Patient ID Serial No Language Change Lockout Pressure Select Bolus Request Titration Power Off Version No TABLE 1 DATA RECORDED Date and Time Infusion parameters See Table 2 Infusion parameters See Table 2 Total Volume Infused Time of Restart Total Volume Infused Rate Volume Total Volume Infused Alarm Type Total Volume Infused Total Volume Infused Malfunction Type Infusion parameters See Table 2 Date Patient ID Number Serial Number New Language Modes Locked Out New Pressure Setting Given Not Given Bolus Amount New Parameters Time of Power Off Software Version Number Referring to Table 1 when the power to the infusion pump 10 is turned on the date and time of the power turn on is recorded When the pump is completely programmed pur suant to one of steps 420 424 428 432 or 436 FIG 3 the programmed infusion parameters are stored along with the time of such storage The particular parameters that are stored depend upon which infusion mode was programmed Examples of infusion parameters that are stored for the PCA infusion mode is illustrated in Table 2 below TABLE 2 INFUSION MODE INFUSION PARAMETERS PCA Infusio
10. a United States Patent Bui et al US006231560B1 US 6 231 560 1 May 15 2001 10 Patent No 45 Date of Patent 54 METHOD AND APPARATUS FOR AUTOMATICALLY CONTROLLING THE LEVEL OF MEDICATION 75 Inventors Tuan Bui Green Oaks Doron Levitas Chicago Stephen L Axel Deerfield all of IL US 73 Assignee Baxter International Inc Deerfield IL US Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 U S C 154 b by 0 days 21 Appl No 09 248 492 22 Filed Feb 10 1999 51 Tint Cl iicet A61M 25 00 52 US Cl a Rte 604 500 604 503 604 66 58 Field of Search 604 65 66 67 604 30 31 131 151 500 503 417 2 53 63 56 References Cited U S PATENT DOCUMENTS 3 739 943 6 1973 Wilhelmson et al 222 59 3 858 574 1 1975 Page sene 128 205 T List continued on next page FOREIGN PATENT DOCUMENTS WO 98 19734 5 998 WO OTHER PUBLICATIONS McMorris J L Kelleway B Tapadia and E L Dohm ann Are Process Control Rooms Obsolete taken from Control Engineering pp 42 47 Jul 1971 Abbott Laboratories The Blue Line System Lifecare copy right 1990 L C Sheppard Computer Based Clinical Systems Auto mation and Integration taken from 39th ACEMB Sep 13 16 1986 pp 73 75 Block Medical Growing With Home Infusion Therapy taken from Invivo The Business an
11. ary pump wheel and an output pressure sensor 272 for detecting the liquid pressure within the flexible tube 40 at a point downstream of the rotary pump wheel The input pressure sensor 270 generates an analog signal indicative of the input pressure which is transmitted to the A D converter 200A via a line 274 The output pressure sensor 272 generates an analog signal indicative of the output pressure which is transmitted to the A D con verter 200A via a line 276 Each of the pressure sensors 270 272 which detect occlusions with the flexible tube 40 or the tubing 52 54 connected thereto may be provided in the form of a strain gauge or beam not show which is in contact with the exterior of the flexible tube 40 and a high gain amplifier not shown connected to the strain beam The pressure sensors 270 272 are connected to and receive power from a power switch 280 which is connected to a battery 282 through a system power switch 284 a voltage regulator 286 and a system power line 287 The system power switch 284 selectively supplies power from the battery 282 to the voltage regulator 286 based on the state of a pump on off switch 288 connected to the system power switch 284 The power switch 280 is controlled by the controller 200 via the bus 212 the I O interface 204A and a line 294 which interconnects the I O interface 204A and the power switch 280 The pump 10 has an air in line sensor 300 which may be provided in the form of a
12. centage of successful bolus request as discussed below b level of side effect including the frequency and intensity of vomiting and or constipation the restoration of physical function such as the limb movement and d the effective time when the algorithm becomes active The effective time is required to ensure that the system has adequate time to capture relevant information about the patient pain level side effect and the restoration of bodily functions One embodiment of a patient algorithm for controlling basal rate and bolus dose is shown in Table 3 and Table 4 below 10 15 20 30 35 40 45 50 60 65 12 TABLE 3 Input of Output Successful Restoration Change Change Bolus Side of to Basal to Bolus Request Effects Function Rate Dose 100 No No 30 0 100 No Yes 30 20 100 Yes No 30 0 100 Yes Yes 50 20 50 No No 10 20 50 No Yes 20 20 50 Yes No 0 10 50 Yes Yes 0 20 TABLE 4 Input Output Restoration Change Change Pain Side of to Basal to Bolus Level Effects Function Rate Dose 2 No No 30 0 2 No Yes 30 20 2 Yes No 30 0 2 Yes Yes 50 20 10 No No 10 20 10 No Yes 20 20 10 Yes No 0 10 10 Yes Yes 0 20 Other values for increasing or decreasing the basal rate may be used depending on the particular pain medication and other factors Capturing Pain Level Data Table 3 requires input on Percent of Successful Bolus Request Side Effects and Restoration of Function As d
13. conventional piezoelectric trans mitter and receiver not shown coupled to a sensing circuit not shown to detect the presence of any significant air bubbles within the flexible tube 40 The air in line sensor 300 receives power from a power switch 302 which is connected to the system power line 287 and controlled by the controller 200 via a line 304 connected to the I O interface 204a 10 15 20 25 30 35 40 45 50 55 60 65 6 The pump 10 has a shaft encoder sensor 308 and a Hall effect sensor 310 which receive power from a power switch 312 coupled to the system power line 287 and controlled by the controller 200 via a line 314 The shaft encoder sensor 308 which is disposed on the shaft of the motor 51 may be a two phase motion sensing encoder which provides two signal outputs to the controller 200 The rotational speed of the motor 51 and its direction of rotation are determined by the controller 200 based upon the rate and phase relationship between the two signal outputs The Hall effect sensor 310 is disposed adjacent the rotary pump wheel and detects magnetic encoding on the pump wheel for detecting rotation of the wheel A cassette sensor 320 which is also connected to the power switch 312 detects the type of cassette which is inserted into the pump 10 Referring to FIG 2 the ambient light sensor 18 is connected to a power switch 326 which is controlled by the controller 200 via a line 328 from
