BACKGROUND A patient may be ventilated and supplied with anaesthetic gas via an airway in the form of an endotracheal tube inserted via the mouth or nose, the patient end being located in the trachea below the vocal chords. In other cases, a laryngeal mask airway may be used for ventilation, the patient end of this device terminating in the region of the pharynx. Alternatively, the patient may be ventilated by means of a tracheostomy tube, the patient end of which is inserted in the trachea via a surgically made opening in the patient's neck. Tracheostomy tubes are preferable for long term use because they do not provide any obstruction in the mouth and are better tolerated by the patient. In some cases, a patient may be ventilated initially using an endotracheal tube and then by a tracheostomy tube, when it becomes apparent that the patient will need prolonged ventilation. The surgical operation needed to introduce the tracheostomy tube involves cutting through the skin and tissue over the trachea in order to make the tracheostomy. One problem with this is that, if the cut is made too deep, it can cause damage to the posterior wall of the trachea. This risk is particularly great where a percutaneous or cricothyroid puncture tracheostomy is made.

OBJECT OF THE INVENTION The object of the present invention is to provide an improved endotracheal tube, which offers major protection of the posterior wall of the trachea during any kind of tracheostomy procedure.

SUMMARY OF THE INVENTION According to the aspect of the present invention there is provided an endotracheal tube of the above-specified kind, characterized in that it has a main part that shields the posterior wall of the trachea and protects it from damaging by the tracheostomy instruments during tracheostomy procedure. This main part of the tube lies just above the patient's end of the endotracheal tube, which is located in patient's trachea. Just above this main part there is a middle part of the tube that lies just below the inflated cuff, which is placed (the cuff) just above the vocal cords during the tracheostomy procedure.

The endotracheal tube may have a black line at the concave side as a guide to ensure that the tube is not twisted The endotracheal tube may be black colored at an area that can include the inflated cuff, the middle part and the main part in order to help anyone who wants to use a light-guided instrument (a track-light for example), as a guide of the exact location of the main part of the endotracheal tube.

The endotracheal tube may have an indicator cuff at the front side of the main part to ensure that the tracheostomy instrument is at the right position.

The endotracheal tube may have a main part with stiff edges that can be expanded after the inflation of an expandable balloon which can also be used as an indicator cuff.

The endotracheal tube may have at the one or at both sides some holes in order to maintain the proper ventilation in cases of tracheal bronchus.

The endotracheal tube may also have a smooth, round-shaped, patient posterior end, (like a golf-club) in order to protect the posterior wall of the trachea during the insertion of the tube.

DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of a usual endotracheal tube in use just before tracheostomy.

Figure 2 is a front view of a usual endotracheal tube just before tracheostomy.

Figure 3 is a sectional front view of the patient end of a usual endotracheal tube.

Figure 4 is a sectional side view of a usual endotracheal tube during the tracheostomy procedure Figure 5 is a side view of the trachea-over-protection endotracheal tube in use just before tracheostomy.

Figure 6 is a front view of the trachea-over-protection endotracheal tube just before tracheostomy.

Figure 7 is a sectional front view of the patient end of the trachea-over-protection endotracheal tube Figure 8 is a transverse sectional view of the trachea-over-protection endotracheal tube between levels I-II Figure 9 is a transverse sectional view of the trachea-over-protection endotracheal tube between levels lI-m Figure 10 is a transverse sectional view of the trachea-over-protection endotracheal tube between levels III-IV Figure 11 is a transverse sectional view of the trachea-over-protection endotracheal tube between levels 100-I Figure 12 is a sectional side view of a the trachea-over-protection endotracheal tube during the tracheostomy procedure Figure 13 is a front view of the trachea-over-protection endotracheal tube with the black linel6 Figure 14 is a sectional side view of the trachea-over-protection endotracheal tube with indicator-cuff 19 during the tracheostomy procedure Figure 15 is a transverse sectional view of the trachea-over-protection endotracheal tube with an indicator-cuff 19 during the tracheostomy procedure Figure 16 is a transverse sectional view of the trachea-over-protection endotracheal tube with the expandable edges 20 (like swing doors) and the expanding cuff 21 during the tracheostomy procedure Figure 17 is a front view of the trachea-over-protection endotracheal tube which is black colored at an area 17 that can include the inflated cuff 15, the middle part and the main part 18.

Figure 18 is a front view of the trachea-over-protection endotracheal tube which is black colored at an area 17 that can include the inflated cuff 15, the middle part and the main part 18 with the black linel6.

Figure 19 is a side view of the trachea-over-protection endotracheal tube in use with some holes 22 at the middle and the main part 18.

