US3614951A

US3614951A - Switch-connected system for monitoring hospital patients

Info

Publication number: US3614951A
Application number: US792299*A
Authority: US
Inventors: Cecil Caro
Original assignee: TERRELL SUPPLY CO
Current assignee: TERRELL SUPPLY CO
Priority date: 1969-01-21
Filing date: 1969-03-17
Publication date: 1971-10-26
Anticipated expiration: 1988-10-26

Abstract

A SYSTEM WHICH INCLUDES A PATIENT SELECTOR SWITCHER FOR ENABLING A GROUP OF PRIMARY CARDIOSCOPE INSTRUMENTS LOCATED AT A CENTRAL NURSING STATION TO BE INDIVIDUALLY CONNECTED TO ANY ONE OF A NUMBER OF CARDIAC SENSOR INSTRUMENTS LOCATED AT DIFFERNT HOSPITAL BED POSITIONS AND FOR ENABLING THE PRIMARY CADIOSCOPE INSTRUMENTS TO DRIVE FOR ENABLING THE PRIMARY CARIOSCIPE INSTRUMENTS TO DRIVE POSITIONS. THE SYSTEM FURTHER INCLUDES A MEMORY TAPE LOOP SWITCHER FOR ENABLING A GROUP OF MAGNETIC RECORDER INSTRUMENTS TO BE INDIVIDUALLY CONNECTED TO ANY ONE OF THE PRIMARY CARDIOSCOPE INSTRUMENTS. THE SYSTEM ALSO INCLUDES A TELEVISION SWITCHER FOR ENABLING A GROUP OF TELEVISION MONITORS LOCATED AT THE CENTRAL NURSING STATION TO BE INDIVIDUALLY CONNECTED TO ANY ONE OF A NUMBER OF TELEVISION CAMERAS LOCATED AT THE DIFFERENT BED POSITIONS.

Description

C. CARO Oef. 26, 1.971

v 'SWITCH-CON.\IIEIO'J`.ED SYSTEM FOR MONITORING HOSPITAL PATIENTS Filed Jan. 21 1969 4 Sheets-Sheet l C. CARO Oct. 26, 1971 SWITCH-CONNECTED SYSTEM FOR MONITORING HOSPITAL PATIENTS Filed Jan.. 2l. 1969 4 Sheets-Sheet 2 c. CARO 3,614,951

SWITCH-CONNECTED SYSTEM FOR MONITORING HOSPITAL PATIENTS 4 Sheets-Sheet 5 Oct. 26, 1971 'Filed Jan. 21 1969 hwl?, l k kw Q mw Oct. 26, 1971 Q CARO 3,614,951

SWITCH-CONNECTED SYSTEM FOR MONITORING HOSPITAL PATIENTS Filed Ja. 2l, 1969 v4 Sheets-Sheet /L I L I@ /g 4 71/ Jw/rc/ff@ 46 /0V (54M (j 4915 457C d 4.0/

b3 iC I I I I I I I I I: I I? I( V I I 92a g3g' .04a Ill I I j 0 00 ooo '000000 I/ I I I I I 9 2 I f1.3 I if I I II 055 l 05 I/ 25d i I I I I I I I I/ l/I/l/E/v'rok Cef/Y fafa 'Magda phone? f MnIIIqewA /TTRNE YS United States U.S. Cl. 12S- 2.06 R 11 Claims ABSTRACT OF THE DISCLOSURE A system which includes a patient selector switcher for enabling a group of primary cardioscope instruments located at a central nursing station to be individually connected to any one of a number of cardiac sensor instruments located at different hospital bed positions and for enabling the primary cadioscope instruments to drive slave cardioscopes located at the corresponding bed positions. The system further includes a memory tape loop switcher for enabling a group of magnetic recorder instruments to be individually connected to any one of the primary cardioscope instruments. The system also includes a television switcher for enabling a group of television monitors locatedrat the central nursing station to be individually connected to any one of a number of television cameras located at the different bed positions.

BACKGROUND OF THE INVENTION This invention relates to electrical systems and apparatus for monitoring hospital patients.

It has been heretofore proposed to utilize various types of remote monitoring apparatus for enabling some condition of a patient in a hopsital room to be monitored at a location which is some distance removed from the hospital room. With the increased emphasis on more intensive patient care, particularly in coronary cases, together with the increasing shortage of highly trained nursing personnel, it is becoming increasingly desirable to provide a larger number of hospital rooms and hospital beds with such remote monitoring capability. In this manner, one or a small number of nurses positioned at a central nursing station can closely watch the conditions of a larger number of patients located in different hospital rooms or hospital beds.

A major disadvantage of many of the previously proposed patient monitoring systems is that the amount of monitoring equipment and, hence, its cost increases in direct proportion to the hopsital beds which are provided with this remote monitoring capability. If twice the number of beds are so equipped, then twice the amount of monitoring equipment is required. As a consequence, the usual practice has been to equip only certain special rooms with this remote monitoring capability. This, however, may present problems and inconveniences in allocating rooms to new incoming patients. It may sometimes be necessary to move an old patient out of one of these specially equipped rooms in order to enable a new incoming patient to occupy such room.

Another disadvantage of the previously proposed systems is that if the central station monitoring equipment connected to any given room should suiIer an equipment failure, then there is no quick and foolproof way of replacing the defective equipment with properly operating equipment. Among other things, the services of a trained service technician may be required to make the necessary equipment changes.

