CA1146224A - Infusion controlling apparatus and method - Google Patents

Abstract

INFUSION CONTROLLING APPARATUS AND METHOD

Abstract Portable electronic medical apparatus for controlling the flow rate of a fluid for medically treating a patient may receive flow rate information representing sequences of up to 20 flow rates and their durations from an individual and from an electronic data processor, and operate continuously without the presence of an operator for in the range of 40 hours. Upon the incorporation of an infusion pump into the apparatus, the desired regimen of treatment may be accomplished; and through a keyboard input for the apparatus, an operator may in certain respects modify a regimen which is being carried out. The apparatus may be used in a method of treatment including: coupling the apparatus to the processor; providing the apparatus with the flow rate information; decoupling the apparatus and processor; transporting the apparatus to the patient; coupling the apparatus to a supply of the fluid and regulating the flow rate of the fluid according to the information. It may be similarly used in a method including the providing of an electrical signal representative of a sequence of, e.g., at least 8 discrete fluid flow rates and their durations.
The signal may then, if desired, be independent of changes in the condition of the patient during such providing. Safety features in the apparatus include: a frequency detector for monitoring the frequency of a clocking signal for the apparatus; the selec-tive testing of output signals of the apparatus, the portable power supply for the apparatus and the frequency detector against stored predetermined standards; and the provision of warning signals to an operator to indicate divergences from such standards.
Additionally, fail safe signals for the apparatus are coupled to relay circuitry to interrupt the output of the apparatus if a central processing unit for the apparatus enters undesired modes of operation.

Description

I.~!FIISIO~l CO~lTROLLING APPARATUS A~ IETllOD

Field of the Invention 1'he invention pertains to apparatus emploved in medically treatin;; a patlent, more particularly '~
such apparatus ~hich is employed to regulate the flo~
rate oE a fluid used in treating a patient.

13ackground nd Summary of the Ir,vention The progress of r.edicine over the years may perha~s somet~hat inaccurately but usefully be thought Oc in terms of its proqress from an "art" toward a "science". The development and systematizing of infor~,lation used in treating patien~s with drugs int.avenously and throuqh inhalatior is particularly interestinq. Computer programs which provide regimens of drug trea~ment based on systematized information and charaçteristics of a particular patient have in fact provided doctors in a number of instances with the capability to approach more closely the goals of such treatment while avoiding the pitfalls and dangers (e.g.
inade~uate or toxic levels of the drug in the blood-stream~. See, e.g. R.W. Jelliffe, J. Rodman, and E.
~olb, '`Clinical Studies with Computer-Assisted L'idocaine (L) Infusion Regimens", Circulation, Vol. 54, ~o. 4, Suppl. II, p. 211, 1976; R.~. Jelliffe, F. Goicoech~a, D. Tuey, ~1. Wvman, J. Rodmall and B. Goldreyer, "An z~ ~

Improved Computer Program for Lidocaine Infusion Regimens", _linical Researc'l, Vol. 23, p. 125~, ~eGruary 1975; and P~ T. Jelliffe, "A Computer Program for Xvlocaine Infusion Regimens", Federation Proceedin~s, Vol. 32, No. 3, p. 812 Aab, 1973.
Focusing, by way of example, on the drug lidocaine and its use in the treatment of heart attack victims, an historical problem has been achieving sufficient serum levels as early as possible durins the first hours of treatment an~ then reaching and main-taining a target serum level. At the same time, one of course wishes to avoid serum levels which are toxic or which approach toxiciry. These goals are of course contradictor~ in nature, particularly in liqht of the proL,lein of obtaining a uniform distribution of the drug in the bloodstream a..d the related delayed reacticn of a patient tc a change in the infusion rate. As indi-cated by the above references, compu.er programs are of significant value in balancing such aoals. Further, in response to the requirements which mav be called fGr by such programs, and also as a ~eneral matter, a capab~lity to regulate a rate of flow of a drug to a patient in a somewhat automatic, systematic and safe fashlon is of great interest to medical practitioners. `
This is particularly true if a capability to incorpor-ate a large number of frequent changes, or to "fine tune", is included.
The opportunity to free medical personnel for _rher tasks to the-e~tent that such drug treat-ment regimens can be mechanized has been some~hat recogni~ed. For example, apparatus has been devel-oped which employs a chart coated with a conductiv~

zz~

material and a probe which ~ill follow a curve scratched along the surface oE the chart when the chart is placed on a rotating drum to move the curve past the pro~e.
This apparatus may then be used in coniunction with ~e.g. ~n anesthesia pump. See catalog and specification material related to Qan, Inc. Dose Regulated Anesthesia Pump ',`lar~ II) and Research, Inc. ~odel 55~ Data ~rak Programmer incorporated in such pump; and H.J. Lowe, Ch. 7--"Automated Programmed Anesthesia", in Dose-Regulated Penthane (~1ethoxyflurane) Anesthesia, Abbott Laboratories, 1972. The scratched curve creates two isol~ted planes along the chart which become electrically ener~1ized with oppositely phased ~C voltages when the chart is placed on the drum. The probe then see:~s ~he zero potential scratched curve, and as it moves along the curve is ~sed to mechanically adjust a potentiometer and ~nus affect an electrical signal.
A related hut quite different approach em- r-ploys the incorporation of the control of in-house, ;~
e.g. in hospitals, devices tG control fluid flow rates, such devicec themselves under the control of in-house compu~ers. Such in-house systems are particularly L
adapted to a so-called closed loop operation involving !~
evaluation by the computer of the condition of the ;:
patient being treated during such treatment, and adjust-ment under the control of the computer in liqht of such condition. Exemplary of this approach is a computer controlled intensive care unit at the Univer-sity of Alabama Medical Center.
The present invention is directed to an appar-atus and method for controlling the flo~ rate of a fluid for medically treatin~ a patient, incorporating types and degrees of flexibility and safety of great interest and value to medicdl practitioners.

2z4 . I

~, -1 Such a~paratus has the flexihility to con~rolthe flow rate of a fluid according to fluid flow rate 3 information available from an individual, and available frolr a source electronic data processor, the available information representing sequences of flow rates and their durations. Thus, in accordance with the invention, such apparatus includes: operator input means for receiving flow rate information provided by the individ-~' ual and for providing electrical signals representative of the inform~ation; source processor input means for receiving flow rate information provided by the source proc~ssor and for providing electrical signals represen-tati~e of the information; and electronic data processina means for receiving such el~ctrical signals, for ' providing and storing storaqe signals representati~e of such signals and for providing flow rate output signals, representati~e of the storaqe signals, for regulating ! the flow rate of the fluid. Regulator means may then be incorporated into the apparatus for regulating the ! . low rate of the fluid in response to the output ~' signals. Similarly, the source processor input means may include means for electrically coupling the appa;a.us to and decoupling the apparatus from the source electronic data processor; and the electronic data ~rocessing means may include a portable power supply having a power capacity sufficient to power the apæa~tus.
Along related lines, and in accordance with the invention, a method of regulating the flow rate of a fluid for medically treating a patient may then include the steps o.: coupling portable electronic control apparatus to an electronic information source