Figure 20 shows a sagittal cut (in the middle) of the trachea-over-protection endotracheal tube in use with a smooth, round-shaped, patient posterior end 23. (like golf club) DETAILED DESCRIPTION OF THE INVENTION In order to understand better this invention it is described at first a usual endotracheal tube during tracheostomy procedure and after that the trachea-over-protection endotracheal tube during the tracheostomy procedure. With reference at first to figures 1,2, 3 and 4 it is shown a usual endotracheal tube oral or nasal 50 with a concave 53 and a convex 54 side, having a machine end 51 with a connector projecting from the patient's mouth or nose and a patient's end 52 located in the patient's trachea 60. An inflated cuff 55 close to the patient's end 52 is inflated to seal the outside of the tube with the inside of the trachea 60.

Normally the cuff 55 is inflated bellow the vocal cords-level 100-and gas is administered to the patient via the tube 50. When it becomes apparent that the patient will require a tracheostomy, such as, for example, if he is thought to need prolonged ventilation, the cuff 55 on the tube 50 is deflated and the tube 50 is pulled out of the patient's mouth by a distance sufficient to bring the cuff and inflate it again above the vocal cords-level 100-this time, to the position shown in figures 1 and 2.

During the percutaneous tracheostomy as shown in fig. 4, an incision is made through the skin and tissue of the neck overlying the trachea 60 with a tracheostomy instrument 90 (like a needle) as a guide. The risk of damaging the posterior wall 70 of the trachea 70 is great, especially under circumstances like tracheomalacia or others.

With reference now to figures 5-12 it is shown the trachea-over-protection endotracheal tube 10 (oral or nasal) with a concave 13 and a convex 14 side, having a machine end 11 with a connector projecting from the patient's mouth or nose and a patient's end 12 located in the patient's trachea 60.

An inflated cuff 15 close to the patient's end 12 is inflated to seal the outside of the tube with the inside of the trachea 60. The cuff 15 is normally inflated bellow the vocal cords (level 100) and gas is administered to the patient via the tube 10. When it becomes apparent that the

patient will require a tracheostomy, such as, for example, if he is thought to need prolonged ventilation, the cuff 15 of the tube 10 is deflated and the tube 10 is pulled out of the patient's mouth by a distance sufficient to bring the cuff and inflate it again above the vocal cords- level 100-this time, to the position shown in figures 5 and 6.

During the percutaneous tracheostomy as shown in fig. 12, an incision is made through the skin and tissue of the neck overlying the trachea 60 with a tracheostomy instrument 90 (needle) as a guide. The main part 18 of this invention lies between levels I-E of the trachea-over-protection endotracheal tube. As shown in fig. 12 during the tracheostomy procedure the main part 18 of the trachea-over-protection endotracheal tube protects the posterior wall 70 of the trachea from any damage the tracheostomy instrument could cause. In fig. 9 a transverse sectional view of the trachea-over-protection endotracheal tube is shown between levels lI-m and shows the protection of the posterior wall 70 of the trachea.

The main part 18 of the trachea-over-protection endotracheal tube 10 can be made of the same material-plastic or any other material used nowadays in industry for usual tubes-as the whole trachea-over-protection endotracheal tube, it can be enforced by another material or it can be made from a material totally different.

In order to ensure that the main part of the trachea-over-protection endotracheal tube is not twisted, the trachea-over-protection endotracheal tube has a black line 16 in the concave 13 side to help the man who is rensponsible for the intubation of the patient, as shown in fig. 13.

The trachea-over-protection endotracheal tube can be black colored at an area 17 that can include the inflated cuff 15, the middle part and the main part 18 in order to help anyone who wants to use a light-guide instrument (a track-light for example), as a guide of the exact location of the main part of the endotracheal tube which is the right position of the tracheostomy instrument 90, as shown in figs. 17-18.

As shown in figs. 14-15 the trachea-over-protection endotracheal tube can have an indicator- cuff 19, which is positioned at the front side of the main part 18 of the trachea-over-protection endotracheal tube. During the tracheostomy procedure the tracheostomy instrument passes through the indicator-cuff 19 and the man who makes the tracheostomy is sure about the right progress of the procedure.

In fig. 16 is shown a trachea-over-protection endotracheal tube with a stiff part 20 at both edges of the main part 18 that can expand-like swing door-after inflation of an expandable balloon 21 which can also be used as an indicator cuff.

The trachea-over-protection endotracheal tube as shown in figure 19 (which is a side view) may also have at the one or at both sides of the middle and/or the main part 18 some holes 22 in order to maintain the proper ventilation in cases of tracheal bronchus.

As shown in fig. 20 the trachea-over-protection endotracheal tube may also have a smooth, round-shaped, patient posterior end 23 (like a golf club in a sagittal cut) in order to protect the posterior wall of the trachea during the insertion of the tube.

Because of natural differences between patients (men-women, adults-children, tall-short etc) the length, the exact diameter or even the material of every part of the trachea-over-protection endotracheal tube can vary without departing from the spirit of the invention.