close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3090388

код для вставки
May 21, 1963
P. F. sALlsBURY ETAL
3,090,377
ELooD PRESSURE MEASUREMENT
Filed Oct. 30, 1961
5 Sheets-Sheet 1
[TRANSDUCER
LTITRANSDUCER
Pe’rer F. Salisbury,
Tracy F. Wichmann,
ÍNVENTORS.
5)’.
ATTOR/VE Y.
May 21, 1963
P. F. sALlsBURY ETAL
3,090,377
BLOOD PRESSURE MEASUREMENT
Filed OC’C. 30, 1961
5 Sheets-Sheet 2
BmCh
A r f e r V.
Humerus Bone
Radial Arfery
5o
Peter F. Salisbury,
Tracy F. Wichmann,
Bone
/NvE/vroRs.
5y.
A T ron/v5 X.
May 21, 1963
P. F. sALlsBURY ETAL
3,090,377
BLOOD PRESSURE MEASUREMENT
Filed Oct. 30, 1961
5 Sheets-Sheet 3
PeTer F, Salisbury,
TrGCy F. Wichmann,
/NVENTO/Qs.
5y.
if@
ATTORNEY.
May 21, 1963
P. F. sALlsBURY ETAL
3,090,377
BLOOD PRESSURE MEASUREMENT
Filed OCT.. 50, 1961
5 Sheets-Sheet 4
¢NN@NNh
MNNNSN
@NM
@NNW
w
A
Nam
Iî
v` .
L_œoN N_N QoSN_N M,
\_
mmmlm
N NomN
+m
nInl
NmNooï_
_
NvN. 3N
owN
3NHîNN_mi
Hn!AWYMN/
_1„__„
3N«MT
NmNmN
Fu'
Pe’rer F Sollsbur
Tracy F. Wichmon n?
/NVEA/rons.
1
ATTORNEY.
May 21, V1963
P. F.vsA|_|sBURY ErAL
3,090,377
BLOOD PRESSURE MEASUREMENT
5 Sheets-Sheet 5
Filed OGL 50, 1961
XT
ovm
w«Nwm w w@om
om» @Em m
___. 4|
»_.mSm«Nmom»m
9m
__
Pe'fer F. Salisbury,
Tracy F. Wichmann,
BY.
@MM
United States Patent O "ÍCC
l
3,699,371?
Patented May 21, 1963
2.
ity of such pulse Waves is known to vary with blood ves
3,096,37 7
BLÜQD PRESSURE MEASUREMENT
Peter F. Salisbury, 11750 Cmton Place, Studio City,
Calif., and Tracy F. Wichmann, 4116 Green Bush Ave.,
Sherman Galas, Calif.
sel rigidity. ln turn, blood vessel rigidity is known to
vary directly with intra-vascular pressure. The apparatus
forming the subject of the present invention provides an
applied pulse of short duration to a chosen artery and
measures the velocity of the resulting pulse wave. The
apparatus further computes arterial blood pressure from
12 Claims. (Cl. 12S-2.05)
the measured pulse wave velocity.
This invention relates to an improved apparatus for
The present invention provides an apparatus which is
the measurement or monitoring of blood pressure, and 10 not subject to any of the disadvantages discussed above
more particularly to an apparatus for the continuous
in connection with prior art devices, and further pro
recording of blood pressure by indirect measurement.
vides all of _the desired features listed above.
The arterial blood pressure, hereinafter referred to
It is an object of the present invention to provide a
as blood pressure, is one of the most important param
continuous monitoring of blood pressure.
eters yielding information concerning the condition of 15
Another object of the present invention is to provide
an individual. Devices which yield a continuous or, at
blood pressure measuring apparatus which records either
systolic or diastolic pressures.
the very least, a frequently repeated measurement of
blood pressure, satisfy an important need in clinical
Still another object of the present invention is to
medicine as Well as in the recently developed and highly
provide accurate blood pressure measurements.
important area of aviation, space and military medicine. 20
A further object of the present invention is to provide
The traditional method of measurement of blood pres
blood pressure measuring apparatus not requiring the use
sure, which contemplates the use of a cuff and sphygmom
of a sensor which perforates the skin or penetrates into a
blood vessel of a subject.
eter, is subject to a normal error of twenty-live percent
File-:ì Oct. 30, 1961, Ser. N . 148,527
(25%). In some instances the error has been found
A still further advantage of the present apparatus is
to be as large as fifty percent (50%) of the true simul 25 that the act of measuring blood pressure does not modify
taneously measured intra-arterial blood pressure. Fur
the blood pressure nor does the act of measuring inter
ther, it is impossible with this procedure to provide a
fere with the blood supply to parts of the body.
continuous recording of blood pressure, and relatively
Yet another advantage is that blood pressure monitor
infrequent readings are the best which can be obtained.
ing does not cause discomfort or mental stress in the
The only presently available technique for obtaining ac 30 subject.
curate, continuous blood pressure recording is accom
This invention possesses many other advantages and
plished by the use of a pressure transducer connected with
the lumen of an artery by a needle or cannula which
penetrates the skin or the arterial Wall. This is the so
has other objects which may be made more clearly ap
parent from a consideration of a form and method em
bodying the invention. This form and method are shown
called “direct” method of blood pressure monitoring. 35 and described in the present specification and in the draw
However, this system is subject to disadvantages. In
ings accompanying and constituting a part thereof. They
order to avoid obstruction of the cannula with blood
will now be described in detail, for the purpose of illus
clots, the needle must be ñushed periodically or the sub
trating the general principles of the invention; but it is
ject’s blood must be made incoagulable. Such a device
to be understood that such detailed description is not to
poses danger to the subject in that infection may result 40 be taken in a limiting sense, since the scope of the in
or that hemorrhage, clotting or other obstruction of the
vention is best defined by the appended claims.
blood vessel may be caused. In addition, it is clear that
Referring to the drawings:
such monitoring will cause discomfort or mental stress
FlGURE 1 is a schematic or block diagram of the
in the subject.
present invention;
The present invention provides a method and appara 45
FIG. 2 is a diagrammatic representation of a human
tus for the practice thereof which indirectly and con
arm, showing the cuifs or transducers, forming part of
tinuously measures the systemic arterial pressure. Such
the apparatus, in position;
'
apparatus should ideally meet the following specifica
FIG. 3 is a cross-section taken along the line 3-3 of
tions:
FIG. 2;
(a) Systolic (ie. peak) and diastolic (ie. minimal) 50 FIG. 4 is a cross-section taken along the line 4_4 of
pressures should be continuously recorded;
(b) These pressures should be measured accurately;
(c) Sensing devices which generate the recorded or
observed signal should be applied to regions of the body
FIG. 2;
FIG. 5 is a plan View of the distal transducer or cuff;
FIG. 6 is a cross-section through the transducer or
cuff shown in FIG. 5;
-FIG. 7 is a perspective view of the proximal cuif or
which do not “over-react.” Examples of such over-reac 55
tion regions are the ears or iingertips of a subject. The
blood pressure measured at such points can be decreased
transducer;
by cold air or by changes of total blood volume, while
shown in FIG. 7;
central blood pressure remains unchanged or increases.
FIG. 8 is a cross-section of a portion of the transducer
FIG. 9 is a diagram of a portion of the electrical and
Thus, such measurements do not necessarily parallel the 60 electronic circuitry of the apparatus;
pressure in more central arteries;
FIG. 10 is a diagram of the remaining portion of the
(d) Sensors should not perforate the skin or pene
electrical and electronic circuitry of the apparatus.
trate into blood vessels;
The operation of the apparatus forming the subject
(e) The act of measuring blood pressure should not
interfere with the blood supply to parts of the body nor 65 of the present invention is based upon the principle that
the elasticity of an arterial wall is a function of intra
should the act of measuring modify the parameter Which
arterial pressure. l'Iluat is, the walls of arteries become
is being measured;
more rigid (or less distensible) when the pressure in the
(f) Blood pressure monitoring should not cause dis
comfort or mental stress in the subject.
vessels increases. It is also a fact that the velocities of
Brielly described, the present invention provides an 70 the blood volume pulse, as well as that of the blood pres
sure pulse (the two are not identical), bear a direct rela
apparatus for measuring the propagation in arteries of
tionship to the stiffness of the arterial wall. Accordingly,
externally applied pulses of short duration. The veloc
3,090,377
3
' 4
blood pressure may be measured by appropriate treat
complished by hydraulic pressure transmission, as shown
ment of measurements of pulse wave velocity.
