An apparatus to innervate a deinnervated lung diaphragm and pace the deinnervated diaphragm with a normal innervated lung diaphragm. The apparatus has a sensing device sense operation of normal innervated lung diaphragm. The device produces a signal representative of the operation of the normal innervated diaphragm. The signal is modified in accordance with a set pattern to provide a modified signal showing the rate and duration of inspiration for the normal, innervated diaphragm. A pulse generator is fed by the modified signal to produce a pulse. A stimulator innervates the deinnervated diaphragm at the same rate and duration as a normal innervated lung diaphragm. A method of operating the apparatus is also described.

FIELD OF THE INVENTION 
The present invention relates to an apparatus to innervate a deinnervated 
lung diaphragm and unilaterally pace the deinnervated diaphragm to the 
normal innervated diaphragm. 
DESCRIPTION OF THE PRIOR ART 
For a person who has lost innervation of one of the lung diaphragms as a 
result of trauma, surgical damage, acquired disease of congenital 
malformation, the prior art permits the electrical pacing of the 
deinnervated diaphragm by producing an electrical stimulus which 
intermittently stimulates the diaphragm to contract by electrically 
stimulating the phrenic nerves innervating that diaphragm or by 
stimulating the diaphragm muscle directly. However the prior art does not 
synchronize the contraction of the deinnervated diaphragm with the 
normally innervated diaphragm. This generally results in asynchrony which 
provides inefficient respiratory efforts, since normal respiratory 
physiology requires synchronous contraction of both diaphragms. 
Patients who have a deinnervated diaphragm are living by virtue of their 
innervated diaphragm. For this reason, it is undesirable to interfere in 
any way with the innervated diaphragm or the innervated nerve supply to 
the innervated diaphragm muscle, since any disruption may result in 
bilateral diaphragmatic paralysis and the patient would then be dependent 
upon a respirator. 
Attempts have been made to use the phrenic nerve of the innervated 
diaphragm as an indicator of diaphragmatic contraction and inspiration, 
and transmit a signal representing contraction rate and duration to a 
pulse generator for providing a pulse to the deinnervated diaphragm. These 
attempts have not been clinically acceptable because of the possibility of 
bilateral diaphragmatic paralysis that could occur if the normal phrenic 
nerve was damaged by the sensing device. 
SUMMARY OF THE INVENTION 
The present invention provides a sensor within the body of a patient that 
indicates the contraction of the innervated diaphragm. The sensor senses 
the functioning of the innervated diaphragm as it contracts to produce 
inspiration. A signal from the sensor is transmitted to a signal modifier 
which generates an appropriate command to a diaphragmatic pulse generator. 
This pulse signals either the deinnervated distal phrenic nerve or the 
deinnervated diaphragmatic muscle and results in contraction of the 
deinnervated diaphragm. The signal modifier commands the rate and duration 
of the pulse and is modified in accordance with a predetermined pattern or 
an algorithm. As this is controlled by the contraction of the innervated 
diaphragm, the deinnervated diaphragm tracks the normally innervated 
diaphragm which in turn responds to the different physiological demands of 
the diaphragms as indicated by the central nervous system of the body. 
This variation in the rate and duration of respiration for the innervated 
diaphragm is tracked and substantially synchronous contraction of both 
diaphragms occurs. 
The sensor may be a temperature sensing device adapted to be located in an 
upper air way passage to the normal innervated lung diaphragm to produce a 
signal representative of temperature change resulting from an inspiration 
of colder air. In further embodiments the sensor may be a device able to 
sense skeletal muscle pressure. The muscles preferably sensed are of the 
pharynx or the diaphragm. 
Whereas the present invention provides a sensing device to sense the 
operation of the innervated lung diaphragm, my co-pending application Ser. 
No. 522,708 filed concurrently with the present application, discloses a 
muscle sensing device to produce a signal from the skeletal muscle 
representative of muscle contraction at the onset of inspiration. 
Furthermore, my co-pending application Ser. No. 522,779 filed concurrently 
with the present application discloses a system of innervating lung 
diaphragms from a signal modified from an electrocardiogram pick up so 
that the respiratory rate and duration is generated by an algorithm 
related to the heart rate. 
The present invention provides an apparatus to innervate a deinnervated 
lung diaphragm and pace the deinnervated diaphragm with a normal 
innervated lung diaphragm, comprising: 
a sensing device adapted to be located to produce a signal representative 
of a change resulting from normal operation of the innervated diaphragm; 
means to modify the signal in accordance with a predetermined pattern to 
provide a modified signal representative of the rate and duration of 
inspiration for the normal innervated lung diaphragm; 
pulse generator means fed by the modified signal to produce a pulse; and 
stimulating means adapted to innervate the deinnervated diaphragm at the 
same rate and duration as the normal innervated lung diaphragm. 
