Patient monitoring system

A system for monitoring and computer analyzing select physiological variables of a patient in real time in order to alert medical personnel to the need for medical treatment or automatically administering such treatment under computer control. Such physiological variables monitored by the system may include lung sounds, respiratory rate and rhythm, heart rate and rhythm, heart sounds, and body temperature. Coded signals relating to the physiological variables are produced and compared with reference versions of same by a decision computer in order to evaluate the patient's condition. If the evaluation indicates medical treatment is needed, the decision computer activates a local and/or a remote alarm to alert medical personnel and/or activates one or more actuators for adminstering a medical treatment such as the injection or infusion of a drug.

BACKGROUND AND SUMMARY OF THE INVENTION 
This invention relates to systems and methods for monitoring physiological 
variables of patients. Most patient monitoring equipment in use today is 
relatively invasive, requiring the application of cannulas, mouthpieces, 
catheters, and other paraphernalia to the patient. Not only do such 
obtrusive devices tend to have an adverse psychological effect on the 
patient, but they may have physiologic effects as well. Such effects may 
affect the accuracy of any measurements taken. 
In accordance with the invention, one or more sensors for measuring or 
detecting a physiological variable are disposed at or near the surface of 
the patient's body. Such physiological variables may include heart sounds, 
respiratory sounds, electrical activity of the heart (ie., an EKG), and 
body temperature. Digital signals corresponding to the physiological 
variable are generated from analog signals output by a transducer and fed 
to a computer which then passes them to a signal analyzing module (which 
may be a separate computer or a software module) for each type of 
physiological variable. The signal analyzing module then compares the 
digital signal with reference versions of the same signal and produces a 
coded signal in accordance with the comparison. The reference versions of 
the digital signals may, for example, correspond to the normal range of 
the physiological variable, prior measurements from the same patient, or 
to signs of specific pathology or condition. The coded signals generated 
by the signal analyzing module are next analyzed by a decision module 
(which may be a separate computer or a software module) which, from the 
information contained in such coded signals, generates an evaluation of 
the patient's present condition. If such evaluation indicates the need for 
medical treatment, the decision module activates a display or alarm to 
alert medical personnel or activates an actuation device for administering 
the treatment automatically under computer control. 
It is therefore a primary object of the present invention to provide a 
system for monitoring one or more physiological variables of a patient 
and, from a computer analysis of the variables, generate an evaluation of 
the patient's condition. 
It is a further object for the system to alert medical personnel when such 
evaluation indicates the need for further medical treatment or activate an 
actuator for administering medical treatment under computer control. 
It is a further object for the system to monitor physiological variables by 
sensing body sounds of the patient. 
Other objects, features, and advantages of the invention will become 
evident in light of the following detailed description considered in 
conjunction with the referenced drawings of a preferred exemplary 
embodiment according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION 
In FIG. 1 is shown a medical electronic system 10 for computer analyzing 
signals of physiological variables such as body sounds, vibrations, heart 
beat and temperature of a living being and detecting by such analysis the 
onset of a life threatening condition, such as a heart attack, apnea, 
stroke, grave degree of sickness, etc. System 10 employs one or more body 
sound or vibration sensors in sensing relation with the body of a living 
being, such as a person resting or sleeping on a mattress, pad or similar 
support which contains one or more sensors or transducers of one or more 
physiological variable associated with the body reclining or otherwise 
resting thereon. Prolonged monitoring of the physical condition of such 
living being is effected while the living being or person is asleep and/or 
awake and is in operable relation with respect to such transducer or 
transducers. When a deteriorating or life threatening condition is 
detected by one or more computers processing and analyzing generated by 
sensing body sounds and vibrations and, in certain instances, body 
temperature, select code signals are generated which may be employed to 
locally and/or remotely indicate to one or more persons that such 
condition exists and, in certain instances, the location of the person 
being monitored. 
In my U.S. Pat. No. 4,299,233 entitled Patient Monitoring Device and Method 
discloses a cushioning device, in the form of a water filled mattress on 
which a baby, child or grown up person may recline and sleep. Disposed 
within the mattress and in contact with the water filling same, is a 
vibration pick-up or transducer for sensing body vibrations, such as heart 
beat and other sounds generated by a person reclining on the mattress, as 
illustrated in the drawings, wherein the resulting sensing signals are 
electronically analyzed and employed to activate an alarm when a serious 
body condition occurs. I also teach in such patent that body temperature 
may also be monitored by a temperature sensor supported within the 
mattress. 
