Compact interactive training manikin system

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This invention relates to training manikins, and more particularly to a training manikin system having a very compact controller with a prerecorded human voice interface for coaching the user.

BACKGROUND

MANIKINS USED WITH LIVE INSTRUCTORS

Models of the human body called manikins are used in teaching many skills. In the medical and safety fields, manikins are a common and important aid in teaching Cardiopulmonary Resuscitation (hereafter "CPR"), a combination of artificial respiration and heart massage.

Traditionally a class of students is first taught the CPR procedure by a live instructor, after which the instructor divides the class into teams to practice on a manikin. During practice the instructor goes from team to team, commenting, correcting and coaching. The students use the manikin to practice mouth-to-mouth breathing, chest compressions for restoring circulation, and first aid procedures for choking.

Prior art training manikins for CPR have generally been equipped with an electronic signal box the front panel of which has lamps that give some feedback to the student. For example, in a typical arrangement the panel has three different colored lamps to signal the following:

Green lamp: Lights up when 800 cc of air enters the manikin's lungs. Is off when less than this amount is in the lungs.

Yellow lamp: Lights up when the chest is compressed 11/2 inches. Is off when the chest is compressed less than this amount.

Red lamp: Lights up as a warning when an incorrect hand position is used during chest compressions.

Also, an electronic metronome has been provided which emits an audible "tick".

In addition to the above-mentioned lights, the higher cost manikins have been equipped with strip charts that record the student's performance as he practices. This enables an instructor to come by, read the chart, and discuss the results with the student. The instructor may also show the student how to read the chart himself.

Some CPR training manikins have been equipped with other internal and external devices that allow for some degree of measurement, recording, and visual indication of the student's efforts when he or she is practicing various procedures. But even the most sophisticated of these have many shortcomings and limitations. Also, most conventional training manikins, except for very expensive systems, are designed for use in training courses having a live instructor.

INSTRUCTORLESS SYSTEMS

Systems that do not require a live instructor have advantages, since there is a shortage of trained, highly motivated persons with the required time and temperament for the very repetitive, vocalized teaching required. Another benefit is standardization of instruction.

Until now, however, complete elimination of the instructor has required an elaborate, complex, and cumbersome array of electronic hardware. In one such system, the manikin is internally fitted with sensors and coupled via an electrical cable to a system consisting of a computer, keyboard and light pen, two television monitors, a video disc machine, and a computer controlled audio machine. All of this is cabled together and powered by the AC line.

Such systems are not easily portable, and are also very expensive (in the neighborhood of $25,000). Their maintenance entails additional cost and requires highly skilled personnel. A principal objective of the present invention is therefore to equal or at least approach the performance of such a system at a far more reasonable cost, with a far less complex, much more compact, rugged and portable product.

SUMMARY OF THE INVENTION

This invention provides an improved teaching manikin system having an interactive teaching system with voice coaching which is expected to sell for about $1,000. The electronic controller for this system, in addition to being inexpensive, is compact enough to fit in a space about the size of a textbook.

This system enables one-on-one training and interaction with the student via sensors in the manikin, input buttons on a touch panel, and immediate voice feedback. The sensing means in the manikin are proportional in nature rather than simple on/off limit switches.

The system monitors the student and gives him or her instant coaching feedback by means of a natural-sounding prerecorded voice. It also allows the student to select the particular phase of training he or she wishes to practice.

The invention also provides a means of simulating shallow breathing and a carotid pulse in the manikin at times preselected or secretly chosen by an instructor so that the student has a more realistic opportunity to learn to recognize these faint signs of revival and adjust his or her actions accordingly.

Thus, in keeping with one aspect of the invention, a simulation manikin system is provided for use by a student attempting to practice a procedure normally applied to the human body, such as cardiopulmonary resuscitation. The system includes a manikin that has an artificial lung into which the student can blow to expand the lung, and a resilient chest which the student can compress.

Sensors are provided in the manikin to accurately detect the instantaneous amount of lung expansion and chest compression. An A/D converter converts the analog sensor output signals to digital codes, and inputs them to a compact controller based on an inexpensive microcomputer chip governed by a control program stored in a ROM.

Pushbuttons on the controller's front panel enable the student to select any one of a variety of teaching routines prestored in the microcomputer's ROM. The microcomputer then uses lamps on the panel and a speech synthesizer having prerecorded human speech stored in ROM chips to issue instructions and advice to the student. These are contingent on his performance of the selected routine as detected by the sensors. However, a prestored interrupt routine always enables the student to switch from the current routine to any other or to get an immediate repeat of the last message from the system.

