Note: Descriptions are shown in the official language in which they were submitted.
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The.presen.t invention relates to a respirator for cli-
nical use.
The respirator of the present invention can be used in
adult, child and new-born infant intensive care and resuscita-
tionunits and can be used in all treatments requiring artificial
ventilation, and has the important advantage that all the acces-
sories normally used in these types of treatments are integrated,
forming part of the basic equipment, which is the respirator.
According to the present invention there is provided a
respirator for clinical use, comprising a pneumatic module and a
control module connected to the pneumatic module by data lines
and control lines, the.pneumatic module comprising means for con-
nection to supplies of compressed gases, a pneumatically operated
pxessure equalizer for receiving said compressed gases connected
to a mixing chamber controlled by a dual pressure switch, two
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main manifolds supplying batteries of valves with series-connected\
resistances extending ~rom the mixing chamber, one said bat-tery
being coupled to an inhalation valve assembly, the other said bat-
tery being coupled to an exhalation valve, said one battery feed-
ing a patient supply line and incorporating a flow transducer,
and said control module comprising a microprocessox associated
with a keyboard for receiving data and instructions and a cathode
ray screen for displaying alpha-numeric and graphic information,
said data lines which connect the control module to the pneuma-
tic module being connected in the control module to a plurality
of amplifiers followed by analog/digital converters, which are
. connected to ~he-~u~e~-e~the microprocessor~ said data buses
also being connected to a plurality of amplifiers and optical cou-
plers producing signals controlling components::of the pneumatic
30 module
The respirator of this invention comprises two main mo-
dules which will hereinafter be referred to as:
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~NEUMATIC UNIT
GENERAL CONTROL MODULE
The general contro1 module contains a microprocessor,
preferably of 8 bits, including all its accessor~ and peripheral
circuits. The microprocessor is controlled by various pneumatic
and electromechanical controllers from data derived from sensors
arranged throughout the pneumatic unit. This control takes place
following the programmed instructions registered in permanent
memories cooperating with the microprocessor. As the intercom-
municating element between the operator of the respirator and the
general control module, there is provided a keyboard ~hich per-
mits data and instructions to be introduced and a cathode-ray
s~creen capable of simultaneously displaying alpha-numerical data
and graphic representations, by means of which the performance
and effectiveness of the respirator is highly improved when com-
pared with conventional respirators.
The pneumatic unit, in turn, comprises the respective
manifolds for supplying gases compressed at the pressures normal-
ly used in hospitals, as well as a mixer and a mixing chamher to
supply the pati~nt with the appropriate amount of gases, and a
plurality of valves, flow transducers, pressure regulators/ etc.,
all of which are duly interrelated with the control module to
transmit and receive the adequate information to permit the com-
plete auto~ation of the respirator.
More specifically, the pneumatic unit comprises:
a) a gas mixer
b) a mixing chamber
c) an inhalation valYe
d~ an oxygen analyzer
e) a flow transducer
f) a system for controlling an expiraticn valve
g~ an exhalation valve
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h~ a system for measuring the patient's pressure
i) measuring and safety systems.
All these units~ as previously mentioned, are duly in-
terrelated through corresponding optical couplers, analyzers,
sensors, or other elements to the general control module, which
is controlled hy a main processing unit based on a microproces-
sor.
The supply of gas to the patient is regulated in composi-
tion and pressure with the help of a gas mi~er. The gas mixer
makes the air/O2 or O2/N2O mixture ~rom the corresponding gases
under pressure, which reach same through suitable manifolds. The
process used preferably consists in controlling the relative
times of the passage of each gas through the same fixed resistance.
In this respect, it should be pointed out that the preferred em-
bodiment uses a time controlled mixer, object of Spanish Utility
Model No. 231,608.
The mixing chamber serves as a gas accumulator so that
elevated instantaneous flows are obtained, besides permitting the
homogenization of the mixture of gases.
From the mixing chamber there extends a manifold coupled
to a battery of valves forming the inhalation valve assembly.