2~

having inEormation representative of a sequence of fluid flow rates and their durations; providing the control apparatus with the sequence information;
decoupling the control apparatus and source; trans-~porting the control apparatus to the vicinity of apatient requiring medical treatment with the fluid;
coupling the apparatus to a supply of the fluid; and regulatina the flow rate of the fluid according to the sequence information. The method may then include the additional step of modifyir.g the regulating to differ from the sequence wnile regulatina according to the sequence, f~r example under the control of an operator 1~ of the apparatus.
P~eturning tO the apparatus, in accordance with other, including certain flexibility, features of the invention, medical apparatus for controlling the flow rate of a fluid for medically treating a patient includes: storage means for storing electrical signals representative of a sequence of at least 8 discrete ~.
flow rates for the fluid and their durations; and e~ecution ~eans for automatically providing output signals corresonding to the sequence in response to the stored signals, upon initiation of such pro~riding by the execution means; and a portable power sapply having a power capacity sufficient to power the apparatus. It is noted that the discreteness of the flo~ rates is indicative of digital apparatus and the ad~antages thereof, while the number of fluid flow rates is indicative of a capaoility to approach the advantayes '.
of continuous variation, simple or complex, in a ~`
digitai environment. It is additionally noted that the human mind is not psycholoaically adapted to readily remember more than 6 or 7 items. This is evidenced, for example, by telephone numbers. Also, a number of flow rates yreater than 6, 7 or 8, e.g. 12 or 20, ~ay of course ~e required for complex cases. Related to sucn features, and in accordance with method aspects of ~the invention, a method of regulating the flow rate of a fluid for medically treating a patient includes the step of providing an electrical signal representative of a sequence of at least 8 discrete fluid flow rates and their durations. The signal may then, for example, be independent of the condition oE the patient; and the ~`
duration of the sequence may, for example, be for at least 8 hours.
In accordance with yet other apparatus aspects, includinq safety features, of the inventicn, medical apparatus for controlling the flow rate of a fluid for medically treatin? a patient includes:
storaae means for storing electrical signals represen-tative of a sequence of discrete flow rates for the fluid and their durations; and execution means for providing output signals corresponding to the sequence in response to the storage signals; wherein the execu-tion means includes means for providing a clocking signal for the execution means, and a frequency detector for providing an output signal representative of the frequency of the clocking signal. The execution means may then further include means for selectively testina the output signals of the execution means and frequency detector against predetermined standards and for providing a warning si~nal in the event of a divergence from such standards. In accordance with yet other appa~atus aspects, including other safety features, such medical apparatus includes: storage means, as above; and execution means for providing output signals in response to the storage signals, as above, and for further providing at least one control signal for indicating an undesired mode of operation for the execution means; wherein the execution means includes means for interrupting the provision of the output signals in response to an indication of an undesired mode of operation by the control signal.
In an embodiment, output signals for transmittal to an infusion pump, of a power supply, and of a frequency detector monitoring a clocking signal frequency, may be selectively tested against predetermined standards, and provision is made for warning signals to an operator, controlled by the outcome of such testing.
Brief Description of the Drawings In the drawings, exemplary embodiments demonstrating the various objectives and features hereof are set forth as follows:
Figure 1 is a block diagram showing medical apparatus in accordance with the invention in the context of a system incorporating the regulated provision of a fluid for medically treating a patient.
Figure 2 is an illustrative timing diagram for the apparatus of Fig. 1.
Description of Illustrative Embodiments As indicated above, detailed illustrative apparatus and method embodiments of the invention are disclosed herein.
However, embodiments may be constructed and performed in accor-dance with various forms and acts, some of which may be rather different from the disclosed illustrative embodiments. Conse-quently, the specific structural, functional and performance details disclosed herein are merely representative, yet in that regard are deemed to provide the best embodiments for purposes of disclosure and to provide a basis for the claims herein which define the scope of the present invention.
In Fig. 1, apparatus 10, in the context of a system, is shown which is particularly adapted to receive lnformation representative of sequences of fluid flow rates, such infor-mation be~ng provided by an individual through a keyboard K
incorporated into the apparatus and/or by an electronic data processor P through a terminal T for the processor;
to store digital signals representative of such sequence information in a memory M; and to provide generally analog output signals, representative of such sequence information which may be stored, for driving an infusion pump IP through output lines 12. The infusion pump IP in turn mechanically controls the flow rate of a fluid from a s~ringe-type, storage-drive 13 for a supply of fluid 14 which i5 intra-venously infused into the bloodstream of a patient PT
through a tube 16 and a needle 20 penetrating the bloodstream of the patient. A Harvard Model 2620 infusion pump, for example, is particularly well adapted to implementing the function of the infusion pump IP of Fig. 1.
An input interface 22 receives the flow rate information provided by the individual through the keyboard K and provides digital electrical signals representative of the information to the memory M. The flow rate infor-mation so provided is received and stored in a random-access portion 23 of the memory M (RAM). Along somewhat similar lines, flow rate information provided by the electronic data processor, which in turn is provided by the processor terminal T, is received for input into the apparatus 10 by a terminal-CPU interface 24 which provides digital electrical signals representative of such information to a central processing unit CPU, which places the flow rate information (and other types where necessary) in a form compatible for the memory M and for operational use by the apparatus 10, before providing the flow rate information (in digital form) to- the R~M
23 for storage.
While the apparatus 10 is operating to provide its output to the infusion pump IP, various safety functions are carried out by the apparatus. Such functions include the selective testing of the output of the apparatus, of a power signal Vl for the apparatus from a portable power supply 26, and of the output signal of a frequency detector 28, representative of the frequency of a clocking unit 30 for the apparatus. The selective testing is carried out by the selection of the signal to be tested by an analog device selector 31 according to signal-represented information from the memory M, and the conversion of the generally analog signal to a digital representation for comparison with digitally-represented standards for such signals stored in the memory. Warning signals, implemented alphanumerically in a display panel DP, through display panel warning lights 32 and 34 and through a display panel sound alarm 36 (for warnings related to these and other functions), are employed to warn an operator of divergences from such standards. (As is indicated in Fig. 1, the warning lights, sound alarm and a visual display, all addressed in detail subsequentlyr are in a common display panel). In addition, the absence of a high pulse along either of the control signals FSl and FS2, over an unexpectedly long interval, such absence being in certain circumstances indicative of an undesired mode of operation for the central processing unit CPU, will cause a relay associated with the signal in fail safe relay circuitry 40 to open and interrupt the pro-vision of the output of the apparatus to the infusion pump IP.

~, Typically, either the electronic data proces-sor P or the keyboard ~ is used to provide a sequence of up to 2~ flot~ rates and their durations. In this regard, a conventional program is incorporated in a first read-only portion 42 of the memory ~1 (RO:'l(A)) to inte-act with the electronic data ~rocessor P through the central processing unit CPU, terminal-CP~ interface 24 and processor terminal T. A conventional, monitor program, e.g. implemented on a 512 word read-only memory portion, having 8-bit words, may be conveniently used in the apparatus, for implementing the interaction.
Also, the communication betweeen the electronic da.a processor P and the processGr terminal T might be conveniently implemented over a telephone line, the terminal then having an acoustic to digital transducer t to permit intercommunication between the electronic data processor P and the apparatus. The terminal-CPU
interface 24 then may be readily implemented using the well ~nown RS~232C communication protocol in the interface 24. ~ith a view toward fle~ibility and to~Jard compatibility with the above, in the system of Fig. 1 it may then be assumed that the information received by the interface 24 and provided to the eentral processing unit CP~ of the interface is in the American Standard Code for Information Interchange (ASCLI ~, and that such information is converted by the central processiny unit to a form for storage in the RAM 23. In the system of ~ig. 1, this form is, along conventional lines, assumed to be standard binary eoded decimal (in some cases, e.g. a siynal-represented flow rate about to be used, converted to standard binary by the central processing unit and also stored in tnat form for immediate use) , and a RA~ 23 having a capacity of 256 8-bit ~/ords is deemed adequate for the ~L~