SUMMARY OF THE INVENTION It is an object of the invention, therefore, to provide a new and improved system for monitoring hospital patients which enables a sizeable number of hospital bed ice positions to be provided with a remote monitoring capability with a minimum amount of monitoring equipment.

It is another object of the invention to provide a new and improved system for monitoring hospital patients which provides a high degree of operating flexibility without impairing the safety or reliability of the monitoring operation.

It is a further object of the invention to provide a new and improved system for monitoring hospital patients which provides an increased degree of safety in case of failure of some of the monitoring equipment.

In accordance with one feature of the invention, a system for monitoring hospital patients comprises a plurality of patient sensor instruments individually located at different hospital bed positions for producing electrical signals representing physical conditions of patients. The system also includes a plurality of primary monitor instruments located at a central nursing station for displaying indications of patient sensor signals. The system further includes a plurality of secondary monitor instruments individually located at the different hospital bed positions for providing bedside indications of patient sensor signals. The system additionally includes switch means for enabling each primary monitor instrument to be coupled to the patient sensor instrument and the secondary monitor instrument at any one of the bed positions for receiving signals from the patient sensor instrument and for supplying signals to the secondary monitor instrument.

In accordance with another feature of the invention, the system includes a plurality of magnetic recorder instruments each having recording means for recording patient sensor signals and control means responsive to alarm signals for controlling the operation of the recording means of such instruments. The system also includes switch means for enabling the recording means and the control means of each magnetic recorder instrument to be coupled to any one of the primary monitor instruments for respectively recording signals corresponding to the patient sensor signals applied to such primary monitor instrument and for responding to any alarm signal produced by such primary monitor instrument.

For a better understanding of the present invention, together with other and further objects and features thereof, reference is had to the following description taken in connection with the accompanying drawings, the scope of the invention being pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings:

FIG. l shows an overall block diagram of a patient monitoring system constructed in accordance with the present invention;

FIG. 2 is a detailed circuit diagram of a patient selecto switcher used in the FIG. l system;

FIG. 3 is a detailed circuit diagram of a memory tape loop switcher used in the FIG. l system; and

FIG. 4 is a detailed circuit diagram of a television switcher used in the FIG. 1 system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. l of the drawings, the hospital patient monitoring system there shown includes a group of four hospital bed positions 11-14. These bed positions 11-14 may be located in four separate hospital rooms or may be grouped into a smaller number of rooms, The showing of four bed positions is merely for sake of example because the system can readily accommodate a much larger number of bed positions. Each of the bed positions 11-14 includes a patient sensor instrument, a secondary monitor instrument, and a television camera instrument. In this particular example, the patient sensor instruments at the different bed positions take the form of electrocardiograph (EKG) sensors 15a-15d. Each of these sensors includes the customary set of five electrodes which are to be fastened to the arms, legs, and chest of a patient being monitored. The secondary monitor instruments at the different bed positions take the form of individual slave cardioscopes 16a-16d. Each of these slave cardioscopes comprises a cathode ray tube oscilloscope upon the display screen of which can be displayed the cardiac complex waves for the pair of EKG electrodes which are selected to be monitored. The television camera instruments at the different bed positions are represented by television camera 17a-17d. These cameras may be of the type used in closed circuit television systems.

EKG sensors 15a-15d and slave scopes 16a-16d are coupled by means of multiconductor cables 18a-18d and 19a-19d to a patient selector switcher 20 located at a central nursing station. Also located at the central nursing station are a group of primary monitor instruments for displaying indications of patient sensor signals. In the illustrated embodiment, these primary monitor instruments take the form of cardioscope and heart rate monitors 21-24. The cardioscope portions of these monitor instruments 21-24 include cathode ray tube Oscilloscopes for reproducing on the display screens thereof selected cardiac complex waves which are supplied thereto by the patient seelctor switcher 20 by way of multiconductor cables 25a-25d. The cathode ray tube Oscilloscopes forming the cardioscope portions include xed time base circuits for producing the horizontal dellections on the cathode ray tube display screens and the incoming cardiac signals are supplied to the vertical deflection circuits for producing the vertical deections on the cathode ray tube display screens. Each of the cardioscope portions of the monitor instruments 21-24 includes an appropriate input selector switch for selecting two of the live EKG electrodes for providing the cardiac signals `which are dis played on the cathode ray tube display screen. Each of these cardioscope portions also includes a signal amplifier for amplifying the signals from the selected pair of EKG electrodes before they are applied to the vertical deflection elements of the cathode ray tube. These amplified cardiac signals are also supplied by way of cables 26a-26d to the patient selector switcher 20 for purposes of providing the driving signals for the slave cardioscopes 16a-16d.