14. d Medicine Report Apr 1991 pp 7 9 TEEE 488 and VXIbus Control Data Acquisition and Analysis the Most Choices select pages taken from National Instruments Application Software Products and Application Software Overview 1991 17 pages LabView 2 User Manual Chapter 2 The Front Panel taken from National Instruments Corporation Jan 1990 pp 1 36 J C Crone Jaromir Belic and Roger W Jelliffe M D A Programmable Infusion Pump Controller taken from 30th Annual Conference on Engineering in Medicine and Biol ogy Nov 5 9 1977 A 35827 through A 35837 Selective portions of Chapter 9 of Mayhew Principles and Guidelines In Software User Interface Design Prentice Hall PTR Englewood Cliffs New Jerssey 1992 Electronic s Article of Feb 1990 by Jack Shandle entitled Who Will Dominate the Desktop in the 90s 48 50 Chapter 5 entitled Direct Manipulation from Shneiderman Designing the User Interface Strategies for Effective Human Computer Interaction Addison Wesley Publish ing Company Second Edition 1992 reprinted with cor rections 1993 Literature of Baxter s MultiPlex Series 100 Fluid Man agement System 2 pp no date listed Literature of Baxter Introducing MultiPlex Series 100 Fluid Management System copyright 1988 Literature describing Baxter s Flo Gard amp 6201 Volumetric Infusion Pump copyright 1992 List continued on next
15. de was not utilized the caregiver or the patient could turn the pump on program the desired infusion mode and then press the Run key to start the infusion without every turning the pump off Pump Operating System A flowchart of the operating system 500 of the infusion pump 10 is illustrated in FIG 4 The operating system 500 determines how the operations and tasks shown in the flowchart of FIG 3 are performed Referring to FIG 4 if the pump is not operating in the run mode 460 as determined at step 502 the program branches to step 504 where any of the processing tasks of steps 402 436 including called subroutines of FIG 3 may be performed As described above these tasks relate to the initial programming of the infusion pump 10 and are user interactive When there are no more of such tasks to be performed for example when the user has paused during the programming of the pump or has completed the pump programming the program branches to step 506 where the controller 200 is placed in its idle mode described above via a software command The controller 200 exits the idle mode upon the generation of an interrupt that is generated at step 508 The interrupt is periodically generated by the controller 200 for example every 20 milliseconds Thus when the pump is not in the run mode 460 the program cycles through steps 502 508 where it alternately performs at step 504 one or more of the processing tasks shown at steps 402 436
16. e display 16 whether the previous infusion should be resumed If the caregiver answers yes via the keyboard 14 the program branches to a ready to run step 410 If the previous infusion is not to be resumed the program branches to step 412 The infusion pump 10 has a lockout mode in which the patient may be prevented from programming the infusion parameters such as the volume to be infused or the rate of infusion For example the pump 10 could be programmed by a caregiver to deliver a particular infusion having a particular flow profile flow rate and volume to be infused After programming that infusion the caregiver could place the pump in lockout mode which would prevent the patient from changing any of the infusion parameters At step 412 if the pump 10 has been previously placed in lockout mode the program branches directly to the ready to run step 410 bypassing all programming steps At step 412 if the pump is not in lockout mode the program branches to step 414 at which point the program prompts the caregiver via the display 16 to input whether the patient should be allowed to program the pump during the subsequent infusion If the pump is not to be US 6 231 560 B1 7 programmable the program branches to step 416 where a lockout sequence is performed by requesting the caregiver to input which infusion modes should be locked out If the pump is to be programmable by the patient the program bypasses step 416 The i
17. e infusion pump or by a caregiver or by a combination of both After completion of inputting all data the data is pro cessed by the algorithm and the patient s PCA medication rate is conformed to the algorithm or adjusted if indicated by the algorithm In an alternative embodiment of the invention if the patient s vital signs are being monitored they can be used to provide data regarding the side effects and patient function alities Vital sign data can be input to the programmable infusion pump via a data port processed by the algorithm and the patient s PCA medication adjusted These and other features and advantages of the present invention will be apparent to those of ordinary skill in the art in view of the detailed description of the preferred embodiment which is made with reference to the drawings a brief description of which is provided below BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a perspective view of an infusion pump embody ing the present invention and a cassette which is insertable into the pump FIG 1A is a block diagram showing the connection of the infusion pump of FIG 1 to a patient FIG 2 is a block diagram of the electronic and electrical components of the infusion pump shown in FIG 1 FIG 3 is a flowchart of the overall operation of the infusion pump shown in FIG 1 FIG 4 is a flowchart of the operating system used by the infusion pump shown in FIG 1 FIG 5 is a flowchart of the operat