20 flow rates and durations and for other signals which the RAM 23 is employed to store.
- A second read-only portion 44 of the memory M
(ROM~B)) is employed to store another conventionall-implementbd program for controlling the interaction of the apparatus with, ultimately, the individual who might provide sequence information, and for controlling the operation of the apparatus in accordane with sequence information and, generally, in accordance with the various safety and related functions of the apparatus.
A capacity of 4096 8-bit words is certainly adequate for the ROM(B) 44, and a capacity of half that size is considered at least marginally sufficient.
During the provision of initial sequence information through the keyboard K, a digitally-represented data signal (e.g., a number in a flow rate sequence) or a digitally-represented input control signal may be stored in an input register in the input interface 22. The transmission of such a stored, digitally-represented signal, however, is controlled by the occurrence of a pulse along an appar-atus control signal IOTI, as indicated in Fig. 1, which will not occur unless a status signal ST from the inter-face (caused to go high by receipt of an input by the interface) to the central processing unit CPU indicates that a new input has occurred. The presence of a sub sequent digitally-represented input control signal (e.g., ENTER) in the input register in the interface 22, indic-ating that the individual has decided to enter the just-provided input for incorporation into the operation of the apparatus, will permit such incorporation. Alter-natively, such incorporation might be blocked by, e.g., a CLEAR signal entered subsequently to the prior input signal, but before an ENTER signal has been provided to the input register.

2~

The appar tus is programmed (R~1(B) 4~) to pro~iiae the control signal IOTI ~if the status signal ST is high) at intervals both during an initial input procedure from the keyboard K ancl during operation of -the a2paratus to regulate the flow rate of the fluid ld. This will be treated in somewhat more detail below. ~owever, for present purposes it is e~phasized that the occurrence of this signal during such operation enables the incorporation into such o?eration of modifications in an initially input flow rate seauence durinq the performance of the sec~uence by the apparatus.
For xafety, among other reasons, it is considered beneficial, however, to provide only a limited capability for such modifications. More specifically, through the program in the ROM(B) 44, the incorporation of a GO TO
modification of a previously input sequence during the performance of the s~equence or an ADJUST modification during such sequence are considered beneficial and consistent with safety requirements. The GO TO with the related data is to provide a jump to the beginning of a subsequent or earlier infusion number in the sequence and to continue the sequence from that point (or to the beginning of the current infusion numbe- to continue, starting at the beginning of the running of the time for that number). The ADJUST is to adjust the current and all subsequent flow rates by a multiplication factor rangil1c3, e.g., from O.l to 9.9.
The apparatus is adapted to implement such modi~ications, through keYhoard input of data and input control signals (e.g., GO TO and ADJ~ST), which interact with, e.g. the ENTER and CLEAR input control signals, alona the lines noted above, independently of whether the initial sequence information was pro-vided throuoh the keyboard ~ or by the processor P.

z~

The changes are oE course implemented through the eventual storage of disitally-represented modification signals in the RA~ portion of the memory M, e.q., during the regulation of the flow rate of the fluid 14.
- ~efore ~roceeding to the operation of the apparatus of Fig. 1 as it regulates the flow rate of the fluid 14, it might be noted that in Fig. 1, the communication between the processor terminal T and the term~inal-CP~ interface 24 is serial, i.e. one bit at a time (e.g., in the ASCII code). Similarly, the com-munication between the terminal-CPU interface 24 and the central processing unit CPU is also serial (e.g., also in ~SCII). Thus, although many of the apparatus control signals (to :,e described, being somewhat analogous to the apparatus control signal IOTI) which occur during such regulating operation of the apparatus will also occur while the processor P and the apparatus are interacting during the receipt of initial sequence data by the apparatus, the actual operation inside the central processing unit CPU during such receipt ~ill not be tvpical of the regulating operation rnode. Thus, during such receipt of initial seauence information provided by the processor P, the central process~ng unit CP~ will be interacting with the processor P, receiving di~itally-represented information provided t-serially, and interpreting that information and trans-lating at least some of the information into, e.g., standard binary coded decimal.
Also, before proceeding to the regulating ~-operation of the apparatus, it will be appropriate to describe the mode of start-up of the apparatus and several other aspects of the apparatus.
In the apparatus of Fig. 1, start-up is accomplished through conventionally-implemented ~:~4~

apparatus and interactions, including start-up control circuitr~ 46. Start-up is initiated by a pushing of, e.g a POWER keyboard button, resulting in a high pulse along-a start-up signal SU, which in turn causes a high pulse along a clearing signal CL from the start-up control ~ircuitry 46 to the central processing unit CPU
and a number of other elements of Fig. l. This clearing signal CL is employed to clear stale signal-represented information in the central processing unit and various of the other elements which should be cleared prior to start-up. The clearing may for example be accomplished along the rising edge of the high pulse along the control signal CL. Other modes for these signals and for such start-up will be readily apparent. In Fig. l, the start-up control circuitry 46 includes a capacitor-resistor interaction to delay, e.g. for 2 milliseconds, the rising of another start-up signal P to a level sufficient to transfer control to the central processing unit CPU. Following such transfer of control, as a safety precaution of particular concern in medical apparatus, the integrity of each RAM storage location may be checked under the control of start-up aspects incorporated into the ROM(A) program, prior to the receipt of processor or keyboard provided sequence information. By integrity, is meant the capability of such storage location to have signal-represented information written into it and read out of it. In the event of a problem in this regard, a warning signal may be provided generally along lines described in another context below, and, for example, the program may deactivate the apparatus (or provide a zero output).
The central processing unit CPU will in the absence of an indication to the contrary (next paragraph) assume that it is to receive initial input flow rate information ~.

~L~4~

1~
,~

from an inclividual through the keyboard K. In this "keyboard" case, a "keyboard~case" word in ~he memory ~' will be addressed to start ~he receipt of such informa-tion In the processor input, or "processor", case, the central processing unit CPU will sense through a signal along a serial input line 48 from the terminal-CPU interface 24, controlled by the electronic data processor P, that the apparatus has been electrically cou~pled to the processor P to receive flow rate sequence information from the processor. In this case, the ~`
central processing unit CPU will start the receipt of information by addressing another "processor-case"
word in the memory M. The electronic data processor P, central processing unit CPU and ROM(A) program can then interact to provide the RAM with the sequence informa-tion from the elecronic data processor P. The sequence ';
infcrmation in the aforementioned processor case may be checked following input, by interaction between the RO~(A) program and the electronic data processor P, to '~
provide a warning signal and/or deactivation (or a zero output) in the event oE a problem.
The foregoing safety precaution and checking interactions and capabilities (RA~ storage location 'r integrity and checking of sequence information) are conventionally implemented and well-known and understood by those skilled in the art.
Upon completion of the desired interaction, in the so-called "processor" case, between the processor P - ~;
and the apparatus, the receipt of a termination signal along the serial input line 48 will indicate to the central processing unit CPU that its interaction with the processor P should be ceased. The apparatus may then be electrically decoupled from the processor terminal T. Then, if the ~atient PT, or the pati~nt z~ t ) together with infusion pump IP, is at a different location, the apparatus may be transported from the location where it was coupled to the processor P to the vicinity of the patient PT, or patient and infusion `pump IP, to be coupled to the fluid 14 and to then perform the desired regulating of the flow rate of the fluid 14.
The capability o the apparatus to receive input information from the processor P without a human interface is considered a significant advantage. Thus, t~here the critical safety concerns of medical apparatus are present, and complicated regimens for using drugs are desired, e.g. including up to 20 flow rates and their durations, it is deemed of great conc~ril from a safeti standpoint to not interface ~n individual in the provision of the sequence information that will control the flow rate of, e.9., a potentially hazardous drua. This is particularly true where the drug may be infused over long periods when an attendant is not ~;
present or may be occupied ~ith other duties or when the attendant is not ~nowledgeable with regard to the treatment or the operation oE equipment which is being used. This is particularly critical in the instant situation in which one may desire to provide the patient with the drug treatment without the monitoring that would be required in the absence of apparatus such as the present apparatus having a capability to auto-