Transducers are provided for simulating a carotid pulse and shallow breathing in the manikin which can be activated by remote control using a wireless transmitter and receiver pair.

The invention is suitable for use in retrofitting "dumb" manikins which are already out in the field, as well for incorporation into new manikin-controller assemblies; a fact which should be taken into account in interpreting the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be best understood by reference to the following detailed description of a preferred embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of an interactive CPR training system including a simulation manikin and a control unit incorporating the principles of the invention;

FIG. 2 is a top plan view of a control panel for the training system of FIG. 1;

FIG. 3 is a flow diagram of a typical training sequence achieved by the training system of FIG. 1;

FIG. 4 is a functional block diagram of the control unit shown in FIG. 1;

FIG. 5 is a simplified schematic of a shallow breathing simulator for use in the system of FIG. 1;

FIG. 6A is a cross-section of a first embodiment of a carotid pulse simulator installed in the neck of the manikin of FIG. 1;

FIG. 6B shows a circuit for providing a bipolar driving voltage waveform for activating the motor of the carotid pulse simulator of FIG. 6A;

FIG. 6C is a cross-section of a second embodiment of a carotid pulse simulator for use in the manikin of FIG. 1;

FIG. 6D is a side elevational view of the carotid pulse simulator of FIG. 6C;

FIG. 7A is a simplified cross-section of a manikin fitted with a ventilation sensor and a combined hand position and chest compression sensor, seen at a time when there is little air in the ventilation sensor;

FIG. 7B is a simplified cross-section of the manikin of FIG. 7A seen at a time when air has been blown into the ventilation sensor;

FIG. 7C is a circuit diagram of an analog detection circuit used with the ventilation sensor or chest compression depth sensor shown in FIGS. 7A and 7B;

FIG. 8A is a simplified cross-section of a combined hand position and chest compression sensor for use with the manikin of FIGS. 7A and 7B;

FIG. 8B is a plan view of the lower face of a handplate of the combined sensor along the line C--C of FIG. 8A;

FIG. 8C is a plan view of the upper face of a switchplate of the combined sensor along the line C--C of FIG. 8A;

FIG. 8D is an enlarged view of the switchplate of FIG. 8A, showing its cooperation with a potentiometer for detecting its position;

FIG. 8E is a circuit diagram of an analog detection circuit used with the detecting potentiometer of FIG. 8D;

FIG. 8F is an enlarged cross-section of a top portion of the combined sensor of FIG. 8A near the edge;

FIG. 9A is a simplified schematic of a conversion circuit which converts measurements of the student's efforts to an eight bit digital code;

FIG. 9B is a curve showing the relationship between an input analog voltage measurement and an output digital code of the measurement;

FIG. 10 is a detailed schematic of a remote-controlled instructor intervention system used with the control unit of FIG. 4;

FIG. 11 is a block diagram of an embodiment of a Control Program for use with the control unit of FIG. 4;

FIGS. 12, 12A and 12B are flow chart for an embodiment of the Interrupt Routine incorporated in the Control Program of FIG. 11 and includes the Repeat, Message Subroutine of FIG. 11;

FIGS. 13, 13A and 13B are flow charts for an embodiment of the Ventilation Teaching Routine incorporated in the Control Program of FIG. 11;

FIG. 14 is a flow chart for an embodiment of the Carotid Pulse Teaching Routine incorporated in the Control Program of FIG. 11;

FIG. 15 is a flow chart for an embodiment of the Hand Placement Teaching Routine incorporated in the Control Program of FIG. 11;

FIG. 16 is a flow chart for an embodiment of the Single Chest Compression Teaching Routine incorporated in the Control Program of FIG. 11;

FIGS. 17, 17A and 17B are flow charts for an embodiment of the Chest Compression Rhythm Teaching Routine incorporated in the Control Program of FIG. 11;

FIG. 18 is flow chart for an embodiment of the Heimlich Thrust Teaching Routine incorporated in the Control Program of FIG. 11;

FIG. 19 is map showing how voice messages and phrases are stored in memory;

FIG. 20 is a flow chart for an embodiment of the Message Subroutine incorporated in the Control Program of FIG. 11;

FIG. 21A is a flow chart for an embodiment of the A/D Conversion Subroutine incorporated in the Control Program of FIG. 11, and FIG. 21B is a graph of a typical sensor signal as a function of time;

FIG. 22A is a flow chart for an embodiment of the Hand Position Check Subroutine incorporated in the Control Program of FIG. 11, and FIG. 22B is a map of the bits in a variable word HPSTORE used therein;

FIG. 23 is a flow chart for an embodiment of the scoring subroutine SCORC1 incorporated in the Control Program of FIG. 11;

FIG. 24 is a flow chart for an embodiment of the scoring subroutine SCORC2 incorporated in the Control Program of FIG. 11; and

FIG. 25 is a flow chart for an embodiment of the scoring subroutine SCORC3 incorporated in the Control Program of FIG. 11.