The patient selector switcher 20 enables each of the input cables 25a-25d for the monitor instruments 21-24 to be coupled to any one of the output cables 18a-18d coming from the EKG sensors 15a-15d. In this manner, each of the monitor instruments 21-24 may receive cardiac signals from any one of the sets of EKG sensors 15a-15d. The patient selector switcher 20 also enables each of the amplied output signal cables 26a-26d coming from the monitor instruments 21-24 to be coupled to any one of the input cables 19a-19d which run to the inputs of the slave cardioscopes 16a-16d. As a consequence, the amplied cardiac signals produced by each of the primary monitor instruments 21-24 may be supplied to any one of each of the slave cardioscopes 16a-16d for purposes of driving same. Switch controls knobs 27a-27d located on the front panel of the patient selector switcher 20` enable the selection of the bed position to which each of the monitor instruments 21-24 are to be connected. Switch control knob 27a, for example, enables the input and

output cables

25a and 26a of the monitor instrument 21 to be connected to the cables for the EKG sensor and slave scope for any one of the four bed positions 11-14. The construction of the patient selector switcher 20 is such that the two cables for any given one of the monitor instruments 21-24 are always connected to the EKG sensor and slave scope located at the same bed position.

The heart rate monitor portions of the primary monitor instruments 21-24 each include means for counting the R-wave peaks of the cardiac complex waves being displayed by the cardioscope portion of the corresponding one of the monitor instruments 21-24. In each case, this counting means drives` an appropriate meter movement for providing a visual indication of the patients heart rate and, as such, is calibrated in pulses or beats per minute. Associated with each of these heart rate meter movements are adjustable upper and lower limit switch mechanisms which function to produce an alarm signal whenever the patients heart rate reaches either the upper or lower selected heart rate limit.

The cardioscope and heart rate monitor instruments 21-24 may be of the type manufactured by Dallons Instruments of El Segundo, Calif.

The alarm signals produced by the monitor instruments 21-24 are supplied by way of cables 28a-28d to a memory tape loop switcher 30. These alarm signals are, in turn, supplied by the memory tape loop switcher 30 by way of a set of cables 31a-31d to an automatic central station 32. The cardiac signals which are being displayed by the monitor instruments 21-24 are also supplied by way of cables 33o-33a' to a set of patient sensor signal input terminals of the automatic central station 32. The signals supplied by way of these cables 3fm-33d are the unamplilied cardiac signals obtained from the pairs of EKG electrodes selected by the initial input switches in each of the monitor instruments 32-24. The automatic central station 32 is adapted to supply a selected cardiac signal by way of a cable 34 and a selector switch 35 to a first input of a chart recorder 36. The automatic central station 32 is also adapted to supply a selected alarm signal by way of a cable 37 to a second input of the chart recorder 36. Chart recorder 36 may be of the type normally used for making ink records of electrocardiograph signals on a moving strip of chart paper.

In the absence of an alarm condition, the chart recorder 36 is in a standby condition and is not making a record. Upon the occurrence of an alarm condition on one of the alarm signal cables 31a-31d, the automatic central station 32 operates to do two things. First, it operates to select the particular one of the EKG signal cables 33a-33d which is connected to the same one of the monitor instruments 21-24 which is giving rise to the alarm signal and to couple this selected EKG signal cable to the output cable 34 of the automatic central station 32. This supplies the selected EKG signal to the data signal input of the chart recorder 36. Secondly, the automatic central station 32 operates at this same time to supply an alarm signal by way of cable 37 to the alarm signal input of the chart recorder 36. This alarm signal switches the chart recorder 36 from its standby condition to its fully operative condition, whereupon the recorder 36 commences to record the EKG signal from the patient in the alarm status.

The automatic central station 32 may be of the type Ialnifactured by Dallons Instrument of El Segundo,

The amplified cardiac signals produced by the monitor instruments 21-24 are also supplied by way of cables 38u-38d to the memory tape loop switcher 30. Memory tape loop switcher 30 connects selected ones of these amplilicd cardiac signal cables 38u-38d to dilTerent ones of a set of magnetic recorder instruments represented by a pair of memory tape loop units 40a and 40h. These connections are made by way of cables 41a and 41b which run to the data signal input terminals of the memory tape loop units 40a and 40b. The memory tape loop switcher 30 also connects a selected pair of alarm signal circuits in the switcher 30 to the memory tape loop units 40a and 40h by way of cables 42a and 42h.

Each of the memory tape loop units 40a and 401; is a magnetic tape recorder instrument which is adapted to record data signals on a closed loop of magnetic recording tape. Such recording tape may be housed in a suitable removable type of tape cartridge and the length of tape in the cartridge may be selected to provide anywhere from 40 seconds to 15 minutes of recording time. In addition to the data signal recording portion, each of the memory tape loop units 40a and 4Gb includes operating control means which are responsive to alarm signals supplied by way of the cables 42a and 42b for controlling the operation of the data signal recording portions of the units. The memory tape loop units 40a and 40b may be of the type manufactured by Dallons Instruments of El Segundo, Calif.

The memory tape loop switcher includes a pair of switch control knobs `43a and 43h for individually coupling each of the memory tape loop units 40a and 40h to any one of the monitor instruments 21-24. The control knob 43a, for example, serves to couple the data signal cable 41a to any one of the cables 38u-38d and the alarm signal cable 42a to the corresponding one of the alarm signal cables 28a-28d. In the case of the alarm signal cable 42a, the coupling is not a direct one, but the net effect is the same as though it were.

Each of the memory tape loop units 40a and 401) includes a playback mechanism for playing back the signals recorded on their magnetic tapes. These playback signals are supplied by way of cables 44a and 44h to the selector switch associated with the chart recorder 36. By manipulation of the switch 35, the chart recorder 36 can be caused to make a paper chart recording of the playback signals from either of the memory tape loop units 40a and 4011. It is, of course, also necessary to switch the chart recorder 36 to the active operating condition at this time, because an alarm signal would probably not be present on the cable 37.