Naturally occurring pulse waves, generated bythe ejec-~
tion of blood from the left ventricle of the heart, do not
provide suitable signals for the purpose of measuring
blood pressure, because their ascending and descending
slopes change too gradually to be useful for this purpose.
Further, the shape of pressure pulses is changed as the
in the present system, or by mechanical pressure trans
mission or other means.
When a desired portion of the pulse Waves is sensed
by a phase detector 26 connected to the first transducer
22, a pulse generator 28 is triggered and a short (1-5
millisecond) pulse is generated by the pulse generator
2S. This pulse .is also used to trigger a sweep circuit 30
which produces an electrical signal whose current in
ditions present, pulse Wave velocity can be Imeasured by 10 creases with the passage of time. The sweep signal is
used to drive a diode function generator 32 which pro
using the peak of a naturally occurring pulse wave. In
duces, as `an output, an electrical signal proportional to
addition, naturally occurring pulse pressure waves in
wave travels in a centrifugal direction.
With these con
the natural logarithm of elapsed time. This signal is,
clude superimposed harmonic oscillations which have
-in turn, sent to a differentiating circuit 34, which pro
different characteristics, .are reflected in varying modes,
and may interfere with each other unpredictably.
15 duces as an output an inverse voltage function. Thus,
The natural blood volume pulses travel at a velocity
which is only about ten percent (10%) of that of the
propagation velocity of the pressure pulse waves. These
volume pulses can be measured readily, but are dampened
to an extent which precludes accurate and consistent
measurements of changes of blood pressure from their
velocity.
The present invention uses .the principle that any seg
the output of the diiferentiaitng circuit 34 .is an electrical
signal Whose magnitude is inversely proportional to the
The second transducer 24 provides an
electrical signal to a pulse detector 36 which detects the
presence of the «applied pulse at a distance L along the
artery from the ñrst transducer 22 and supplies, as its
‘ elapsed time.
output, »an electrical signal occurring simultaneously with
the leading edge of 'the applied pulse.
An “and” gate 38 has two inputs. The ñrst input to
ment of a pressure pulse wave contour can be labelled
:or identified by brief (1-5 millisecond) superimposed 25 the “and” gate 3S receives the signal from the pulse
square waves which modify theV outline of the pressure
detector 36 and the second input to the “and” gate 38
receives the signal from the differentiating circuit 34.
When an electrical signal exists at the output of `the pulse
detector 36, the voltage appearing at the output of the
trifugal direction, and its outline can be recorded distally,
30 differentiating circuit 34 is permitted to pass .through the
as shown, or may be recorded proximately, if desired.
ygate 38 to a boxcar circuit 440. 'Ille boxcar circuit 40
The present invention includes apparatus for imposing
pulse Without significantly affecting the normal ñow of
blood.
The modified pulse wave propagates in a cen
4a brief monitoring square wave upon either the systolic
has a dual function.
lts first function is to remember
or store an electrical voltage :transmitted to it. Its second
peak, the diastolic plateau, or other desired segments of
function is lto apply a fixed gain or amplification to an
.the pressure pulse wave. The »apparatus constituting the
present invention then measures the elapsed time be 3,5 input voltage so that effectively the input voltage may be
multiplied by a constant factor. This gain is controllable,
tween the imposition of the monitoring lwave and the
and must be adjusted, in the present apparatus, Ito a factor
arrival of its leading edge at the distal sensing device.
equal «to 12.2L. The output of the boxcar circuit 40
Suitable treatment of this measurement yields an indica
may also be controlled, by an appropriate negative bias,
tion of the intra-arterial blood pressure existing at that
phase of the pulse wave upon which the monitoring Wave 40 so that it is proportional to blood pressure in millimeters
was imposed.
The relationship of pulse Wave velocity and blood pres
sure is given by:
in which V is the pulse velocity in meters per second
and p is the pressure in millimeters of mercury.
An approximation of this formula, which has been
found to be accurate within 1.5%, is given by the rela
tionship:
'
’
of mercury.
Variations of arterial elasticity, such as caused by age,
arteriosclerosis, or other factors, may be compensated
for by appropriate adjustments of lthe boxcar circuit, de
45 pending upon the characteristics of the subject under ex
amination.
Abnormal shapes of natural pulse waves will
not interfere with .the blood pressure measurement be
cause the duration -of the applied monitoring pulse or
wave is far shorter than any significant portion of a
50 natural wave, normal or abnormal.
The method described herein permits blood pressure
Since electronic circuitry can measure time differences
measurements at the systolic, the diastolic, or other de
very accurately and conveniently, the present system
sired phases of the pulse wave. When both systolic and
As shown in FIG. 1, a member such as an arm of the
quire the insertion of fixed time delay elements between
diastolic pressures are measured, separate channels are
determines the pulse velocity or blood pressure by meas
uring the time an applied pulse takes lto .travel a known, 55 required for each phase. The same transducers can be
used for both phases, and in some instances electronic
fixed distance. If L is the fixed distance, the blood pres
circuits may be time-shared. However, since the strain
sure equation may be written as
gauge in the first transducer cannot easily be used to detect
the diastolic phase, »it is appropriate to measure diastole
in which At is the measured time difference referred to 60 by making a measurement at a fixed time after the detec
tion of systole. This measurement would merely re
above.V
the detector 26 and the pulse generator 28, and between
subject, which contains a convenient artery 20, has a
the pulse detector 36 and the gate 38. Such fixed time
pair of cuffs or transducers 22 and 24 applied ythereto and
spaced a known distance apart. The first transducer 22 65 delay elements lare well known in the lart and will not -be
described in detail herein. The output of the boxcar
contains means such as a solenoid for applying a mark
circuit 40 may be observed :by any convenient metering
ing pulse and sensing means to >detect the systolic peak
or recording unit.
or other portion of 4the pressure pulse wave so that the
In FIG. 2, a proximal cuff 42 and a distal cuff 44 are
applied pulse can be applied to «the desired phase of the 70 shown in position on the arm of a subject.V The proximal
pressure pulse Wave. The second transducer 24 corn
cuff 42 is wrapped around the upper arm of the subject
prises sensing means, such >as a strain gauge, to sense
such that pressure may be exerted on the brachial artery
the time that the applied pulse arrives at the second trans
and extends approximately 405° around the arm. As
ducer 24. The transmission of pressure indications from
shown in FIG. 4, «the brachial artery is embedded rela
the artery to the transducers and vice-versa may be ac 75 tively deeply rwitlu'n the arm structure and in order to
5
3,090,377
apply significant pressure to the artery, it is necessary to
apply pressure uniformly around the circumference of
6
into the cavity 74 through a pair of plug closed ports 76
tends approximately 60° around the circumference `of the
which serve to Íìll and “bleed” the cavity ’74. A cylin
der 78 is also filled with silicon oil :and is connected to
the cavity 74. The cylinder ’78 is provided with a piston
lower arm. This cuff is maintained in contact with the
radial artery and is used to sense the condition of the
82 threaded therein, which is positioned axially along
«the cylinder to control the pressure in the cavity 74, acting
the arm.
FIG. 3 shows the distal cuff 44, which ex
radial artery. Since this artery is relatively near the
surface of the arm, it is not necessary to apply the culi
as a “zero” adjust for such pressure. A tension spring 48
is connected to the shell 7 il to retain the proximal cuit 42
around the entire circumference of the lower arm. It
in position on the arm of the subject. An aperture is
should be understood that the brachial artery and the 10 provided in the shell 70 so that a stiliE mica diaphragm
radial artery are, in actuality, a single blood vessel and
86, having a strain gauge 88 bonded thereto, may be
can be considered as one artery for the purpose of this
inserted. The diaphragm 86 and strain gauge 88 serve
invention.
to sense the condition of the brachial artery tand operate
The cuil? 44 is held in position by a strap 46 which ex
in similar fashion to the mica diaphragm 66 and strain
tends around the circumference of the lower arm. A pair 15 gauge 64 bonded to the distal cuff, and described in con
of springs 48 maintains a desired tension in the strap 46
nection therewith. A protective grid 90 is fitted above
while allowing venous drainage of blood to exist in sutil
the diaphragm S6 and the strain gauge S8.
cient quantity that normal circulation is not impaired.