DETAILED DESCRIPTION

A. SYSTEM CONSTRUCTION

1. GENERAL CONSTRUCTION

As shown in FIG. 1, an interactive CPR training system constructed in accordance with the teachings of this invention comprises a simulation manikin 50 coupled by a cable 51 to a control unit 52 comprising a box 54 incorporating a control panel 53. Although control unit 52 is shown separated from the manikin 50, if desired the two may be combined into a single unit. For example, control unit 52 may be mounted in an otherwise unused lower portion of the manikin. Similarly, the electronics for the system may be distributed in any convenient manner between the control unit's box 54 and otherwise unused internal portions of the manikin.

2. CONTROL PANEL

FIG. 2 shows the control panel 53 in greater detail. The various resuscitation routines taught by the system in conjunction with simulation manikin 50 are chosen by the student, using selection buttons 56 for Hand Position, 57 for Carotid Pulse, 58 for Airway Ventilation, 59 for Chest Compression Depth, 60 for Chest Compression Rhythm, and 61 for Heimlich (Abdominal) Thrusts. An important feature of our invention is that the system is always ready to repeat the most recent message to the student if he or she presses the Repeat Message button 62.

Control panel 53 also includes a Pause/Resume button 63. Pressed once, this button causes the system to pause; pressed again this button causes the system to resume where it left off. If button 63 is pressed once for "Pause", the system will wait a predetermined period, for example four minutes, for the button to be pressed again for "Resume". If the second pressing does not occur within the predetermined period, the system abandons the routine that was "Paused" and resets itself to its standby low power state.

The selection buttons 56-61 for the teaching routines and the Repeat Message 62 and Pause/Resume 63 buttons have corresponding lamps 56a-63a, which may be light-emitting diodes (LED's). A Stop Button 64 causes the current routine being executed to halt and resets the system to its standby low power state.

At certain points in the various operating routines, the system is unable to accept inputs from the student. When the system is ready for student input, it blinks a ready lamp 65 on the control panel 53 of FIG. 2.

The system gives oral advice and coaching to the student via a speaker 66, using prestored messages chosen in context in response to various inputs from the user.

As visual feedback during the ventilation and chest compression training routines, an array 68 of colored LED's indicates the results of the student's efforts to breathe air into the manikin's "lungs" or to "restore circulation" by compressing the manikin's chest. This array consists of three yellow lamps Y1, Y2, Y3 for low readings, four green lamps G1, G2, G3, G4 for medium readings, and three red lamps R1, R2, R3 for high readings. The smallest effort above a certain threshold causes the lowest lamp Y1 to light, and successively larger signals light additional lamps in the order Y2, Y3, G1, G2, G3, G4, R1, R2, R3 until all the lamps are lit.

In the teaching routines this colored lamp array provides important visual feedback to the student: An effort (artificial respiration or chest compression) lighting only the yellow lamps is too low. An effort lighting one or more of the green lamps but none of the red lamps is good, an acceptable performance. But an effort that lights one or more of the red lamps is too much, indicating danger to the victim represented by the manikin.

During efforts to compress the manikin's chest, the student's hand position must be in a critical location corresponding to the lower half of the victim's sternum. As visual feedback, a set of lamps 70, 71, 72, 73 arranged around a stylized heart symbol 74 all remain lit if the hand position during compression is correct. If a lamp goes off, it indicates the hand position on the manikin is too far in a direction indicated by the turned off lamp relative to the center of the heart symbol. This allows the student to note his error and correct his hand position accordingly until all lamps are lit during compression.

In cardiopulmonary resuscitation it is important for the rescuer to periodically check to determine if the victim's breathing or heartbeat has resumed. Button 57 enables a training routine in which the student can practice locating and detecting a carotid pulse in the neck area of the manikin. As a more realistic simulation, the system provides for an instructor to secretly turn on in the manikin a simulation of shallow breathing or carotid pulse or both by means of an wireless signal to the control unit 52. With this objective in mind, the control panel 53 can also include a receiver sensor 75 in a convenient location, such as adjacent the Ready lamp 65. If, for example, an infrared beam is used for the wireless signal from the instructor, sensor 75 will be an infrared detector.