3 matically control a complicated infusion regimen. The ~.
capability of the apparatus to be coupled and decoupled ~'~
to a source processor P, through eOg. a simple connector used in implementing an P~S-232C communication protocol (e.g. incorporated in the terminal-CP~ interrace 24), 35 and ~o be transported away from the location of such coupling to a location of a patient PT, e.g. in an ambulance, is also considered to be a significant adval1tage. In implementing this adaptabililty to transport, or portability, the power supply 26 for the ~apparatus is of importance. ~' As in part indicated by Fig. l, the power supply 26 provides three DC output signals for powering the apparatus. The power signal Vl in Fig. l, referred to previously, is a "lower" voltage signal, e.g. +5 volts. Two other signals have greater absolute values, e.g. +lS volts. As indicated in Fig. l, the elements of the apparatus of Fig. l are essentially completely powered hy only these three power signals. The low potter requirement of the apparatus in fact enables the imp1ementation of the power supply 26 with standard alkaline D-cells. Thus, in the apparatus of Fig. l, the power supply 2~ is implemented, with safety requirements in mind, through two separate packs of such ~-cells (each pack having a number of cells in series and in parallel to provide adequate voltage and current). Based on the power requirements of the apparatus, each pack is designed to have a capability to yower the apparatus for in the range of 20 hours, providing a total storage capacity sufficient to power `
the a~paratus for at least approximately 30 hours arld in fact in the range of 40 hours. (~ capacity to so power the apparatus for at least 8 hours would of course cover a typical working shift.) ~1hen the first pack becomes low, the power supply will be switched to the second pack along lines which will be explained in more detail below. ~or the purposes of the present discussion it need only additionally be noted that the + higher absolute value si~nals may be readily derived from lower absolute value ~-cell voltages z~

throuah conventional methods, and that two key factors in limiting the power requirements of the apparatus are the liberal use of C~OS technology in implementing 'he central processing unit CPU and related elements, `and the liberal use of liquid crystals in implementing .
the display panel DP ~or the apparatus. Such crystals may be used to implement, among other information, alphanumeric information provided by the panel.
Certain of the alphanumeric information provided by the display panel DP o~ Fig. 1 is of some interest and will thus be briefly described. It will be e~ident that this information is in many respects related to the keyboard initial input and modification processes which have been previously described.
First of all, with respect to the entry of initial sequence information through the keyboarcl, the displav is adapted to provide the following important instructional information: E~TER RATE to indicate to an operator to enter a rate for a sequence position; and ENTER TIil~ to similarly call for the entry of the duration for a sequence position. Then, generally during regulating operation, which may include the aforementioned modification processes, the display is .
adapted to provide the following information, some of which relates to keyboard inputs: RUN to indicate the apparatus is operating to resulate the flow rate of a fluid; ~NTE~ GO TO to tell the operator that he has pushed a GO TO keyboard button and should provide the number for the sequence position he wishes to go to in .:-modifying the sequence, ENTER ADJUST to similarly tell the operatof he has pushed an ADJUST keyboard button and should now enter the adjustment factor to moclify a sequence; ALTERED PROGRA~ to indicate that a se~uence has been altered by a GO TO or ADJUST; CONTINUE LAST

19 7., INFUSION to indicate that the seauence calls for continuin~ the last flow rate in the sequence indefin-itely; L~ST IMF~SION STOP to, by way of contrast, indicate that the sequence inforr,lation calls for ~terminating the infusion after a ~efinite infusion interval for the last position in the sequence; E~D
to indicate the end of a sequence has been reached and the infusion has terminated; SEPVICE to indicate a divergence in the output from predetermined standards in the RA,~ 23,.tested in a way which will be explained in more detail below; the infusion number i~ a sequence;
the infusion rate entered for that number; any adjust-ment factor entered in modifyinq a secuence and the rate entered tim.es the adjustment factor; the total time elapsecl since the infusion was commenced; and, available to replace the elapsed time upon triggering of a TOTAL MILLILITERS INFUSED keyboard button, the total volu~e of fluid infused since the commencement of the sequence. ' Of related interest, in addition to the key- ~
board push buttons and/or push button instructions previously e~plicitly or implicitly noted, e.g. CLEA2, ENTER, GO TO, ADJUST, TOTAL ML INFUSED, CONTINUE LAST
INFUSION, numbers to enter rates and times, POWER to '~
turn on the power to inititate start-up, other buttons (and functions) of note include a START button (and function) to start a regimen, and a STAND~Y button (and function) to hold a sequence in suspension to e.g.
change a syringe. In ad~ition, an input button (func-tion) capability conveniently called ~FVIEW is useful to provide a display panel review of the initially input flow rates and durations startinq with the first triagering of the button at the first infusion number.

z~

, Each subsequent triggerinq ~ould then result in the provlsion of display information for the next infusion number. A capability may then he included to leave the review procedure without carrying out a full review and .to revert to the nonreview display information after an .
interval (e.g. 20 seconds) following initiation of review. A qreat many variations in display information and input buttons and functions are of course possible, and may be readily implemented.
~ lo~ finally returning to the regulating operation of the ap~aratus to provide a sequence of flo~ rates, incorporating the modification features previously noted and initiated through keyboard inputs, such operation can be readily understood by reference to various of the control sianals shown in Fig. 1.
Referring to that figure, the timing for the eentral processing unit CPU is controlled by a eloeking sianal C from a eonventional erystal clocking unit 30. A eloeking signal having a fre~ueney of, for e~ample 2 megahertz, is appropriate for the operation of the system of Fig. 1. A typieal elocking signal C, assumed herein to be operative, is represented in Fig. ;.
2(a). The eloeking signal eontrols the output of eontrol signals Tl, T2, R and W from the eentral proeessing unit CPU.
As snown in Fig. 2(b) and (e), the central proeessing unit plaees a high pulse along the control signal Tl near the beginning of an 8 clock pulse eentral processing unit eyele and similarly plaees a high pulse along the control signal T2 near the end of the cycle. Similarly, as indieated in Fig. (d) and 2(e), the eentral processing unit places a high interval along the control signal R, indicating a "read" interval during a cycle, along an interval starting near the middle of the high pulse along the control signal Tl and endinq after the falling edge of ~the high pulse along the control signal T2, or a high interval along the control signal h-, indicating a "write" interval during a cycle, beginnina somewhat after the middle of the cycle and ending near the time mar~ing the middle of the high pulse along the control signal T2. Typically, the central orocessinq unit continuously puts out these four control signals, the high pulses along the control signals Tl and T2 occur-ring Eor each eight clock pulse cycle, and either the high interval along the control signal R or the hiah interval along the control signal rA~ occurring during a cycle, but not both.
The inte.raction between the central pro-cessin~ unit CPU and mernory ~ by which signal-represented information mav be transferred between the t~o elements or by which the mer,1ory may be enabled to transmit stored, signal-represented information to various of the L
other elements or receive signal-represented information from various of the other elements, is readily understood ~, in light of the aforernentioned control signals and other t.iming aspects illustrated in Fig. 2. In Fig. l, ~;
it.is assumed that such cata communication between the central processing unit and memory, and in fact generallv between the memory and other digital elements, is generally in parallel, no more than 3 bits at a time.
~ther choices are of course readily available and possible.
Proceeding along these lines, the addressing of tne desired portion (ROM(A) 42, R0~1(B) 44 or ~A;1 23) and storage location in a portion of the memory Y ls ~4~Z~