The memory tape loop units 40a and 4Gb are normally operating in their active recording modes as to continuously record any signals that may be present on the input cables `41a and 41h. In view of the fact that the magnetic tape in each unit is of the closed loop type, this means that after a iirst traverse of the magnetic tape has been completed, the magnetic recording means will continue to record incoming signals, the later signals replacing the earlier signals previously recorded on the magnetic tape. Thus, if the length of the magnetic tape is such as to accommodate, for example a ve-minute interval of the signals, then, because of the continuous operation of the recording mechanism, the tape will hold the most recent tive-minute interval of the signals. With this mode of operation, any alarm signal provided by the memory tape loop switcher 30 over either of the alarm signal cables 42a and 4211 operates to stop or discontinue the recording operation in the corresponding one of the memory tape loop units. This preserves the record of the cardiac signal which gave rise to the alarm. This operation should be contrasted with the operation of the chart recorder 36, which operation takes place after the occurrence of the alarm signal. Thus, the memory tape loop unit provides a record of the signal before the occurrence of the alarm, while the chart recorder 36 provides a record of the signal after the occurrence of the alarm.

In most cases, it is desirable to also include in each of the memory tape loop units 40a and 40h a suitable time delay device such that the alarm signal will not turn off the tape loop unit until some short period of time, say 30 seconds, after the occurrence of the alarm signal. This provides a short overlap of the records provided by the memory tape loop unit and the chart recorder 36, which overlap is helpful for matching the two records and also for insuring that none of the cardiac signals are missed in the process of turning oft the tape loop unit and turning on the chart recorder 36.

If the number of memory tape loop units is less than the number of the primary monitor instruments 21-24, then the switch control knobs 43a and `43h of the memory tape loop switcher 30 may be set so as to connect the memory tape loop units to the primary monitor instru-- ments which are monitoring the patients who are believed to be in the more critical condition.

The television camera instruments 17a-17d located at the diierent bed positions 11-14 are coupled by way of cables 45u-45d to a television switcher 46. Television 46 is, in turn, coupled by way of cables 17a-47d to a group of television monitors 48u-48d. These television monitors 18a-48d may be of the type normally used in closed circuit television systems. Television switcher 46 is provided with a set of front panel switch control knobs 19a-49d which can be manipulated to connect each of the television monitors 48u-48d to any one of the television cameras 17a-17d. The control knob 49a, for eX- ample, can be manipulated to couple the cable 47a of television monitor 48a to any one of the output cables 45u-45d coming from the television cameras 17a-17d. The television monitors 48a48d operate to produce on their picture tube display screens visual pictures of the patients as seen by the selected ones of the television cameras l7a-ll'7d.

The patient selector switcher 20, the cardioscope and heart rate monitor instruments 21-24, the memory tape loop switcher 30, the automatic central station 32, the chart recorder 36, the memory tape loop units 40a and 40h, the television switcher 46 and the television monitors 48u-48d are all located at the central nursing station. The television monitors 48u-48d are located adjacent the primary monitor instruments 21-24 in an appropriate manner, such that the television monitor and the cardioscope and heart rate monitor for a given patient may be readily observed by a nurse stationed at the central nursing station.

Referring now to FIG. 2 of the drawings, there is shown a detailed circuit diagram of the patient selector switcher 2t). The groups of conductors contained in the various cables which are coupled to the patient selector switcher Ztl are identilied by the same reference numerals as were used for the corresponding cables in FIG. l. As indicated in FIG. 2, each of cables 18a-18d and 25a-25d is a four-conductor shielded cable, with the shielding being used as a fifth conductor. Cables 19a-19d and 26a-26d, on the other hand, are two-conductor shielded cables. The individual conductors in each of the cables 18a-18d are connected to different ones of the EKG electrodes at the corresponding bed position, the cable shield being connected to the reference electrode used on the right leg.

The patient selector switcher 20 includes a first group of switch mechanisms indicated at 50 and including switch mechanisms 51-54. Switch mechanism 51 includes switch subassemblies Sla-51d, switch mechanism 52 includes switch subassemblies 52a-52d, switch mechanism 53 includes switch subassemblies 53a-53d, and switch mechanism 54 includes switch subassemblies 54a-54d. Each of the various switch subassemblies, such as the switch subassembly 51a, is in the form of what is known as a wafertype switch. Since each of the various switch subassemblies is of the same construction, only the subassembly 51a will be treated in detail. To this end, the switch subassembly Sla includes a movable contact element 55 in the form of a conductive tab which is attached to or extends from a circular rotatable conductive disc 56. A fixed wiper ar-m 57 makes a slidable electrical contact with the disc 56. The switch subassembly 51a further includes a series of stationary contacts 58 which are arranged concentrically with respect to the disc 56 and which are adapted to be contacted one at a time by the movable contact element 55 when the disc 56 is rotated.