The proximal cuiî 42 also contains means for applying
The details of construction of the proximal cuff 4Z and
a marking pulse to the pressure pulse wave. A solenoid
the distal culi 44 will be described hereinafter. A fixed 20 spring :arrangement applies a brief constriction to the arm
distance L is maintained between the proximal cuff 42
of the subject, constricting the brachial artery and effec
and the distal cuff 44 by a non-elastic connecting member
tively notching the pressure pulse wave at any desired
S4, which may be a chain or strap.
point. In order to preserve uniformity of pressure appli
FIGS. 5 and 6 show the details of construction of the
cation to all areas of the arm of the subject, a plurality
distal culi 44. Supporting structure for the distal cuff 44 25 of constricting devices may be used, as shown.
is provided by a semi-rigid shell Sil which supports the
The details of construction of Ia constricting device are
remainder of the structure. Attached to the shell 50 is
shown in FIG. 8. A cylindrical support 94a is fitted into
an elastic thin plastic membrane 52 forming a space or
an aperture in the shell '70 and supports the remainder of
cavity 54. The cavity 54 is filled with silicon oil or
the constricting apparatus. A flexible diaphragm 92,
other hydraulically suitable medium which may be in 30 which may be composed of mica or other suitable ma
serted into the cavity 54 through a pair of plug closed
ports 56 which serve to ñll or “bleed” the cavity 54. An
adjusting screw SS penetrates the shell 50 and is adapted
to press on a stiif diaphragm 60 to control the pressure
in the liquid ñlled cavity 54 and to serve as an effective 35
“zero” adjust for said pressure.
terial, is held in position by a retaining ring 94. A sup
porting shell 96 is secured to the cylindrical support 90
by a plurality of screws 98 (FIG. 7). The supporting
shell 96 contains, and maintains the position of, a solenoid
winding 160. A plunger 102 is adapted to move along
the axis of the solenoid winding 160' and to provide pres
A hook 62 is mounted at each side of :the semi-rigid
shell 50 and serves to connect the cuir” 44 to the springs
48, :as shown in FIG. 2.
sure against the stiff diaphragm 92 upon the electrical
may be composed of mica or other suitable material.
The diaphragm 66 containing the strain gauge 64 is in
shell 96 by a plurality of screws 108.
If more than one constricting device is used, each of
sorted through the shell 50 into an aperture in said shell.
the constricting devices is energized simultaneously by
actuation of the solenoid winding 100x A spring 104
retracts the solenoid plunger 102 when the solenoid wind
The sensing portion of the cuiî 44 comprises a strain 40 ing 100 is not energized. A circular cap HB6 encloses
gauge 64 which is bonded to a stiff diaphragm 66, which
the constricting apparatus and is secured to the supporting
A protective grid 68 is litted over the diaphragm and 45 the application of an electrical pulse to the solenoid wind
strain gauge.
ing ¿100. When a pulse is received, the solenoid winding
In operation, the membrane S2 is closely fitted against
dit@ is energized and causes the plunger 102 to press
the arm of the subject such that the membrane 52 forms
against the stiff diaphragm 92. The pressure thus pro
an intimate connection with the radial artery. Thus,
duced will be transmitted uniformly throughout the hy
changes in the condition of the radial artery will cause 50 draulic medium contained in the cavity 74Y causing a
deformations of the membrane 52 and resulting changes
constriction around the arm of the subject and notching
in pressure which are transmitted by the silicon oil ñlling
the pressure pulse Wave as desired.
the cavity 54 to the diaphragm 66 which responds by
The constricting device described above, while operable
deforming in accordance with the pressure variations ap
to produce the desired result, may be designed to operate
plied thereto. Deformations of the diaphragm 66 will, 55 in accordance with other principles. Por example, a
in turn, deform the bonded strain gauge 64. The strain
single solenoid arrangement could be used to actuate a
gauge 64 is of a type which changes its electrical resist
plurality of hydraulically operated pistons which would
ance in accordance with changes in its shape. Thus,
in turn exert pressure upon the diaphragms 92. Alter
changes in the condition of the radial artery will produce
natively, a magnetostrictive device could be used to apply
corresponding changes in the electrical resistance of the 60 the required constrictive force to the arm of the subject.
strain gauge 64. These changes in electrical resistance
FIGS. 9 and 10 show the details of the electrical and
are used as will be described hereinafter to sense the
electronic portions of the present invention. This ap
state of the radial artery.
paratus must receive signals in the form or” changes in elec
FIGS. 7 and 8 show the details of construction of the
trical resistance from each of the strain gauges 64 and
proximal culi? 42 shown in FIG. 2. As stated above, the 65 3S, and must compute from these signals, the instantane
proximal cuff extends circumferentially around the upper
ous blood pressure of the subject. In addition, the elec
arm of the subject, extending approximately 405 degrees.
trical and electronic apparatus must furnish an electrical
This provides an overlap as shown in FIGS. 2 and 7.
pulse at the proper time and `of the proper magnitude to
Supporting structure for the proximal cuff 42 is provided
actuate the solenoid windings i60. A complete descrip
by a semi-rigid shell 70 upon which is mounted the re 70 tion of this circuitry follows.
mainder of the structure. Attached to the shell 70 and
In the description which follows, the D_C. `supply vo-lt
in intimate contact with the upper arm of the subject is
an elastic thin plastic membrane 72 forming a space or
cavity 74. The cavity 74 is filled with silicon oil or other
ages are furnished by a full-wave rectitier circuit con
structed according to well known principles of the prior
ait. A power .transformer 1l@ has its primary wind-ing
hydraulically suitable medium, which may be inserted 75 connected across a 115 volt, 60 cycle, AC. line. The sec
».
3,090,377'V
.
ondary winding of the transformer 110 is centertapped
and has its tap connected to ground.
One end of the sec
ondary winding of the power transformer 110 is connected
to the cathode of a iirst diode 112 and to the anode of a
second diode 114. The other end of the secondary wind
ing of the power transformer 110 is connected to the
.
8
.
150. The base terminal of the t-ransistor 142 is also con
nected to B minus through a resistor 152, and to ground
through a resistor 154. The resistors 152 and 154 control the base bias of the transistor 142. The output cur-4
rent of the transistor 142 appears across a resistor 156,
which is connected at one end to the emitter terminal of
the transistor 142 and, at its other end, to ground. The'
collector terminal of the transistor '142 is connected tol
B minus.
nected together and the cathodes of diodes 114 and 118
The output of the transistor 142 appears at the emitter
are connected together. The transformer diode combina 10
term-inal, which is connected directly to the base terminal
tion described above provides full-wave rectification ol‘: the
of the PNP transistor 144. The emitter terminal of the
A_C. source.
»
transistor 144 is connected to one end of a parallel combi
The rectified A.C. voltage is iiltered by an RC network
nation 'of a resistor 158 and a capacitor 160. The other
comprising a resistor 12th connected in series with the
anodes of the diodes 112 and 116 and a resistor 122 con 15 end of the parallel combination is connected to ground.
The parallel combination of the resistor 158 and the
nected in series with the cathodes of diodes 114 and 113.
capacitor 169 provides D.C. bias for the transistor 144.
A capacitor 124 is connected from the junction of the
A resistor 162 is connected to the collector terminal of
anodes of diodes 112 and 116 with the resistor 120 to
the transistor 144 at one end, and has its other end con
ground. A second capacitor 126 is connected from the
nected to B minus. The output current of .the transistor
junction of the cathodes of diodes 114 and 113 with the
144 appears across the resistor 162. The output of the
resistor 122 to ground. A third capacitor 12S is con
transistor 144 appears at the collector terminal of the tran
nected between the opposite end of the resistor 120 and
sistor 144 and is connected to the base terminal of the
ground. A fourth capacitor 136 is connected between
PNP transistor 146 through a resistor 164 and a capaci
the opposite end of the resistor 122 and ground. rPhe
resistors 120 and 122 and 4the capacitors 124, 126, 128 25 tor 166. The resistor 164 -is an isolation resistor limiting
'the current into `the capicitor 166. The capacitor 166 pro
and 13G form a iilter network which converts the rectified
vides D.C. isolation between -the transistors 144 and 146.
A.C. voltages into D.C. voltages. The junction of the
The base terminal yof the transistor 146 is connected
resistor 126 and the capacitor 128 is connected to an out
through a pair of resistors 168 and 170 to ground. The
put terminal which provides a negative D.C. voltage (B
minus), which ymay be approximately minus 22.5 volts. 30 junction of -the resistors 16S and 170 is connected to B
minus through a resistor 172. The resistors 168, 170
The junction of the resistor 122 and the capacitor 113€) is
and 172 control the bias of «the transistor 146. The collec
connected to an output terminal which provides ya positive
tor terminal of the transistor 146 is directly connected to
D.C. voltage (B plus), which may be approximately plus
B minus. The emitter terminal of the transistor 146 is
22.5 volts. A negative D.C. bias voltage, which may be
connected to ~a capacitor 174, which has its other end
approximately minus 13 volts is obtained by connecting
connected to the junction of the resistors 168 and 170.
a resistor 132 in series with the B minus output terminal.