accGmplished, ~irst, by the output by the central processina unit of a number of hits inclucling higher order bits oE an address requiring more than 8 bits, which bits are received by an address register in a CPU-memory interface 50 and stored along the rising edae of a high pulse along the control signal Tl. These first addressing bits are followed during the same cycle by bits which include the remainina required address information. The timing of the transmittal of both the former and these latter bits is represented in Fig. 2~f), ~1here the interval for transmitting the first part of the addressins information is shown by a portion labeled A~Dl and the interval for the second, by the portion labeled ADD2.
After the CPU-memory interface SC has stored ;
the ~irst group of bits and received the second group, it may then transmit the full address, requ ring both groups, to the memory ,11 It is noted that the interface r~
need not store the second group of bits. Thus, the fulL a~ress will be stabilized during a "read" interval somewhat after the commencement of the high period along the control signal R, and during a '~write"
interval, well before the onset of the high period alona the control signal ~
Assuming a "read" interval and the trans-mittal of information from the memory (e.g. the R0~1(A) ~2, ~rom ~ storage location containing an instruction for the central processing unit) to the central processina unit, the central processing unit will be enabled to receive the-signal-represented information during a period represented by the high pulse along the timing signal labeled CPU DATA IN in Fig. 2(j), and the memory will be transmitting the correct information after the addressing information has stabilized. An .

internal data-in register in the CP~ may then store this information alony the rising edge of a clock pulse occurring ~hile the central processing unit is enabled to receive information (while CP~ D~TA-I~' is high). On the other hand, assuming that information is to be transmitted by the central processing unit to the memory ~i, the timing siqnal in Fig. 2(h), labeled CPU ~ATA OUT, represents, while it is high, an interval during which the central processing unit will be transmitting information; and the desired storage location in the memory may then receive the transmitted information after the onset of the high interval along the control signal ~, and store it along the falling edse of the control signal. This sort of interaction is of course well understood. In this regard, it is noted that the functions of a central processina unit such as that in the system of Fig. 1 may be readily implemented using the RCA CDP1802 CMOS Microprocessor.
See COS~IAC ~icroprocessor ~roduct Guide (MPG-180A), RCA
Corporation, 1977.
In addition to generating the control siqnals Tl, T2, R and ~, signal-represented addressing informa-tion for the memory, as well as other signals, the central processing unit CP~ also transmits control signals IGT to an I/O and testing controller 52. In Fig. 1, these signals are transmitted along a control cable 5~, and are assumed to be three signals transmit-ted in parallel along the control cable. Further, any or all of these signals may have a high interval during any central processing unit cycle, beginning near the rising edge of a high pulse along the control signal Tl and ending near the falling edge of a high pulse along the control signal T2. Also, during any such cycle, all of these signals may lack a high pulse, and thus z~

be in ~ lo~ state. The timing of a high interval along an IOT control signal is represented in rig. 2(g). In response to the IOT control signals, the I/O and testinq controller 52 may, during a central processing unit cycle, provide a high interval along any one of '`
eight control signals emanating from it which control various of the input and output, as well as safety and testinq, functions of the apparatus.
Tne eight control signals from the I/O and testing controller 52 are logically generated in conventional fashion from the three input IOT control signals from the central processing unit, and from the control signals R, ~ and T2, also received by the I/O
and testing controller 52 from the central processing unit. The threet IOT control siqnals, representing a possible seven alternative combinations in which at least one of the signals has a high interval during a cycle, are each sensed in conventional fashion by the I/O and .esting controller 52. The IOT and testing controller in turn provides a high interval along one of six internal signals, each associated with one of six of the combinations which are employed, during essentially the same interval as the one or more IOT
control signals are high. These internal signals, which will be generically called IOTG, are used to provide a high interval during a cycle with a "read" interval, along one oE the ~ollowing groups of control signals transmitted by the I/O and testing controller 52: IOTA, IOTD, ITOC, IOTS, IOTLI and IOTHI. In the system of Fic3. 1, this is accomp~ished bv the logical operations IOTG ~ND R, performed for each of the internal IOTG
signals. Thus, during a "read" cycle, one of the aforementioned group of control signals transmitted by the controller 52 may have tne high interval along it ;s -represented by the timing diagram of Fia. 2(h).
However, of course, one of this group need not neces-sarilv have a hiyh interval during such a "read" cycle.
Similarly, three of these same six internal IOG signals are employed to generate high intervals which may occur ~uring "write" cycles along the followina control signals transmitted by the IjO and testing controller:
IOTI, IOTLO and IOT~O. Such high intervals are accom-plished by the logical operations (IOTG A~D r~J) OR T2, performed for each of the group of three signals from ~;
the group of IOTG signals. Again, any one of the signals IOTI, IOTLO and IOTHO may have a high pulse durin~ a "-.rite" cycle, as illustrated in Fig. 2(i), but there need not be a hiqh pulse along one of them during such a cycle. The described techniques for providing the control signals tramsitted by the IOT and testing controller 52 are commonly employed; and in light of the above and the later detailed explanation of how such control signals are employed, a great many ^~
variations which satisfy the requirements herein will be readily apparent.
With the above understanding, the way of accomplishing input, output and various testing and safety functions of present interest is readily under-stood. The functions referred to encompass the input of information from the input intecface 22 to modify ~durina regulating operation) a Elow rate sequence; the receipt and storage of a digitally-represented flow rate from the RAM 23 by a digital to analog conversion system ~6 and the conversion of the digitally-represented flow rate signal to an analog sianal for output;
the selective testing of such signal (and, through this, testing of the signal at the output lines 12), of the generally analog power signal Vl, and of the generally zz~ -r.

analog OUtpllt signal of the conventionallv im21emented frequencv detector 28, representative of the frequency of the cloc~ing signal C; and the updating of display panel information.
As is evident from the figure and from the above discussion of the control signals provided by the I/O and testing controller 52~ the testing may be accomplished by alternative selections by the conven-tionally implemented analog device selector 31, according to signal-represented device addressins information received from the RA~I 23, and by the transmittal of the u selected signal to an analog to digital conversion svstem 6n which, after converting the received analog signal to a digital representation, prov-ides the digital representation to the RA.~ 23 for comparison by interaction between the central processing unit CP~ and memory ~1, with predetermined standards for the signal.
In the case of the output signal o the digital to analoq conversion system 56, the predetermined standard would be the signal-represented information representing the flow rate which had been transmitted to the analog to digital conversion system. In the case of the power supplv signal V1, it would be a digitally-represented range of acceptable voltage levels (e.g. 4.75 to 5.00 volts). And in the case oE the output signal from the fre~uency detector 28, it would typically be a digitally-represented range of acceptable frequencies for the clocking signal. '~
~ 7ith respect to updating the display, this function is, summarily, accomplished by, first, the receipt and storage of signal-represented addressing information, e.g. for a given digit, by a memory-display and fail safe interface 62, and the subsequent receipt and storage by the interface 62 of signal-represented 2~1L

data, e.g. for this digit, which is then received and stored by the display.
Before addressing these functions and other matters in somewhat more detail, it will be valuable to provide a glossary of various relevant signals, as follo~s:

Source 21ement(s) To Summary Signal ~lement Which Provided Functional Description _ _ . ..................... ..

R CPU CPU-Memory Defines "Read" interval Interface; during CPU cyclei en-~lemory; I/O and ables memory to be read Testing Con-troller W CPU CPU-~iemory Defines "Write" inter-Interface; val during CPU cycle;
t~lemory; I/O and enables memory to store r Testing Con- input signal along troller falling edge of control signal IOTI I/O and Input inter- Input register in inter-Testing face face transmits stored ~-Control- input signal ~Ihile con-ler trol siqnal is high.

