Apparatus for Measuring the Pressure of the Blood.
Year: 1899

page_text: Date of Application, 24th May, 1900
Complate Cornifination 1 oft 21st Eub 1000 Accented 31st Mar
1900
Complete Specification Loft, 21st Feb., 1000 Accepted, 31st Mar, 1900
PROVISIONAL SPECIFICATION.
Apparatus for Measuring the Pressure of the Blood.
I, Dr. GUSTAV GAERTNER, of I Schuler Strasse, 1-3, Vienna, in the Empire
of Austria, University Professor, do hereby declare the nature of this invention
to be as follows:-
In the employment of any instruments used for measuring the pressure of
the blood, the accuracy of the result depends upon fixing the precise moment
at which the pulsation ceases in an artery compressed by slowly increasing
pressure, beyond which position the blood is shut off. The accurate determining
of the pressure of the blood is consequently not only dependent upon the
individual sensibility of the person who is noting the pulse, but the anatomical
conditions of the individual who is being examined, such as rigidity and
position of the arteries, are the cause of inevitable sources of error
where the sense of touch has been cultivated to the finest degree.
even
The apparatus constituting the subject of this invention is suitable for giving
reliable indications as the fixing of the moment for making the observation is
effected by the eye-sight.
..
In the use of the apparatus referred to, the first step is to expei the blood
from the finger-end by means of an instrument hereinafter described, and then,
by means of an inflatable ring, to shut off the part mentioned so as to prevent a
reflow of blood thereto. The inflation of the shutting-off ring" is effected by
means of a measurable pneumatic pressure, which the operator then slowly and
steadily reduces. At the moment when the pressure which effects the "shutting-
off" exactly equals that of the blood, the latter will again flow into the finger-
end, which is immediately observable by the flushing of the latter. If, con-
sequently, at this moment the degree of the pneumatic pressure in the "shutting-
off" ring, be read off on a suitable apparatus, the extent of the blood pressure
will be ascertained.
..
In the accompanying drawing one form of an apparatus for determin-
ing the pressure of the blood is illustrated. Fig. 1 is a general view
of the actual apparatus. Fig. 1 is a section of the shutting-off" ring, and
Figs. 2 and 3 represent modifications of the auxiliary apparatus for expelling
the blood from the finger-end.
The principal part of the apparatus is the "shutting-off" ring shown in Fig. 1
and in cross section in Fig. 1. It consists of a rigid hoop a, to the inside
of which a circular, elastic, and inflatable tube is fixed, which is connected,
by means of an intermediate tube c, on the one hand with an elastic bulb d,
and on the other with a pressure measuring apparatus e (some sort of mercurial
manometer or membrane areometer).
If the pressure be increased by the compression of the bulb 7, the "shutting-off"
ring a will be inflated, whereby the finger end put through the ring can
be shut off from the flow of blood. The degree of the pressure is shown on the
manometer. If the pressure be gradually diminished, the mercury will slowly
fall, in the case illustrated, and it is only necessary to observe the precise

page_text: moment at which the diminution of the pressure enables the blood to flow
back again into the finger-end in order that the degree of pressure of the blood
may be read off from the manometer.
Fig. 2 illustrates a form of apparatus to be used for previously expelling the
blood from the finger end. This apparatus consists of a cap e in which an
elastic membrane f is fixed in such a manner that a space g filled with air is
left between the inside of the cap and the membrane. Upon the finger end
being pressed into the cap, the air in the space g is compressed by the pressing
back of the elastic membrane, whereby a counter-pressure is produced which
forces the blood out of the finger-end.
A modification of this auxiliary apparatus illustrated at Fig. 3 consists of a
rigid cape the interior of which is furnished with an inflatable elastic lining f
which is connected with a bulb g. This cap is put over the finger-end
previously inserted through the ring a b, and pressure produced in the elastic
lining by the compression of the air-bulb y, the blood being thereby forced
out of the finger-end.
As soon as the blood has been driven out of the finger-end by means of one
of the described apparatuses, the stoppage of circulation is effected by vigorous
compression of the air bulb on the principal apparatus, whereupon the
auxiliary apparatus is removed from the finger-end, so that it is now possible
to observe in the finger-end now exposed to view, the exact moment at which,
with gradually diminishing pressure in the bulb d, the blood flows back again
into the end of the finger.
It is obvious that the apparatus can be so arranged that the air bulb d and
"shutting-off" ring a b may form its ends, and the instrument for reading off
the pressure may be situated in the middle.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.
Apparatus for Measuring the Pressure of the Blood.
1. Dr. Gustav GAERINER, of I Schulerstrasse, 13, Vienna, in the Empire
of Austria, University Professor, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
In the employment of any instruments, used for measuring the pressure of
the blood, the accuracy of the result depends upon fixing the precise moment
at which the pulsation ceases, in an artery compressed by slowly increasing pressure
beyond which position the circulation of the blood is shut off. The accurate determin-
ing of the pressure of the blood is consequently not only dependent upon the
individual sensibility of the person who is noting the pulse, but the anatomical
conditions of the individual who is being examined, such as rigidity and
position of the arteries, are the cause of inevitable sources of error even
where the sense of touch has been cultivated to the finest degree.
The apparatus constituting the subject of this invention is suitable for giving
reliable indications, as the fixing of the moment for making the observation is
effected by the eye sight.
In the use of the apparatus referred to, the first step is to expel the blood
from the finger end by means of an instrument hereinafter described and then,
by means of an inflatable ring, to shut off the part mentioned so as to prevent a

page_text: "
+
reflow of blood thereto. The inflation of the shutting off" ring is effected by
means of a measurable pneumatic pressure, which the operator then slowly and
steadily reduces. At the moment when the pressure which effects the shutting
off exactly equals that of the blood, the latter will again flow into the finger
end, which is immediately observable by the flushing of the latter. If, con-
sequently at this moment the degree of the pneumatic pressure in the "shutting
off" ring be read off on a suitable apparatus, the extent of the blood pressure
will be ascertained.
In the drawing accompanying my Provisional Specification one form of an
apparatus for determining the pressure of the blood is illustrated:-Fig. 1, is a
general view of the actual apparatus. Fig. 1a is a section of the "shutting-off"
ring and Figs. 2 and 3 represent modifications of the auxiliary apparatus for
expelling the blood from the finger end.
The principal part of the apparatus is the "shutting" off ring shown in Fig. 1
and in cross section in Fig. 1. It consists of a rigid hoop a to the inside
of which a circular, elastic and inflatable tube b is fixed, which is connected
by means of an intermediate tube c, on the one hand with an elastic bulb d,
and on the other with a pressure measuring apparatus e (some sort of mercurial
manometer or membrane aerometer).
If the pressure be increased by the compression of the bulb d, the "shutting-off"
ring a will be inflated, whereby the finger end put through the ring can
be shut off from the flow of blood. The degree of the pressure is shown on the
manometer. If the pressure be gradually diminished, the mercury will slowly
fall, in the case illustrated, and it is only necessary to observe the precise
moment, at which the diminution of the pressure enables the blood to flow
back again into the finger end, in order that the degree of pressure of the blood
may be read off from the manometer.
Fig. 2 illustrates a form of apparatus to be used for previously expelling the
blood from the finger end. This apparatus consists of a cap e in which an
elastic membrane f is fixed in such a manner that a space y filled with air is
left between the inside of the cap and the membrane. Upon the finger end
being pressed into the cap, the air in the space y is compressed by the pressing
back of the elastic membrane, whereby a counter pressure is produced which
forces the blood out of the finger end.
A modification of this auxiliary apparatus illustrated at Fig. 3 consists of a
rigid cap e the interior of which is furnished with an inflatable elastic lining f
which is connected with a bulb g. This cap is put over the finger end
previously inserted through the ring aband pressure produced in the elastic
lining by the compression of the air bulb g, the blood being thereby forced
out of the finger end.
As soon as the blood has been driven out of the finger end by means of one
of the described apparatuses the stoppage of circulation is effected by vigorous
compression of the air bulb d on the principal apparatus, whereupon the
auxiliary apparatus is removed from the finger end, so that it is now possible
to observe in the finger end, now exposed to view, the exact moment at which,
with gradually diminishing pressure in the bulb d, the blood flows back again
into the end of the finger.
It is obvious that the apparatus can be so arranged that the air bulb d and
shutting off ring ab may form its ends and the instrument for reading off
the pressure may be situated in the middle.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. In apparatus for measuring the pressure of the blood, the combination of
a ring consisting of a rigid hoop a furnished with an elastic infiatable lining b,
an elastic air bulb and an instrument e connected with said elastic inflatable

page_text: lining for indicating the pressure prevailing at any particular time and an
apparatus for forcing the blood out of the finger tip, substantially as herein
set forth.
2. In combination with an apparatus for measuring the pressure of the blood,
an auxiliary apparatus for forcing the blood out of the finger end, consisting of a
thimble shaped cap e in which an elastic membrane is fixed in such a manner
that between the latter and the inside of the cap a free space is left so that upon
the finger end being compressed thereby the air filling this space is compressed
and forces the blood out of the finger end by the counter pressure produced,
substantially as herein set forth.
3. A modification of the auxiliary apparatus mentioned under Claim 2, con-
sisting of a cap e with an internal inflatable elastic lining f, which is in connec-
tion with an air bulb g, substantially as herein set forth.
Dated this 21st day of February 1900.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.