The capacitor 174 provides an A.C. short circuit. A re
The power supply described above provides all of the
cathode of a third diode 116 and the anode of a fourth
diode 118. The anodes of diodes 112 and 116 are con
sistor -176 is connected, at one end, yto the emitter «ter
miual of the transistor 146, and has its other end con
nected to ground. The output current of lthe transistor
vention.
Y
40
146 appears across the resistor 176.
The ñrst sensing element or transducer, which forms a
supply voltages necessary for the operation of the elec
’tricai and electronic circuitry comprising the present in
part of the proximal cuff described above, has been de
scribed as providing a varying electrical resistance. This
The three-stage ampliñer described'above includes the
transistors 142, 144 and 146.
The ñrst two stages of `arn
plitication, provided by the transistors 142 and 144 pro
in a bridge circuit with resistors 136, 138 and 141). That 45 vide a high voltage gain. The third stage of amplication,
provided by the transistor 146, provides a high power
is, a first end of .the resistance V134 is connected to a iirst
resistance is shown as a resistance 134 -and is connected
output. This output appears at lthe emitter terminal of
end of the resistor 136. The second end of the resistor
the transistor 146. A capacitor 178 is connected to the
136 is connected to a íirst end of the resistor 138. The
emitter terminal of the transistor 146 and provides D.C.
Vsecond end of the resistor 138 is connected to a lirst end
isolation, i.e., it allows only the A.C. port-ion of the out
of the resistor 140. The second end of the resistor 140
put signal to pass.
is connected to the second end ot the resistance 134.
Peak detection is accomplished by three diodes 180, 182
The junction of the resistors 134 and 141) is also yconnected
and 184, forming a gate circuit. At systole, the signal
to the B minus supply. The junction or” the resistors
appearing at the capacitor 178 has a high positive polarity.
136 and 'i138 is also connected to the B plus supply. The
junction of the resistors 13S and 140 is connected to 55 This signal is coupled to the anode terminal of the diode
V180 through a resistor V136 which limits the current sup
ground. The choice of values of the resistors 136, 138
plied to the anode terminal of the diode 1311. The diode
and 140 depends upon the value of the resistance 134;
180 is effectively actuated by the peak of the applied
however, the resistor 149 should have a value equal to
signal. The signal appearing at the capacitor 178 is dif
the mean value of the strain gauge resistance 134, and
ferentiated and applied to the cathode terminal of the
the resistors 138 and 136 must have the same values.
The junction of the resistors 134 and 136 forms the input 60 diode 182. The differentiation of this signal enables the
.detection of the polarity of the signal. This is necessary
to a peak detector circuit.
since the negative going part of «the systolic -pulse must
The peak detector serves to detect the systolic peak of
not actuate the circuit; This is important since the low
the blood pressure wave. This peak detector comprises
pressure reversal portion of the pressure wave could con
four transistors 142, 144, 146 and 148, with their associ
ated circuitry. The transistors 142, 144 and 146 together
form a three~stage ampliiier. The transistor 148 forms
a part of a differentiating circuit which will be described
ceivably ibe amplified and mistaken for the systolic peak.
The differentiation is accomplished -by the transistor 148
and its associated circuitry.
The capacitor 178 is connected to the base terminal of
,
the transistor 14S. This transistor, which is an NPN
The output of the bridge circuit described above, ap~
pearing at the junction of the resistors 134 and 136 forms 70 transistor, is biased by a common bias circuit including
a capacitor 188 and a resistor 196. The capacitor 188 has
the input to the first ampliñcation stage, the transistor
hereinafter.
142. The transistor 142 -is a PNP transistor having an
emitter terminal, a base terminal, and a collector termi
nal.' The output of the bridge circuit is fed to the base
terminal of the transistor 142 through an isolating resistor
one terminal connected to the emitter terminal of the
. transistor 148 and has its second'terminal connected to
ground. The resistor `191i` has its ñrst terminal connected
to the emitter terminai of the transistor 148, and has its
opposite end connected to the negative bias supply. The
input voltage to the transistor 148 is developed across a
resistor 192, which is connected Kbetween the base terminal
of the transistor .148 and ground. The collector terminal
of the transistor 148 is connected to the B .plus supply
through a resistor -194 across which the output current
ofthe transistor 148 appears. A ditierentiating feedback
loop is provided tfrom the output of »the transistor 148 to
collector terminal of the transistor 216 through the small
coupling capacitor 216 will establish current ilow through
.the transistor 212, leaving the base terminal of the tran
sistor 21@ positive with respect to ground and decreasing
the collector current of the transistor 216i. When the
collector current of the transistor 212 has risen suiiiciently
to permit a loop gain of unity, the transistor 210 will
become rapidly cut 0H. This action produces a positive
.pulse of magnitude approximately 9 volts and having a
its input. This connection comprises a resistor 196 con
nected to the collector terminal of the transistor 14S, and 10 rise time of a few microseconds, at the collector or” the
a capacitor 198 in series with the resistor 196. The ca
transistor 212. The circuit remains in this condition until
pacitor 198 is connected to the base terminal of the tran
sistor 148. T'ne output current from the transistor 148
is applied to the cathode terminal of the diode »182
the charge on the capacitor 228 has leaked ofi through
the resistor 22h and through the reverse direction of the
transistor 210. At this time, emitter current ñows in the
through a resistor 200 which serves to limit the current 15 transistor 21u, and the circuit will restore itself to its
supplied to the cathode terminal.
original condition. The capacitor y224» provides an A.C.
The third element of the gate formed `by «the diodes `180,
short circuit and the potentiometer '226, as discussed, pro
182 and 184 is supplied -by the diode `184. This diode
vides the necessary bias. The resistors 218 and 222 pro
essentially sets a minimum or threshold level. The
vide the collector current necessary to produce the out
threshold level is controlled by a potentiometer 202 which 20 put voltages which drive the transistors 219 and 212. The
is connected between B plus and ground and which has
wave form produced 4by the monostable multivibrator is
used throughout the rest of the circuitry to control its
its variable tap connected to a resistor 294. The resistor
timing.
204 is, in turn, connected to the anode terminal of the
One of the functions of the electrical and electronic
diode 184. The potentiometer 202 and the resistor 204 set
the desired threshold level. When the current through 25 circuitry is to provide a pulse which may be used to
actuate the solenoid windings lil@ shown in FiG. `8. This
the diodes 180 and 41.82 exceeds that threshold set by the
pulse is obtained by suitable treatment of one of the
diode 134, current ilows in a resistor 206, which is con
outputs of the multivibrator. The leading edge of the
nected to the junction of the cathode terminals of the
monostable multivibrator output pulse is ditferentiated by
diodes 180 and 184 and the anode terminal of the diode
132. The other end of the resistor 265 is connected to 30 a transistor 228 and its associated circuitry, and is used to
ground. Thus current flow through the resistor 206
drive the solenoids 1%@ shown in FIG. 8. Electrical con
represents the occurrence of the systolic peak. "lhe cur
nection is made ‘between the collector terminal of the
rent flow is detected by a pulse generator which comprises
transistor 212 and the base terminal of the transistor 22S
through a capacitor 23o. A resistor 232 is connected
transistors 20S, 216 and 212, along with associated cir~
cuitry.
35 between the base terminal of the transistor 22S and
The transistor 20S ampliiies the current flow through
ground. The input circuit to the transistor 228, compris
the resistor 296. The junction of the cathode terminals
ing the capacitor 236 and the resistor 232, provides a
necessary time constant. The emitter terminal of the
of diodes 180 and 184 and the anode terminal of the
transistor ‘22S is connected to ground through a capacitor
diode 182 is connected to the :base terminal of the tran
sistor 208, which is a PNP transistor. The collector ter 40 236 and is also connected to the bias supply through a
resistor 234. The resistor 234 and the capacitor 236 pro
minal of the transistor 208 is connected to B minus. The
vide the proper bias lfor operation of the transistor 22S.
emitter terminal of the transistor ‘208 is connected to
ground through a resistor 214, which generates the output
The transistor 22S, which is an NPN transistor, has its
collector connected to 'B plus through a resistor 233. The
voltage of the transistor 208. This voltage, through a
coupling capacitor 216, triggers a monostable multivibra 45 output of the transistor 223 appears across the resistor
238. The feedback loop for differentiation comprises a
tor formed by the transistors 210 and 212 and their asso
ciated circuitry. The transistor 210, which is a PNP tran
resistor 24€) and a capacitor 242 connected, in series, be
tween the collector terminal of the transistor 22S and the
sistor, has its collector terminal connected to B minus
through a resistor 213. The out-put voltage of the transis
'base terminal of the transistor 22S.
tor 293, appearing at the capacitor 216 is also supplied
to the collector terminal of the transistor `21% by a con
The output of the transistor 22S, appearing at the col
lector terminal, is connected to the base terminal of a
tnansistor 242 through a capacitor 246 and a diode 248,
nection from the capacitor 216 to the collector terminal.