This valve comprises the end controller of the servo-system which
regulates the rate of flow to the patient, depending on the sig-
nal transmitted thereto by the flow transducer and on the instan-
taneous value necessary at each moment. The practical embodi-
ment of this valve is a battery of valves with a digital stepping.
Inserted :in the manifold which supplies the mixture of
gases to the patient, there is a flow transducer, an element
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which permanently sends information~to the general control. This
transducer has a bidirectional character, it has a low charge loss,
and a rapid response.
I'he exhalation valve consists of a pneumatically operated
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membrane valve. The election of the pneumatic operating system
is preferred due to the simplicity, reliability and lightness
thereof.
The pneumatic controller of the expiration provides the
pneumatic signals for the control of the exhalation valve, de-
pending on the electrical signals received from the general con-
trol. It uses 2 or compressed air as the pneumatic supply.
The system for measuring the patient's pressure compris-
es a préssuré transducer and an electrically controlled three-way
lQ valve, which permits the transducer to be periodically placed in
communication with theatmosphere, to automatically measure same.
Finally, there are various elements, such as pressure
switches, filters, and :unidirectional safety valves which func-
tion as auxiliary measuring control and safety elements.
With respect to the general control module, it can be
said that the same monitors all the elements of the system de-
pending on the input signals, so that the functions requested and
which are contained, in a programmed manner, in the memories in-
corporated ther~in are carried out.
As the main active members, there is an 8 bit micropro-
cessor provided with its corresponding RAM and ROM memory blocks,
as well as its various associated circuits, such as output-input
units, drivers, etc.
The programs regulating and controlling the operation
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of the assembly are structured as clearly ~ m~t~-functional
blocks, so that the writing of said programs i5 facilitated, ma-
ximum use being made of the flexibility of the microprocessor,
which also allows for the possibility ofincluding new functions
at a later da-te, or of adapting the existing functions to speci-
fic needs of any ~articular application.
For the in'troduction to the microprocessor of digital
data and controls, there is used a keyboard which, in the prefer-
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red embodiment of the respirator, comprises keys for diyits,
keys for introducing parameters, ~nd keys for selecting the
different functions.
The microprocessor includes various routines to verify
parameters, monitoring the validity of the data introduced, both
with respect to the number and combination thereof and to the ab-
solute values of the digital data introduced, a circumstance
which minimizes the possibility of erroneous use of the respira-
tor.
The capacity of the microprocessor to effect arithmetic
operations, permits the following parameters and variables to
be computed:
Maximum alveolar pressure, resistance, correction of
volumes, exhalation pressures, representation of curves, etc.
- In addition, the respirator is capable of displaying on
the screen the simulated curves which would be the result of
applying new respiratory conditions to the patient being treated.
This simulation can be ef~ected while ventilation continues with
the pre-established parameters and only in the event that the new
values are satisactory, can the operator request the chan~e in
the ventilation of the patient, whose control is carried out by
the microprocessor with the new parameters computed during simul-
atiGn .
Another characteristic of this respirator resides in itscapacity to effect a "clinical history". ~Ience, reserving a cer-
tain portion of the memory for stora~e, the values of the measured
parameters of the patient during the last few hours can be accu-
mulated therein. A simple comparison of each new value with the
prior, automatically made value or values gi~es a clear idea of
the tendency in the clinical evolution of the patient.
Likewise, there can be established advice or alarm con-
ditions when certain absolute values are surpassed or ~ariations
are produced.
The microprocessor controlled respirator eliminates
the need for monitoring on the part of the operator, which is
presently required by conventional respirators.
The pre~ent invention will be further illus-trated by
way of the accompanying drawing, which shows a general scheme
of the respirator in which the pneumatic unit and the general
control module are clearly delimited.
