GB2105994A - A laryngoscope - Google Patents

Abstract

A laryngoscope suitable for both directly and indirectly viewing the glottis and trachea regions of a patient, for example during an intubation process, comprises an elongate substantially rigid blade (21) and a handle means (12) connectable to a proximal end portion of the blade at an angle to the blade. A light source (51) is disposed along one longitudinal edge of the blade and visual image transmitting means (36) are provided along the other longitudinal blade edge for transmitting images beyond a curved portion (22) of the blade to viewing means (30) to allow both direct and indirect viewing of the laryngeal area. <IMAGE>

Description

SPECIFICATION A laryngoscope This invention relates to a laryngoscope suitable for viewing the laryngeal area of a patient's body and, in particular to a laryngoscope which provides for both direct and indirect viewing of the glottis and trachea regions.

Laryngoscopes are employed in the medical field generally to facilitate endotracheal intubation of a patient during surgery to provide an air passageway for the administration of anesthesia or from the mechanical ventilation of the patient's lungs. In the human anatomy, the epiglottis normally overlies the glottis opening into the larynx to prevent the passage of food into the trachea during eating; therefore, in endotracheal intubation, it is necessary to displace the epiglottis from the glottal opening to permit an air tube to be inserted into the trachea.

Various laryngoscopes are known for use in carrying out an intubation procedure. One commonly used structure comprises a scope holder having an elongated rigid blade extending from the holder.

The laryngoscope is generally provided with a light source whose beam is directed along the blade to illuminate the area beyond the distal end of the blade. Normally, the laryngoscope is inserted through the patient's mouth and the blade tip is directed to the pharyngeal area where it is utilized to displace the tongue and epiglottis to permit direct visualization by the physician of the glottis region.

The scope operator ordinarily sights through the mouth opening normally from an observation position above and beyond the patient's head with the line of sight being along the longitudinal axis of the laryngoscope blade. The endotracheal tube is inserted, either orally or transnasally, and passed along the scope blade into the glottis and trachea.

This type of laryngoscope has been widely used for a number of reasons. Initially, the scope is relatively comfortable to hold and, in many instances, can easily and readily be manipulated to the desired location within a patient's body. Further, this particular device permits an operator to look down the blade and have direct vision through the mouth opening into the glottis region. Further, one can learn to utilize this type of laryngoscope in a relatively short period of time compared to the learning time associated with other laryngoscopes presently available.

In a number of patients, however, there are abnormalities in the throat structure or other problems which interfere with the operator's direct vision such that the use of the above-described conventional rigid blade laryngoscope is not possible.

In such cases, a laryngoscope is employed which permits indirect visualization of the glottis so that the trachea can be located and the necessary endrotracheal tube inserted. Laryngoscopes of this second type are illustrated, for example, in U.S.

Patents 4,086,919 and 3,677,262. Laryngoscopes which permit indirect viewing of the glottis region employ a fibre optics means whereby an operator will insert the scope into the patient's mouth and will then view the path of travel of the blade or tube through an eyepiece. While these indirect viewing types of laryngoscopes permit one to pass the laryngoscope blade or tube over or around an abnormality in the patient's throat region to locate the patient's glottis and trachea, they suffer from a number of severe limitations. Initially, the field of vision achieved with the fibre optic system usually employed on an indirect viewing laryngoscope is reduced substantially from the direct visualization afforded with a rigid blade laryngoscope.Because the field of vision is reduced and the viewing is accomplished indirectly through the scope eyepiece, experience has shown that, in many instances, an excessive amount of time is required to locate a patient's glottis region and trachea in order that an endotracheal tube can be inserted. This time factor can be critical for, in some cases, the failure to provide an appropriate air passage in a matter of minutes can result in the loss of a patient's life or the utilization of a radical surgical procedure.

Moreover, it has been found that with scopes that utilize indirect viewing, an operator must be more skilled in its operation. Indirect viewing and its attendant reduced range of vision often causes a scope operator to become disoriented as to the scope location within the body. Accordingly, it has been found that the intubation procedure with a laryngoscope that utilizes indirect viewing is often more difficult and takes longer to perform than an intubation procedure accomplished with a laryngoscope which affords the operator direct viewing of the glottis and trachea.

What is desired is to have a laryngoscope which permits direct visulaization but, at the same time, in those cases where it is required, affords an operator with indirect visualization means thereby allowing for both direct and indirect visualization with the same instrument during an intubation procedure. It is also desired that in the event indirect visualization is required for an intubation procedure, the problem of disorientation be obviated.

According to the present invention, there is provided a laryngoscope suitable for directly and indirectly viewing the glottis and trachea regions of a patient, the laryngoscope comprising: a substantially rigid elongate blade of greater width than thickness: a handle assembly connectable to a proximal end portion of the blade so as to be disposed at an angle to the longitudinal axis of the blade; light source means disposed along one longitudinal edge of the blade for generally illuminating a space beyond distal end of the laryngoscope; and means for transmitting visual images of an area beyond a curved portion of the blade to viewing means to permit indirect viewing of the area through the viewing means, the visual transmission means being disposed on the other longitudinal edge of the blade to provide a substantially unobstructed direct view along at least a substantially straight portion of the blade to allow both direct and indirect viewing of the laryngeal area of a patient.

