Bite block assembly adapted for adjustable mounting and holding of oral airways and method of using same

A bite block and airway assembly comprising a generally U-shaped resilient block having upper and lower teeth or gum-engaging surfaces and having an aperture formed centrally through the block between such surfaces and communicating between the interior and exterior of the block for matingly receiving and frictionally holding a tongue depressor type oral airway tube. The frictional engagement of the block with the airway tube provides slidable adjustability with respect to the depth of insertion of the tube while firmly holding the tube in any of a plurality of slidably adjustable positions. The tube-engaging aperture formed in the block is of oval shape for matingly and adjustably engaging any of a number of different types of airway tubes having different cross-sectional configurations. The device is usable as an oral protective device in electro-convulsive therapy or, alternatively, as an oral filler for the administration of gaseous anesthetic to edentulous patients.

BACKGROUND OF THE INVENTION 
This invention relates to improvements in bite block and airway assemblies 
adapted for use in electro-convulsive therapy of mental patients and also 
in the administration of gaseous anesthetic to edentulous patients. 
During a seizure resulting from electro-convulsive therapy, an extremely 
strong mandibular contraction occurs requiring protection of the teeth and 
soft tissues of the mouth and lips. In additon, the possibility of 
respiratory emergencies during such therapy requires the maintenance of a 
free approach to the oral cavity and throat throughout the therapy so that 
resuscitative measures such as the administration of oxygen are possible. 
For these reasons various types of bite blocks equipped with airways have 
been used in the past for insertion into the mouth prior to the 
electroconvulsive therapy. Some of the bite block devices simply contain 
an air passageway through the mouth piece as shown in the Oberto U.S. Pat. 
No. 2,521,084. However such products provide inadequate airways partially 
obstructed by the patient's teeth and permit the patient's tongue to be 
drawn upwardly against the roof of the mouth shutting off the air passage 
into the throat. A number of bite block assemblies have attempted to solve 
this problem by providing a combination airway and tongue depressor tube 
which extends into the mouth and down the throat of the patient while the 
bite block is in place. One such assembly is shown in the Godfroy U.S. 
Pat. No. 2,882,893 wherein an airway-tongue depressor tube is formed 
integrally with the bite block. The primary problem with such type of 
assembly is that the depth of insertion of the tube into the throat is 
fixed when the bite block is in operative position in the mouth, such 
depth of insertion being insufficient for some patients and too great for 
other patients. Incorrect depth of insertion in turn can impair the 
effectiveness of the airway tube and cause serious patient discomfort. 
Another problem is that the airway tube is of a single fixed structure not 
necessarily adapted for the particular conduit functions desired, which 
are variable. For example there are a number of different types of 
airway-tongue depressor tubes presently on the market having different 
cross-sectional configurations and channels for performing different 
functions such as air supply and suction. Therapists may prefer different 
airway tube configurations for different situations, and an integral bite 
block and airway tube structure such as Godfroy's does not permit such 
flexibility. 
Bite block assemblies which permit a separate or nonintegral tongue 
depressor-type airway tube to be inserted into the mouth and extend into 
the throat while the bite block is in operative position have also 
previously been used. However such assemblies do not positively hold the 
position of the airway tube while the bite block is in operative position 
nor maintain sufficient control of the degree of airway tube insertion 
throughout the therapy, thereby permitting operational difficulties and 
patient discomfort similar to those referred to in the previous paragraph. 
In the somewhat unrelated field of administering a gaseous anesthetic to an 
edentulous patient by means of a face mask, it has been discovered that a 
bite block and airway assembly of the general type discussed above can 
overcome a certain special problem. The problem referred to is that the 
patient's absence of teeth tends to permit substantial looseness of the 
facial tissues in the area of the mouth and cheeks such that the face mask 
does not form an adequate seal with the face, causing harmful leakage 
between the anesthetic gas and the surrounding air. The use of a proper 
bite block and tongue depressor-type airway tube assembly during the 
administration of the anesthetic can solve the problem by the bite block's 
filling out the mouth region and correcting the looseness of tissue, 
thereby overcoming the otherwise defective fit of the face mask. The 
assembly however must be such as to overcome the foregoing disadvantages 
of present bite block and airway tube assemblies discussed above. 