Each of the various wafer switch subassemblies included in any given one of the switch mechanisms 51-54 is mounted on a common control shaft such that rotation of such shaft will cause simultaneous rotation of all of the movable Contact element discs of such switch mechanism. The presence of these control shafts is represented schematically by the dash-line constructions 59a-59d which denote the control shafts for the switch mechanisms 51- 54, respectively. These control shafts E9n-59d are mechanically connected to the front panel control knobs 27a-27d, respectively. Thus, for example, rotation of the control knob 27a causes rotation of the control shaft 59a and hence the movable contact discs of the subassemblies Sla-51d.

The four non-grounded conductors of the tirst monitor instrument input cable 25a are individually connected to different ones of the wiper arms of the switch subassemblies Sla-51d which make up the first switch mechanism 51. The four non-grounded conductors of the first EKG sensor output cable 18a are individually connected to stationary contacts at first positions on different ones of the switch subassemblies Sla-51d. The four non-grounded conductors of the second EKG sensor output cable 18b are individually connected to stationary contacts at second positions on different manner, the four non-grounded con- 51a-51d. In a similar manner, the four non-grounded conductors of the third and fourth EKG sensor output cables 18e` and 18d are connected to stationary contacts at third and fourth positions on each of the switch subassemblies Sla-51d. Thus, by rotating the control knob 27a and hence the movable contact elements of the subassemblies Sla-51d. In a similar manner, the four non-grounded conductors of the cable 25a running to the first monitor instrument 21 can be connected to the four non-grounded conductors in any one of the cables 18a-18d, which cables run to the different EKG sensors a-15d.

The remainder of the switch mechanisms of the first group 50, namely, the switch mechanisms 52-54, are wired up in a similar manner. The conductors for the monitor instrument cables 25h-25a' are connected to the wiper arms of the switch mechanisms 5254 respectively, in the same manner as were the conductors of the first cable 25a connected to the wiper arms of the first switch mechanism S1.

The patient selector switcher 20 further includes a second group of switch mechanisms indicated at 60. This group includes switch mechanisms 61-64. Each of these switch mechanisms 61-64 includes a pair of switch subassemblies of the wafer type. Switch mechanism 61, for example, includes switch subassemblies 61a and 61b. The switch subassemblies 61a and 61b of the first switch mechanism 61 are mounted on the same control shaft 59a as are the switch subassemblies Sla-51d of the first switch mechanism 51 of the first group S0. Similarly, the subassemblies of the other switch mechanisms 62-64 are mounted on the control shafts 59b-59d, respectively. The conductors of the cables 26a-26d which carry the amplified cardiac signals from the primary monitor instruments 21-24 are connected to the wiper arms of their respective ones of the switch mechanisms 61-64. The conductors of the cables 19a-19d which run to the inputs of the slave cardioscopes 16a-16d are connected to the stationary contacts of the switch mechanisms 61-64, the conductors of the first cable 19a being connected to the first position stationary contacts, the conductors of the second cable 191) being connected to the second position stationary contacts, and so forth. In this manner, manipulation of the control shafts 59a-59d by means of their respective control knobs 27a-27d enables the conductors of each of the cables 26a-26d to be connected to the conductors of any one of the cables 19a-19d. Thus, each of the primary monitor instruments 2124 may be connected to any one of the slave cardioscopes 16rz-16dy The use of common control shafts 59a-59d interconnecting the movable contact means of the corresponding switch mechanisms in the two groups 50 and 6() guarantees that any given primary monitor instrument will only be connected to an EKG sensor unit and a slave cardioscope which are located at the same bed position. This is an important feature because, otherwise, the cardiac signals supplied to a slave carioscope at a given bed position might not be the cardiac signals produced by the EKG sensors at that saine bed position. Such an undesired occurrence could, of course, have very serious consequences. With the present apparatus this type of undesired occurrence cannot happen.

Referring now to FIG. 3 of the drawings, there is shown a detailed circuit diagram of the memory tape loop switcher 30. This switcher 30 includes a first group of switch mechanisms indicated at 7). This group 70 includes

switch mechanisms

71 and 72. Switch mechanism 71 includes a pair of wafer switch subassemblies 71a and 7lb, while the switch mechanism 72 includes a pair of wafer switch subassemblies 72a and 72b. The movable contact means of the switch subassemblies 71a and 71b are mounted on a first control shaft 73a which is connected to the front panel control knob 43a. The switch subassemblies 72a and 72b are mounted on a second control shaft 73h which is connected to the second front panel control knob 43h.

The conductors of the first memory tape loop unit sensor signal input cable 41a are connected to the wiper arms of the first switch mechanism 71, while the conductors of the second memory tape loop sensor signal input cable 411) are connected to the wiper arms of the second switch mechanism 72. The conductors of the amplified output signal cables 38a38d' coming from the primary monitor instruments 21-24 are connected to different ones of the stationary contacts of the

switch subassemblies

71a, 71b, 72a and 72b. The conductors of the first cable 38a are connected to the first position stationary contacts, the conductors of the second cable 38h are connected to the :second position stationary contacts, and so forth. Manipulation of the first control knob 43a and, hence, the first control shaft 73a, enables the conductors of the first memory loop input signal cable 41a to be connected to the conductors of any selected one of the primary monitor output signal cables Stia-38d. Similar considerations apply for the second control knob 43b and the second switch mechanism 72.