18. escribed below Percent of Successful Bolus Request data is stored by the pump along with other pump information This data can be accessed from memory Percent of Suc cessful Bolus Request information is used as an indirect measure of pain level If the patient requests bolus requests after the maximum number has already been administered this is an indication that the patient is in pain and needs either a higher basal rate higher bolus dose or greater number of bolus doses or a combination thereof Alternatively pain level information can be determined by querying the patient directly For example the patient can be queried at specific intervals or whenever the patient requests a bolus dose about pain level using a pain scale Every hour the pump prompts the patient to enter a pain scale into the pump based on a scale of from 0 to 10 with 10 being the highest level of pain Instead of the 0 to 10 pain scale an alternate pain scale suggested by the Acute Pain Management Guideline Panel is shown in FIG 6 The information is stored in pump memory for use by the PCA mode modification routine An attending caregiver may also ask the patient about pain level at regular or other intervals and enter the information into the patient s chart for later input into the pump or directly into the pump Capturing Data on Side Effects Information for patient side effects is preferably acquired by prompting the patient to input responses to a se
19. et 33 125 C 5 423 748 6 1995 Uhala 4 624 661 11 1986 Arimond s 604 151 5 429 602 7 1995 Hauser sseeee 604 65 4 676 776 6 1987 Howson 604 31 5 469 855 11 1995 Pompei et al 128 664 4 696 671 9 1987 Epstein et al 604 67 5 482 446 1 1996 Williamson et al 2 417 474 4 731 051 3 1988 Fischell 606 67 5 485 408 1 1996 Blomquist 364 578 4 756 706 7 1988 Kerns et al 604 66 5 509 422 4 1996 Fukami 128 670 4 797 840 1 1989 Fraden see 364 557 5 522 396 6 1996 Langer et 128 696 4 803 625 2 1989 Fu et al s 364 413 03 5 544 651 8 1996 128 633 4 810 243 3 1989 Howson 604 31 5 558 638 9 1996 Evers et al 604 66 4 828 545 5 1989 Epstein et al 604 66 5 573 506 11 1996 Vasko 604 65 4 850 972 7 1989 Schulman et al 604 151 5 582 593 12 1996 Hultman aaa 604 65 4 865 584 9 1989 Epstein et al 604 67 5 643 212 7 997 Coutr et al 4 901 221 2 1990 Kodosky et al 364 200 5 681 285 10 1997 Ford et al sss 604 151 4 925 444 5 1990 Orkin et al 604 80 5 840 026 11 1998 Uber et 604 66 X 4 933 843 6 1990 Scheller et al 364 413 01 5 935 099 8 1999 Peterson et al see 604 65 4 942 514 7 990 Miyagaki et al 364 190 6 010 483 1 2000 Spencer 4 952 928 8 1990 Carroll et al 340 825 54 4 995 268 2 4991
20. hter 128 710 James D Foley and Andries Van Dam Fundamentals of 5 230 623 7 1993 Guthrie et al 433 72 Interactive Computer Graphics selected pages from Chap 5 256 157 10 1993 Samiotes et al 604 246 ters 1 and 2 Addison Wesley Publishing Company 1982 5 291 190 3 1994 Scarola et al 340 825 06 reprinted with corrections 1983 5 295 062 3 1994 Fukushima 364 188 5 297 554 3 1994 Glynn et al 128 665 cited by examiner 604 67 patients printed in The Orange County Register D section 128 633 Nov 21 1991 250 341 U S Patent May 15 2001 Sheet 1 of 7 US 6 231 560 1 15 17 bas T 13 U S Patent May 15 2001 Sheet 2 of 7 US 6 231 560 1 contROLLER 200 U S Patent May 15 2001 Sheet 3 of 7 US 6 231 560 1 400 402 E 404 maa 2 e ANY REMAINING VOL OR TIME 41 4 0 PROGRAMMABLE YES DO LOCKOUT SEQUENCE 464 410 460 Fi9 3 U S Patent May 15 2001 Sheet 4 of 7 US 6 231 560 1 Nw 502 lt gt 510 STEALTH MODE PERFORM PROCESSING TASKS 550 PERFORM PROCESSING TASKS WITHIN 30 MINUTES OF NEXT DOSE 552 STROBE WATCHDOG OK FOR SLEEP IDLE MODE YES AUDI TURN OFF POWER TO SENSORS BEEPS 522 SLEEP MODE START CLOCKS 524 9 4 508 U S Patent May 15 2001 Sheet 5 of 7 US 6 231
21. in FIG 3 and is idled at step 506 to conserve battery power Under certain conditions the pump may operate in the sleep mode described above The pump may operate in the sleep mode when it is in the run mode 460 FIG 3 and is pumping below a relatively low infusion rate threshold such as five milliliters hour To deliver such a low infusion rate the motor 51 is not activated continuously but is instead turned on periodically the motor 51 has a minimum rate at which it must be driven or else it will stall to deliver a relatively small volume of liquid medicant 50 microliters for example and then is turned off It is when the motor 51 is turned off when the controller 200 is placed in the sleep mode When the programmed infusion rate is below the threshold the fre quency with which the motor turns on and off is determined by the programmed infusion rate If the programmed infu sion rate is above the threshold the motor 51 will pump continuously Referring to FIG 4 at step 510 if the pump is not in a stealth mode described below the program branches to a step 512 where a number of processing tasks relating to the infusion may be performed At step 514 the watchdog timer US 6 231 560 B1 9 250 is strobed and at step 516 the program determines whether the controller 200 may be placed in the sleep mode As described above the controller 200 may be placed in the sleep mode if the selected infusion rate is less than a prede
