Laryngoscope with enhanced viewing capability

A laryngoscope (10) with handgrip (14) and blade portion (16) has an optical system (44) secured to the blade portion with a prism lens (50) at the forward end and an eyepiece lens (48) which shifts the view toward the blade portion tip (46). A light pipe (60) directs a light beam toward the larynx to improve viewing thereof.

This application claims the benefit of U.S. Provisional Application No. 
60/036,212 filed Jan. 28, 1997. 
BACKGROUND 
1. Field of the Invention 
The present invention relates generally to a laryngoscope for use by 
medical personnel for viewing the larynx, and, more particularly, to such 
a device having an expanded angular range of view. 
2. Description of Related Art 
As to its major parts, a laryngoscope includes a handgrip and integrally 
related blade portion in an overall generally L-shape arrangement. Light 
directed along the blade portion to aid examination typically is powered 
by a battery pack contained within the handgrip. In use, the blade portion 
is inserted into a patient's mouth lifting the tongue and mandible and 
removing them from obstructing the view of the larynx. 
In addition to enabling visual examination of the mouth and larynx, a 
primary advantageous use of this instrument is to facilitate insertion of 
an endotracheal tube into the trachea. 
A continuing difficulty in use of laryngoscopes in the past has been to 
obtain a satisfactory view of the larynx considering the usual space 
restrictions to be expected, the rather difficult viewing angle at all 
times, and variation in anatomical features encountered among patients. 
SUMMARY OF THE INVENTION 
It is, therefore, a primary aim and object of the present invention to 
provide a laryngoscope having an improved field of view. 
In the practice of the present invention there are provided a laryngoscope 
with handgrip and blade portions and an optical system mounted on the 
blade portion providing a wide-angle field of view to one making an 
examination. The enlarged field of view is bent (angled) toward the outer 
end of the blade portion which would otherwise be out of view. 
A further aspect of the invention is the provision of a light pipe mounted 
on the blade portion for directing a beam of light into the region of 
examination interest.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Turning now to the drawing and particularly FIG. 1, there is shown the 
laryngoscope instrument of the present invention enumerated as 10 placed 
in the mouth of a patient 12 for viewing the larynx 13 and to aid in the 
insertion of an endotracheal tube. The instrument includes a handle or 
handgrip 14 and a blade portion 16, the latter being used to lift the 
tongue and mandible 18. Also, on occasion the blade portion is levered on 
the front teeth of the patient in order to see the larynx. 
With reference now particularly to FIGS. 2 and 3, the instrument 10 is seen 
to specifically include three separable parts, namely, the handle 14, 
blade portion 16 and a handle cap 20. As will be more specifically 
described, these different parts can be readily assembled together for 
use. 
The handle 14 is essentially a hollow tube having a closed lower or outer 
end 22 and an open upper end 24. One or several dry cell batteries (not 
shown) are typically located within the handle cavity to provide power for 
an examination light to be described. 
The cap 20 is a hollow cylindrical member with one end 26 open and 
containing internal threads for mating with threads 28 plus a washer or 
O-ring (not shown) to sealingly close off the handle open end 24. The 
upper or closed end of the cap has a parallel-sided slot 30 with a 
securement pin 32 having its ends affixed to the parallel sides and spaced 
from the slot bottom. A light source shown schematically at 34 is 
automatically interconnected with the battery power source in the handle 
upon full assembly of instrument. The securement technique between the 
handle, cap and blade portion can be identical to that disclosed in U.S. 
Pat. No. 5,501,651. FLUID SUBMERSIBLE LARYNGOSCOPE PREVENTING ELECTROLYTIC 
CURRENT FLOW. 
The blade portion 16 as seen in elevation (FIGS. 2-5) includes an elongated 
flat base 36 which has a substantially straight part 38 adjacent where it 
is connected to the cap 20 and an integral part 40 which curves generally 
toward the handle. A stiffening sidewall 42 extends along one lateral edge 
of the base. Overall blade surface features and shape for accomplishing 
tongue and mandible elevation during examination of a patient can be the 
same as disclosed in the U.S. Pat. No. 5,501,651. 
