WO2001024861A1

WO2001024861A1 - Ventilator tube

Info

Publication number: WO2001024861A1
Application number: PCT/SE2000/001894
Authority: WO
Inventors: Ola Stenqvist
Original assignee: Instrumentarium AB
Current assignee: Instrumentarium AB
Priority date: 1999-10-01
Filing date: 2000-09-29
Publication date: 2001-04-12
Anticipated expiration: 2002-04-01
Also published as: SE9903548L; SE522361C2; SE9903548D0; AU7821700A

Abstract

A dead space eliminator (21) for an endotracheal tube (1) or a tracheostomy tube the endotracheal tube (1) or the tracheostomy tube both having a proximal end (9) and a distal end (8), the dead space eliminator (21) comprises a tube (11) insertable into an endotracheal tube (1) or a tracheostomy tube the insertable tube (11) having a proximal end (23) and a distal end (22), the insertable tube (11) having sealing means (24) at the proximal end (23).

Description

Ventilator tube

TECHNICAL FIELD

The present invention relates to a dead space eliminator for an endotracheal tube or a tracheostomy tube, an endotracheal tube or tracheostomy tube which comprises the dead space eliminator, and a method for eliminating the dead space in an endotracheal tube or a tracheostomy tube by using the dead space eliminator.

BACKGROUND ART In patients with acute lung injury (ALI) or adult respiratory distress syndrome (ARDS) it is common, during ventilator treatment, with an increase in dead space causing high carbon dioxide levels or necessitating large harmful ventilation volumes. During ventilator treatment of these patients they are connected to a ventilator by breathing tubes that are connected with a Y-piece to a tube introduced into the windpipe of the patient (an endotracheal tube typically 8 mm inner diameter). The tube which is introduced into the windpipe of the patient may also be a tracheostomy tube. The lumen of the Y-piece and the tube form a dead space that increases the carbon dioxide load of the patient. The dead space is the volume between the alveoli in the lungs where gas exchange occur and the Y-piece at the endotracheal tube, or a tracheostomy tube, where the inspiratory gas from the ventilator and the expiratory gas from the lungs are separated. Patients that undergo treatment with ventilators often have increased dead space ventilation leading to an increase in carbon dioxide levels in arterial blood with concomitant decreases of pH in blood which may be dangerous for the patient. The most common way to counteract increased dead space ventilation is to increase the volume of each breath. However, an increase in breath volume leads to increased pressure in the lungs which is known to have damaging effects on the lung tissue (barotrauma), which may lead to worsening of the disease.

It has been advocated that this dead space can be eliminated by so called tracheal gas insufflation (TGI) by introducing a thin catheter through the endotracheal tube, or the tracheostomy tube, positioning the tip of the catheter in the wind-pipe, with either a continuous flow or a expiratory synchronised flow. It is difficult to predict the effect of continuous TGI and the synchronised version needs electronic governing from the ventilator.

There has also been described double lumen endotracheal tubes having a first lumen which is used for inspiration and a second lumen which is used for expiration. However, the earlier described double lumen endotracheal tubes are constructed by permanently dividing a volume of an endotracheal tube into a first volume (lumen) used for inspiration and a second volume (lumen) used for expiration. The permanent division of the volume of the endotracheal tube makes the resulting double lumen endotracheal tube rigid and expensive, and the treating physician has to foresee which patient who will need this type of double lumen endotracheal tube to avoid changing from a standard single lumen endotracheal tube to the double lumen endotracheal tube in a critical situation, and thus the earlier described double lumen endotracheal tubes are inconvenient to use.

DISCLOSURE OF INVENTION

The present invention relates to a dead space eliminator for an endotracheal tube or a tracheostomy tube.

Particularly the present invention relates to a dead space eliminator for an endotracheal tube or a tracheostomy tube during ventilator treatment.

More particularly the present invention relates to a dead space eliminator for an endotracheal tube or a tracheostomy tube the endotracheal tube or the tracheostomy tube both having a proximal end and a distal end, the dead space eliminator comprises a tube insertable into an endotracheal tube or a tracheostomy tube the insertable tube having a proximal end and a distal end, the insertable tube having sealing means at the proximal end.

Another object of the present invention is a dead space eliminator for an endotracheal tube or a tracheostomy tube the endotracheal tube or the tracheostomy tube both having a proximal end and a distal end, the dead space eliminator comprising a tube insertable into an endotracheal tube or a tracheostomy tube the insertable tube having a proximal end and a distal end, the insertable tube having sealing means at the proximal end, and the distal end of the insertable tube coinciding with the distal end of the endotracheal tube or the tracheostomy tube, when the insertable tube is in an inserted position into the endotracheal tube or the tracheostomy tube.