The memory tape loop switcher 30 further includes a group of relay mechanisms indicated at 75. This group 75 includes relay mechanisms 76-79. Each of these relay mechanisms 76-79 includes relay switch means and relay control means for controlling the relay switch means. The relay control means for the first relay mechanism 76 is represented by relay armature coil 76a and the relay switch means are represented by switches 76b-76d. The relay mechanism 76 is of the normally open type. This means that when no current is flowing through the armature coil 76u, the switches 76b-76d are open. Conversely, when sufficient current is owing through the armature coil 76a, the magnetic field established by such coil serves to close the switches 76b-76a. The other relay mechanisms 77-79 are constructed in a similar manner.

The relay control coils 7Go-79a are individually coupled in circuit with the alarm signal producing means associated with different ones of the primary monitor instruments 21-24. This coupling is provided by means of the conductors of the alarm signal cables 28a-28d and the output circuit of a direct-current power supply unit 80. The power supply 80 is rendered operative by plugging a line cord plug S1 into a suitable 60-cycle alternatingcurrent wall outlet and closing a master on-ofi switch 82. The power supply 80 provides a direct-current output voltage of l2 volts.

It will be recalled that the primary monitor instruments 21-24 included limit switch mechanisms for signaling when the heart rate of a patient reached an alarm condition. The limit switch mechanisms of each monitor instrument include a switch which is connected between the monitor instrument ends of the pair of conductors in the corresponding one of the alarm signal cables 28a-28d. When an alarm condition is reached, one of these switches is closed to effectively connect together the two monitor instrunient ends of the conductors in the appropriate alarm signal cable. Assume, for example, that it is the primary monitor instrument 21 which detects an alarm condition. The limit switch mechanism in such instrument 21 then connects together the ends of the two conductors in the cable 28a at the end thereof which is connected to the monitor instrument 21. This enables direct current to flow from the power supply 80 out through one of the conductors of the cable 28a, back through the other of the conductors of the cable 28a, through the relay control coil '76a and then back to the power supply 80. This current flow energizes the relay control coil 76a and closes the relay switches 76b-76d. The closing of these switches serves to actuate an alarm signal mechanism in the automatic central station 32 and, if one of the control knobs 4311 and 43b is in the first position, an alarm signal mechanism in one of the memory tape loop units 40a and 40b.

The other relay mechanisms 77-79 are energized in a corresponding manner whenever the limit switch mechanisms in their primary monitor instruments 22-24 reach an alarm condition.

The first relay switches 76b, 77h, 78h and 79h of the relay mechanisms 76-79 are connected by way of the conductors in cables 31a-31d to the alarm signal circuits in the automatic central station 32. Closure of one of these switches 761:, 77h, 7 8b and 7911 serves to complete one of these alarm circuits in the automatic central station 32 which then operates to supply cardiac signals from the appropriate monitor instrument to the chart recorder 36.

The memory tape loop switcher also includes a second group of switch mechanisms indicated at 85. This group 85 includes the switch mechanisms 86 and 87. The first switch mechanism 86 is mounted on the same control shaft 73a as is used for the first switch mechanism 71 of the first group 70, while the second switch mechanism 87 is mounted on the same control shaft 73b as is the second switch mechanism 72 of the first group. These switch mechanisms 86 and 87 of the second group 8S operate to individually couple each of the memory tape 'loop alarm signal input cables 42a and 42b to any selected one of the relay mechanisms 76-79. More particularly, the relay switches 76e, 77C, 78e and 79C of the relay mechanisms 76-79 are connected to first, second, third and fourth stationary contact positions on the switch mechanism 86. If, for example, the relay coil 76a of relaymechanism 76 is energized and the switch mechanism 86 is in the first position, then the closing of switch '76e operates to connect together the switcher 30 ends of the two conductors in the memory tape loop alarm signal cable 42a. This completes an alarm circuit in the first memory tape loop unit 40a which in turn activates the operating control means of the tape recorder mechanism in such unit 40a. By setting the switch mechanism 86 to different positions, the activation of different ones of the relay coils 76a, 77a, 78a and 79a is effective to tie together the ends of the two conductors in cable 42a.

In a similar manner, the relay switches 76d, 77d, 78d and 79d are connected between the respective ones of first, second, third and fourth stationary contacts of the switch mechanism 87 and a common one of the conductors in the second alarm cable 4211 running to the second memory tape loop unit 40h. Thus, manipulation of the switch mechanism 87 by means of control knob 43b serves to associate the alarm signal cable 42h of the second memory tape loop unit 4Gb with a selected one of the relay mechanisms 76-79.

The use of the common control shafts 73a and 7319 which interconnect the corresponding switch mechanisms in the first and

second groups

70 and 85 operates to insure that any given memory tape loop unit will receive patient sensor signals and alarm signals only from the same one of the primary monitor instruments.

Referring now to FIG. 4 of the drawings, there is shown a detailed circuit diagram of the television switcher 46. This television switcher 46 includes a group of switch mechanisms 91-94. Each of these switch mechanisms 91-94 includes a pair of wafer switch subassemblies. The switch mechanism 91, for example, includes subassemblies 91a and 91b. These subassemblies v91a and 91b are mounted on a common control shaft a which is also connected to the front panel control knob 49a. Similarly, control shafts 95h -95d, individually associated with the other switch mechanisms 92-194, are connected to corresponding ones of the other control knobs 49h-49d. Considering, for example, the first switch mechanism 91, the two wiper arms of the subassemblies 91a and 91b are connected to the two conductors of the input signal cable 47a running to the input of the television monitor 48. The pairs of conductors for the various television camera output signal cables 45u-45d, on the other hand, are connected to stationary contacts at different contact positions on the subassemblies 91a and 91h. Thus, by manipulation of the control knob 49a, and hence the control shaft 95a, the conductors of the television monitor cable 47a may be connected to the conductors of any one of the television camera cables 45u-45d. Similar considerations apply to the remainder of the switch mechanisms 92-94.