IOTA I/O and ~lemory-Display Address register in '-Testing and Fail Safe interface stores Control- Interface display address sig-ler nal along falling edge of control signal L

;Z2~X

~0.3rce Element(s) To ~Summar~
Siqnal ~lement ~hich Provided Functional Description ~ . _ IOTn I/O and l~iemory-Display Display reqister in inter-Testinq and Fail Safe face stores display data Control- Interface signal along falling edge ler of control siqnal IOTS I/O and Analog 3evice Address register in Testinq Selector selector stcres device Control- address sianal alonq ler fallinq edqe of control signal, selectinq-analog siqnal to be transmitted by selector IOTC AND I/O and ~nalog to Digi- System starts conversion SC Testing- tal conversion alona falling edqe of Control- system IOTC AND SC
ler and Memory (through loqic qate) .`
OTLO I/O and Analoq to Diqi- System transmits part, Testing tal conversion includinq lower order Control- system bits, of diqital out-ler put siqnal while control signal is hiqh OTHO I/O and Analog to Digi- System transmits part, Testing tal conversion including hiqher order Control- system bits, of diqital output ler t~hile control signal is Source Element(s) To Summary Signcl Element ~.hich Provided Functional Description ,.
IOTLI I/O and Digital to Ana- System stores part, in- F
Testing log conversion cluding lo--ler order bits, - Control- system of digital input alona ler falling edge of control signal IOTHI I/O and Digital to Ana- System stores part, in- .;
Testing log con~ersion cluding higher order bits, Control- system of digital input along ler falling edse of control signal .;
IOTC AND I/O and Digital to Ana- System starts conversion LCR Testing log conversion along falling edge of ~.
Control- system IOTC AND LCR through c ler and storaqe of digital signal ~lemory . for conversion in conver-(through sion register in system logic aate ) IOTC AND I/O and Power Supply Supply switches to second SBP Testing battery pack along fallina Control- edge of IOTC AMD SBP
ler and ~lelTIory (through lo~ic aate) 2~1 Source ~lement(s) To Summary Siqnal Eiement l~hich Provicled Functional Description FSl ~1emory- Fail Safe Relay r~laintains closure of a Displav Circuitry first relay in circuitry and Fail to permit passage of out-Safe put si~nal to infusion Interface pump when frequency of (throuqh high pu]ses along control logic) signal is sufficient FS2 ~lemory- Fail Safe Relay L~laintains closure of a Display Circuitry second relay in circuitry and Fail to permit passage of out-Safe put signal to infusion Interface pump when frequency of (through high pulses along control logic) signal is sufficient CI Interrupt CPU Interrupts CPU alonq Clocking rising edge of control Unit signal to instruct CPU
to include input from n input interface (if ST
signal is high) and dis-play updatinq in the operations being car-ried out ,~.
As mentioned earlier, the interaction of the input interface 22 with the memory ~, even with an individual rapidly working the keyboard ~, would not generally require a capability to receive an input signal by the memorv at intervals shorter than 100 2~

milliseconds. Thus, referring to the control sianal CI
above, an interrupt clockin~ unit 64 acts along conven-tional lines in effect as a frequency divider to provide an interrupt clockinq signal CI having a frequency, e.g. with a 2 meqahertz clocking signal C, of lQ ~1ertz and a period of l00 milliseconds. Essentially the same situation obtains with the display ~P and the memory-display and fail safe interface 62 in that it is not considered necessary to update the display at intervals greater than l00 milliseconds. Thus, the r, interrupt clocking signal CI to the central processing unit CP[1 interrupts the central processing unit, e.g.
every l00 ~illiseconds, to initiate a mode of operation of the CP[1 which will result in the occurrence of high pulses alona the control signals IOTI (if ST signal is high), IOTA a-nd IOTD. Only one IOTI high pulse (enabling one occurrence of an input) will occur during the interval; however, a number of IOTA, then IOTD, high pulse sequences will occur during the interval, as the display includes a number of elements (e.g., ~`
alphanumeric digits and letters) for which the enabling of updating is required. Thus, the interrupt clocking unit essentially provides a slow clock to control the input of information by and the output of information to an individual. The control signals Tl, T2, R and will of course generally still be operative during the mode of operation triggered by the interrupt clocking signal, and the regulation of the flow rate of the t fluid 14 will continue.
The control signals FSl and FS2 are of great significance from a safety standpoint in that they are signals which check whether the central processing unit is acting in certain undesired ways or modes ~2 eather than in expected and desired modes. Thus, as the central processinq unit CPU carries OUt its oper-ations, receiving signal-re~resented information, r transmitting address information and control signals R, W, Tl and T2, and IOT, the central processinq unit will if it is not functioning in certain undesired ways, and assuming other "secondary" events related to the FSl and FS2 signals occur, cause high pulses to occur along the control signals FSl and FS2 at expected intervals 10 to fail safe relay circuitry 40. This circuitry, implemented along conventional lines (e.q., charge on a capacitor dependent upon frequency of high pulses) will maintain a relay responsive ~o each of these control signals closed if it receives high pulses along the 15 signal at frequent enough intervals. Each relay, in series with the other relay, will however open if the high pulses are not frequent enough. In this re~ard, t it may be considered desirable to allow for the absence or a number of expected pulses before the relay opens, r~
2~ indl~ative, e.g., of a clear case of an undesired mode. This checking capability is particularly cr~ ical, for in its absence a patient could continue to receive a drug while the system may appear to act generally normally while operating abnormally. Since the 25 control signals FSl and FS2 relate in some respects to the operation of the memory-display and fail safe interface 62, they will be addressed in more detail after the operation of that interface has been described in connection with the updating of the display.
Somewhat similar concerns are present with r~
regard to the frequency detector 28 and its detection of the frequency of the clocking signal C. As one illustrative example, the clocking unit 30 may fail in a fashion causing its frequency to double. In such a ~ ~ .

z~ :
-3 3 r`

case the system, in the absence of a check stemminc~rom the ~requency detector 28, might continue to operate, but at twice the expected rate.
The operation of the digital to analog ~conversion system 56, analog to digital conversion ;.
system 60, analog device selector 31, memory-display and ~ail safe interface 62 and display panel DP is in 10 large part readily evident by reference to Fig. 1 and the ahove table. Regarding the ~igital to analoq conversion system 56, during a central processing unit cycle in which the implementation of a flow rate for a new infusion number is to be commenced, the control 15 signal IOTLI will have a hi~h interval which, along its fa~l ~ edge, will cause a ~irst input register in the system to stcre input information, including lower order bits of the digital representation to he con-verted to the analog siqnal for controlling the flow 20 rat~. Durinq a subsequent cycle, which may conveniently be the ne~t cycle, a second input register will store, ff, along the falling edge of the control signal IOTHI, input information, including higher order bits of the .
just-mentioned digital representation. This two~step 25 transfer is required in ~ig. 1 due to the assumption of `.
generally eight-bit parallel communication, and a similar assumption that more than 8 bits are used in ~`
the conversion process. Then, during another subsequent cycle, which again may conveniently be the next one, a 3~ high interval along the signal IOT~ AND LCR from an AND
qate 66, along its falling edge, will cause an internal conversion register in the digital to analog conversion system to store both the lower and higher order bits which it receives from the input registers. Bits in 35 this register are the bits upon which the conversion is 3~