Control panel 53 also includes a cadence switch 67 to turn on a 1.5 Hz audible cadence beat to guide the student in performing a rhythmic series of chest compressions to restore blood circulation.

3. GENERAL TEACHING SEQUENCE

FIG. 3 shows a flow diagram of a typical training sequence enabled by the training system of FIG. 1, in which the student can proceed in the following sequence: Ventilation of the Airway (T1), Carotid Pulse Detection (T2), Hand Placement for Chest Compression (T3), Single Chest Compressions (T4), Chest Compressions in Rhythm (T5), and Heimlich Abdominal Thrusts to Remove Airway Obstructions (T6).

The system does not force the student to pursue the training in this sequence. Instead, the student is permitted to select any training routine at a time using the selection buttons 56-61 on the control panel of FIG. 2. However, like a good coach, as the student completes one training routine (e.g. Ventilation), the system vocally suggests the next appropriate sequence (Carotid Pulse), and for a brief interval even blinks the corresponding selection button for the suggested sequence. For example, at the close of the ventilation training the system plays the stored message "Excellent Ventilation. If you feel confident, you should now practice checking the carotid pulse. If you don't, try giving two breaths again," and blinks the selection button lamp 57a of FIG. 2 located on the carotid pulse selection button 57.

4. CONTROL UNIT

FIG. 4 shows a functional block diagram of control unit 52 of FIG. 1. At the heart of control unit 52 is a microcontroller 80. It is a feature of our invention that while the monitoring, feedback, and vocal coaching of the student is a sophisticated simulation of a human coach, all this can be accomplished with relatively modest computational power, cost and size. While control unit 52 could be implemented by a suitably programmed personal computer or a minicomputer or the like, the necessary associated input/output circuits alone would be at least as complicated and expensive as our microcontroller-based system. Instead, our invention can be satisfactorily realized based on a much simpler single-chip microcomputer

For example, microcontroller 80 be can a single chip microcomputer 80a such as the 8 bit HD637B05VOC microcomputer unit (MCU) available from Hitachi America, Ltd. of San Jose, Calif. Such a microcomputer 80a has a 4 kilobyte ROM (read only memory) 81 for holding a prestored control program and its associated prestored data. It also has a 192-byte RAM (random access memory) 82 which can be used as a scratchpad memory. The microcomputer's basic clock frequency can be set at a convenient frequency, such as 8.0 MHz (megahertz) by a suitable external crystal XTAL attached to terminals X1 and X2. To enable battery operation, the microcomputer unit is made with complementary metal-oxide semiconductor (CMOS) integrated circuits which have low power consumption.

FIG. 4 shows a number of peripheral chips used with microcomputer chip 80a, primarily as interface (input/output) chips. It is feasible, however, to use a more powerful microcomputer chip that will incorporate many of the functions of these external circuits. For example, Hitachi America, Ltd. also makes the HD63705ZO microcomputer unit that incorporates 8 channels with built-in A/D converters of 8-bit accuracy.

To enable it to respond to external control inputs, such as the selection buttons 56-63 on the control panel 53 of FIG. 2, microcomputer 80a has an interrupt port (INT) 83 for an external hardware interrupt. These selection buttons 56-63 provide inputs to a switch coder 84. Each time a selection button is pushed, switch coder 84 sends a coded interrupt signal on line 85 to interrupt port 83. The coded interrupt indicates which of the selection buttons has been pushed. The microcomputer 80a then interrupts its current task, storing internal register information in a stack (not shown) so it can return to it later The microcomputer 80a responds to the interrupt by means of an Interrupt Routine (FIG. 12) that implements the function corresponding to the button pushed.

Microcomputer 80a has an eight-bit timer on board which can be configured to use an external timer clock input received at a TIMER input. The on-board timer in microcomputer 80a includes an eight-bit timer data register TDR, which contains the current value of the on-board timer.