22. ion to modify the PCA programming of the infusion pump shown in FIG 1 FIG 6 shows sample pain intensity scales suggested by the Acute Pain Management Guideline Panel FIG 7 is a flowchart of the operation of the program PCA mode of the infusion pump shown in FIG 1 and 10 15 20 25 30 40 50 55 60 65 4 FIG 8 is a flowchart of the operation of an on off control routine of the infusion pump shown in FIG 1 DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings and specifically to FIGS 1 and 1A a portable infusion pump embodying the present invention is shown therein and generally identified by ref erence numeral 10 The infusion pump 10 provides liquid medicant to patient 11 via catheter 13 Bolus cord 15 is connected to pump 10 Patient 11 makes a bolus request by pressing bolus button 17 A signal from bolus button 17 travels down bolus cord 15 to bolus infusion request switch 332 see FIG 2 where the request is processed by controller 200 see FIG 2 The infusion pump 10 provides automatic adjustment of a patient s pain medication A cassette 12 is insertable into the pump 10 The portable pump 10 may be carried in a pouch or other device not shown attached to a patient so that the pump 10 may be carried wherever the patient goes The infusion pump 10 has a keypad 14 via which a user may input data and commands a selectively backlighted dot matrix or LCD display 16 f
23. is affected by pain and side effects Controlling of the amount of pain medication 1 the basalrate the bolus dose and the maximum number of bolus doses available to the patient is a delicate balance of competing requirements To increase pain relief a physician will prescribe greater medication However large doses of some pain medication can increase the side effects and can impair patient functionalities Using a pain medication may 10 15 20 30 35 40 45 50 55 60 65 2 reduce pain sufficiently to enable the patient to move about Using a level of pain medication which produces confusion detracts from the patient s mobility During acute care when the patient is in greater need of additional pain medication it is important to be able to adjust the PCA basal rate the bolus rate and the bolus amount more frequently always taking into account the effect of side effects and impairment of patient functional ities Infusion modes are programmed into the infusion pump by the caregiver or physician In a hospital or other caregiver facility a physician or caregiver can visit a patient once or twice a day to check if the programmed infusion mode dose and frequency are providing appropriate relief to the patient If the patient is receiving medication at home or away from a caregiver facility such visits may be less frequent In most of the pre programmed modes rechecking the mode dose and frequency o
24. laim 16 wherein the evaluating the patient s physiological conditions step includes evaluating the patient s pain level the patient s side effects and the patient s impairment of functionalities 18 The method of claim 16 further comprising querying the patient about his physiological conditions and storing the patient s responses
25. le beep to the user as a reminder that the next dose is a multiple of ten minutes away Thus when the intermittent infusion mode is being used and the pump is in the stealth mode the patient is given three audible warnings to reassure or warn the patient that the next dose is imminent a first warning at 30 minutes prior to the dose a second warning at 20 minutes prior to the dose and a third warning at 10 minutes prior to the dose If the next dose is not given on schedule a fourth warning is generated at the time of the dose and three additional warnings spaced 10 minutes apart are given after the time for the dose 10 15 20 25 30 35 40 45 50 55 60 65 10 Data Storage and Recording During programming and operation the infusion pump 10 automatically records in the memory 204 all significant infusion data to generate a complete historical data record which can be later retrieved from the memory 204 and used for various purposes including clinical purposes to aid in determining how effective a particular infusion therapy was and treatment purposes to confirm that the prescribed infu sion was actually delivered The infusion data recorded in the memory 204 is set forth in Table 1 below A number of events which trigger the storage of data are listed in the left hand column of Table 1 and the infusion data that is recorded upon the occurrence of each event is listed in the right hand column of Table 1
26. lustrates an off control routine 530 that is peri odically invoked to determine whether the on off switch 288 FIG 2 of the infusion pump 10 has been turned off In that case as determined at step 532 the program branches to a step 534 where it determines if it is okay to turn the pump off it is okay to turn the pump off as long as it is not in the run mode 460 If it is okay to turn the power off the program branches to a step 536 If the pump 10 is not in the intermittent mode as determined at step 536 the power is turned off If the pump is in the intermittent mode the program branches to step 538 which determines whether there are any more periodic doses infusions to be made If there are no more doses the power is turned off If there is at least one additional dose the pump 10 is placed in the stealth mode at step 540 Referring back to step 510 of FIG 4 if the pump is in the stealth mode the program branches to a step 550 which determines whether the next dose in the intermittent mode is scheduled within the next 30 minutes If not the program branches to steps 520 522 where the controller 200 is put to sleep If the next dose is within 30 minutes as determined at step 550 the program branches to step 552 where it determines whether the time until the next dose or the time after that dose if not given is a multiple of ten minutes If it is then the program branches to step 554 where the pump 10 generates an audib