SUMMARY OF THE PRESENT INVENTION 
The present invention is directed to a bite block and tongue depressor-type 
airway tube assembly comprising a generally U-shaped block of monolithic 
resilient material having upper and lower teeth or gum-engaging surfaces. 
These surfaces are formed to tilt toward one another in cross-section, 
tending to converge in an outward direction so as to prevent outward 
dislodgement of the bite block when the teeth are clamped together with 
great intensity, as occurs in electro-convulsive therapy. The surfaces are 
also wider apart adjacent the rear of the block than at the front to 
insure that the majority of the clamping pressure is absorbed by the 
molars rather than the frontal teeth which are more susceptible to 
splintering. An aperture is centrally formed through the front of the 
U-shaped block running between the upper and lower teeth-engaging surfaces 
and extending from front to rear in a direction between the two sides of 
the U-shaped block. The aperture matingly receives and frictionally holds 
a tongue depressor-type airway tube which extends through the aperture. 
The frictional engagement of the block with the tube provides slidable 
adjustability with respect to the depth of insertion of the tube while 
firmly holding the tube in any of a plurality of slidable positions. 
Preferably the aperture is of an oval shape for matingly and adjustably 
engaging any of a number of different types of airway tubes having 
different cross-sectional configurations. 
In use, the assembly acts as an oral protective device in 
electro-convulsive therapy wherein the depth of insertion of the type of 
airway tube used can be adjusted to the most effective and comfortable 
position or removed entirely while the bite block is in place in the 
patient's mouth. Despite the adjustability, the bite block holds the 
airway tube firmly and reliably in whichever adjustable position is 
selected throughout the period of usage. The assembly may also be used in 
administering gaseous anesthetic by face mask to edentulous patients 
wherein the assembly fills out and firms up the otherwise loose tissue 
around the mouth and cheeks and ensures a proper sealing fit of the face 
mask with respect to the face, thereby avoiding leakage. 
It is accordingly a primary objective of the present invention to provide a 
bite block assembly adapted to receive any of a number of different tongue 
depressor-type airway tubes and permit adjustability of depth of insertion 
of the airway tube with respect to the bite block while providing a firm, 
reliable, frictional engagement of the block with the tube in any of its 
adjustable positions so as to maintain the proper depth of insertion of 
the tube throughout use. 
It is a further primary objective of the invention to ensure proper sealing 
fit of a face mask to an edentulous patient during the administration of 
gaseous anesthesia by utilizing such a bite block and airway tube assembly 
for filling out and firming up the facial tissues in the area of the mouth 
and cheeks of the patient. 
The foregoing and other objectives, features and advantages of the present 
invention will be more readily understood upon consideration of the 
following detailed description of the invention taken in conjunction with 
the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to FIGS. 1, 2 and 3, the bite block of the present invention 
comprises a generally U-shaped, molded monolithic block indicated 
generally as 10 made of a resilient, nontoxic material impervious to 
moisture such as polyurethane. The degree of resiliency may be variable 
depending upon usage of the block, less resiliency being desirable for 
electro-convulsive therapy where intense clamping force of the teeth is 
encountered than in the administration of gaseous anesthetics to 
edentulous patients, where much milder clamping force is encountered and 
protection of the tender gum tissue is desired. The bite block comprises 
an upper teeth or gum-engaging lateral surface 12 and a lower teeth or 
gum-engaging lateral surface 14, each formed in a U-shape with the base of 
the U at the front of the bite block and the sides of the U extending 
longitudinally rearwardly. 
As seen in the rear view of FIG. 2, the surfaces 12 and 14 respectively are 
tilted in transverse cross-section with respect to one another so as to 
tend to converge in an exterior direction. This feature is very useful in 
preventing the bite block from being dislodged outwardly from its 
operative position by the intense clamping force of the teeth normally 
experienced in electro-convulsive therapy. Rather the cross-sectional 
wedge shape resulting from the tilt of the surfaces 12 and 14 with respect 
to one another utilizes the clamping force to retain the block against 
outward dislodgement. As will be seen, the position of the bite block in 
the patient's mouth also determines the depth of insertion of the airway 
into the patient's mouth, so that the prevention of outward dislodgement 
of the block has special significance not only with respect to protection 
of the teeth but also with respect to the maintenance of proper airway 
positioning. 