The present invention also provides a method of operating an apparatus to 
innervate a deinnervated lung diaphragm and pace the deinnervated 
diaphragm with a normal innervated lung diaphragm, comprising the steps of 
sensing a function of the normal innervated lung diaphragm and producing a 
signal representative of that function; 
modifying the signal in accordance with a predetermined pattern to provide 
a modified signal representative of the rate and duration of inspiration 
for the normal innervated lung diaphragm; 
utilizing the modified signal with a pulse generator means to provide a 
pulse; and 
feeding the pulse to stimulating means to innervate synchronously the 
deinnervated diaphragm at the same rate and duration as the normal 
innervated lung diaphragm.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A body 10 is shown in the FIGURE with a normal innervated right lung 
diaphragm 11 and a deinnervated left lung diaphragm 12. The left diaphragm 
12 is illustrated as being partially collapsed. The right diaphragm distal 
phrenic nerve 14 stimulates the diaphragmatic muscle 16 to contract the 
right diaphragm 11. Similarly the left diaphragm distal phrenic nerve 20 
stimulates the diaphragmatic muscle 22 to innervate the left diaphragm 12. 
In order to avoid in any way interfering with the right phrenic nerve 14 
for the normal innervated right diaphragm 11, a temperature sensing device 
24 is located in the upper airway to the right diaphragm 11. The 
temperature sensor 24 may be placed within the wall of the pharynx or 
within the thorax. The temperature sensor 24 senses the temperature change 
within the body tissues resulting from the inspiration of outside air 
through the upper airway. This signal is modified in accordance with an 
algorithm in the modifying circuit 26 to a predetermined pattern 
representing rate and duration of respiration for the normal right 
diaphragm 11. The temperature sensor 24 is able to identify changes in the 
rate of respiration and the duration of respiration, during the 
inspiration of colder, outside air. The modifying circuit produces a 
modified signal representative of the rate and duration of inspiration, 
which is fed to an electrical stimulus generator 28. The generator 
produces a pulse which in turn is fed to subcutaneous induction coils 30 
about the left distal phrenic nerve 20 for the deinnervated left diaphragm 
12. 
The pulse produced by the electrical stimulus generator 28 is sufficient to 
stimulate the left distal phrenic nerve 20 to produce contraction of the 
diaphragmatic muscle 22 to innervate the deinnervated left diaphragm 12. 
Whereas the subcutaneous induction coils 30 are shown about the left 
distal phrenic nerve 20 it will be apparent to those skilled in the art 
that electrodes may be placed directly associated with the diaphragmatic 
muscle 22 for the deinnervated left diaphragm 12 to produce contraction. 
The subcutaneous induction coils 30 are placed within the body 10 and the 
electrical stimulus generator 28 placed outside the body so the pulse 
generated is transmitted from an external induction coil to the 
subcutaneous induction coils 30 within the body 10. 
As an alternative the pulse generator and modifier can be implanted in the 
patient. 
In operation, the temperature sensor 24 senses the relatively cold air in 
the upper airway entering the normal innervated right diaphragm 11 as 
inspiration commences. A signal from the sensor 24 sensing duration and 
rate of duration, is modified utilizing the servo loop modifying circuit 
26 to provide a modified signal to the electrical stimulus generator 28 
which in turn provides a pulse to the induction coils 30 to stimulate the 
contraction of the left diaphragmatic muscles 22 for the deinnervated left 
diaphragm 12. This permits synchronous contraction of the unilateral 
deinnervated left diaphragm 12 with that of the normally innervated right 
diaphragm 11. Whereas the left diaphragm 12 has been shown here as the 
deinnervated diaphragm, it will be apparent to those skilled in the art 
that the innervated and deinnervated diaphragms may be reversed. 
The drawings illustrate a temperature sensor 24. However, sensor 24 may 
equally sense pressure generated by operation of the pharyngeal muscles or 
pressure generated by operation of the innervated diaphragm muscle. Indeed 
sensor 24 may sense pressure developed by any skeletal muscle that 
functions in the operation of the innervated diaphragm. In those 
circumstances, the signal modifier 26 will be appropriately changed from 
that illustrated to respond to signal generated by the pressure sensor. 
Various changes may be made to the embodiment disclosed herein without 
departing from the scope of the present invention which is limited only by 
the following claims.