The instant invention employs a number of computing arrangements to not 
only detect the onset of a serious, life threatening physiological 
condition requiring medical attention but which may also operate to 
predict the onset of such a condition or a number of conditions some time 
before they occur to permit medical steps to be taken by a doctor or nurse 
and/or by a computer, to prevent the actual onset of the condition. 
Predictive computer circuitry and programmed software is provided to 
automatically analyze, on a continuous basis, signals output by one or 
more transducers sensing body variables and to predict and generate code 
signals indicative the nature and immanence of the serious condition or a 
plurality of select serious physiological conditions that will occur if 
select preventive steps are not taken by a medical attendant. In one form, 
a display indicates such information as the developing condition based on 
the computer analysis of the body signals. In another form, a speech 
signal generating computer operates to generate signals which are 
transduced to sounds of select words of speech by a remote and/or local 
speaker to inform a person present of the condition detected. 
System 10 uses a power supply 31 and switches 17, 20, 23, and 25 to provide 
electrical power. 
System 10 also employs a central controller in the form of a computer or 
microprocessor 11 having a RAM 12 and ROM 13 to which are connected 
various sensors and computers as well as devices controlled thereby. A 
body sound sensor 15, located in the mattress, pad or near the patient, 
senses body sounds and outputs analog signals which are digitized in an 
analog-to-digital (A/D) converter 16 wherein the resulting train(s) of 
digital signals are passed through the microprocessor 11 to a sound signal 
analyzing computer 33 which processes and compares such sound signals with 
recordings in its memory 34 to detect changes in body sounds, such as 
respiration sounds which are indicative of the onset and/or are 
predicative of the near future onset of a serious condition of the patient 
being monitored. Such computer analysis results in generation by computer 
33 of code signals which are indicative of one or more body conditions, 
which signals are passed through computer 11 to a decision computer 43 
connected also to computer 11. 
A body vibration sensor 18 which may comprise sensor 15 or be separate 
therefrom, is supported by the mattress or a pad disposed beneath the 
patient, senses body vibrations caused by body movements, heartbeat and 
respiration and generates output analog electrical signals which are 
digitized in an A/D converted 19 and passed through microprocessor 11 to a 
body vibrations analyzing computer 35. Here again the trains of digital 
signals generated by detected body vibrations and/or movements are 
compared with code signals recorded in a memory 36 wherein computer 35 
generates code signals which are indicative of a select physiological 
condition or the onset of a serious physical condition requiring medical 
attention. 
A heart beat sensor 21, which may comprise or be part of the sound sensor 
15 or may be separate therefrom and attached to the mattress or pad or to 
the patient, senses and generates output signals indicative of heart beat, 
which signals are digitized by an A/D converter 22 and passed through 
computer 11 to a heart beat analyzing computer 37 which queries its memory 
38 and generates code signals on its output to microprocessor 11 which are 
passed to decision computer 43 or similar circuitry in a common computer 
operable to receive and analyze all physiological parameter sensing 
sensors. It is noted that sensors 15,18 and 21 may be separate sensors or 
may be combined in one sensing arrangement coupled to receive and 
transduce all body sounds and vibrations to analog electrical signals 
which may be computer analyzed as to their separate information contents. 
The output of A/D converter 23 is also passed to a heart rate analyzing 
computer 39 which generates output codes which are passed to computer 43 
through microprocessor 11 for automatic analysis along with the digital 
codes generated by computers 33,35 and 37. 
A body temperature sensor 24 is in temperature sensing relationship with 
the body of the patient and generates output analog signals indicative of 
body temperature which signals are digitized in an A/D converter 25 and 
passed through computer-microprocessor 11 to a body temperature analyzing 
computer 41 having a memory 42, which after analyzing same, generates code 
signals which it passes to computer 43 having a memory 42 through 
microprocessor 11. 
As aforesaid, body sounds of the patient are detected via sound sensor 15 
and/or vibration sensor 18 which produce digital signals in accordance 
with the sensed sounds or vibrations. Such digital signals are then 
analyzed by the sound signal analyzing computer 33 or body vibrations 
analyzing computer 35 which compare the digital signals with reference 
versions of the signals of the same signal and produce coded signals in 
accordance with the comparisons. The reference versions of the digital 
signals may, for example, correspond to the normal range of the particular 
physiological variable, to prior measurements from the same patient, or to 
a specific pathology or condition of the patient. 