A further object of the present invention is a dead space eliminator having an insertable tube the insertable tube together with an endotracheal tube or a tracheostomy tube forming a double lumen endotracheal tube or a double lumen tracheostomy tube, when the insertable tube of the dead space eliminator, is inserted into the endotracheal tube or the tracheostomy tube.

Still another object of the present invention is a dead space eliminator as described herein and where the sealing means are sealing, when the insertable tube of the dead space eliminator, is inserted into the endotracheal tube or the tracheostomy tube.

During ventilator treatment of patients, the patients are connected to a ventilator by breathing tubes that are connected with a Y-piece to a tube, an endotracheal tube (e.g. 8 mm inner diameter) or a tracheostomy tube, which is introduced into the windpipe of the patient. The dead space is defined as the volume of gas in the airways between the alveoli in the lungs where gas change occur and the Y-piece at the proximal end of the endotracheal tube or the tracheostomy tube where the inspiratory gas from the ventilator and the expiratory gas from the lungs are separated. Moreover the dead space which is formed by the lumen of the Y-piece and the endotracheal tube or the tracheostomy tube increases the carbon dioxide load of the patient. Further, the dead space during ventilator treatment may be divided into a mechanical dead space and an anatomical dead space, the division of the dead space is illustrated in FIG. 4.

A dead space eliminator according to the present invention eliminates the technical dead space, i.e. the part of the dead space that is formed by an endotracheal tube or a tracheostomy tube, connectors and an Y-piece, when the dead space eliminator is inserted into an endotracheal tube or a tracheostomy tube. The insertable tube may be of any suitable material, e.g. plastic, teflon, rubber or woven metal.

The insertable tube may be of a flexible material.

The insertable tube may be introduced into an endotracheal tube (e.g. a standard endotracheal tube) or a tracheostomy tube. The insertable tube has sealing means which ensures a tight connection between the insertable tube and the endotracheal tube or the tracheostomy tube. A tight connection means a gas tight (or at least an essentially gas tight) connection, and a leak free connection. The sealing means also ensure that the insertable tube keeps its position, when inserted into the endotracheal tube or the tracheostomy tube. Further, when the insertable tube is inserted into a standard endotracheal tube it has a design which allows the insertable tube to be introduced through a standard connector, e.g. a swivel connector, of a standard endotracheal tube, e.g. a snap lock ensures tight connection between the standard swivel connector and a connector of the insertable tube. The connector of the insertable tube is when present a suitable construction at the insertable tube, which construction ensures tight connection between the inserted tube and the tube into which the insertable tube is inserted.

The tube introduced into the windpipe of the patient may optionally be an endotracheal tube, which is inserted into the windpipe through the nose or the mouth of the patient, or a tracheostomy tube, which is inserted by surgery or percutaneously, tracheostomy, into the windpipe of the patient.

The insertable tube of the dead space eliminator may optionally be used for inspiration or expiration, when inserted into an endotracheal tube or a tracheostomy tube.

The proximal end (ventilator end) of the insertable tube is the end of the insertable tube which is outside the patient. The distal end (patient end or tracheal end) of the insertable tube is the end of the insertable tube which is inside the patient. The proximal end (ventilator end) of the endotracheal tube or the tracheostomy tube is the end of the endotracheal tube or the tracheostomy tube which is outside the patient. The distal end (patient end or tracheal end) of the endotracheal tube or the tracheostomy tube is the end of the endotracheal tube or the tracheostomy tube which is inside the patient.

When the distal end of the insertable tube is said to generally coincide with the distal end of the endotracheal tube or the tracheostomy tube, it is not necessary that the distal ends coincide at exactly the same level.

The insertable tube of the dead space eliminator may be inserted into an endotracheal tube or a tracheostomy tube so as to form together with the endotracheal tube or the tracheostomy tube, a double lumen endotracheal tube and the double lumen tracheostomy tube. The double lumen endotracheal tube and the double lumen tracheostomy tube both have a volume (lumen) used solely for inspiration and another volume (lumen) used solely for expiration. One lumen, the peripheral lumen, is limited by the interior wall of the endotracheal tube or the tracheostomy tube, and the exterior wall of the inserted tube, and the other lumen is limited by the interior wall of the inserted tube

The present invention also relates to endotracheal tubes or tracheostomy tubes, having a dead space eliminator inserted.