Referring to the Figure, the manifolds 2, 3 and 4 of
the pneumatic unit, which contain ni-trous oxide, oxygen and com-
pressed air, respec-tively, are provided with -the corresponding
pressure switches 18, l9a and l9b, a hand opera-ted pressure re-
ducer 20 coupled to all the manifolds. The pressure reducer produces
a reference pressure for the operation in the pressure equalizer
21. This pressure equalizer 21, which is pneumatically operated
as previously mentioned, guarantees that the pressure of the two
gases to be mixed, oxygen and air or oxygen and nitrous oxide,
is the same.
The pressure equalizer 21 communicates with the mixing
chamber 22 through the corresponding valve 23 to provide air/
N2O and valve 24 to provide 2' which valves reach a common flow
resistor 25. The mixing chamber 22 permits the homogenization
of the mlxture of gases and serves as a reserve to reduce the
variations in pressure of the supply to the valves 7. Filling
iof the mixing chamber 22 is controlled by the highly sensitive
dual pressure switch 26, which acts on -the different valves
of the mixer. Likewise, a safety valve 27 is incorporated which
insures that the opera-ting pressure of the mixing chamber 22
will, in no event, be surpassed.
Further, there is an 2 analyzer 28 which, through
valve 29 and its associated resistor 30, permits a sample of the
gas contained in the mixing chamber 22 to be taken, analyzing
6 -
it and thus verifying the corresponding fllnc-tioning o~ the mixer.
This oxygen analyzer 28 can be verified and corrected by cu-tting
off the passage of gas from the mixing chamber 22 and allowing
the necessary time to lapse so that the gas contained in the
measuring chamber is only air.
The inhAlation valves 7, besides communicating wi-th the
mixing chamber 22, converge in the flow transducer 15 of the
patient's block. The instantaneous flow transducer is directional
and is located close to the patient in the line common to both
inhalation and exhalation. This -transducer 15 is joined to a
block 31 which conditions the signal transmitted by the trans-
ducer 15 and through line 32 sends it to the general control
module 6.
A pressure transducer 11 is also connected to the pa-
tient's circuit through the three-way valve 33. This arrangement
permits the patient's circul-t to communicate with the atmosphere.
The respiration valve 14 is pneumatically controlled
and can be closed completely or partially, a fact which permits
continuous positive pressure to be generated during the exhala-
tion phase. This valve 14 is controlled by a ba-ttery of valves
controlling the final pressure. This permits a variable pres-
sure to be generated which, applied to the control oE the valve
14, produces the closure or the desired pressure in the patient's
circuit.
All these members are controlled by the general con-
-trol block 6 comprising an 8 bit rnicroprocessor 35, which through
the various buses thereof communica-tes with the remaining ele-
ments of the contro:L module, inter alia, the block or ROM storage
memory 36 and the block or RAM storage memory 37.
The data, controls and functions are in-troduced by the
keyboard 38, which is connected to -the microprocessor 35 through
-the corresponding interphase and codifica-tion unit 39 thereof,
while the visual represen-tation of the alpha-numeric or graphic
information -takes place on a cathode ray screen 40 connected
to the microprocessing system through the corresponding screen
refreshing unit 41 thereof.
The blocks 42, 43 and 44 correspond to amplifier
blocks and analog/digital converters which receive, respectively,
the signals from the signal conditioner 31 of -the flow trans-
ducer lS, from the pressure transducer ll and from -the 2 analy-
zer 28 and the signals originating from -the various sensors
arranged throughout the respirator which are connected to ter-
minal block 45.
The blocks 46, 47, 48 and 49 comprise optical couplers
and amplifiers for -the signals which, originating from this con-
trol block 6, control the operation of the respirator. The
second set of reference numerals indicates the devices in the
pneumatic module with which they are associa-ted. The output
block 49 is reserved for transmitting operating members having
a minor functional importance.
In this diagram of the general control block the power
supply has been omitted. Under normal conditions this should
be connected to the mains supply. Electrical batteries are
provided which are capable of guaranteeing the automatic func-
tioning of the assembly for a determined period of time in the
'event of a power failure.
Thus, a program controlled respirator, which is capable
of effecting a wide range of functions and modes of operation,
discarding the human operator presently required by this type of
device, is provided.