27. method of automatically adjusting the medication level in patient con trol analgesia using a predetermined set of criteria which is patient specific yet provides the patient the ability to have his medication adjusted without having to contact a car egiver or physician SUMMARY OF THE INVENTION A preferred embodiment of the invention is directed to a method and apparatus which captures relevant information pertaining to pain level side effects and patient impairment and automatically adjusts the amount of medication within a pre determined level selected by the patient s physician to optimize the treatment of pain and improve the patient s quality of life Prior to prescribing pain medication to be provided via a programmable infusion pump the physician or caregiver must program the pump for the specific patient In addition to programming in the specifics of a PCA treatment by programming in basal rate maximum number of bolus doses and volume amount of each bolus dose in accordance with the preferred embodiment of the invention the program mable infusion pump includes a routine for modifying the PCA treatment The PCA modification routine stores pre US 6 231 560 B1 3 programmed values of basal rate bolus number and amounts for the specific patient which are input the by physician or caregiver The routine also includes a pain relief algorithm which modifies the PCA treatment in response to input regarding the patient s
28. n Mode Basal Infusion Rate Volume To Be Infused Delay Time Total Bag Volume Bolus Dose Amount Max No of Bolus Doses Number of Doses Dose Time Dose Volume KVO Rate When the pump enters the run mode at step 460 FIG 3 the time at which the run mode was begun along with the parameters pursuant to which the infusion is performed are stored The pump also stores the time at which the hold key US 6 231 560 B1 11 was pressed along with the total volume infused at the time the hold key was pressed The pump stores any infusion rate changes such as changes caused by switching from a continuous rate to a keep vein open KVO rate or in the intermittent mode changing from a KVO rate to a higher infusion rate the new rate and the time at which the new rate started If any alarms are generated the alarm type the time at which the alarm occurred and the total volume infused at the time of the alarm are recorded If the infusion is completed the program stores the time at which the infusion was completed along with the total volume infused If there is a malfunction the malfunction type the time at which the malfunction occurred and the total volume infused at the time of the malfunction are recorded If the infusion is resumed when the pump is turned back on after having been turned off during an infusion the time at which the infusion is resumed along with the infusion parameters are stored Upon the completion of the
29. nce or twice a day may be sufficient If the patient is in the PCA mode however the patient s condition may vary more requiring more frequent adjustment and more frequent visits by the physician or caregiver If the patient is not able to receive additional adjustments or visits from the physician or caregiver whether in the home or the hospital the patient may be in extreme pain and may not receive appropriate pain relief for many hours U S Pat No 5 643 212 to Coutre et al discloses an infusion pump management system in which the patient s physiological signs are used in a biofeedback loop The system evaluates the patient s physiological signs and sug gests alternate infusion treatment based on those signs The proposed modifications are then sent to the operator for confirmation Delivery rate changes are made by the opera tor physician or caregiver so the patient must wait until the operator can evaluate the proposed changes before the patient can receive any relief There is a need for an automatic method of adjusting the medication level in patient control analgesia taking into account the patient s pain level side effects and any impair ment of functionalities There is a need for an apparatus for automatically adjusting the medication level in response to input from a patient regarding his pain level side effects and impairment of functionalities without having to contact the caregiver or physician There is a need for a
30. nfusion pump 10 has five basic modes of infusion 1 a continuous mode in which the pump delivers a single volume at a single rate 2 an auto ramp mode in which the pump delivers liquid at a rate that gradually increases to a threshold rate stays constant at the threshold rate and then gradually decreases 3 an intermittent mode in which the pump delivers discrete liquid volumes spaced over relatively long periods of time such as a liquid volume every three hours 4 a custom mode in which the pump can be pro grammed to deliver a unique infusion rate during each of 25 different time periods and 5 a pain controlled analgesic PCA mode during which the pump will periodically infuse boluses of analgesic in response to periodic requests by the patient which requests are made via the bolus request key 332 At step 418 the pump 10 generates on the display 16 the prompt Continuous to the caregiver If the caregiver desires to use the pump in its continuous mode the caregiver answers yes via the keypad 14 and the program branches to step 420 at which the continuous mode is programmed by the caregiver by entering a number of infusion parameters such as the desired infusion rate the volume to be infused etc At step 418 if the caregiver does not want to use the continuous mode the caregiver answers No and the program branches to step 422 Steps 422 436 are generally the same as steps 418 and 420 except that the caregive
