U.S. patent number 3,795,240 [Application Number 05/239,264] was granted by the patent office on 1974-03-05 for respiratory distress stimulator system.
This patent grant is currently assigned to Hoffmann-La Roche Inc.. Invention is credited to Ulrich Anton Frank.
United States Patent |
3,795,240 |
Frank |
March 5, 1974 |
RESPIRATORY DISTRESS STIMULATOR SYSTEM
Abstract
A patient care system for monitoring respiratory distress
problems and providing therapeutic treatment comprising, a sensor
for generating patient derived respiratory activity signals,
detecting an apnea episode from the signals, and providing in
response to a detected apnea episode, stimulation of the patient by
a momentary inflation of a pneumatic means adapted for placement
under the patient to raise the patient and induce loss of
equilibrium for startling the patient into a natural respiration
pattern.
Inventors: |
Frank; Ulrich Anton (Yardley,
PA) |
Assignee: |
Hoffmann-La Roche Inc. (Nutley,
NJ)
|
Family
ID: |
27510341 |
Appl.
No.: |
05/239,264 |
Filed: |
March 29, 1972 |
Current U.S.
Class: |
600/534;
340/573.1; 601/41 |
Current CPC
Class: |
A61H
31/008 (20130101); A61H 31/006 (20130101); A61H
31/005 (20130101); A61H 31/00 (20130101); A61B
5/113 (20130101); A61H 1/003 (20130101); A61H
2201/5058 (20130101); A61H 2230/40 (20130101); A61H
2201/1238 (20130101) |
Current International
Class: |
A61H
1/00 (20060101); A61H 31/00 (20060101); A61B
5/11 (20060101); A61B 5/113 (20060101); A61b
005/08 () |
Field of
Search: |
;128/2S,2R,2.08,2A,28,33,1B ;340/279 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Howell; Kyle L.
Attorney, Agent or Firm: Welt; Samuel L. Leon; Bernard
S.
Claims
I claim:
1. A patient care system for monitoring and treating respiratory
distress problems comprising:
means for sensing and generating respiratory activity signals;
means responsive to said respiratory activity signals, for
detecting a respiratory distress problem; and
stimulating means responsive to said detecting means including
inflatable fluid means adapted for placement under a patient to
cause a loss of patient equilibrium, by a startling momentary
raising action of a non-oscillatory type.
2. A patient care system according to claim 1 wherein said
stimulating means further includes fluid supply means electrically
connected from said detecting means and adapted for momentarily
inflating said pneumatic means.
3. A patient care system according to claim 2 wherein said fluid
supply means includes air reservoir means for maintaining a
predetermined air pressure value for inflating the fluid means.
4. A patient care system according to claim 1 including means
responsive to said detecting means for counting each respiratory
distress problem detected.
5. A patient care system for monitoring and treating respiratory
distress problems comprising:
mesans for sensing and generating respiratory activity signals;
monitoring means responsive to said respiratory activity signals
for providing an output signal upon detection of a respiratory
distress problem;
inflatable pneumatic means including an air mattress adapted for
placement under a patient;
pneumatic supply means including air reservoir means for
maintaining a predetermined air pressure valve, energizable to
inflate said pneumatic means; and
means of a non-oscillatory type, responsive to said monitoring
means output signal, for momentarily energizing said pneumatic
supply means to provide a startling raising action adapted to cause
a loss of patient equilibrium.
6. A patient care system according to claim 5 wherein said
pneumatic supply means further includes: valve means; an
energizable pump connected to said air reservoir through said valve
means; and, a pressure switch when activated responsive to less
than a predetermined level of air pressure in said air reservoir
means for energizing said pump.
7. A patient care system according to claim 6 including switch
means connected from the monitoring means for activating said
pressure switch in the absence of an output signal from said
monitoring means.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an apnea monitoring and
therapeutic system and more specifically a system directed at
stimulation of a patient in respiratory distress.