Microcomputer 80a also has various ports P1-P8 which it uses for input/output of data or control signals to external circuits and devices. A coded signal output at port P5 is used to control the indicator lamps on control panel 53 of FIG. 2. A lamp decoder circuit 88 receives the coded output of port P5 and uses it to determine which lamps are to be lit. Lamp decoder circuit 88 sends control signals to a lamp driver circuit 87 via line 88a to switch on or off LED's 56a (HAND POSITION), 57a (CAROTID PULSE), 58a (AIRWAY VENTILATION), 59a (CHEST COMPRESSION DEPTH), 60a (CHEST COMPRESSION RHYTHM), 61a (HEIMLICH THRUSTS), and 63a (PAUSE/RESUME) on control panel 53. To provide for blinking of the lamps, an oscillator signal OSCI is fed to lamp decoder 88 via blink control line 88b.

In a similar manner, the output at port P4 is used to control the panel lamps 62a (REPEAT MESSAGE) and 65 (READY) via a lamp decoder 90 and a lamp driver 89. To provide for blinking of the lamps 62a and 65, the oscillator signal OSC1 is also fed to lamp decoder 90 via blink control line 90b.

A port P2 is used to control a carotid pulse transducer 91 for simulating a carotid pulse in the manikin's neck. The two inputs of an AND gate 93 receive respectively the output of port P2 and a digital oscillator signal OSC2 of about 1 pulse per second (simulating the carotid pulse rate). The output of AND gate 93 is inputted as a control signal to a transducer driver circuit 92 whose output drives carotid pulse transducer 91.

Similarly, a port P3 is used to control a shallow breathing transducer 94 to enable the manikin to simulate a victim's shallow breathing. The output of port P3 is input as a control signal to a transistor driver 95 which drives shallow breathing transducer 94. An oscillator signal OSC3 having a period of about 4 seconds (simulating a breath every four seconds) is also input to shallow breathing transducer 94.

Electrical power for operating the system is provided by a power supply 97 that outputs supply voltage +V at 97c. It is an important feature of the invention that its circuits and auxiliary devices are small and efficient enough that a compact low-voltage battery 97a, such as six "D" size 1.5 volt dry cells, can provide the necessary electrical energy for the power supply. This permits the manikin to be conveniently portable. However, the power supply can also include an input jack 97b for an external DC supply voltage, such as can be provided by a conventional AC adapter (not shown) that depends on a 110 V. AC line cord for power.

Power supply 97 outputs a standby voltage V.sub.a at 97d and a main voltage +V at 97c. Standby voltage V.sub.a is always available if battery 97a is connected or there is a DC voltage input at 97b from an AC adapter. Standby voltage V.sub.a powers those few circuits which must always be able to respond to the pressing of a selection button , such as switch coder 84 and a power supply control flip-flop 97e.

The main voltage +V is turned on to run the teaching routines and turned off for power saving. The output of flip-flop 97e is inputted to power supply 97 so that the state of flip-flop 97e controls whether main voltage +V is on or off.

When the output of flip-flop 97e is a logical 1 (high), main voltage +V is turned on. This is done by inputting a signal that is a logical 1 to the S (SET) input of flip-flop 97e. Pressing any of program switches 56-63 causes selection switch coder 84 to output a power up PSET signal that is a logical 1 on line 85a to input S of flip-flop 97e. This puts flip-flop 97e in its 1 state, turning on main voltage +V for microcomputer 80a and its peripheral circuits. Pressing any of selector switches 56-63 also causes selection switch coder 84 to send an interrupt signal on line 85 to microcomputer 80a.

Once provided with the main voltage +V, microcomputer 80a automatically initializes itself and then services the interrupt signal from selection switch coder 84 to provide the teaching routine corresponding to the switch (56-63) which has been pressed.

Inputting a signal that is a logical 1 to the R (RESET) input of flip-flop 97e causes the flip-flop to output a logical 0 (low), turning off main voltage +V. The R input of flip-flop 97e is fed by the output of an OR gate 97f having two inputs, one from a power off port PO of microcomputer 80a and the other from the STOP button 64 on control panel 53 of FIG. 2. If either of these two inputs is a logical 1, OR gate 97f outputs a logical 1, resetting flip-flop 97e to turn off main voltage +V, putting the system in its standby low power state.

Thus pressing the STOP button 64 on control panel 53 stops the system by turning off the main voltage but leaves it in the standby state. Normally, pressing the PAUSE/RESUME button on control panel 53 once causes the system to temporarily halt its present routine and wait a preset period for the button to be pressed again for RESUME. However, if the preset period, for example four minutes, is exceeded, microcomputer 80a outputs a logical 1 via power-off port P0, line 99, and OR gate 97f to turn off the main voltage +V.