Examples of body sounds which may be detected by the present invention are 
respiratory sounds and heart sounds. In the case of the former, the signal 
analyzing computer produces coded signals representing the rate and rhythm 
of breathing by the patient derived from the respiratory sounds. Thus the 
system is able to detect abnormal breathing patterns such as apnea, 
tachypnea, hyperpnea (eg., Kussmaul breathing associated with metabolic 
acidosis), bradypnea, Cheyne-Stokes breathing, ataxic breathing, and 
obstructive breathing. Coded signals may also be generated from the 
respiratory sounds which indicate the presence of added lung sounds such 
as rales associated with pneumonia and pulmonary edema, wheezes associated 
with obstructive lung disease, and pleural rubs due to inflammation of the 
pleural membranes. 
Coded signals derived from heart sounds are also produced by the signal 
analyzing computer which the represent the patient's heart rate and 
rhythm, magnitude and time relation of the first and second heart sounds 
due to the closure of the mitral and aortic valves, the presence of 
murmurs occuring in systole or diastole due to valvular abnormalities, and 
the presence of other abnormal heart sounds such as a pericardial friction 
rub due to inflammation of the pericardial sac. 
Sensing devices and signal analyzing modules which are relatively more 
invasive than those illustrated in FIG. 1 may also be employed to measure 
physiological variables such as blood pressure, urinary output, blood 
gases, and the electical activity of the heart (ie., an EKG waveform). In 
the case of an EKG, coded signals are produced which represent not only 
the heart rate and rhythm (as in the case of heart sounds described above) 
but also abnormalities in the waveform which are indicative of cardiac 
dysfunction such as myocardial ischemia or abnormalities in the ionic 
composition of the patient's blood. 
If the physical condition of the patient detected by the decision computer 
43 as a result of comparing its computed information with information in 
its memory 44 is determined by such computer to indicate or predict the 
onset of a serious physical condition, such as a heart attach, apnea or 
other condition requiring immediate medical treatment, decision computer 
43 generates control codes which are passed through computer 11 to (a) 
operate a local alarm 27 which may be located at bedside or in a nearby 
room, by driving or activating a drive 28 therefor; (b) activate a code 
generator 30 connected to a shortwave transmitter which is also energized 
thereby and generates and short wave transmits a select code to a remote 
monitor station 14 which, upon short wave receipt of such code applies 
same to an electronic display which displays the location of the patient 
to an attendant and/or to a speech signal generating computer which warns 
the attendant of the condition detected or predicted and the name or 
location of the patient. 
Code signals output by the decision computer 43 may also be passed to one 
or more drives 32 for one or more solenoids or motors 31 operable to 
automatically operate in response thereto to operate one or more pumps, 
valves or other medical devices employed which apply first aid to the 
patient such as inject or pass a select amount of a drug or drugs into the 
patient too prevent or delay the onset of the serious change in physical 
condition requiring medical attention. 
The decision computer 43 may also be operable to analyze the code signals 
it receives from the one or more auxiliary computers 33,35,37,39 and 41 it 
is connected to and generate code signals which define such variables and 
the identification of the serious condition detected and/or predicted 
thereby, the time predicted to the onset of same, a quantitative 
indication of the degree of the condition detected or predicted, etc. Such 
code signals may be passed through microprocessor 11 directly to the short 
wave transmitter to short wave same to the remote monitor station wherein 
the information defined by such codes is displayed on an electronic 
display or computer screen along with an indication of the patient's 
identity and location. Such latter code signals may also be employed to 
selectively control the operation of the first aid servos 31 or other 
corrective devices such as radiation and/or electrical energy applying 
devices operable to beneficially affect heart and/or lung operation, etc. 
Moreover, microprocessor 11 may be linked by an interface 47 to other 
peripheral hardware. As shown in FIG. 1, microprocessor 11 may be linked 
through the interface to a display and/or keyboard 46. 
Although the invention has been described in conjunction with the foregoing 
specific embodiment, many alternatives, variations, and modifications will 
be apparent to those of ordinary skill in the art. Those alternatives, 
variations, and modifications are intended to fall within the scope of the 
following appended claims.