31. ontact with and applies a downward force on an upper surface 42 of a vertically movable platen 44 As shown in FIG 1 the upper surface 42 of the platen 44 is disposed within an elongated slot or aperture 43 disposed in the upper surface of the cassette housing 12 The platen 44 has a lower curved surface 46 against which the flexible tube 40 is pressed by a number of rollers disposed on a conventional rotary pump wheel not shown to effect peristaltic pumping of liquid through the tube 40 The cassette 12 has a flow stop mechanism 60 that automatically clamps the flexible tube 40 shut when the cassette 12 is not disposed in the pump 10 with the silicone tube 40 in its fully engaged position or when the pump door 30 is open This prevents an open or uncontrolled liquid path being made available between the medicant source and the patient The flow stop mechanism 60 has a housing 62 Infusion Pump Electronics Referring to FIG 2 the infusion pump 10 includes a controller 200 with a built in analog to digital A D con US 6 231 560 B1 5 verter 200A an electrically programmable read only memory EPROM 204 having a built in input output I O interface 204A a random access memory RAM 208 a real time clock 210 and the display 16 all of which are interconnected by a communications bus 212 The display 16 has a backlight 220 which is selectively activated by an enable signal generated on a line 222 interconnecting the controller 200
32. or displaying textual messages to the user a light sensor 18 for detecting the level of ambient light and a pair of light emitting diodes LED 20 a green LED for indicating the normal operation of the pump 10 and a red LED for indicating an alarm or abnormal operating condition of the pump 10 As described below the level of the light sensed by the ambient light sensor 18 is used to control when the display 16 is backlighted A data port 22 which is preferably an RS 232 port is used to download and upload data between the pump 10 and a remote controller or other device Data port 22 would be used to upload vital sign data from a vital sign monitor such as heart rate respiration rate for example A door 30 is pivotally attached to the upper portion of the infusion pump 10 via a plurality of hinges 32 An underside 33 of the door 30 which is shown in FIG 1 has a pair of slots 34 formed therein in which a pair of metal rods 35 are fixed Each of the metal rods 35 selectively engages a pair of slidable latching members not shown to retain the door 30 in the closed position during operation of the pump 10 An arcuate metal leaf spring 36 is disposed on the underside of the door 30 The two ends 37 of the leaf spring 36 are anchored by a pair of retaining elements 38 fixed to the door 30 When the cassette 12 in which a flexible silicone tube 40 is disposed is inserted into the pump 10 and the door 30 is closed the leaf spring 36 makes c
33. patient s intravenous line or to the epidural space or an interthecal space Usually the medication is delivered at a constant rate called the basal rate The physician programs the basal rate into the pump However the patient is allowed within bounds to give himself additional medication to reduce the pain level if desired This is done via a bolus cord The patient presses a button on the bolus cord and the pump delivers a small bolus of medication to the patient The maximum level of medication given in response to each press of the bolus cord button is programmed into the pump by the physician The maximum number of button presses which will result in a discharge of a bolus is also pro grammed into the pump by the physician Once the pump is programmed by the physician the patient can give himself a bolus whenever he needs it regardless of time between requests However if the patient exceeds the maximum number of boluses programmed any additional requested boluses will not be successful and will not result in the delivery of medication The physician limits the amount of medication given to the patient at any one time and over a period of time to reduce the level of side effects Some pain relief medications have highly undesirable side effects such as nausea vomiting itching and confusion cardiac and respiratory depression or in sufficient quantity may result in death Patient functionality e g mobility and awareness
34. program ming of a lockout sequence the time at which the program ming of the lockout was completed is stored along with the infusion modes that were locked out Upon the detection of a bolus request the time at which the bolus was requested is stored along with an indication whether the bolus was actually given and the amount of the bolus Patient Algorithm Prior to assigning a particular infusion pump to a patient the physician or caregiver programs in the patient s algo rithm for automatically changing his PCA dose The patient s algorithm defines the range of values for the basal dose the bolus dose the maximum amount of drug to be administered The patient algorithm can increase or reduce the amount or duration of any of the PCA elements depend ing on the patient s pain level side effects and any impair ment of the patient s functionalities The physician takes into account the patient s condition the pain medication being provided and the range of medi cation to be provided based on the patient s pain level side effects and impairment of functionality The physician deter mines the course of therapy for the individual patient by changing the patient algorithm For PCA the patient algo rithm includes a number of input parameters to control the basal rate and the bolus dose The input parameters could include a pain level which could be captured by querying the patient directly or indirectly measuring the per
35. r may be prompted for different infusion parameters depending on which of the five possible infusion modes is selected Program PCA Mode A flowchart of the operation of the Program PCA mode 436 is shown in FIG 7 In Pain Control Analgesic PCA mode the caregiver programs the patient s algorithm as provided by the physician described below a basal rate which is a continuous basic rate of drug delivery and a bolus amount which is the additional drug that can be delivered on top of or in addition to the basal rate at specific time intervals In step 702 the program prompts the caregiver to program patient algorithm In step 704 the program prompts the caregiver to program the basal rate The caregiver inputs an amount to be infused to the patient continuously After entering the desired rate e g 10 mg hr the caregiver then enters the total volume and selects Limit Med by of Dose hour The program then prompts the caregiver for the basal amount in step 706 the caregiver enters the desired value Then the program prompts the caregiver for the maximum number of boluses at step 710 After the caregiver inputs the desired number the program stores the pro grammed values at step 714 and returns to the main program at step 716 Referring back to FIG 3 after the completion of one of the steps 420 424 428 432 or 436 the program branches to the ready to run step 410 During the run mode 460 the pump 10 infuses the patient with