Returning now to FIG. l and considering briefiy some of the general features of the overall system it will be seen that the system provides a high degree of iiexibility in the patient monitoring operation. By manipulation of the control knobs 27a-27d of the patient selector switcher 20, any of the primary monitor instruments 2ll-24 can be connected to any one of the bed positions 11-14. By manipulation of the control knobs 43a and 4311 of memory tape loop switcher 30, the memory tape loop units 40a and 4Gb can each be connected to any one of the primary monitor instruments 21-24. This, in effect, means that each of these memory tape loop units 40a and 40b can be connected to record the signals coming from any selected one of the different bed positions 11-14. Similarly, by manipulation of the control knobs 49a-49d of the television switcher 46, any one of the television monitors ld8a-48a.' can be connected to any one of the bed positions 11-14.

The value of this fiexibility is even further appreciated when it is borne in mind that the present system is in no way limited to the illustrated case of four bed positions. In particular, the patient selector switcher 20, as shown in FIG. 2, is, in fact, constructed to accommodate a total of twelve bed positions. This is indicated by the fact that each of the various switch subassemblies, for example, switch subassembly 51a, includes a total of twelve stationary contact positions. Thus, eight additional bed positions can be accommodated by making the appropriate connections to the eight additional stationary contacts on each of the switch subassemblies.

The patient selector switcher 20 can also be constructed to accommodate more than four primary monitor instruments. In terms of the circuit diagram of FIG. 2, this is accomplished by adding additional switch mechanisms (like 54 and 64) to each of the first and second groups 50 and 60. This would, of course, require the use of additional control knobs on the front panel of the patient selector switcher 20.

Considerations of a similar nature also apply to the memory tape loop switcher 30 and the television switcher 46. In particular, the memory tape loop switcher 30, as shown in FIG. 3, is constructed to accommodate a total of twelve primary monitor instruments, while the television switcher 46, as shown in FIG. 4, is constructed to accommodate a total of twelve bed positions. Either of these

Switchers

30 and 46 can be constructed to accommodate either a greater number of signal producing instruments or a greater number of signal receiving instruments, or both.

The system of the present invention provides a greater degree of safety in the monitoring of hospital patients. Assume, for example, that one of the primary monitor intruments 21-2-4 should fail to operate. It is then a fairly simple matter to switch one of the other primary monitor instruments into its place so as to monitor the same l. l patient. This other monitor instrument might be one that is not being used at the moment, or one that is being used for a patient in less critical condition. Similar considerations apply to the memory tape loop units and the television monitor instruments.

It should be further noted that the system of the present invention is not limited to use with electrocardigraph type patient sensors. It can also be used with temperature sensors, blood pressure sensors, and the like. In such cases, the primary monitor instruments would take the form which is appropriate for the particular type of sensor being used.

While there have been described what are at present considered to be preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modications may be made therein without departing from the invention, and it is, therefore, intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A system for monitoring hospital patients comprismg:

(a) a plurality of patient sensor means individually located at different hospital bed positions for producing signals representing physical conditions of patients;

(b) a plurality of primary monitor means located at a central nursing station for amplifying and displaying indications of the patient sensor signals;

(c) a plurality of secondary monitor means individually located at the different hospital bed positions for providing bed-side indications of patient sensor signals; and,

(d) switch means for enabling each of said primary monitor means to be coupled to the patient sensor means and the secondary monitor means at any one of the bed positions for receiving signals from the patient sensor instrument and for returning the amplified sensor signals to the secondary monitor means.

2. A system for monitoring hospital patients in accordance with claim 1 wherein the patient sensor instruments are electrocardigraph sensor instruments for producing signals representing cardiac conditions of patients, the primary monitor instruments are primary cardioscope instruments for displaying visual indications of electrocardigraph signals, and the secondary monitor instruments are slave cardioscope instruments which are driven by amplified electrocardiograph signals produced by the primary cardioscope instruments.

3. A system for monitoring hospital patients in accordance with claim 1 wherein the switch means comprises:

first switch means for enabling each primary monitor instrument to be coupled to the patient sensor instrument at any one of the bed positions for receiving signals therefrom;

second switch means for enabling each primary monitor instrument to be coupled to the secondary monitor instrument at any one of the bed positions for supplying signals thereto; and

means for causing the first and second switch means to couple any given primary monitor instrument only to sensor and secondary monitor instruments located at the same bed position.

4. A system for monitoring hospital patients in accordance with claim 1 which further includes:

a plurality of television camera instruments individually located at the different hospital bed positions for producing television signals representing the visual appearance of patients;

a plurality of television monitor instruments located at the central nursing station adjacent the primary monitor instruments for producing visual pictures from television signals; and

second switch means for enabling each television monitor instrument to be coupled to the television camera instrument at any one of the bed positions.