performed. The high LCR interval is from a high bit in a memory M storage location which is being addressed.
The use of memory bits for essentially control-purposes, as here, is of some interest; however, satisfactory alternatives, including the incorporation of an addi-tional control signal from the IOT and testing control-ler 52 are readily apparent.
Now referring to the analog device selector 31, a high interval along the control signal IOTS
permits the analog device selector 31 to receive addressing information from the memory representative of an upcoming selection of the power signal Vl, of the output signal of the frequency detector 28 or of the output signal of the digital to analog conversion system 56. This addessing information will be stored in an address register in the selector along the falling edge of the control signal IOTS. These events result, along conventionally implemented lines, in the selection by the selector 31 of one of the three generally analog signals for transmittal to the analog to digital conversion system 60. By way of example, it will be assumed that the output of the digital to analog conversion system 56 has just been selected.
During a "read" c~vcle subsequent to the selection cycle, which could conveniently be the next cycle, a high interval along the control signal IOTC, interacting with a high LCR,interval from a bit in an addressed storage location in memory and a second AND
gate 68 will, along`lines described above with regard to the digital to anal~g conversion system, commence the analog to digital conversion by the conversion system 60. This will occur along the falling edge of the high IOTC interval. Then, during subsequent "write" cycles, bits, first including lower order bits, 6'~

and then higher order bits, of the digital representa-tion resulting from the conversion, will he transmitted from an output register in the system for receipt by the RAM 23 and storage by the RAM in addressed storage 'locations. The first and second of these cvcles will, respectively, be characterized by high intervals, enabling the transmittal by the conversion system, along the control signals IOTLO and IOT~10. Following the receipt of the digital representation, the central' processing unit CPU and memory ~l will interact along `~
conventional lines to compare the received information with information already stored in the ~AM 23 which was the source o~ the signal converted to analoa form by the digital to analog conversion system 56. In the event of a discrepancy, after the occurrence of the ne~t interrupt of the central processing unit by the interrupt clocking signal, a warning signal, the word SEP~VI~E, will be provided by the displav panel, and, in ~;
addition, the output of flow rate information to the infusion pump may be ceased -- i.e., a zero output level to the infusion pump IP may be established, or deactivation of the output may he implemented, all under the control of the RO~(B) program.
The testing of the output signal from the frequency detector and of the power signal Vl is along analogous lines. ~lowever, in these cases, since the standards for the fre~uency detector output signal and for the power supply signal Vl may be essentially permanently programmed'into the system, the precleter-`mined standards may be.stored in digitally representedform on a permanent basis in the ~OM(B) 44 rather than on a temporary basis in the ~AM 23. Also, different warning sianals and/or consec3uences may be provided as

4 b noted in connection ~lith the description of the up-dating of the display, to follow.
Referrinq to the process of updating the display, as previously noted such updating may occur -at intervals of, e.g. 100 milliseconds, the onset of such an interval being controlled by the interrupt clocking signal CI. Thus, typically, during a cycle after the onset of an interrupt, the control signal IOTA will go high, causing an address register in the interface to receive signals from the RA~I 23 for addressing an element of the display panel DP, and to store such signal along the falling edge of the high interval. Then, during a subsequent, conveniently the next, cycle, a data register in the memory-displav interface 62 will sirnilarly receive and store a data signal for that display element. In the case of a liquid crystal display element for a number, to e.g.
display the digit 5, a single control bit will be received with the data, causing a high level along the signal CC which will trigger the receipt by the display panel circuitry of the data from the data register, and the subsequent storage (along the falling edge) of the data by a register for that element. The so stored digital signal, in the register for the element, will then determine which liquid crvstal portions of the element are excited by the oscillation signals conventionally incorporated into display panel circuitry uitilizing liquid crystals, causing a 5 to appear in that display element. In this regard, it is r again noted that successive occurrences of high intervals along the control signals IOTA and IOTD will typically occur after the onset o each interrupt so that many oe all of the display elements may be updated essentially every 100 milliseconds.

2~

,, Besides, e.g. the various alphanumeric information which may be ~rovided by the display panel, the sound alarm 36, first warning light 32 and second warning liqht 34, previously noted, are also .incorporated in the displav panel ~P of Fig. 1. ~-In the apparatus of Fig. 1, the first warning light 3 is employed to indicate that the central processing unit has, through the selective testing process descibed earlier, detected that the first battery pack in the power supplv 26 was putting out insuficient power and that as a result, the power supply has received a high IC AND SBP interval during a "read" cycle causing it to switch in the second power supply. The first warning liaht will then be turned on through addressing and data information channeled through the mernory-display and fail safe interface 62, along lines previously noted, with a hiah C~L interval provided in the same fashion as the aforementioned hiah CC. Similarly, the second warnina light 34 will be similarly activated following the next interrupt after a detection of an input o a rate, through an ADJ~ST
modiEication, exceeding the maximum of the infusion pump IP, e.g. 99.9 milliliters per hour.
Additionally, the alarm is addressed and activated as a result of an indication, through the selective testing, that the second battery pack is low, or that the frequency of the clocking unit has diverged from the predetermined standards for it. In this regard, the beeping rate of the alarm may be varied to ,;
indicate one or the other of these occurrences.
Thus, the sound alarm 26 itself has several addresses, the receipt of activating data at one, activating one beeping rate, and the receipt of activating data at the other causing the onset of a second beeping rate.

7 ~ith the occurrence of both conditions, the sum heeping signal ~ill then occur. Alternatively, for e~ample, such rates might be controlled by the rate of channeling of activating data (an activating signal) to a sinale address for the alarm.
~89~ It is also noted that it is considered use-~ `~~ ful to activate the alarm upon the end of a secuence in which a continuation of the flow rate of the last infusion number has not been indicated. A different beeping frequency then might be employed for this condition. The employment of warning lights, warning sound alarms and alphanumeric warning information (e.g.
SFRVICE) may of course be varied. For exampIe, the SERVlCE alphanumeric infor~ation and sound alarm might ~` " toaether be emploved to indicate a check sum on the flow rate information in the R~M has come up with a discrepancy with respect to an originally stored sum, ~g or that the output signal of the digital to analog _ conversion system has become zero or been deactivated as a result of the determination that it did not correspond to the stored, digitally-represented output - level in the RAM. Such variations may be readily implemented along the lines described above. ~arnings such as the above in effect act as an inter~ace between the selective testing capability and other safety aspects of the apparatus and an individual monitoring ~ ~he operation of the apparatus, continually or at _ j intervals, and possibIy from a distance.
~eturning to the control signals FS 1 and FS2, their generation may now readily be understood.
Continuing ~ith the assumption of senerally 8-bit, parallel communication in the apparatus of Fig. 1, it is ` 1 further assumed that the number oE display elements to be addressed throuqh the address cegister in the ~;

memorv-display and fail safe inter~ace ~2 ~oes not require more than 6 bits tc accomplish ~he addressing.
There ~ill then be at least 2 bits remaining in, e.g., the address code for addressing the last dlgit in the elapsed time indicated by ~he display. For example, the address for this digit night be _111010, where the unused bits are of no concern with respect to such addressing.
Utilizing this situation, in Fig. 1, the two otherwise unused bits stored in the memory storage location from which the address for this digit is obtained are assumed to be set to 10, a code essentially arbitrarily chosen. For addressin~ the other display elements, th~ unused bits may, for e.Yample, be filled with ~eros, or codes other than 10. Then, when the element for this digit is addressed, logic circuitry, including a first fail safe AND gate 70 and an inverter 20 72 will, through the occurrence of a high interval ;-along the control signal FS 1, indicate that the central processing unit CPU has correctly functioned to the extent of reaching this point (as well as tha~ -other events required to achieve the high interval have occurred).
Similarly, with respect to the data used in updating, e.g. the last digit in the elapsed time, for which orly 4 of R availdble bits will be required, after the storage location for the data to be used for a given update has been determined (by the central processing unit), the central processing unit, under the control of the PRO~(B) program, will write an .-essentially arbitrarily chosen code, assumed to be 1010 in Fig. 1, in the otherwise unused 4 bits. rrhen a second fail safe AND gate 74 and two associated inverters 76 and 78 will, assuming the required events, including CP~