In a preferred embodiment, a laryngoscope in accordance with the present invention includes a holder assembly having a substantially rigid metal or plastic elongated blade extending therefrom. A first light source is disposed along one of the two blade side edges to illuminate the area beyond th distal end of the curved blade. A fibre optic bundle is disposed along the remaining blade edge and extends substantially along the length of the blade.

At the distal blade end the bundle is positioned to rest on the longitudinal axis of the blade so that both direct and indirect viewing along the longitudinal axis of the blade is accomplished.

For a better understanding of the present invention and to show how the same may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which: FIGURE 1 is a side view of a laryngoscope in accordance with the present invention positioned within a patient's mouth area with the scope operator having direct visualization provided along the blade length into the mouth; FIGURE 2 is a side view of the laryngoscope of Figure 1 with scope operator employing indirect visualization of a patient's trachea and glottis region; FIGURE 3 is a perspective view of the laryngoscope; FIGURE 4 is a sectional view of the laryngoscope taken along lines 4-4 in Figure 3; FIGURE 5 is a perspective view of the laryngoscope with a blade portion disassembled from a battery holder assembly;; FIGURE 6 is a side, fragmentary, sectional view of the laryngoscope taken along lines 6-6 in Figure 5; FIGURE 7 is a fragmentary sectional view taken along lines 7-7 in Figure 6; and, FIGURE 8 is an enlarged, fragmentary cross-sectional view of a blade tip and optical fibre bundle at a curved end of the laryngoscope.

Referring now to the drawings and more particularly Figure 5, there is shown a disassembled laryngoscope 10 which comprises a battery holder and knurled handle assembly 12 having a yoke 13 with a bar 16 disposed within the yoke arms 14, 15.

Recesses 17, only one of which is shown, are adapted to receive detents 18 located in a blade assembly 20.

The blade assembly 20 comprises a thin, substantially rigid blade 21 of anatomically curved configuration which is constructed of a suitable high strength material, such as metal or plastics. An anterior or inner curved surface 22 of the blade is relatively wide in transverse direction compared to the blade thickness.

A proximal end 23 of the blade is provided with a connection member 24 having a projecting finger like element 25 defining a groove 26 and a movable detent means, not shown. Upon assembly of blade connection member 24 to assembly 12, bar 16 is inserted in groove 26 and spring biased detents 18 on connection member 24 are disposed in recesses 17 located on the yoke arms. The assembled laryngoscope 10 is shown in Figure 3.

An eyepiece 30 containing a lens means 32 is attached to and extends outwardly from the connection member 24 in a direction opposite that of blade 21. The eyepiece is disposed below blade 21 and the sight centre line 29 of eyepiece 30 preferably is parallel to the longitudinal axis of the blade 21. Lens member 32 optically communicates with the end of a coherent bundle 36 of optical fibres. Bundle 36 extends along the length of blade 21 and is located along one side 37 of the blade so that the straight portion of the blade surface 22 is substantially unobstructed. At a location 40 where blade 21 commences to curve slighly as it extends outwardly from the member 24, the bundle 36 is seated on the blade surface 22 so that, as shown in Figures 3 and 5, it is located on the longitudinal axis of the blade at or contiguous with a distal end 25 of the blade 21.

Although the bundle is disposed on the surface 22 of the covered portion of the blade 21, an unobstructed view is provided looking down the substantially straight portion of the blade.

Surrounding the optical fibre bundle 36 is a second bundle or group of optical fibres 39 which extends from a light bulb 43 to a light source opening 40 to transmit light from the light source into the area beyond the distal end of the curved blade. The fibre bundle may be insulated with a material which is the same as or different from the material from which blade 21 is manufactured.

A second light source 51 is disposed along a side edge 52 of the blade 21. Light source 51 comprises a group of optical fibres 53 which extend from the light source bulb 43 to the light source 51 located at the tip of the substantially straight portion of blade 21 to transmit light to the area beyond at least the straight portion of blade 21. Accordingly, two light sources are provided, one at the distal end 25 of blade 21 and the other at the end of the relatively straight portion of the blade 21.

Fibre bundle 53 and light source 51 are disposed at the blade side edge 52 so that, as shown more clearly in Figure 4, they do not obstruct the view along at least the straight portion of surface 22 of blade 21.

Bulb 43 is maintained in contact with batteries in the holder 12 by a spring means 44.

Figures 1 and 2 illustrate the operation of the laryngoscope. With a patient in the supine position and with the patient's head 70 resting normally on an upper surface 71 of an operating table, the blade 21 is inserted into the patient's mouth by an anesthesiologist or laryngoscope operator. The blade 21, which is relatively thin in the anterior-posterior dimension, is passed between the teeth and through the oral and pharyngeal passageway 72 depressing the tongue 73 upward out of the operator's line of sight. This portion of the procedure, as shown in Figure 1, can be carried out with the operator having direct vision into the passageway 72. When the operator observes the location of the epiglottis 74, the tip 50 of the laryngoscope can be turned upwardly thereby raising the epiglottis 74.