Ports P6, P7 and P8 are used to provide a simulated speech output including coaching instructions to the student. As will be explained in more detail below, all messages to the student are composed of short, prestored phrases. Therefore, a message is reproduced by sequentially synthesizing each of the prestored phrases making up the message. The real voice sounds which make up the phrases sampled, and sample numbers from which the phrases can be synthesized by a speech processor 108 have been stored as bytes in speech memory chips.

To reproduce a prestored phrase, port P6 is used to output a signal on line 101 to a speech chip decoder 100 that sends an enable signal to the speech memory chip 104 holds the sample numbers for that phrase. Then port P7 is used to output an address on address bus 105. The contents at that address in the enabled speech chip are read out via a data bus 107 to speech processor 108. After synthesizing the corresponding sound from contents of that address, speech processor 108 sends a signal to port P8 of microcomputer 80a via line 111 to indicate that it is ready to receive the next sample number. The microcomputer 80a responds by outputting the next address on address bus 105. This process is repeated until all stored sounds of the phrase have been synthesized.

The synthesized output of speech processor 108 is smoothed by a low-pass filter 109 having a high frequency cutoff of about 4 kHz. The smooth audio output of low-pass filter 109 is amplified by audio amplifier 110, which drives the output speaker 66 on control panel 53 of FIG. 2.

To assist the student in developing the proper rhythm for chest compressions, a cadence beat is provided by a 1.5 Hz cadence signal. A cadence switch 67 on the control panel 53 connects this signal to audio amplifier 110 for audio output by speaker 66.

An external oscillator 112 is provided to generate a reference clock for the relatively low frequency signals. The output frequency of this oscillator is divided by frequency divider circuit 113. That circuit 113 has outputs for the various reference input signals OSC1 (indicator lamp flashing), OSC2 (carotid pulse), OSC3 (shallow breathing), as well as the 1.5 Hz cadence beat, and a 125 Hz timer clock signal that is inputted to microcomputer 80a at a TIMER terminal.

The normally closed switches S12, S3, S6, S9 shown in FIG. 4 are located on the manikin's chest to detect of the student's hand position during chest compression exercises. As will be discussed below in more detail in connection with FIGS. 8A-8F, a misplaced hand will open one or more of these switches. Each of the switches has one side connected to ground and the other side connected to a corresponding LED 70, 71, 72, 73 on the control panel 53 of FIG. 2. Each of the LED's is connected to the supply voltage +V via a respective load limiting resistor 86a. As visual feedback to the student, when a switch S12, S3, S6, S9 is closed, its corresponding LED 70, 71, 72, 73 will be ON, and when the switch is open, the corresponding LED will be OFF.

The non-grounded side of each of the switches S12, S3, S6, S9 has a respective output line 70a, 71a, 72a, 73a connected to a position switch coder 86 and through a respective load resistor 86b to the supply voltage. When a switch S12, S3, S6, S9 is closed, the voltage on the corresponding output line 70a, 71a, 72a, 73a will be a logical 0 (ground), and when the switch is open the output line voltage will be a logical 1 (high). Position switch coder 86 encodes the state of each of the switches and inputs the coded information to microcomputer 80a via port P9.

The manikin is fitted with position sensors for measuring the student's efforts to compress the manikin's chest and to ventilate the manikin's artificial lungs. In FIG. 4 a chest compression sensor 116 is shown as a potentiometer whose main resistive element is connected between ground and supply voltage +V, and whose output slider is mechanically linked to move as the chest is compressed. The output slider voltage is inputted to an A/D (analog to digital) converter 117 when a suitable READ pulse is received on READ/WRITE line 121. The digitized output of A/D converter 117 is inputted to port P1 of microcomputer 80a via a multiplexing I/0 port 120.

Similarly, a ventilation sensor 118 is shown as a potentiometer whose main resistive element is connected between ground and supply voltage +V, and whose output slider is mechanically linked to move as air is blown into the manikin's artificial lungs via a mouth opening of the manikin.

The output slider voltage is inputted to a corresponding A/D converter 119 when a suitable READ pulse is received on READ/WRITE line 122. The digitized output of A/D converter 119 is inputted to multiplexing I/0 port 120. By sending suitable control signals to the multiplexing I/0 port via port P1, microcomputer 80a can read in either the digitized signal from the chest compression sensor 116 or the digitized signal from the ventilation sensor 118.

The slider outputs of the chest compression sensor and ventilation sensor are also outputted as analog signals to output jacks 123 and 124 respectively, which can be used to attach a strip chart recorder or other device for recording or monitoring the student's efforts.