36. ries of specific questions For example for a patient receiving US 6 231 560 B1 13 intravenous medication the patient could be prompted to answer Yes or No to questions such as Cognitive Impairment Nausea For neuraxial medication the patient could be prompted to answer Yes or No to questions such as Motor Impairment Dizziness This information can be requested each time the patient presses the bolus cord Alternative methods of acquiring side effect data can be employed such as after a Yes response asking the patient to expand on a scale of 0 to 10 for that side effect The pump stores the results for use by the PCA mode modification routine Capturing Data on Function Impairment As with data on side effects data pertaining to the patient s function impairment can be obtained by prompting the patient to respond to a series of questions Each time the patient requests a bolus dose the pump with respond with a series of questions that the patient responds to with a Yes or No answer and optionally a rating of from 0 to 10 Examples of questions include Ability to move lower limbs Restoration of bowel motility Automatically Modifying the PCA Program FIG 5 shows the routine to modify the PCA programming of the infusion pump 10 Referring to FIG 5 the PCA programmed values can be modified in one of two methods In the first method the PCA programmed values are modi fied by a patient initiated request while
37. rols the amount of liquid medicant administered to the patient a memory storing a set of patient specific predetermined rates and amounts of liquid medicant to be adminis tered to the patient a data acquiring routine for obtaining information per taining to the patient s pain level side effects and impairment of functionalities and a control routine for processing the data pertaining to the patient s pain level the patient s side effects the patient s impairment of functionalities and a current rate and amount of liquid medicant being administered to the patient and for automatically changing the rate and amount of the liquid medicant to be administered to the patient in accordance with the set of patient specific predetermined ranges of medication 10 The infusion pump of claim 9 further wherein the memory stores data regarding the liquid medicant adminis tered to the patient over a predetermined period of time and wherein the modification routine processes the data regard ing liquid medicant administered to the patient 11 The infusion pump of claim 10 wherein the current rate and amount of liquid medicant being administered to the patient comprises a basal delivery rate a bolus dose and a number of bolus allowed within a certain time frame 10 15 20 25 30 35 40 16 12 The infusion pump of claim 11 wherein data pertain ing to the patient s pain level comprises the number of bolus reques
38. termined threshold rate There are also other condi tions which must be satisfied For example the motor 51 cannot be active an audio beep in response to a key being pressed for example cannot be active no timed functions can be active such as a timed LED illumination the backlight 220 cannot be on and the display 16 cannot be scrolling text If these conditions are satisfied the program branches to a step 520 where the power to a number of sensors is turned off and to step 522 where the controller 200 is placed in its sleep mode The controller 200 remains in the sleep mode until it is awakened by any of three occurrences 1 any key being pressed including the bolus request key 332 2 the watch dog timer timing out or 3 a one second strobe generated by the real time clock 210 In the absence of conditions 1 and 2 the controller 200 will be awakened every second by the strobe from the real time clock 210 Upon being awakened the internal clocks of the controller 200 are started at step 524 and the program branches to step 508 where it waits for the next interrupt generated by the controller 200 The infusion pump 10 also has a stealth mode relating to the intermittent infusion mode of FIG 3 In this mode the pump 10 delivers an infusion spaced at relatively large time intervals such as minutes or hours Between infusions the pump is placed in a stealth mode in which the controller 200 is put to sleep FIG 8 il
39. the I O interface 204A Signals generated by a door open sensor 330 a bolus infusion request switch 332 the keypad 14 and the data port 22 are transmitted to the controller 200 via the I O interface 204A Although not shown in FIG 2 for purposes of simplicity the controller 200 the EPROM 204 the RAM 208 and the display 16 are also connected to and receive power from the system power line 287 Overall Pump Program Operation The operation of the infusion pump 10 is controlled by a computer program stored in the EPROM 204 and executed by the controller 200 The programming of the pump is usually performed by a caregiver following a prescription described by the patient s physician In some cases the patient is allowed to alter certain parameters of the pump A flowchart of the overall operation is illustrated in FIG 3 Referring to FIG 3 when the pump 10 is turned on via the on off switch 288 at step 402 the pump is initialized and a test of the pump operation is performed The pump 10 may be turned off temporarily during an infusion in which case the pump 10 may continue the infusion when it is turned back on as described below At step 404 if there is any remaining volume of liquid to be infused by the pump or any additional time remaining for an infusion which would be the case where the pump was temporarily turned off during an infusion the program branches to step 406 where the caregiver is asked via a message displayed on th