During this portion of the intubation procedure, light from the light source 51 serves to illuminaste the area directly beyond the instrument.

After the epiglottis 74 has been moved out of the operator's line of sight, the operator, without needing to move the instrument, can view the glottis region and trachea indirectly through the eyepiece 30. Light from the light source opening 40 serves to illuminate the area beyond the blade distal end 25 during indirect viewing through the eyepiece 30.

An endotracheal tube may then be passed either orally ortransnasally along blade 21 and inserted through the glottis into the trachea 80. Blade 21 is then withdrawn from the mouth to complete the intubation procedure.

As shown in Figures 1 and 2, the handle assembly 12 is preferably disposed at right angles to the blade 21 both for direct and indirect viewing. This permits an operator to achieve maximum direct viewing while at the same time being in a position to resort to indirect viewing through the eyepiece 30 without the need for reorientating the laryngoscope and without concern about becoming disoriented because the indirect viewing point is preferably fixed at a point immediately beyond the tip of the laryngoscope.

Further, as shown in Figure 4, placing of the light and optic sources at the respective sides of the blade serves to provide an unobstructed direct view along the straight portion of the blade. Moreover, both direct and indirect viewing can be accomplished by sighting along lines in a plane which intersects the longitudinal axis of the laryngoscope.

If desired, the blade optic fibre bundles and light sources can be integrally moulded as one member as illustrated in Figure 4. It is desriable, however, that the mid-line of blade 21 along at least the substantially straight portion of its length be unobstructed so that a scope operator has a relatively clear view along the blade during the direct viewing portion of the intubation procedure.

The curvature of the blade at its distal end can be varied as desired; however, it has been observed that an angle X in the range of approximately 35 -65 appears to be satisfactory.

Use of a laryngoscope in accordance with invention permits an anesthesiologist or other operator to achieve both direct and indirect viewing of the pharyngeal laryngoscope and without suffereing the disadvantages of disorientation heretofore experience with indirect viewing laryngoscopes.

A laryngoscope described above permits both direct and indirect viewing and therefore serves to allow an operator to insert the instrument by direct viewing into a patient's mouth and sight directly along the longitudinal axis of the blade to the patient's glottis region. If indirect viewing is required, the operator may then view through the eyepiece without concern of becoming disoriented inasmuch as the fibre bundle is located along the longitudinal axis of the blade. The fibre bundle can either be integral with the blade along its entire length or part or all of the fibre bundle can be adapted for movement relative to the blade end.

Preferably, and for ease of operation, it is desired to employ a fibre bundle which is fixed to the blade and intersects its longitudinal axis.

Further, the straight section of the elongate blade is unobstructed so that an operator has a substantially clear view when sighting directly along the length of the blade.

Claims (10)

1. A laryngoscope suitable for directly and indirectly viewing the glottis and trachea regions of a patient, the laryngoscope comprising: a substantially rigid elongate blade of greater width than thickness: a handle assembly connectable to a proximal end portion of the blade so as to be disposed at an angle to the longitudinal axis of the blade; light source means disposed along one longitudinal edge of the blade for generally illuminating a space beyond a distal end of the laryngoscope; and means for transmitting visual images of an area beyond a curved portion of the blade to viewing means to permit indirect viewing of the area through the viewing means; the visual transmission means being disposed on the other longitudinal edge of the blade to provide a substantially unobstructed direct view along at least a substantially straight portion of the blade to allow both direct and indirect viewing of the laryngeal area of a patient.

2. A laryngoscope according to claim 1, wherein the visual transmission means is arranged along the curved blade portion.

3. A laryngoscope according to claim 1 or 2, wherein the visual transmission means terminates adjacent the distal end of the blade.

4. A laryngoscope according to claim 1, 2 or3, wherein the visual transmission means is disposed in a plane which intersects the longitudinal axis of the curved blade portion.

5. A laryngoscope according to claim 1,2,3 or 4 wherein the curved portion of the blade is arranged at an angle in the range of 350 to 650 relative to the substantially straight blade portion.

6. A laryngoscope according to claim 1,2,3,4 or 5 wherein the handle means is connectable so as to be disposed generally at right angles to the blade.

7. A laryngoscope according to claim 1,2,3,4, 5 or 6 wherein the visual transmission means includes further light source means for illuminating the space beyond the distal end of the laryngoscope.

8. A laryngoscope according to any preceding claim, wherein the viewing means has a sight centre line which is substantially parallel to the longitudinal blade axis.

9. A laryngoscope suitable for directly and indirectly viewing the glottis and trachea region of a patient substantially as hereinbefore described with reference to the accompanying drawings.

10. Any novel feature or combination of features described herein.