During ventilation and chest compression training routines the LED array 68 on the control panel 53 of FIG. 2 provides visual feedback to the student of the magnitude of his or her efforts. This LED array consists of three yellow lamps Y1, Y2, Y3 for the lowest readings (student's efforts too weak or shallow to be effective), four green lamps G1, G2, G3, G4 for the medium readings (student's efforts acceptable), and three red lamps R1, R2, R3 for the high readings (student's efforts too strong, i.e. dangerous to victim). The smallest effort above a threshold causes the lowest lamp Y1 to light, and successively larger signals light additional lamps in the order Y2, Y3, G1, G2, G3, G4, R1, R2, R3 until all the lamps are lit. LED array 68 can be driven by a commercially available display decoder driver circuit used in a bar mode that increases the number of LED'S lit in proportion to the magnitude of the signal input received by it. For example, National Semiconductor's LED dot/bar generator chip LM3914 can be used for this circuit.

Because the student will not be attempting to compress the manikin's chest and ventilate the manikin's lungs simultaneously, the outputs of the chest compression and ventilation sensors may be visually displayed with a single LED array 68.

The chest compression sensor 116 and the ventilation sensor 118 are each adjusted to give a zero output in the "inactive or default position" corresponding to no activity by the student. The analog signals from chest compression sensor 116 and ventilation sensor 118 are added together by an adder circuit 126. The output (sum) signal of adder 126 is proportional to the magnitude of the active sensor, there being substantially no output contribution from the inactive sensor. The output of adder 126 is inputted to the display decoder driver 125 to drive the common LED array 68.

A rescuer giving cardiopulmonary resuscitation must regularly check for and be alert to whether the victim exhibits a carotid pulse or shallow breathing. The control panel 53 provides a selection button to practice sensing the carotid pulse in the manikin's neck. But an important element of realism is added by enabling the instructor to surreptitiously switch the carotid pulse and shallow breathing transducers on and off by remote control without warning. Additional control inputs 131 (to activate the carotid pulse transducer 91) and 134 (to activate the shallow breathing transducer 94) are provided on selection switch coder 84 for this purpose. Selection switch coder 84 treats control inputs 131 and 134 as if they were additional selector switch inputs for sending a coded interrupt to microcomputer 80a to enable the carotid pulse and shallow breathing transducers. If input 131 or 134 is a logical 1 (voltage high), the corresponding transducer is enabled by microcomputer 80a via the corresponding port P2 or P3. If input 131 or 134 is a logical 0 (voltage low), the corresponding transducer is not enabled.

The remote control can be by means of a two-channel wireless transmitter 128 that can signal to a matching receiver 129 the logical state desired for two receiver outputs, SB (shallow breathing) and CP (carotid pulse). Device controllers in the form of matching sets of transmitter and receiver circuits that work with infrared or ultrasonic emitters and detectors are commercially available for this purpose.

For example, Motorola Semiconductor Products of Schaumburg, Ill. makes a transmitter (MC14457) and receiver (MC14458) pair of CMOS chips designed for either infrared or ultrasonic ON/OFF remote control of up to 16 channels. If infrared signals are used, the transmitter circuit 128 receives the instructor's selection of the carotid pulse or shallow breathing transducers by means of corresponding selection buttons CP1 and SB1. Transmitter circuit 128 then encodes these choices and transmits them by modulating an output LED that emits an infrared beam. The matching receiver is provided with a receiving photodiode detector sensitive to infrared, whose detected signal is demodulated to determine the desired state of corresponding outputs CP and SB. Similarly, if ultrasonic signals are used, transmitter circuit 128 modulates an ultrasonic output transducer and matching receiver circuit 129 demodulates the output signal of an ultrasonic microphone detector.

The remote control can also be by means of control wires 132 and 135 to remote locations where the instructor can actuate corresponding pushbuttons CP2 and SB2 to send logical 1 signals for the carotid pulse or shallow breathing routines respectively.

In FIG. 4 both wireless and direct wire remote control are provided for. The two inputs of an OR gate 130 respectively receive the output CP of receiver 129 and the signal on wire 132 from pushbutton CP2. The output of OR gate 130 is inputted as a carotid pulse transducer control signal to input 131 of selection switch coder 84. Thus, if wireless output CP or signal wire 132 is a logical 1, OR gate 130 will output a logical 1 to input 131 to signal microcomputer 80a to activate the carotid pulse transducer 91.