The emitter terminal of the transistor 210 is connected to
in series. A resistor 250 is connected between the junc
ground. The base terminal of the transistor 210> is con
tion of the capacitor 246 and the diode 248 and ground.
nected to ground »through a resistor 220.
55 The capacitor 246 and the resistor 25o provide the neces
The transistor 212, which is a PNP transistor, has its
sary time constant for correct operation of the transistor
collector terminal connected to B minus through a resistor
244, and the diode 24S ensures that Ithe solenoid will not
222. The base terminal of the transistor '212 is also con
be tired when the monostable multivibrator resets. The
nected to the output of the transistor 268 by a connection
collector terminal `of the transistor 244, ywhich is a PNP
to the collector terminal of the transistor 2161. The emit 60 transistor, is connected to B minus. The emitter terminal
ter terminal of the transistor 212 is connected to ground
`of the tnansistor 244, which provides the output of the
through a capacitor 224 and is also connected to B minus
transistor, is connected to one side of a solenoid coil 100.
through a potentiometer 226. The potentiometer 226
The remaining side of the solenoid ycoil is connected to
has its ends connected between B minus and ground and
ground. If more than one `solenoid ‘is used the coils 10i)`
its adjustable center tap connected to the emitter terminal 65 of each of the soienoids are connected in parallel between
of the transistor 212. A capacitor 228a is connected be
the emitter terminal of the transistor 244 and ground.
tween the base terminal of the transistor 21tr, and the
With the above described circuitry, proper operation of
collector terminal of the transistor 212.
the solenoids 16@ is obtained.
The monostable multivibrator operates as follows. In
To provide the necessary inverse time function, the
the absence of an input pulse, the transistor 210 conducts,
iiat, approximately 9 volt, positive pulse which forms the
i.e., current ñows bet-Ween the emitter and collector ter
output `of the ‘multivibrator circuit, is integrated by a
transistor 250 yand its associated circuitry to generate a
minals of the transistor 219. Simultaneously, the tran
sweep signal. The output of the pulse ‘generator is con
sistor 212 is :biased to collector current cutotf by a suitable
nected to the input of the sweep generator by a connec
adjustment of the potentiometer 226. When the circuit
is in this condition, a negative trigger pulse applied to the 75 tion between the collector terminal :of the transistor 212
3,090,377
11
and [the base terminal of the transistor 250 through a
resistor 252. The base terminal of the transistor 250
is further connected to ground through a resistor 254.
"The lresistors 252 and 254 constitute a voltage divider
which apportions the correct input voltage to the transistor
250. Correct -bias for the operation of the transistor 250
is provided by -an RC combination comprising a resistor
256 connected between the emitter terminal of the NPN
transistor 250 andthe negative bias supply, and a capaci
tor 258, connected between the emitter terminal of the 10
transistor 250 and ground.
A feedback loop provides the necessary integration.
,
12
276 is connected to the input of an amplifier comprising
a transistor 288 and associated circuitry. This connection
is effected through a variable resistor or potentiometer
290 which connects .the emitter terminal of the transistor
276 to the base terminal of the transistor 288. The
emitter terminal of the transistor 288, which is a PNP
transistor, is connected to B plus through a resistor 292.
The bias for .the operation of the transistor 288 is pro
vided by a resistor 294 connected between the collector
terminal ofthe transistor 288 and ground and a capacitor
296 »also lconnected between the collector terminal of the
transistor 288 and ground. The variable resistance or
potentiometer 290 is used to adjust the gain or amplifica
This loop comprises a diode 260 and a variable resist-ance
tion of the circuit to accommodate any desired type of
262, connected, -in series, between -the collector terminal
of the >transistor 250 and the base terminal of the transis 15 output recording device or alarm. Such an output de
vice would be connected to the collector terminal of the
tor 250. A capacitor 264 is connected directly between
transistor 288.
the collector terminal of the transistor 250 and the base
The distal strain gauge 64 supplies, as its output, a
terminal of the transistor 250, forming a parallel combina
varying electrical resistance 298. This resistance is used
tion with the series combination of the potentiometer 262
and the diode 260. The presence of the diode 260 in the 20 in a bridge circuit with resistors 300, 203 and 304. The
bridge is -Íormed by connecting »a nist end of the resist
feedback loop causes a non-linearity Áin the integration
and thereby, through the adjustment of the potentiometer
ance 298 to a first end of the resistor 300. The second
end of the resistor 300' is connected to a ñrst end of the
262, the wave `form constituting the output of the transis
resistor 302. The second end of the Iresistor 302 is con
tor 250 can be made to very closely approximate the
inverse time function. A variable resistance or poten 25 nected to a ñrst end of the resistor 304. The second end
of the resistor 304 is connected to the second end of the
tiometer 266 is connected between the collector terminal
resistance 298. The junction of the resistances 300 and
of the transistor 250 «and B plus, and essentially adjusts
302 is `connected to B plus, and the junction of the resist
the overall integrator gain to multiply the inverse time
ances 298 and 304 is connected to B minus. The junc
function by a desired constant.
Three diodes 268, 270 and 272, along with associated 30 tion of the resistors 302 and 304 is connected to ground.
The loutput of the bridge circuit is connected ,to an
circuitry, from a boXcar detector. This circuit essentially
amplifying stage comprising a transistor 306 and associ
receives the inverse time sweep voltage and stores this
ated circuitry. This connection is accomplished by a
voltage at the value attained when an output pulse from
resistor 308 connected to «the junction between the resist
the second strain gauge occurs. The voltage is stored in
a capacitor 275 , ‘after having been ampliñed by a transistor 35 -ances 298 and 300, at one end, and to a ñtrst terminal of
276. Before the initiation of the sweep voltage, the ca
a capacitor 310, at its other end. The capacitor is con
pacitor 275 is essentially discharged by a negative pulse
nected ait its second terminal to the lbase terminal of the
transistor 306. The resistor 308 and the capacitor 310
from :the emitter terminal of the transistor 212 which is
eiîectively isolate the strain gauge bridge circuit as an
connected tothe -capacitor 275 through a coupling capaci
40
input to the transistor 306. The base terminal of the
tor 267 and a diode 268. The diode 268 prevents the
transistor 306, ywhich is `a PNP transistor, is connected to
leak-ott ofthe voltage to be stored on the capacitor 275.
B minus through a resistor 312. The base terminal of
The sweep voltage is applied to the base terminal of
the transistor 306 is also connected to ground through
the transistor 276 through a coupling capacitor 278 and
a resistor 314. The resistors 312 and 314 bias the transis
the diode 270, connected in senies, between the collector
terminal of the transistor 250 and the base terminal of 45 tor 306 `for proper operation. ~ The collector terminal of
the «transistor 306 is directly «connected to B minus, and
the transistor 276. The base terminal of the transistor
the emitter terminal of the transistor 306 is connected to
276 is also connected to ground through a resistor 280.
ground through a resistor 316 which develops the output
The emitter tof the transistor 276, which is a PNP transis
of the transistor 306.
tor, is connected to B plus through a resistor 282. The
The emitter terminal of the transistor 306 is directly
collector terminal of the transistor 276 is directly con 50
connected to the base terminal of a transistor 318. The
nected to ground.
emitter of the transistor 318 is connected to a parallel
The `distal strain gauge 64, as will be described herein
combination of a resistor 320 and a capacitor 322, which
after, provides a signal, which, after appropriate treat
is connected, in turn, to ground. The resistor 320 and
ment, is introduced to the boxcar circuit through the diode
272. The diode 270 has its cathode connected to the 55 the capacitor 322 provide bias for the transistor 318. The
collector terminal of the transistor 318 is connected to B
capacitor 278 and its anode connected to the base termi
minus through a resistor 324, across which the output of
nal of the ltransistor 276. The diode 272 has its cathode
the transistor 3-18 is developed.