A primary contribution of this invention is the addition of an optical 
system 44 to the blade portion 16 which provides a wider angle of view to 
the one making an examination than is possible by taking an otherwise 
unassisted view along the blade. More particularly, the system 44 provides 
a view that extends beyond and just above the outer end 46 of the blade 
portion. As can be best seen in FIG. 5, the normal line of sight 45 (i.e., 
unassisted by optics) is considerably higher than desired for viewing the 
larynx. On the other hand, with the described optics the new line of sight 
47 is directed downwardly substantially from the normal line 45, and 
therefore, requires at most a very minor physical shifting of the 
instrument to have a satisfactory view of the larynx. 
For the ensuing detailed description of the optical system 44, reference is 
made to FIG. 6. The system includes a plano-convex eyepiece lens 48 which 
as the name implies is located at a point that can be conveniently 
accommodated to the eye of a user of the instrument preferably at a point 
just rearwardly of the handle 14. A prism-lens 50 serves as the 
forwardmost optic in the system located approximately at the point of 
demarcation between the flat base straight part 38 and curved part 40. The 
front face of the prism slopes rearwardly from bottom to top at a total 
angle of 110 degrees. 
A hollow tube 52 affixed to the blade portion base 36 has the eyepiece lens 
48 received in one end and the prism-lens 50 in the other end. The tube 52 
may be separately constructed and suitably secured to the base 36. 
Alternatively, the tube and base 36 may be constructed unitarily from 
metal or plastic (e.g., injection molding). 
In a practical construction of an optical system 44 for the present 
invention, the eyepiece was constructed of optical quality acrylic having 
a smooth flat surface facing the user's eye and an opposite surface having 
a radius of 54.3337 mm providing a focal length of +110 mm. The prism-lens 
50 was constructed of optical grade acrylic and consisted of a prism optic 
54 cemented to a further lens 56 having a concave surface with a radius of 
12.3555 mm facing the eyepiece. Prism optic 54 and lens 56 when assembled 
together (or optionally molded in one piece) provide a smooth sloping 
prism face of 110 degrees to the system axis, and has a focal length of 
-25 mm for the prism/lens combination. The prism and lenses may be 
optionally made of glass, or a number of transparent plastics, e.g., 
polycarbonate, acrylic, or crystalline polystyrene. 
With respect to the functional operation of the optical system 44, the 
concave portion of lens 56 serves to produce a wide-angle view, while the 
companion prism lens 54 directs the view toward the blade tip 46 to better 
expose the larynx. Also, the lens 56 "miniaturizes" objects view, while 
the eyepiece lens 48 compensates for the miniaturization as well as 
providing for focusing. 
A further aspect of the present invention is the provision of a light 
direction means 58 which extends from the light source 34 along a path 
generally parallel to the optical axis of the optical system 44 and 
closely spaced thereto (FIGS. 3 and 4). Specifically, the direction means 
includes a light pipe 60 consisting preferably of a cylindrical rod of a 
good light transmitting material (e.g., optical quality acrylic). The 
light pipe is located within a tubular housing 62 which can be secured to 
the optical system housing 64, or, alternatively, the two housings can be 
unitarily constructed with the blade base 36. The forward end 64 of the 
light pipe is preferably located forwardly of the prism 54 so as not 
produce any undesirable glare in the optical system. Moreover, the forward 
end face 64 is sanded or etched to produce diffused light which reduces 
glare or undesirable back reflection. 
In accordance with the present invention there is provided laryngoscopic 
apparatus which overcomes certain prior existing deficiencies in such 
equipment, especially viewing difficulties encountered when the apparatus 
is being used in connection with insertion of an endotracheal tube into a 
trachea. The described apparatus achieves a highly expanded viewing region 
and bends or angles the line of sight toward the outer end of the blade; 
thereby approximating a direct line of sight view of the larynx and 
trachea. 
Although the present invention is described herein in connection with a 
preferred embodiment, it is to be understood that those skilled in the 
appertaining arts may contemplate changes that come within the spirit of 
the invention as described and within the ambit of the appended claims.