Similarly, the inputs of an OR gate 133 receive the outputs SB of receiver 129 and the signal on wire 135 from pushbutton SB2. If wireless output SB or signal wire 135 is a logical 1, OR gate 133 will output a logical 1 to input 134 to signal microcomputer 80a to activate the shallow breathing transducer 94.

5. SHALLOW BREATHING SIMULATOR

FIG. 5 shows a detailed example of the shallow breathing transducer 94 and transistor driver 95 of FIG. 4. Transistor driver 95 is a switching transistor having its emitter connected to ground receives at its base input 137 an enabling high signal (logical 1) from port P3 of the microcomputer whenever the operating program determines that the shallow breathing simulation is needed or has been requested (e.g., by instructor intervention). This switches transistor 95 ON, so that a circuit line 139 of a transducer driving circuit 94a is essentially at ground, enabling the driving circuit. Driving circuit 94a is adapted to simulate a "breathing" waveform to drive a miniature output speaker 153 located in the manikin's throat area.

Driving circuit 94a produces an amplitude-modulated random or white noise signal having an amplitude envelope that is a periodic triangular shaped wave with a period of about four seconds (one shallow breath every four seconds). To generate random noise, two reverse-biased diodes 140 and 141 are connected in series between the main voltage +V and grounded line 139 to create random "shot noise" at their connection point 140a. This random noise is input at 144 to an operational transconductance amplifier 145, such as LM 13600 made by National Semiconductor, which provides for a voltage controlled gain input 147. The output of the amplifier at 146 is passed through a bandpass filter 151, such as National Semiconductor's MF5CN100 filter, having a bandpass of about 1 to 5 kHz, and then drives miniature speaker 153.

The gain of amplifier 145 is modulated at gain input 147 by a voltage output at 150 from a triangular waveform generator 149 having a period of 4 seconds. In the functional block diagram of FIG. 4, frequency divider 113 provides a suitable 0.25 Hz low-frequency clock signal OSC3 which can be inputted to triangular waveform generator 149 at 152 to regulate its 4-second triangular periodic waveform.

Each new four-second period of shallow breathing simulation begins with the gain of amplifier 145 set to zero, after which the gain is increased steadily to raise the volume of the white noise. The volume peaks after two seconds, and then the gain of amplifier 145 is steadily reduced to zero in the remaining two seconds of the period, causing the white noise sound to fade away. Thus, the volume of the white noise passed to speaker 153 via bandpass filter 151 rises and falls during the four second period of the triangular waveform, simulating the sound of breathing.

If desired, the movement of air from the mouth and nose during breathing can be simulated by providing a small fan 156 powered by a miniature DC fan motor 155 in the manikin's airway passage area. One terminal of DC motor 155 is attached to the main supply voltage +V and the other terminal is attached to a line 138 wired to the collector of switching transistor 95. Whenever transistor 95 is turned ON by the input at base 137, line 138 is essentially grounded, turning on motor 155 to drive fan 156.

6. CAROTID PULSE SIMULATOR

A person performing cardiopulmonary resuscitation must initially determine if the victim's heart has stopped (cardiac arrest), and during the procedure to restore circulation by chest compressions must periodically check for a return of the heart function. This is done by checking the victim's pulse, preferably the carotid pulse in one of the arteries found on either side of the neck. This is done by placing the tips of the index and middle fingers at the correct pulse location at the side of the victim's neck.

FIG. 6A shows a first embodiment of a carotid pulse simulator 91 that can be suitably located in the hollow area 161 of the manikin's neck 160. The neck is a tubular structure enclosed by a cylindrical wall 162 of plastic "skin". A layer of resilient material 163, such as foam rubber, is attached, by adhesive or the like, to the inside face of neck wall 162. A small DC motor 164 is then axially mounted to the front of neck wall 162 with its drive shaft 164a parallel to the axis 160a of the manikin's neck. The resilient material 163 is used to provide a cushion between motor 164 and neck wall 162. For example, the motor can be attached to the resilient material by a suitable adhesive.

A pair of linkages 165 are symmetrically mounted at approximately a right angle to each other on the motor shaft 164a, and are driven by it. Mounted to each linkage at approximately a right angle is an outwardly directed radial beater arm 166 that rests against the resilient material. Each time DC motor 164 is driven in a clockwise direction, the beater arm 166 on the right impinges on resilient material 163 lining the manikin's neck wall 162. This delivers an impulse of force F to the neck wall in the "carotid" region that can be felt by the student's fingers as a simulated beat of a carotid pulse on that side of the neck. Similarly, when motor 164 is driven counterclockwise, beater arm 166 on the left impinges on material 163, delive