connected to the junction of the capacitor 278 and the
The collector terminal of the transistor- 318 is connected
cathode of diode 270, yand has its `anode connected to the
source of the treated strain gauge signal through a resistor 60 to the base terminal of a transistor 326 through a series
combination of a resistor 328 and a capacitor 330. The
284. A resistor 286 connects the junction of the cathode
resistor 328 acts to limit the current to the capacitor 330.
of the diode 270 and the cathode of the diode 272 to
The capacitor 330 provides D'.C. isolation between the
transistor 3118 and the transistor 326. The transistor 326
Considering now the input to the transistor 276, the
inverse time sweep begins and charges the capacitor 275 65 is used in an emitter follower circuit. The base terminal
of the transistor 326 is connected to ground through a
through the transistor 276 and the diodeV 270. This con
series combination of a resistor 332 and a second resistor
tinues until the diode 272 becomes positive with respect
334. The junction of the resistors 332 and 334 is con
to the diode 278, at which time the diode 270 stops con
nected to B minus through a.- resistor 336. The emitter
ducting -and the charge on the capacitor 274 remains 70 of the transistor 326, which is a PNP transistor, is con
constant. The resistor 280 biases the diode 27 0 «and lthe
nected to ground through a resistor 338 which serves as the
resistor 286 biases the diode 272 tor correct operation.
emitter follower. A capacitor 340 is connected between
The resistor 284 effectively isolates the input pulse from
the emitter terminal of the transistor 326 and the junction
the distal strain gauge signal and the resistor 282 is used
of the resistors 332 and 334. The emitter follower cir
to bias the transistor 276. The output of the transistor 75 cuit is biased by the combination of the resistors 332 and
B plus.
3,090,377
13
334, the capacitor 340 and the resistor 336. A capacitor
342 is connected between the emitter terminal of the
transistor 326 and ground. This capacitor tends to in
tegrate the voltage appearing at the emitter terminal of
the transistor 326. 'I‘he capacitor 342 is connected to the
resistor 284 as has been described above, and supplies the
signal from the distal strain gauge to the boxcar circuit
described above.
14
pled to said second transducer and responsive to said sec
ond electrical signals for detecting said notch in said blood
pressure pulse wave and for providing a second electrical
pulse indicative of the time of -occurrence thereof, signal
generating means electrically coupled to said peak detec
tor for providing an electrical signal whose magnitude is
inversely proportional to the time elapsed after the occur
rence of an actuating signal, said means adapted to be
The operation of the apparatus comprising the present
actuated by said first electrical pulse, and output means
invention has been described above in detail, however, the 10 electrically coupled to said signal generating means and
procedural steps involved in making blood pressure meas
to said signal providing means and responsive to said elec
urements will again be summarized.
trical signal and to said second electrical pulse for register
The proximal cuff 42 is Wrapped around the upper
ing the magnitude of said electrical signal at the time of
arm of the subject, connecting the spring 84 to the shell
occurrence of said second electrical pulse, said magnitude
70, so that the cuff 42 is retained in position around the 15 being indicative of the blood pressure Within the artery.
arm of the subject. The strain gauge 88, mounted on the
cuff 42, may now sense the condition of the brachial
2. Apparatus for the continuous measurement of blood
pressure comprising a iirst transducer responsive to the
condition of an »artery and adapted to be mounted ad
jacent thereto for sensing the blood pressure pulse Wave
artery, and a marking pulse may be applied to a desired
portion of the pressure pulse wave by the constricting de
vice forming a part of the cuff 42.
20 within the artery and for providing first electrical signals
The distal cuff 44 is placed in contact with the radial A proportional thereto, a peak detector electrically coupled
artery of the subject, at a ñxed distance from the proximal
to said first transducer and responsive to such first elec
cuff 42. This fixed distance is determined by mounting
trical signals for detecting that portion of said electrical
the cuiî’ 44 such that the connecting member 84 is ex
signals corresponding to the systolic peak of said blood
tended to its full length. The distal cuff 44 is retained in 25 pressure pulse Wave and for providing a first electrical
position by connecting the springs 48- and the strap 46 to
pulse indicative of the time of occurrence thereof, mark
the shell Si). The strain gauge 64 may now sense the
ing means adapted to be mounted adjacent the artery and
condition of the radial artery.
responsive to said first electrical pulse for notching said
Both the proximal and distal cuffs being in position,
blood pressure pulse wave at the systolic peak of said
the electrical and electronic circuitry shown in FIGS. 9‘ 30 blood pressure wave upon the occurrence of said first
and 10 will perform all the necessary functions and com
electrical pulse, a second transducer responsive to the
putations to provide an accurate and continuous indica
condition yof the artery and adapted to be mounted ad
tion of the blood pressure of the subject to any convenient
jacent thereto at a fixed distance from said iirst trans
metering or recording unit which may be. electriccally con
ducer for sensing the blood pressure wave Within the
nected to the collector terminal of the transistor 288.
35 artery and for providing second electrical signals pro
There has thus been described improved apparatus for
portional thereto, signal providing means electrically cou
the measurement of blood pressure which yields a con
pled to said second transducer and responsive to said sec
tinuous recording of blood pressure by indirect measure
ond electrical signals for detecting said notch in said
ment. Although one embodiment of the present inven
blood pressure pulse Wave and for providing a second
tion has been described with great particularity, it is evi 40 electrical pulse indicative of the time of »occurrence there
dent that other embodiments differing only in detail may
of, sweep generating means electrically coupled to said
also be produced, which would perform the same function
peak detector for providing an electrical signal whose
as the apparatus described.
magnitude is proportional to the time elapsed after the
In addition, modiiied methods of operation could also
.occurrence of an actuating signal, said means adapted to
be devised. For example, rather than the single pulse 45 be actuated by said first electrical pulse, function generat
provided by the present apparatus, a continuous series of
ing means electrically coupled to said sweep generating
pulses of relatively high frequency compared with the nat
means for providing an electrical signal whose magnitude
ural pulse wave could also be applied. The arterial pres
is inversely proportional to the time elapsed after said
sure would then be given by the phase relationship between
occurrence of an actuating signal, and output means elec
the applied and detected waves.
50 trically coupled to said function generating means and to
Simple threshold circuits could also be incorporated into
said signal providing means and responsive to said in
the present invention so that a bell could be rung or a
verse electrical signal and to said second electrical pulse
compensating action controlled when the apparatus indi
for registering the magnitude of said inverse electrical sig
cates intentionally selected critical blood pressure levels.
nal at the time of occurrence of said second electrical
We claim:
55
pulse, said magnitude being indicative of the blood pres
l. Apparatus for the continuous measurement of blood
sure within, the artery.