40. the patient s current medication compris ing a set of patient specific predetermined ranges of medi cation stored in the memory a procedure for obtaining information pertaining to the patient s pain level and storing the patient s pain level information automatically a procedure for obtaining information pertaining to the patient s side effects and storing the patient s side effect information automatically a procedure for obtaining information pertaining to the patient s impairment of functionalities and storing the patient s impairment of functionalities information automatically a procedure for obtaining information pertaining to the patient s current medication US 6 231 560 B1 15 a procedure for evaluating stored information of the patient s current medication pain level side effects and impaired functionalities with the stored set of patient specific predetermined ranges of medication and a procedure for automatically modifying delivery of the patient s medication based on the evaluation 9 An infusion pump for administering a liquid medicant to a patients comprising a liquid injection device adapted to be connected to the patient a conduit connected to the liquid injection device a pumping mechanism for pumping the liquid medicant through the conduit and into the patient via the liquid injection device a controller for controlling the pumping mechanism wherein the controller cont
41. ting the medication level for a patient and more particularly to adjusting the basal rate and the bolus rate of administration in a patient control analgesia mode based on the patient s pain intensity Infusion pumps are used to automatically administer liquid medicants to patients The liquid medicant is supplied from a source of medicant and delivered to the patient via a catheter or other injection device The manner in which the liquid medicant is infused is controlled by the infusion pump which may have various modes of infusion An infusion pump typically can operate in five basic modes of infusion 1 a continuous mode in which the pump delivers a single volume at a single rate 2 an auto ramp mode in which the pump delivers liquid medicant at a rate that gradually increases to a threshold rate remains at the threshold rate for a period of time and then gradually decreases 3 an intermittent mode in which the pump delivers discrete liquid volumes spaced over relatively long periods of time such as a liquid volume every three hours 4 a custom mode in which the pump can be programmed to deliver a unique infusion rate during each of 25 different time periods and 5 a pain controlled analgesic PCA mode during which the pump will periodically infuse boluses of an analgesic in response to requests by the patient In pain control analgesia a pain relief medication or analgesic is delivered to the patient via an infusion pump into a
42. ts made by the patient which exceed the maximum number of boluses 13 The infusion pump of claim 11 wherein data pertain ing to the patient s pain level side effects and impairment of functionalities comprises data stored in response to querying the patient regarding the patient s pain level side effects and impairment of functionalities 14 The infusion pump of claim 11 wherein data pertain ing to the patient s side effects comprises data stored from an independent evaluation of the patient s side effects 15 The infusion pump of claim 11 wherein data pertain ing to the patient s impairment of functionalities comprises data stored from an independent evaluation of the patient s impairment of functionalities 16 A method for automatically controlling the level of a patient s medication administered from a programmable infusion pump comprising programming the infusion pump with a set of patient specific predetermined ranges of medication evaluating the patient s current medication and recording the patient s current medication in the infusion pump evaluating the patient s physiological conditions and recording the patient s physiological conditions in the infusion pump and controlling administration of the patient s medication based on the evaluation of the patient s current medi cation and physiological conditions as compared with the programmed predetermined ranges of medication 17 The method of c
43. ty of life Calls to the caregiver by patients in pain can be reduced reducing work load on caregivers Modifications and alternative embodiments of the inven tion will be apparent to those skilled in the art in view of the foregoing description This description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention 10 15 20 25 30 35 40 45 50 55 60 65 14 The details of the structure and method may be varied substantially without departing from the spirit of the invention and the exclusive use of all modifications which come within the scope of the appended claims is reserved What is claimed is 1 A method for automatically controlling the level of a patient s medication administered from a programmable infusion pump comprising programming the infusion pump with a medication algo rithm initiating an evaluation of the patient s medication obtaining information pertaining to the patient s condi tion obtaining information pertaining to the patient s current medication evaluating the patient s current medication and condition with the medication algorithm and controlling administration of the patient s medication based on the evaluation 2 The method of claim 1 wherein the step of obtaining information pertaining to the patient s current medication comprises storing information
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