To prevent against inward dislodgement or slippage of the bite block with 
respect to the patient's mouth, upwardly and downwardly extending flanges 
16 and 18 respectively located at the outer edges of the respective 
teeth-engaging surfaces 12 and 14 each having a rearwardly opening U-shape 
are provided to engage the outer sides of the teeth or gums. 
As is best seen in FIG. 3, the vertical distance "x" separating the upper 
and lower teeth-engaging surfaces 12 and 14 resectively at the rearmost 
ends of the surfaces is preferably greater than the corresponding vertical 
distance "y" separating the two surfaces at the front of the block. The 
purpose is primarily to ensure that the majority of the mandibular 
clamping force during electro-convulsive therapy is borne by the patient's 
molars rather than his frontal teeth, the molars being much more resistant 
to splintering. Moreover, since the airway channel to be described 
hereafter passes between the upper and lower teeth-engaging surfaces at 
the front of the block, high teeth clamping force at that location should 
also be avoided so as to prevent any tendency of the teeth to close or 
compress the airway channel. 
Extending from the front 20 of the exterior of the bite block 10 in a 
rearward direction between the upper and lower teeth-engaging surfaces 12 
and 14, and emerging in the interior space 22 between the two sides of the 
U-shaped block 10, is an aperture 24 of generally oval cross-section. 
Preferably the maximum height of the aperture cross-section is one 
centimeter and maximum width is two centimeters. It has been found that 
the oval-shaped aperture is adapted for slidably and frictionally engaging 
virtually all of the different types of tongue depressor-type airway tubes 
or airway channels which might be desired under variable conditions. For 
example, the tongue depressor-type airway channel 30 shown in FIGS. 4 and 
5 is a preformed device of arcuate shape having two separate channels 30a 
and 30b formed therein for performing two separate gas-conducting 
functions, such as providing oxygen through one channel and suction 
through the other. This particular type of tongue-depressor airway 
requires that flexible tubes be inserted in the respective channels 30a 
and 30b, such tubes running along the sides of the device and conforming 
to the arcuate shape of the airway 30. Other such tongue depressor-type 
airways would also have the preformed arcuate tongue-depressor shape, but 
might be formed as a single closed channel or tube, or a tube having 
multiple channels within the tube. Regardless of the type of such 
tongue-depressor airway, the oval-shaped aperture 24 coupled with the 
resilient material of the bite block 10 is capable of matingly and 
frictionally accepting the insertion of the airway while permitting 
longitudinal sliding of the airway device with respect to the bite block 
for adjustment of the degree of insertion of the airway device. However to 
provide this slidability, it is important that the walls forming the 
aperture not extend too far rearwardly, and certainly no further than the 
rearmost ends 34 of the two sides of the U-shaped block 10, as opposed to 
those bite blocks previously discussed which have integral airway tubes. 
Despite the slidability permitted by the present invention, the frictional 
engagement permits the bite block to hold the airway firmly and reliably 
with respect to the block in any of its slidably adjustable positions. 
In use, the appropriate airway device such as 30 is inserted through the 
aperture 24 in the bite block 10 and the bite block and airway assembly is 
placed in the patient's mouth. Longitudinal adjustment of the degree of 
insertion of the airway 30 can be accomplished either while the bite block 
remains in the patient's mouth or by removing the bite block, sliding the 
airway and replacing the bite block in the patient's mouth. In either case 
the objective is to adjust the airway to a depth such that the inserted 
end of the airway is comfortably adjacent the throat of the patient and 
communicating between the exterior and interior of the bite block when the 
block is operatively inserted in the patient's mouth. 
For the administration of gaseous anesthesia to edentulous patients by 
means of a face mask, the bite block serves as a filler to firm up and 
fill out facial tissues in the mouth and cheek area when placed in the 
patient's mouth prior to the application of the face mask. The resultant 
peripheral seal of the mask with the patient's face when the mask is 
subsequently placed on the face over the block and airway assembly can 
thereby be ensured to be leakproof. 
The terms and expressions which have been employed in the foregoing 
abstract and specification are used therein as terms of description and 
not of limitation, and there is no intention, in the use of such terms and 
expressions, of excluding equivalents of the features shown and described 
or portions thereof, it being recognized that the scope of the invention 
is defined and limited only by the claims which follow.