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Description  |
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BACKGROUND OF THE INVENTION
This invention relates to a laryngeal tube for use in microsurgery in the
region of the larynx with simultaneous ventilation and anaesthesia, with a
tube at the introduction end, the said tube being provided with an
inflatable cuff, and incorporating an inflation channel terminating in the
inflatable cuff, together with a ventilation channel terminating in the
inside lumen of the tube.
Such a tube for use in endolaryngeal microsurgery, is known as the Carden
tube. The tube, which is preferentially provided with a stiffening helical
spring, which is embedded in the material of the tube, is passed into the
trachea of the patient with the aid of a foreign body-removing forceps.
Then, the inflatable cuff is inflated with the aid of the inflation
channel, with the result that it presses firmly against the inside surface
of the trachea. In the introduction end section of the tube, a ventilation
channel is located in such a way that it terminates in the lumen of the
tube; through this ventilation channel, oxygen and an anaesthetic gas is
supplied to the patient by means of a ventilation apparatus. The cuff
prevents blood arising at the site of the operation above the tube from
getting into the bronchi. However, when an operation is being performed in
the region of the larynx, the two channels, which are not immobilized and
which, in addition, move in the flow of air, are disturbing. Admittedly,
the two channels cannot be dispensed with, since one is needed for
ventilation and the other for inflating and deflating the cuff, and also
because, on the other hand, the necessary sealing effect between the tube
and the trachea could then not be achieved.
SUMMARY OF THE INVENTION
The objective of the present invention is to provide an improved laryngeal
tube of the type mentioned initially, which, when surgery is being carried
out, hinders and disturbs the surgeon to a smaller degree.
This objective has been realized by this invention by connecting the
inflation channel and the ventilation channel together so that, as a
result, they are stiffened. Thus, there is only a single tube leading
upwards, so that the surgeon can work better and with more despatch.
Furthermore, on account of its enhanced stiffness, the single tube
(double-tube) moves less. The increased stiffness is a result of the fact
that the two channels are glued or welded to each other, so that, by this
means, each provides support to the other. In a specially preferred
embodiment of the invention, to provide further stiffening, a wire,
provided with a protective sheathing is incorporated, with which the two
channels are connected. In this embodiment of a laryngeal tube of this
invention, the two channels are so well fixed that they virtually do not
move, and cannot disturb the surgeon carrying out the operation. The
sheathing protects the patient from pressure points, and the stiffness of
the wire makes it possible, if necessary, even to pass the tube without
the need for a foreign body-removing forceps and to advance it solely by
means of the wire. Thus, all disadvantageous properties of the known
laryngeal tubes--which are frequently disturbing during operation--have
been eliminated.
The wire can be made of an adequately stiff and mouldable plastic material.
Preferentially, however, it is made of a flexible metal, such as soft
iron, copper, aluminium, stainless steel or suchlike. By this means, the
surgeon can give the channels any shape he likes and fix them, so that
during the surgical operation, no part of their introduced length has a
disturbing influence.
The wire might be embedded in the material of the tube. Preferentially,
however, it terminates in the lumen of the tube in the same way as the
ventilation channel terminates inside the tube. This has technical
advantages for the manufacturing process and, in comparison with an
attachment to the outside of the tube, the advantage that the contours of
the latter remain round.
Preferentially, the wire and the ventilation channel, running next to each
other, are connected together and introduced into the tube, to the inside
surface of whose walls they are attached. In a preferred further
improvement, the inflation channel, which has a smaller diameter, is
located in the wedge-shaped space between the sheathing of the wire and
the ventilation channel and connected with them. This improved version has
the advantage of a particularly low cross-sectional requirement of the
channel and stiffening configuration.
The wire, together with its sheathing, the inflation and the ventilation
channel are separated one from the other only in the extreme end section,
so that connection possibilities of the ventilation channel to a
ventilation unit, in particular an injection ventilation unit, and of the
inflation channel to an appropriate syringe is in no way hindered. Also,
irrespective of the two channels, the extreme end of the wire can be
affixed to a stand, or also to the patient in an expedient manner.
In contrast to the ventilation channel and to the stiffening wire, in
preferred embodiments of the invention, the inflation channel is embedded
within the tube or is arranged in a gutter in the outer surface of the
tube. This has technical advantages for the production process, since the
end of the inflation channel opens into the cuff attached to the outside
of the tube. In this way, a perforation of the tube for the purpose of
leading the inflation channel into the inside space of the cuff is not
needed.
The ventilation channel terminates in the end section of the introduction
end of the tube, while the wire and/or the inflation channel teminates
approximately half-way along the tube. This dimensioning and arrangement
is expedient.
It goes without saying that, instead of the sheathed wire, a rod made of
plastics having comparable properties, the material of which being uniform
or variable over the cross-section, can also be employed. Equally, the
arrangement can be such that the two channels are glued together or welded
together or otherwise connected and the wedge-shaped space remaining
between the two channels filled with an appropriate plastic mass which
provides an adequate stiffness. Further details of, and improvements to,
the present invention can be seen in the following description of one
embodiment represented in the drawing, in conjunction with the claims. In
a simplified and schematic form, the following aspects are illustrated:
IN THE DRAWINGS
FIG. 1 A view of a laryngeal tube of the invention,
FIG. 2 A longitudinal section through the introduction end of the tube
shown in FIG. 1, the view being enlarged as compared with FIG. 1,
FIG. 3 A section along the line III--III of FIG. 2 and
FIG. 4 A section along the line IV--IV of FIG. 2.