S. A system for monitoring hospital patients in accordance with claim l wherein:

each primary monitor instrument also includes means for producing an alarm signal when the patient sensor signals received by such instrument reach an alarm condition;

the system also includes a plurality of magnetic recorder instruments located at the central nursing station and each having recording means for recording patient sensor signals and control means responsive to alarm signals for controlling the operation of the recording means; and

the system further includes a second switch means for enabling the recording means and the control means of each magnetic recorder instrument to be coupled to any one of the primary monitor instruments for respectively recording signals corresponding to the patient sensor signals supplied to such primary monitor instrument and for responding to any alarm signal produced by such primary monitor instrument.

6. A system for monitoring hospital patients in accordance with claim S which further includes:

a plurality of television camera instruments individually located at the different hospital bed positions for producing television signals representing the visual appearance of patient;

third switch means for enabling each television monitor instrument to be coupled to the television camera instrument at any one of the bed positions.

7. Switching apparatus for use in monitoring hospital patients comprising:

a first group of switch mechanisms each having movable contact means and a plurality of stationary contact means;

means for coupling first stationary contact means of the different switch mechanisms of the first group to a first patient sensor instrument located at a first hospital bed position and for coupling second stationary contact means of the different switch mechanisms of the first group to a second patient sensor instrument located at a second hospital bed position;

means for coupling the movable contact means of a first switch mechanism of the rst group to a first primary monitor instrument and the movable contact means of a second switch mechanism of the first group to a second primary monitor instrument;

a second group of switch mechanisms each having movable contact means and a plurality of stationary contact means;

means for coupling first stationary contact means of the different switch mechanisms of the second group to a first secondary monitor instrument and for coupling second stationary contact means of the different switch mechanisms of the second group to a second secondary monitor instrument;

means for coupling the movable contact means of a first switch mechanism of the second group to the first primary monitor instrument and the movable contact means of a second switch mechanism of the second group to the second primary monitor instrument;

means interconnecting the movable Contact means of the first switch mechanisms in the first and second groups for causing such movable contact means to always contact corresponding ones of the stationary contact means of the `first switch mechanisms in the first and second groups; and

means interconnecting the movable contact means of the second switch mechanisms in the first and second groups for causing such movable contact means to 13 always contact corresponding ones of the stationary contact means of the second switch mechanisms in the first and second groups.

8. A system for monitoring hospital patients comprising:

a plurality of monitor instruments for receiving signals from patient sensor instruments located at different hospital bed positions, each such monitor instrument including means for displaying indications of the signals from one of the patient sensor instruments and means for producing an alarm signal when such patient sensor signals reach an alarm condition;

a plurality of magnetic recorder instruments each having recording means for recording patient sensor signals and control means responsive to alarm signals for controlling the operation of the recording means; and

switch means for enabling the recording means and the control means of each magnetic recorder instrument to be coupled to any one of the monitor instruments for respectively recording signals corresponding to the patient sensor signals supplied to such monitor instrument and for responding to any alarm signal produced by such monitor instrument.

9. A system for monitoring hospital patients in accordance with claim S wherein the monitor instruments are cardioscope and heart rate monitor instruments for receiving cardiac signals from electrocardiograph patient sensor instruments and the magnetic recorder instruments are magnetic tape recorder instruments each having recording means for recording cardiac signals on a closed loop of magnetic tape and control means responsive to an alarm signal for disabling the operating of the recording means to preserve a record of the cardiac signals which gave rise to the alarm signal.

10. A system for monitoring hospital patients in accordance with claim 8 wherein the switch means comprises:

first switch means for enabling each recording means to be coupled to any one of the monitor instruments for recording signals corresponding to the patient sensor siganls supplied to such monitor instrument;

second switch means for enabling each control means to be coupled to the alarm signal producing means of any one of the monitor instruments for respond- 14 ing to any alarm signal produced by such monitor instruments; and y means for causing the rst and second switch means to couple the recording means and the control means of any given magnetic recorder instrument to the same one of the monitor instruments.

1l. Switching apparatus for use in monitoring hospital patients comprising:

a first group of switch mechanisms for coupling recording means of individual ones of a plurality of magnetic recorder instruments to any one of a plurality of monitor instruments which receive signals from patient sensor instruments;

a group of relay mechanisms each including relay switch means, relay control means for controlling the relay switch means and means for individually coupling the relay control means in circuit with alarm signal producing means associated with dilerent ones of the monitor instruments;

a second group of switch mechanisms for coupling operating control means of individual ones of the magnetic recorder instruments in circuit with the relay switch means of any one of the relay mechanisms; and

means for causing the rirst and second groups of switch mechanisms to couple the operating control means of any given magnetic recorder instrument to the relay mechanism which is coupled to the same monitor instrument as is the recording means of such given magnetic recorder instrument.

References Cited UNITED STATES PATENTS 2,630,797 3/1953 Marchand 12S-2.06 3,434,151 3/1969 Bader et al. 12S-2.06 2,647,508 8/ 1953 Pelavin 128206 B 3,513,833 5/1970 Finch et al. 128--2-.06 R

OTHER REFERENCES 'Hagan et al.: American Journal of Medical Electronics, April-I une 1963, pp. 147-15l.

WILLIAM E. KAMM, Primary Examiner