-.

operations, have occurred, cause a high interval along the control signal FS2 as .he display data for the digit is provided by the interface to the display. The ~-bit code will be "erased" by the central processing .
unic from the storage location, under the control of the PRO~l(B) program, subsequent to its use. It mav be appreciated that this check on the desired operation of 10 the central processing unit (as well as other aspects of the apparatus) is perhaps more extensive than that through the control signal FS 1.
Given the foreaoing, the control signals FSl and FS2 may then interact with the fail safe relay 15 circuitry 40 in the manner previously described.
It is noted that, if desired, the control signals FSl and FS~ could additionally be used to deactivate the output upor. the occurrence of other ~roblems in the apparatus !e.g., related to the clocking 20 signal frequ~-ncy, power signal Vl or output of the -analog to digital converter, discovered by selective t testing) be~ond certain undesired modes of operation of the central processing unitO However, the role of such ~~
control signals in checking for such undesired modes of ~::
25 operation whlch might otherwise go undetected is deemed !.
to be of great importance. From a different perspective, each of the control siqnals FSl and FS2 is of course used to indicate the absence of certain undesired modes of operation of the central processing unit CP~].
In view of the above description, it may be s~en that the apparatus herein may be variously ;~
implemented and variously used depending upon specific applications. For example, the fluid flow rate could alternatively relate to a li~uid which is being vapo~ized for inhalation by a 22~

~atient; the output to a regulator could indicate a flow rate through its frequency or more directly, through a binary word, which output forms might be accepted by various regulators; control over relatively ~-low rates of flow and small variations might be accom- _ plished by regulation incorporating a piezoelectric material excited in varying degrees; and the regulation could incorporate the use of a bottle for a liquid equipped, for example, with a drip device, a piston-~riven casette drive or a peristaltic pump device.
~ccordingly, the scope hereof shall not be referenced to the disclosed embodiments, but on the contrary, shall be determined in accordance with the claims as set forth below.
. .

Claims (17)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows

1. Portable medical apparatus for controlling the flow rate of a fluid for medically treating a patient according to fluid flow rate information available from an individual, and from a source electronic data processor, the available flow rate information representing sequences of flow rates and their durations, comprising:
operator input means for coupling to the individual to receive flow rate information provided by the individual and provide electrical signals representative of said infor-mation;
source processor input means for coupling to the source electronic data processor to receive flow rate information provided by the source processor and provide electrical signals representative of said information; and electronic data processing means for coupling to said operator input means and to said source processor input means to receive said electrical signals, provide and store storage signals representative of said received electrical signals and provide flow rate output signals, representative of said storage signals, for regulating the flow rate of the fluid;
said electronic data processing means including means for coupling to infusion regulator means for regulating the flow rate of the fluid in response to said output signals.

2. Controlling apparatus according to claim 1 further comprising:
infusion regulator means for said coupling to said electronic data processing means to regulate the flow rate of the fluid in response to said output signals.

3. Controlling apparatus according to claim 1 wherein said source processor input means comprises means for electrically coupling said apparatus to and decoupling said apparatus from the source electronic data processor.

4. Controlling apparatus according to claim 1 wherein said electronic data processing means further comprises a portable power supply having a power capacity sufficient to power said apparatus.

5. Controlling apparatus according to claim 1 wherein said electronic data processing means further comprises:
means for providing control signals for controlling operations of said apparatus, said control signals including at least one signal for indicating an undesired mode of operation of said means for providing; and means for interrupting the provision of said output signals of said data processing means in response to an indication of a said undesired mode of operation by said control signal.

6. Controlling apparatus according to claim 1 wherein said electronic data processing means further comprises:
means for providing a clocking signal for said data processing means; and a frequency detector, electrically coupled to said clocking signal providing means, for providing a detector output signal representative of the frequency of said clocking signal in response to said clocking signal.

7. Controlling apparatus according to claim 1 wherein said electronic data processing means further comprises:
a portable power supply for providing at least one electrical output signal for powering said apparatus; and means for selectively testing said output signals of said electronic data processing means and power supply against predetermined standards and for providing a warning signal to an operator of said apparatus in the event of divergence from said standards.

8. Controlling apparatus according to claim 1 wherein said electronic data processing means further comprises:
a portable power supply for providing at least one electrical output signal for powering said apparatus;
means for providing a clocking signal for said electronic data processing means;
a frequency detector, electrically coupled to said clocking signal providing means, for providing a detector output signal representative of the frequency of said clocking signal in response to said clocking signal; and means for selectively testing said output signals of said electronic data processing means, power supply and frequency detector against predetermined standards and for providing a warning signal to an operator of said apparatus in the event of divergence from said standards.

9. Portable medical apparatus for controlling the flow rate of a fluid for medically treating a patient according to fluid flow rate information available from an individual, and from a source electronic data processor, the available flow rate information representing sequences of flow rates and their durations, comprising:
operator input means for coupling to the individual to receive flow rate information provided by the individual and provide electrical signals representative of said information;
source processor input means for coupling to the source electronic data processor to receive flow rate information pro-vided by the source processor and provide electrical signals representative of said information; and electronic data processing means for coupling to said operator input means and to said source processor input means to receive said electrical signals, provide storage signals representative of said received electrical signals, store simultaneously storage signals representative of a sequence of fluid flow rates and their durations and provide flow rate output signals, representative of said storage signals, for regulating the flow rate of the fluid;
said electronic data processing means including means for coupling to infusion regulator means for regulating the flow rate of the fluid in response to said output signals.

10. Controlling apparatus according to claim 9 wherein said apparatus is decouplable from the source electronic data processor to regulate the flow rate of the fluid independently of the source electronic data processor in accordance with a sequence of flow rates and their durations determined by flow rate information received by said source processor input means from the source electronic data processor.

11. Controlling apparatus according to claim 10, wherein said electronic data processing means comprises a portable power supply having a power capacity sufficient to power said apparatus.

12. Controlling apparatus according to claim 9 wherein said electronic data processing means comprises a portable power supply having a power capacity sufficient to power said apparatus.

13. Controlling apparatus according to claim 10 wherein said electronic data processing means further comprises memory means for simultaneously storing storage signals representative of a sequence of at least eight flow rates and their durations.

14. Controlling apparatus according to claim 13 wherein said electronic data processing means further comprises a portable power supply having a power storage capacity sufficient to power said apparatus for a sequence duration of at least eight hours.

15. Controlling apparatus according to claim 2 further comprising:
fluid introduction means for storing the fluid and for coupling to said regulator means and to the patient to provide the fluid to the patient in accordance with said regulating by said regulator means.

16. Portable medical apparatus for controlling the flow rate of a fluid for medically treating a patient according to fluid flow rate information available from a source electronic data processor, the available flow rate information representing sequences of flow rates and their durations, comprising:
source processor input means for coupling to the source electronic data processor to receive flow rate information pro-vided by the source processor and provide electrical signals representative of said information; and electronic data processing means for coupling to said source processor input means to receive said electrical signals, provide and store signals representative of said received electrical signals and provide flow rate output signals, representative of said storage signals, for regulating the flow rate of the fluid, said electronic data processing means including control means for said processing means and memory means for programming said processing means;
said electronic data processing means further including means for coupling to infusion regulator means for regulating the flow rate of the fluid in response to said output signals.

17. Controlling apparatus according to claim 16 further comprising:
infusion regulator means for said coupling to said electronic data processing means to regulate the flow rate of the fluid in response to said output signals.