The cessation of respiration or the inability to get one's breath
often referred to as apnea, is a serious problem which becomes
dangerous especially in premature infants where such occurrences
are frequent. It is understood that repeated attacks as well as
prolonged attacks of apnea are factors which carry a poor prognosis
both for life and for subsequent mental development resulting from
irreversible cerebral damage sustained during these apneic
episodes. The best prospect of reducing harmful effects of
late-occurring apnea is through constant surveillance preferably
using some automated device to alert attendants so that stimulation
through resuscitation can begin promptly. As a consequence, apnea
monitoring of premature infants has become an accepted practice in
most institutions.
Management of apnea monitoring in the newborn, particularly in
prematures, for the most part includes sensitive devices for
detecting apnea events. Upon detection of an apnea episode a visual
or audible alarm is generated, to call the attending nurse for
prompt manual stimulation of the infant in an attempt to terminate
the episode by restoring normal breathing. Alertness and
responsiveness of the nursing staff is important as it becomes more
difficult to obtain a positive response to stimulation the longer
the apnea persists. Naturally then, most apnea monitors are
designed to provide an early alarm. Unfortunately, however, most of
these apnea episodes are of a short duration and occur almost
randomly during any day of neonatal life. Thus, they place an
unnecessary burden on the nurse to the extent that in some cases it
is conceivable that the alarms may even be neglected.
The purpose of the present invention is to avoid some of the
problems incurred in apnea monitoring by closing the loop of the
automated monitoring system, to provide a therapeutic action by
early stimulation of the respiratory distressed patient. The
preferred innovative technique of automatic mechanical stimulation
in the present embodiment is directed to suddenly induce a loss of
equilibrium and a falling sensation to, in effect, startle the
infant into a natural respiration pattern. This is conveniently
accomplished by sudden inflation, through regulating the pneumatic
pressure, of a small pneumatic mattress which is preferably placed
under the upper half of the infant's body.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram in block form of the invention.
FIG. 2 is a schematic diagram in block form of a typical apnea
monitor 14 illustrated in FIG. 1.
FIG. 3 is a top plan view of one embodiment of a pneumatic
stimulator 25 shown in FIG. 1.
FIG. 4 is a schematic diagram in block form of a preferred
embodiment of the pneumatic supply unit 24 depicted in FIG. 1.
PREFERRED EMBODIMENT OF THE INVENTION
With reference to the drawings there is shown in FIG. 1 a preferred
embodiment of the invention comprising a sensor 11 secured by
suitable means to a patient, the respiratory activity detected by
sensor 11 being converted to an electrical signal which is
conducted by lead 12 to an apnea monitor 14. Respiratory distress
problems are detected from the respiratory signals by an apnea
monitor 14 to emit signals indicative of apnea episodes for
energizing an alarm 15 and for activating a one shot unit 16
serving as a one second timer in the present embodiment.
The apnea monitor 14 could take the configuration of a number of
conventional apnea monitors now commercially available irrespective
of whether the basis of their operation is based on the impedance
pneumography, capacitance respirometry, or any other technique for
detecting the apnea episode. A typical one of such apnea monitors
is shown in FIG. 2 including, an input amplifier 17 which is
driving a Schmitt trigger 18 adapted to be responsive during the
period its input signal penetrates above a predetermined threshold
level for which the Schmitt trigger is set. The Schmitt trigger
output is connected to a timer 19 having a timing capacitance which
will react in response to a predetermined interval for denoting an
apnea interval to in turn produce an output for exciting an alarm
latch 21, the output of which is connected to the one shot unit 16,
illustrated in FIG. 1. The Schmitt trigger 18 output is also used
for energizing a one shot unit 22 which in turn drives an indicator
23 representative of the respiration activity of the patient.
With reference back to FIG. 1, the duration of the one shot timer
16 will determine the period during which stimulation is to be
applied to the patient. The one shot timer 16 is connected for
driving a pneumatic supply unit which in turn is pneumatically
coupled through suitable tubing to an inflatable pneumatic
stimulator 25 placed under the patient. In a patient having an
apnea episode, the pneumatic stimulator is momentarily inflated to
induce a sudden loss of equilibrium which, in effect, startles the
patient back into a normal respiration pattern.