pressure comprising a first transducer responsive to the
3. Apparatus for the continuous measurement of blood
condition of an artery and adapted to be mounted adjacent
pressure
comprising a -first transducer responsive to the
thereto for sensing the blood pressure pulse wave within
the artery and for providing first electrical signals pro 60 condition of an artery and adapted to be mounted adja
cent thereto for sensing the blood pressure pulse wave
portional thereto, a peak detector electrically coupled to
within the artery and for providing first electrical sig
said first transducer and responsive to said first electrical
nals proportional thereto, a peak detector electrically
coupled to said first transducer and responsive to said
pulse wave and for providing a first electrical pulse indica 65 first electrical signals for detecting that portion of said
electrical signals corresponding to the systolic peak of
tive of the time of occurrence thereof, marking means
said blood pressure pulse wave, pulse generating means
adapted to be mounted adjacent the artery and responsive
electrically coupled to said peak detector for providing
to said first electrical pulse for notching said blood pressure
signals for detecting that portion of said electrical signals
corresponding to the systolic peak of said blood pressure
a first electrical pulse indicative of the time of occurrence
pulse wave at the systolic peak of said wave upon the oc
currence of said first electrical pulse, a second transducer 70 of said systolic peak, constricting means adapted to be
mounted adjacent the artery and responsive to said first
electrical pulse for applying a constriction to the artery
at the systolic peak at said blood pressure wave upon
the occurrence of said first electrical pulse, said con
the artery and for providing second electrical signals pro
portional thereto, signal providing means electrically cou 75 striction notching said blood pressure pulse wave, a sec
responsive to the condition of the artery and adapted to
be mounted adjacent thereto at a ñxed distance from said
first transducer for sensing the blood pressure wave within
t;
3,090,377
15
ond transducer responsive to the condition of the ar
tery and mounted adjacent thereto at a fixed distance
from said ñrst transducer for sensing the blood pressure
wave within the artery and for providing second elec
trical signals proportional thereto, signal providing means
16
dicative of the time of occurrence thereof, marking means
adapted to be mounted adjacent the »artery and responsive
to said iirst electrical pulse -for notching said blood
pressure pulse wave at the systolic peak of said blood
pressure w-ave upon the occurrence of said first electrical
pulse, la second transducer responsive to the condition of
electrically coupled to said second transducer and respon
the
artery land adapted to be mounted adjacent thereto at
sive to said second electrical signals for detecting said
a ñxed distance from said iirst transducer for sensing the
notch in said blood pressure pulse wave and for pro
fblood pressure pulse wave within the artery «and for pro
viding a second electrical pulse indicative of the time of
viding second electrical signals proportional thereto, signal
10
occurrence thereof, signal generating means electrically
providing means electrically coupled to said second trans
coupled to said pulse generating means for providing
ducer Yand responsive to said second electrical signals for
an electrical signal whose magnitude is inversely propor
detecting said notch in said blood pressure .pulse Wave
tional to the time elapsed after the occurrence of an ac
and for providing a second electrical pulse indicative of
tuating signal, said means adapted to be actuated by said
the Itime of occurrence thereof, sweep generating means
»first electrical pulse, and output means electrically cou
electrically coupled to said peak detector for providing an
pled to said signal generating means and to said signal
electrical signal Whose magnitude is proportional to the
providing means and responsive to said electrical signal
time elapsed after the occurrence of an Áactuating signal,
and to said second electrical pulse for registering the
said means ladapted to be actuated by said first electrical
magnitude of said electrical signal at the time of occur
pulse, function generating means electrically coupled to
20
rence of said second electrical pulse, said magnitude being
said sweep generating means for providing an electrical
indicative of the blood pressure within the artery.
signal Whose magnitude -is proportional to the natural log
4. Apparatus for the continuous measurement of blood
arithm of the time elapsed yafter said occurrence of the
pressure comprising a tirst transducer responsive to the
actuating signal, differentiating means electrically coupled
condition of an artery and adapted to be mounted adja
to said Áfunction generating means «for providing an elec
cent thereto for sensing the blood pressure pulse wave 25 trical signal Whose magnitude is inversely proportional to
within the artery and for providing iirst electrical signals
the time elapsed after said occur-rence of the actuating
proportional thereto, a peak detector electrically coupled
signal, yand output means electrically coupled to said dif
to said iirst transducer and responsive to such ñrst elec
ferentiating means and to said signal providing means
trical signals for detecting that portion of said electrical 30 and responsive to said differentiated electrical signal and
` to said second electrical pulse for registering the magnitude
signals corresponding to the systolic peak of said blood
of said electrical signal at the time of occurrence of said
pressure pulse wave, pulse generating means electrically
second electrical pulse, said magnitude being indicative
coupled to said peak detector for providing a tirst elec
of the blood pressure within the artery.
trical pulse indicative of the time of occurrence of said
6. Apparatus according to claim 5 in which a first cuiiî
systolic peak, constricting means adapted to be mounted
is »adapted to be mounted on ya member of the subject
adjacent the artery and responsive to said iirst electrical
Whose rblood pressure is being measured, in intimate con
pulse for applying a constriction to the artery at the sys~
tact with the member and adjacent the artery Whose condi«
tolic peak of said blood pressure Wave upon the occurrence
tion is .being sensed, said first cuff comprising support
of said Íirst electrical pulse, said constriction notching
said blood pressure pulse wave, a second transducer re~ 40 means, and having said iirst transducer mounted in said
support means, and having said constricting means
sponsive to the condition of the artery and mounted ad<
mounted in said support means.
7. Apparatus according to claim 5 in which a tirst cuff
is adapted to be mounted on a member of the subject
portional thereto, signal providing means electrically cou 45 whose blood pressure is being measured, in intimate con
tact with ythe member vand -adjacent the artery whose condi
pled to said second transducer and responsive to said
jacent thereto at a fixed distance from said iirst trans
ducer for sensing the blood pressure pulse wave within
the artery and for providing second electrical signals pro
second electrical signals for'detecting said notch in said
blood pressure pulse wave and for providing a second
electrical pulse indicative of the time of occurrence there
tion is being sensed, .said first cuff comprising support
means, said first transducer -being mounted in said sup
port means, and said constricting means being mounted
in said support means, and -a second culi adapted to be
mounted ~on la mem-ber of the subject whose blood pressure
of, sweep generating means electrically coupled to said
pulse generating means for providing an electrical signal
is being measured, in intimate contact with the member
Whose magnitude is proportional to the time elapsed after
and adjacent the artery whose condition is being sensed,
the occurrence of an actuating signal, said means adapted
said second cuff comprising support means, said second
to be actuated by said íirst electrical pulse, function gen
transducer being mounted in said support means.
erating means electrically coupled to said sweep generat 55
8. Apparatus according to claim 5 in which a first cuff
ing means for providing an electrical signal Whose mag
is adapted to be mounted on a member of the subject
nitude is inversely proportional to the time elapsed after
whose :blood pressure is being measured, said iirst cuff
said occurrence of an actuating signal, and output means
comp-rising support means containing la cavity filled with
electrically coupled to said function generating means and
hydraulic iluid, a flexible membrane mounted on said
to said signal providing means and responsive to said 60 support means and. in intimate contact with the member
inverse electrical signal and to said second electrical pulse
and with said hydraulic ñuid and adjacent the -artery whose
for registering the magnitude of said inverse electrical
condition is being sensed, said membrane responsive to
signal at the time of occurrence of said second electrical
variations in the pressure Within the artery for transmitting
pulse, said magnitude being indicative of the blood pres
said pressure variations to said hydraulic iluid and for re
sure within the artery.
65 ceiving pressure variationsV from said hydraulic fluid, said
5. Apparatus for the continuous measurement of blood
iirst transducer mounted in said support-means and in
intimate contact with said hydraulic fluid for receiving
pressure comprising a first transducer responsive to the
condition of `an artery and adapted to be mounted adjacent
pressure variations from» said hydraulic iluid and Afor pro
thereto for sensing the blood pressure pulse w-ave Within
viding said iirst electrical signals in accordance therewith,
the artery and for providing íirst electrical signals pro« 70 and in which said constricting means are mounted in said
Y portion-a1 thereto, a peak detector electrically coupled to
said first transducer and responsive lto said first electrical
support means and in intimate contact with said hydraulic
iluid for transmitting pressure variations to said hydraulic
fluid, said membrane receiving said pressure variations and
signals -for detecting that portion oi said electrical signals
applying said constriction to the artery.
corresponding to .the systolic peak of said blood pressure
lpulse wave and vfor providing a iirst electrical pulse in 75 9. Apparatus according to claim 5 in which a iirst
l7
'3,090,377
cuff is adapted to be mounted on a member of the subject
whose blood pressure is being measured, said first cuff
comprising support means contacting a cavity filled with
hydraulic fiuid, a flexible membrane mounted on said sup
port means and in intimate contact with the member and
with said hydraulic fiuid :and adjacent the artery whose
condition is being sensed, said membrane responsive to
variations in the pressure within the -artery for transmitting
said pressure variations from said hydraulic fiuid and for
lâ
second electrical pulse, said magnitude being indicative of
the blood pressure within the artery.