DETAILED DESCRIPTION OF THE DRAWINGS
The represented laryngeal tube for intratracheal intubation anaesthesia,
for use in microsurgical interventions in the region of the larynx,
comprises a tube, 1, attached at the introduction end, the said tube being
made of soft PVC or rubber or suchlike, and having a diameter matched to
the cross-section of the trachea, the said tube comprising a soft-plastic
tube-like section with rounded ends, and in which a metal helical spring,
2, is embedded in order to increase its stiffness and, in particular, its
resistance to crushing. The coils of the metal helical spring
preferentially have a rectangular cross-section. The metal helical spring
terminates at a short distance before the introduction end of the tube, 1,
and at a larger distance from the opposite end of tube 1. To the outside
of tube, 1, displaced somewhat from the middle of the tube in the
direction towards the introduction end, a cuff, 3, is attached, the said
cuff being made of a thin elastic layer, for example, soft PVC or latex,
and having the form of a section of a tube and whose two ends, 4 and 5,
are affixed tightly to the outside surface of tube, 1. In the empty state,
the cuff, 3, lies virtually flat against the outside surface of the tube,
1, possibly being slightly vaulted, and thus does not hinder the
introduction of the tube, 1 into the trachea. On the outside surface of
the tube, 1, or sunk into its wall, there is a thin inflation channel, 6,
having a very fine lumen, and which passes beneath the end, 5, of the
cuff, 3, and which opens into the annular space which is closed to the
outside by the cuff, 3.
In approximately the same longitudinal plane as the inflation channel, 6, a
ventilation channel, 7, is provided, the said ventilation channel having a
larger inside cross-section as compared with the inflation channel, 6, and
running along the inside surface of the tube, 1, and opening at a distance
from the introduction end of the tube, 1, approximately in the region of
the end, 4, of the cuff, 3 (but within the lumen of tube, 1).
The ventilation channel, 7, serves to supply oxygen for respiration and an
anaesthetic gas, and also for the expiration of carbon dioxide.
Immediately adjacent to the ventilation channel, 7, a mouldable stiffening
wire, 8, made of soft iron, copper, aluminium, stainless steel or other
material with similar properties, is arranged, the said wire being
provided with a sheathing, 9, made of plastics. The stiffening wire, 8,
can be relatively easily moulded, for example, as can a copper or soft
iron wire, but is adequately robust to keep the channels, 6 and 7, in a
desired position. For this purpose, the ventilation channel, 7 and the
sheathing, 9, of the stiffening wire, 8, are connected to each other along
their entire length, for example, by gluing or welding. As from the end of
the tube, 1, directed outwards, the inflation channel, 6, is also
connected to the sheathing, 9, and the ventilation channel, 7, the said
ventilation channel, 7, and the stiffening wire, 8, together with the
sheathing, 9, being arranged next to each other and lying against each
other, and the inflation channel, 6, is located in the wedge-shaped space
between the sheathing, 9, and the ventilation channel, 7, and glued
therein.
At the extreme end of the inflation channel, 6, which is directed away from
the tube, 1, a pilot balloon, 10, is attached, to which, via an
intermediate line, 11, a known inflation funnel, 12, provided with a
spigot, 13, is connected. Through the inflation funnel, 12, and the
intermediate line, 11, an inflating gas can be introduced into the cuff,
3, the state of filling of which being indicated by the pilot balloon, 10.
At the extreme end of the ventilation channel, 7, a connecting funnel, 14,
is attached.
When carrying out microsurgical interventions in the region of the larynx,
the patient is first premedicated with appropriate means prior to the
operation and is given an agent to induce relaxation. After thorough
oxygenation, the laryngeal tube is passed, this generally being possible
without the necessity to employ a foreign body-removing forceps, since the
stiffening wire, 8, possesses adequate firmness. When the tube, 1, has
reached its final position in the trachea of the patient, the cuff, 3, is
inflated via the inflation channel, 6, the result being that the cuff
presses against the inside surface of the trachea, thus forming a seal. To
the connection funnel, 14, of the ventilation channel, 7, an injector
ventilation device is connected, the said device ventilating the patient
with an intermittent positive pressure; the ventilation pressure, and thus
the respiratory minute volume, can be set. Furthermore, the respiration
rate and the ratio of inspiration to expiration can be varied. In
addition, an anaesthetic gas, for example laughing gas (nitrous oxide) is
admixed with the respiratory oxygen.
Thanks to the joining of the inflation channel, 6, with the ventilation
channel, 7, and the additional provision of the stiffening wire, 8,
provided with a sheathing, 9, not only is the placement of the tube, 1,
facilitated, but, in addition, the channels are retained in a position in
which they do not disturb the surgeon carrying out an operation.
It goes without saying that the invention is not restricted to the
embodiment represented here, but that deviations are possible, without
exceeding the scope of the invention. In particular, individual
characteristics or features of the invention can be used, either alone or
combined severally.
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