An embodiment of the pneumatic stimulator is illustrated in FIG. 3,
wherein there is a rectangular shaped flexible casing constructed
of, for example, an elastomeric material which might be rubber,
neoprene, polyethelene etc. The pneumatic stimulator has an air
mattress configuration provided by four partially separated areas
27 each of which is supplied with air through a relatively rigid
tube 28 via apertures 29. The rigid tube is advantageous in that
because of its rigid nature the air mattress cannot be folded or
bent over at an area where one depends on the passage of air
through the several segments for proper air flow. Otherwise, as is
experienced with conventional air mattresses, when folded over the
continuity of air flow is obstructed between adjacent segments to
prevent the air mattress from being completely inflated. By use of
the tubular mattress construction, the height of the mattress when
fully inflated can be better regulated over the entire area of the
mattress, and thus prevent the pneumatic stimulator from billowing
up when inflated to otherwise possibly cause the patient to be
moved to one side. A normal size of the air mattress for an infant
might be about 5 by 8 inches to allow for considerable movement of
the neonate without having the head and neck slide off when used
under the head and neck.
An embodiment of the pneumatic supply unit 24, is shown in FIG. 4,
wherein the input signal from one shot 16 is connected to a relay
unit 31 which controls a relay arm 32 to be either connected to a
first terminal (a) denoted as a non-apnea terminal or a second
terminal (b) denoted as an apnea terminal. In its normally assumed
position the relay arm 32 is connected to terminal (a) which, in
turn, is connected to a pressure switch 38, that is connected via
pneumatic tubing from a gas reservoir 33, preferably air, which is
electrically connected to a pump 34. Air reservoir 33 and pump 34
are also pneumatically connected via a flapper valve 35. With relay
arm 31 in its normal condition (a) the pressure switch 38 senses
the pressure in air reservoir 33 which, if below a predetermined
pressure valve, will be supplied with pressurized air from pump 34
through one-way flapper valve 35.
The terminal point (b) of relay 31 is connected via an apnea lead
to a counter 36 and to a three-way solenoid valve 37, which is
pneumatically coupled from air reservoir 33 to the pneumatic
stimulator 25 and through an exhaust opening. Reservoir 33 assures
the availability of a large quantity of pressurized air to
momentarily inflate the pneumatic stimulator, and also avoids delay
during the inflation cycle of the pneumatic stimulator. In the
present embodiment the time to inflate the pneumatic stimulator
takes less than one-half second assuming a 15 psi reservoir
pressure source and 1/4 inch diameter connecting tube with a final
4 psi system pressure, including the stimulator.
In operation, since relay arm 31 is normally connected to the (a)
terminal, pump 34 will be charging air reservoir 33 through the
flapper valve 35 during periods when the pressure switch 38 senses
approximately 10 percent below a predetermined pressure for the air
reservoir. Respiratory movements which are detected by senspr 11
are fed to the apnea monitor 14. Upon detection of an apnea episode
the one shot timer 16 is activated.
Relay 31 is activated from the one shot unit 16 for a period of one
second during which time relay arm 32 enables power to be supplied
to the three-way solenoid valve and an apnea episode count is made
on counter 36. The three-way solenoid valve is open allowing the
air from reservoir 33 to momentarily inflate pneumatic stimulator
25 to stimulate the patient by suddenly raising the patient up in
the air to introduce his sudden loss of equilibrium and, in effect,
startle the patient into normal respiration. At the end of the one
second period relay arm 32 goes back to terminal (b) to, in effect,
close off the three-way solenoid valve from air reservoir 33 to
pneumatic stimulator 25 and open the exhaust opening of the
three-way valve to the pneumatic stimulator 25 for deflating the
pneumatic stimulator. Because air has been used from the air
reservoir 33, this will be sensed by the pressure switch 38 which
will activate the pump 34 to in turn provide pressurized air in the
air reservoir 33 via the flapper valve 35, to, in effect, set the
system up ready for the next apnea episode when it is detected.
If desired, if the stimulation is found to be unsuccessful in
breaking the apnea episode a continuing alarm might be provided for
until the patient is attended to or a second nurse's alarm might be
initiated within a 5-second period or any other prescribed time
period that would be suitable for providing such a second
alarm.
* * * * *