11. Apparatus for the continuous measurement of blood
pressure comprising Ia first transducer responsive to the
condition of an artery and adapted to be mounted adjacent
thereto for sensing the blood pressure pulse wave Within
the :artery and for providing first electrical -signals pro
portional thereto, a peak detector electrically coupled
to said first transducer and responsive to said first electrical
receiving pressure variations from said hydraulic fluid, 10 signals `for detecting that portion of said electrical sign-als
said first transducer mounted in said support means and in
corresponding to the systolic peak -of said blood pressure
intimate contact with said hydraulic fluid for receiving
pulse wave, pulse generating means electrically coupled
pressure variations from said hydraulic >fiuid and for pro
to said peak detector for providingl a first electrical pulse
indicative of the time of occurrence of said systolic peak,
and in which said constricting means are mounted in said 15 constricting means adapted to be mounted `adjacent the
support means and in intimate contact with said hydraulic
artery and responsive »to said first electrical pulse for ap
fiuid for transmitting pressure variations to said hydraulic
plying a constriction to the artery yat the systolic peak
fluid, said membrane receiving said pressure variations and
of said blood pressure pulse wave upon the occurrence of
applying said constriction to the artery, and a second cuff
said first electrical pulse, said constriction notching said
adapted to ybe mounted on a member of the subject whose 20 blood pressure pulse wave, -a second transducer responsive
blood is lbeing measured, said second cuff comprising sup
to the condition of the artery and mounted adjacent there
port means containing a cavity filled with hydraulic fluid,
to at a fixed distance from said first transducer for sensing
a fiexible membrane mounted on said support means and
the Iblood pressure pulse wave within the -artery and for
in intimate contact with the member and with said hy
providing second electrical signals proportion-al thereto,
draulic fiuid and adjacent the artery whose condition is 25 signal providing means electrically coupled to said second
being sensed, said membrane responsive to variations in
transducer and responsive to said second electrical signals
the pressure within »the artery for transmitting said pressure
for detecting said notch in said blood pressure pulse Wave
variations to said hydraulic fiuid, and in which said second
and for providing a second electrical pulse indicative of the
transducer is mounted in said support means and in inti
time of occurrence thereof, and means electrically coupled
mate contact with said hydraulic fiuid for receiving pres
30 to said pulse generating means and to said signal provid
sure variations from said hydraulic fiuid and for providing
ing means and responsive to said first and second electrical
said second electrical signals in accord-ance therewith.
pulses for providing an output signal proportional to the
l0. Apparatus for the continuous measurement of blood
elapsed time between the occurrence of said first and sec
pressure comprising -a first transducer responsive to the
ond pulses, said output signal being indicative of the blood
condition »of an artery and adapted to be mounted adjacent
35 pressure within the artery, in which a first cufi is adapted
thereto for sensing the blood pressure pulse wave within
to be mounted on a member of the subject whose blood
the artery and for providing first electrical signals propor
pressure is being measured, said first cuff comprising sup
tional thereto, a peak detector electrically coupled to said
port means containing la cavity filled with hydraulic fluid,
first transducer and responsive to said first electrical signals
a iiexible membrane mounted on said support means and
for detecting that portion of said electrical signals corre 40 `adapted to be placed in intimate contact with the member
sponding to the systolic peak of said blood pressure pulse
and with said hydraulic fiuid and adjacent the artery whose
viding said first electrical signals in accordance therewith,
wave, pulse gener-ating means electrically coupled to said
peak detector -for providing a first electrical pulse indica
condition is being sensed, said membrane responsive to
tive of the time of `occurrence of said systolic peak, con
stricting means adapted to be mounted adjacent the artery
and responsive to said first electrical pulse for applying a
constriction to the artery at the systolic peak of said blood
for receiving pressure lvariations from said hydraulic fiuid,
pressure wave upon the occurrence of said first electrical
pulse, said constriction notching said blood pressure pulse
variations in the pressure within the :artery for trans
miting said pressure variations to said hydraulic fluid and
said first transducer mounted in said support means and in
intimate contact with _said hydraulic fiuid for receiving
pressure variations from said hydraulic fluid and for
providing said first electrical signals in accordance there
wave, a second transducer responsive to the condition of
with, and in which said constricting means are mounted
said `artery and mounted adjacent thereto -at a fixed dis 50 in said support means and in intimate contact with said
tance from said first transducer for sensing the blood pres
sure pulse wave within the artery and for providing second
electrical signals proportional thereto, signal providing
hydraulic fiuid for transmitting pressure variations to said
hydraulic fiuid, said membrane receiving said pressure
variations and applying said constriction to the artery.
12. Apparatus for the continuous measurement of blood
responsive to said second electrical signals for detecting 55 pressure comprising ya first transducer responsive to the
said notch in said blood pressure pulse wave and for pro
`condition kof lan artery and adapted «to be mounted adjacent
viding a second electrical pulse indicative of the time of
thereto for sensing the blood pressure pulse wave within
occurrence thereof, sweep generating means electrically
the artery and for providing first electrical signals pro
coupled to said pulse generating means for providing an
portional thereto, :a peak detector electrically coupled to
electrical signal whose magnitude is proportional to the 60 said first transducer and responsive to said first electrical
time elapsed after the occurrence of an `actuating signal,
signals for detecting that portion of said electrical signals
said means adapted to be -actuated by said first electrical
corresponding to the systolic peak of said blood pressure
pulse, function generating means electrically coupled to
pulse wave, pulse generating means electrically coupled to
said sweep generating means `for providing -an electrical
said peak detector for providing Ia first electrical pulse in
signal whose magnitude is proportional to the natural log 65 dicative of the time of occurrence of said systolic peak,
arithm of the time elapsed after said occurrence of the
constricting means adapted to be mounted adjacent the
actuating signal, differentiating means electrically coupled
artery and responsive to said first electrical pulse for ap
to said function generating means for providing an elec
plying -a constriction to the artery at the systolic peak of
means electrically coupled to said second transducer and
trical signal whose magnitude is inversely proportional to
said blood pressure pulse wave upon the occurrence of
the time elapsed `after said occurrence of the actuating 70 said first electrical pulse, said constriction notching said
signal, Iand outpu-t means electrically coupled to said
blood pressure pulse wave, »a vsecond transducer responsive
differentiating means and `to said signal providing means
to the condition of the artery «and mounted adjacent there
and responsive to said differentiated electrical signal and
to at a fixed distance from said first transducer for sensing
to said second electrical pulse for registering the magni
the blood pressure pulse wave within the >artery and for
tude of said electrical signal at the time occurrence of said
providing second electrical -signals proportional thereto,
acces??
ra
20
signal providing means electrically coupled to said second
transducer and responsive to said second electrical signals
-for `detecting said notch in said blood pressure pulse wave
çadapted to be mounted on a member of the subject Whose
and for providing -a second electrical pulse indicative of
the time of occurrence thereof, 'and means electrically
coupled to said pulse generating means and to said signal
providing means and responsive to said ñrst `and second
a flexible membrane mounted on said support means and
electrical pulses for providing `an output signal proportional
tothe elapsed time between the occurrence of said íirst and
blood «is being measured, said second cuff comprising sup
port means containing 4a cavity filled with hydraulic fluid,
in intimate contact with the member and with said hy
draulic tluid land adjacent the artery whose condition is
being sensed, said membrane responsive to variations in
the pressure Within the artery for transmitting said pres
sure variations to said hydraulic fluid, and in which said
second pulses, said output signal :being indicative of
second transducer «is mounted «in said support means and in
the blood pressure within the artery, in which a iirst
cult is :adapted to be mounted on a member of the subject
xintimate contact with said hydraulic fluid for receiving
pressure variations from said hydraulic fluid .and for pro
viding said second electrical signals in accordance there
with.
whose blood pressure is being measured, said ñrst cutî
comprising support means containing a cavity iilled with
hydraulic fluid, `a lflexible membrane mounted on said sup 15
port means and in intimate contact with the member and
with said hydraulic fluid and adjacent the artery whose
condition is being sensed, said membrane responsive to
4variations in the pressure within the artery for transmitting
said pressure variations from said hydraulic iiuid Iand for 20
receiving pressure variations from said hydraulic fluid,
said tirst transducer mounted in said support means and
‘in intimate contact with said hydraulic iluid for receiving
pressure variations from said hydraulic ñuid and for pro
‘References Cited in the tile of this patent
UNITED STATES PATENTS
2,658,505
Sheer ________________ __ Nov. 10, 1953
2,756,741
Campanella __________ __ July 31, 1956
2,827,040
2,865,365
2,875,750
2,944,542
Gilford ______________ -_ Mar. 18,
Newland ____________ __ Dec. 23,
Boucke ______________ ___ Mar. 3,
Barnett ______________ __ Iuly 12,
viding said iirst electrical signals in accordance therewith, 25
and in which said constricting means are mounted in said
support means and in intimate contact with said hydraulic
1958
1958
1959
1960
FOREIGN PATENTS
314,141
Switzerland __________ __ Mar. 31, 1956
OTHER REFERENCES
fluid for transmitting pressure variations to said hydraulic
Pettit: “Electronic Switching, Time, and Pulse Circuits,”
tluid, said membrane receiving said pressure variations and
applying said constriction to the artery, and -a second cuff 30 TK 7870 Pri-McGraw-Hill, 1959, pages 38-39.
Документ
Категория
Без категории
Просмотров
0
Размер файла
2 117 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа