DE2507248A1 - CONTROL DEVICE FOR A PATIENT MONITORING SYSTEM - Google Patents

Description

DEAN KAMEN, 99 Bulson Road, Rockville Center, New York Control device for a patient monitoring system

The invention relates to a control device for a system for monitoring a patient, with a Blood pressure: the like of the patient monitoring monitor and a device for operating a device for drug administration in the event of changes in the monitored body function.

The invention is therefore generally concerned with the use of an electronic monitor for surveillance of body functions, for example blood pressure, heartbeat and the like, of a patient, xvo then to correct a change in body function being monitored by intravenous injection or to others a suitable way to give the patient a suitable one. Drug is delivered. Specifically, it is the invention to a control device for the monitor,

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Bremen office: D-2800 Bremen 1 Posttacli 7Ö6, FeIristraße Telephone: (0421) * 74044 Telex: 244958 bopatd Telegr.: Diagram, Bremen

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Bremen accounts:
Bremer Bank. Bremen
(BLZ 29OuOO 10) 1001449

I ¹ ScIiA Hamburg

(BLZ 20010020! 126083-202

Munich office: D-8000 Munich 90 Schlotthaner Straße 3 Telephone: (089) 652321

ielegr. : Tclcpatcnt, Munich

BOEHMERT & BOEHMERT

through which important medical safety features for the operation of the monitor are to be achieved.

In the case of a typical monitor previously used for patient monitoring, the monitor can do little more perform as a light to light up or to activate an acoustic alarm device, which Getting hospital staff to take whatever medical action is necessary is to address an emergency patient situation correct. The doctor or nurse will then inject an appropriate drug intravenously using an conventional injection syringe. There are automatic injection devices, such as those used for example in U.S. Patents 3 4-56 6 ^ 9 and 3 623 4-74- are described, but these are only seldom used. Their use so far only means greater accuracy in supplying the desired Dose as well as acceleration of administration and other benefits that always occur when automatic working facilities or devices are used instead of manually operated ones. Without a doubt, the minor is based Use of automatic injection devices in connection with monitors for patient monitoring on the fact that the latter only ensure inadequate control and monitoring of the injection devices, such as it would in itself be necessary in order not to endanger the safety of the patient.

The invention is therefore based on the object of a control device for a monitor for patient monitoring, through which the above-described and other disadvantages, familiar to the person skilled in the art, of the known

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directions and systems are avoided. In the actuation of the monitor should be introduced in such a way that an intravenous administration of a drug can only take place if an actual emergency situation is present in the patient is to ensure that the dose following an initial administration only after the lapse a suitable rest period, that is to say a period in which the administered drug causes the desired effect in the patient's body, can be administered.

According to the invention, this object is achieved with a control device deT · initially mentioned type solved by means for generating a selected voltage signal in response to one of the monitor abandoned input signal; a first timer electrically connected to make the signal more selected Voltage is received as input from this for an interval of time which is required to run a capacitor to bring to the value of the voltage signal; by the first timer when the full »capacitor voltage is reached actuating devices for starting the drug delivery device; and a second, timer operated simultaneously with the drug delivery device for a certain time interval to prevent a subsequent actuation of the first timer before the preselected time interval has elapsed, wherein an initial drug dose to the patient through the drug delivery device only after the lapse the time interval of the first timer to decrease any false indication of an emergency situation and a subsequent drug administration only

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after the elapse of the time interval of the second 'timer, which depends on the idle period for the "drug in question is selected, is supplied.

In the control device according to the invention, which the solves the given task and brings numerous advantages, a timer is used that is electric is switched so that it continuously receives an input signal from the monitor for a time interval, which is so long that any false indication of an emergency situation is suppressed or minimized. Only after At the end of this interval, a signal is generated which effects the administration of a corrective drug. After this signal has been sent out, the timer is prevented from receiving a subsequent signal can transmit this type until another time interval has elapsed, which depends on the idle period is selected for the medicine being used.

Overall, the invention is therefore a system in which the body functions of a patient, such as, for example blood pressure, heartbeat or the like can be electronically monitored. The monitor leads to a Administration, for example by intravenous injection, to the patient of a drug which is used to correct any change in the monitored body function of the patient which is indicative of an emergency situation "or" to counteract this.

The invention is a control device for a monitor, which two important security

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tasks fulfilled. The first security task is satisfies that an adequate rest period, i.e. a period which the drug needs to be able to Effect to come between consecutive administrations of drugs is inserted to the patient. The second task of detection is fulfilled by the fact that the drug dose is then administered to the patient when there is a certain degree of certainty that the change in body function, which occurs in the patient actually indicates an emergency situation, but not an insignificant one Is a change that can be corrected without drug administration.

Further features and advantages of the invention emerge from the claims and from the following description, in which an exemplary embodiment is explained in detail with reference to the drawing. It shows:

lig. 1 in a schematic representation by

the monitor control and monitoring device according to the invention in one for monitoring a patient's monitor fulfilled punctures; and

Pig. 2 is a circuit diagram showing details of the control device.

1 shows a schematic representation of a system in which the bodily functions of a patient 10, such as, for example, blood pressure, cardiac activity and the like, are monitored by a monitor 12. In other words, the monitor 12, which can consist of a commercially available electronic device, is connected to monitor the patient 10 in such a way that, for example, a suitable signal 14 is sent to the monitor 12 in the event of a sudden irregularity in the patient's heartbeat.

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Depending on the signal input 14, the monitor generates 12 in turn a signal 16, which in many cases can be of an electronic nature, for example by emitting it a pulse at a certain voltage. So far, the pulse or signal 16 has only been this used to activate an optical or acoustic alarm device, on the display of which the hospital staff took the measures necessary to remedy the emergency situation of patient 10. In the example considered, So with an irregular heartbeat, a doctor or a nurse would be with the previously known procedure administer lidocaine or other such drug to the patient to stop the patient's heartbeat to equalize. Administration of this drug would, in most cases, be by means of a conventional one Injection syringe. However, it would also be possible to inject the drug through an automatic injection syringe 18 to be administered, preferably with a hypodermic syringe of the structure and mode of action, as it is the subject the earlier application P 24 39 269.6 is. The automatic injection syringe described there is indeed preferably used, but an injection device of the type disclosed in the US patents could also be used 3,456,649 and 3,623 4-74 in general is. For the present purpose, it is sufficient to note that the injection device 18 by a suitable electronic signal pulse 20 is actuated, which puts it into operation. During operation, the injection syringe causes 18 an intravenous injection of a drug, such as the already mentioned lidocaine, whereby the emergency situation of the patient is resolved.

According to the invention, a control or monitoring device (so-called "interface unit") is now provided, which as a whole

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is designated by 22 and the monitor 12 is assigned. The control device 22 controls and controls the manner in which the monitor 12 the automatic, Injection syringe 13 serving for drug administration to remedy emergency situations of the patient 10 is actuated. If one looks again at the previously assumed dangerous situation, in which the monitor 12 shows an irregular Determines the heartbeat of the patient 10, which in turn requires the administration of lidocaine, so Any system that monitor 12 has to be medically acceptable should meet two requirements or meet conditions. These two conditions are controlled by the intermediary control device 22 according to the invention impressed on the monitor 12, as will be explained in detail below.

The actual time in which the patient 10 receives the drug via the automatic injection syringe 18 can only be a matter of minutes. However, it may be medically necessary after administration of the drug to prevent further drug delivery for a much longer period of time takes place, namely to enable the dose administered to have the desired effect in the body of the Affects the patient and acts accordingly on the body functions. When the heartbeat is irregular is generally assumed to be consecutive Lidocaine administrations only at intervals of approximately 20 minutes as "refractory" period "should be administered as follows will be described in detail, is therefore a function of the control device 22 is that after the actuation of the drug administration

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acting syringe 18 a rest period of "any Interval duration is switched on before a subsequent actuation of the injection syringe takes place. As already noted, the indicated rest interval for the drug lidocaine is 20 minutes. But in a situation in which the patient is in a state of acute hypertension and the monitor 12 shows the blood pressure of the patient 10 monitored, a change in the patient's blood pressure would indicate an emergency requiring the administration of a appropriate drug required. It might be necessary that this medicine continue to be used continuously until a positive change in the patient's blood pressure is seen. So in this case it is the "refractory period'Or the rest period is zero.

The control device according to the invention should not only ensure that the appropriate "refractory period" or idle period is switched on, rather the control device 22 should also be able to detect any false indications to eliminate an emergency situation with patient 10 or to reduce their risk to a minimum. For example, monitor 12 monitors the blood pressure of a Patient 10, a mere change in the patient's position, for example from lying in a sitting upright position, a momentary change in Effect the patient's blood pressure. However, this change is medically insignificant and should therefore be combined into one properly functioning system does not initiate any corrective action, in other words, this change should not cause the injector 18 to begin delivering drug to the patient. As will be described in detail below, there is another essential task of the control device according to the invention therefore, the occurrence of any false

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display of emergency situations "in the patient 10 to minimize.

The ilontr oil device 22 has a generator 24 for production a fixed voltage, a first timer 26, a second timer 28 and a control unit 30, which is operated by the second timer and controls the operation of the first timer 26. The mode of action of the individual components of the control device 22 are described below.

The voltage generator 24 initiates, as the name suggests, an electronic signal 32 of any predetermined voltage, for example five volts. The signal 32 with a voltage of five volts is continuously transmitted by the generator 2Pr as long as the generator receives an input signal 16. It should be noted that the signal 32 will be at the fixed voltage of five volts even if the input signal 16 has a greater or lesser voltage. This mode of operation of the generator 24- is readily understandable and can be implemented in a large number of commercially available generators which deliver an output signal at any desired, predetermined and selectable voltage. One such commercially available device which has been used with good results in the invention is available from Signetics, Inc., Sunnyvale, California. This model advantageously uses a Zener diode voltage holding circuit and a Schmidt trigger to generate the output signal 32 of five volts for the period in which an input signal 16 is applied to the generator.

Reference is now made to the circuit diagram of FIG

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taken to make it easier to understand in which ' Manner the first timer 26 uses the input signal 32 of five volts to the two essential operating conditions for the system referred to earlier. The timer or clock 26 has a variable Widt ^ -stand 34 and a capacitor on, which is fully charged when the voltage applied to the capacitor plates has a value of approximately five Volt reached, corresponding to the input signal 32. An At this point in the description it is useful to refer to a mechanical analogy regarding the operation of the timer 26 should be pointed out. An electric current or a flow of electrons can, as is known, in an analogous manner a liquid flow can be compared. The variable resistor or potentiometer 34 would then be analog replaced by a valve that regulates the amount of liquid that could flow past a throttle. Of the Condenser 36, in turn, would be a container with a certain volume. So depending on how the resistance 3 ^ is set i? t, a certain instantaneous current 32 is through the resistance 34- flow. This stream becomes whole require special time to "fill up" capacitor 36, or to impress a charge of five volts on this component. So only after this time interval the timer 26 produces an output 38 of five Volt, which is ultimately used to actuate the automatic injection syringe 18 in the form to be described below Way leads. As the previous description shows, it can already be seen in which way the timer 26 between the input of the signal 32 to the timer and the generation of an output signal 38 a time interval switches. Accordingly, the timer 26 can effectively operate the injection syringe

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to minimize the period in which an actual . Emergency situation "is present in the patient 10, which will be remedied would have to. In other words, the variable resistor 34 is set to such a value that a a suitable time interval must elapse before the signal 38 is generated by the timer 26. This helps to eliminate any negative indication of an emergency situation. The size of this actual time interval depends on the body function monitored by the monitor 12 and the medical situation in which the patient is itself is located. For example, when blood pressure is monitored by monitor 12, there is a change in it A size of only a short period of time presumably an indication that the patient is only changing his position in bed has, that is, that he is from a lying position but not a sign of an emergency situation that requires the administration of a corrective Drug required. So if the resistance 3 ^ · is set so that a time interval of 3 minutes must pass in which a continuous Signal 32 is received by timer 26 before it If an output signal 38 is generated, then practically every possibility of a false indication of a Eliminated the patient's emergency.

In the following, reference is now made to FIG. 1 in order to further explain the mode of operation of the control device 22. Assume that the signal 32, as input to the first timer 26, occurs for a period of time which is symptomatic of an emergency situation in patient 10, so this leads to, in the manner already described, that the timer 26 generates an output signal 38 which is transmitted to the second timer 28. The contemporary

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Above 28 can be any commercially available electronic Be device. Such a timer is supplied by, for example, ECA, Harrison, New Jersey. When the input signal J8 is received by the timer There are three processes. The first process is that the timer 28 generates the already mentioned signal 20, which affects the drug delivery Injection device 18 is transferred, whereupon the administration of the drug dose begins. Typically this can be achieved in a relatively short time interval, for example in two minutes. Simultaneously with this, the second timer 28 also begins its timing operation. In the described embodiment the interval of this operation is 20 minutes or, in other words, is the "refractory period" (Rest period) equivalent for the drug lidocaine, which, as is assumed here, by the injection syringe 18 is supplied to the patient 10. Finally, as a third process, note that the timer 28 places the system in an operating state during which time another output signal 38 is not on the timer 28 can be transmitted. This must be prevented for the 20-minute rest period, since there is an output signal 38 would accordingly cause a signal 20 which sets the injection syringe 18 in action. In order to obtain this mode of operation of the timer 28, it is provided that the timer 28 sends out an electronic signal 40 depending on the input of the signal 38, which to the Control unit 30 for the first timer 26 is transmitted. As FIG. 2, to which reference is now made, shows, there is the control unit 30 for the first timer in FIG Act of a short circuit consisting essentially of a transistor or, as shown, a fine triac 42,

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which is short-circuited with the capacitor 36. The signal 40 is fed to the bias plate of triac 42 and puts this in the state of charge, whereby the circuit 44 is grounded. This results in a different one Path for the electrical current of the signal 32, which emanates from the resistor 3 ^ ·. How generally understandable is, the capacitor 36 cannot be charged under these circumstances. For this reason there will be no further output signal 38 by the first timer generated until the signal 40 is interrupted by the second timer. The signal 40 is of course for the duration the rest period for the respective drug supplied to the patient 10 is continuously generated. on in this way the first timer 26 remains inactive for the idle period. This creates the control device 22 a time interval, corresponding to the rest period for the drug in question, between successive ones Signals 38 generated by the first timer. .

From the above description it follows that the intermediate control device 22 is a system, which has a monitor 12 that monitors the bodily functions of a patient 10, two important and important ones Confers security features. The first safety feature is that between successive administrations a suitable rest period is observed from drug doses to the patient. The second security feature is that the drug dose is delivered to the patient only when there is a certain degree of certainty insist that the condition observed in the patient and requiring drug delivery is sufficient takes a long time to indicate that indeed

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there is a medical emergency, so only random or temporary changes in the body function being monitored that are not indicative of an emergency characteristic is disregard.

There are multiple modifications within the scope of the invention and additions to the exemplary embodiment described above possible. Individual features of the invention can also be used without using the rest or the rest Features are used to advantage.

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Claims (5)

BOEHM ^ RT & BOEHMERT Expectations Λ J control device for a system for monitoring a patient, with a monitor monitoring the patient's blood pressure or the like and a device for actuating a device for administering medicaments in the event of changes in the monitored body function, characterized by a device (24) for generating a signal (32 ) selected voltage as a function of an input signal (16) applied by the monitor (12); a.first timer (26) electrically connected to receive the selected voltage signal (32) as input therefrom for an interval of time necessary to bring a capacitor (36) to the value of the voltage signal; means actuated by the first timer (26) upon reaching the full capacitor voltage for starting the drug delivery means (18); and a second timer (28) operated simultaneously with the drug delivery device (18) for a specific time interval to prevent subsequent activation of the first timer before the preselected time interval has elapsed, an initial drug dose being passed to the patient by the drug delivery device (18 ) is only supplied after the time interval of the first timer (26) has elapsed in order to reduce any false indication of a hypothermia situation and a subsequent drug administration is only supplied after the time interval of the second has elapsed 509839/0650 BOEHMERT & BOERMi-RT Timer, which depends on the idle period is selected for the drug in question, supplied will. 2. Control device according to claim 1, characterized by means (34) for selectively varying the Time intervals of the actuation of the two timers (26, 28) independently of one another. 3. Control device according to claim 2, characterized in that the second timer (28) with respect to the Capacitor (34) of the first timer (26) actuates a short circuit, whereby each subsequent actuation of the first timer is prevented until the interval of the clocking operation of the second timer (28) has expired will. 4. Control device according to claim 3i, characterized in that the simultaneous operation of the second tent quake (28) and the drug supply device (18) by an electronic pulse (38) transmitted from the first timer (26) to the second timer (28) ) can be initiated, which is used by the second timer to initiate its own operation and also to actuate the drug delivery device (18). 5. Control device according to claim 4, characterized in that that the pulse (18) transmitted to the second timer (28) continues to start the actuation of the short circuit for the capacitor (36) of the first timer (26) can be used. 5098 3 9/0650