The present invention also relates to an endotracheal tube or an tracheostomy tube the endotracheal tube or the tracheostomy tube comprises a dead space eliminator as described herein.

Another object of the present invention also relates to endotracheal tubes or tracheostomy tubes, having a dead space eliminator inserted, which inserted dead space eliminator comprises of an insertable tube, which insertrable tube has sealing means at the proximal end. Still another object of the present invention is a method for eliminating the dead space in an endotracheal tube or a tracheostomy tube by inserting a dead space eliminator, which dead space eliminator comprises of a insertable tube having sealing means at the proximal end.

A further object of the present invention is a method for eliminating the dead space in an endotracheal tube or a tracheostomy tube the method comprises a dead space eliminator as described herein.

BRIEF DESCRIPTION OF DRAWINGS

The following drawings illustrate, but in no way limit the invention.

FIG. 1 shows a side view of a standard single lumen endotracheal tube ID 8 (SLT), a swivel connector, a Y-piece, part of an inspiratory limb and part of an expiratory limb.

FIG. 2 shows a side view of an insertable coaxial inner tube 5.5/4.5 OD/ID.

FIG. 3 shows a side view of a dead space eliminator comprising a coaxial tube, wherein said dead space eliminator is inserted into a standard ETT resulting in a double lumen tube (DLT).

FIG. 4a shows a side view in section of a ventilator treatment with a standard single lumen endotracheal tube.

FIG. 4b is a schematic view disclosing positions to measure pressure in expiratory limb and pressure in inspiratory limb. FIG. 5 shows a side view in section of a dead space eliminator which comprises an insertable tube and a snap fitting (sealing means) for a swivel connector.

FIG. 6a shows a side view in section wherein a dead space eliminator in use during ventilator treatment is illustrated.

FIG. 6b shows a view in perspective into the opening at the distal end of the endotracheal tube with a dead space eliminator in use position. FIG. 6c is a schematic wiev showing positions inside a ventilator to measure pressure in inspiratory limb and pressure in expiratory limb during ventilator treatment with a dead space eliminator in a use position.

FIG. 7 shows a diagram disclosing pressure recordings from a pressure receptor in the inspiratory limb and a pressure receptor in the expiratory limb.

FIG. 1 shows a side view of a standard single lumen endotracheal tube (SLT), 1, i.e. a standard endotracheal tube (ETT), a swivel connector, 2, a Y-piece, 3, part of an inspiratory limb, 4, and part of an expiratory limb, 5, the standard single lumen endotracheal tube, 1, having an inner diameter (ID) of 8 mm, an inflatable cuff, 6, and a charging valve, 7, to the inflatable cuff, 6. The inspiratory limb, 4, and the expiratory limb, 5, are parts of a breathing system of a ventilator (not shown). The ETT, 1, has a distal end, 8, and a proximal end, 9. FIG. 2 shows a side view of an insertable coaxial inner tube, 11 , having an outer diameter of 5.5 mm and an inner diameter of 4.5 mm (5.5/4.5 OD/ID).

FIG. 3 shows a side view of a dead space eliminator, 21 , comprising a coaxial tube, 11 , wherein said dead space eliminator, 21 , is inserted into a standard ETT, 1 , resulting in a double lumen tube (DLT). The distal end, 22, of the dead space eliminator, 21, inside the ETT, 1 , is shown as a dashed line and the proximal end, 23, of the dead space eliminator, 21, which is situated inside the inspiratory limb, 4, is not shown. Also shown is the swivel connector, 2, and part of the expiratory limp, 5.

FIG. 4a shows a side view in section of a ventilator treatment with a standard single lumen endotracheal tube, 1 , disclosing a trachea, 31 , of a patient, the endotracheal tube, 1 , having the distal end, 8 , in the trachea, 31, an inflated cuff, 6, a swivel connector, 2, a Y-piece, 3, an expiratory limb, 5, to ventilator (not shown), and inspiratory limb, 4, from ventilator (not shown). Here is also technical dead space, 32, which is defined as the area having dots, and anatomical dead space, 33 , which is defined as the area having slashed lines. The technical dead space, 32, is eliminated (abolished) by the dead space eliminator.

FIG. 4b is a schematic view showing a ventilator, 41, a first position, 42, to measure pressure in expiratory limb, 5, and second position, 43, to measure pressure in inspiratory limb, 4. Further, FIG 4b also shows an ETT, 1 , and a trachea, 31 , of a patient. FIG. 5 shows a side view in section of a dead space eliminator, 21 , having a distal end, 22, and a proximal end, 23, wherein the dead space eliminator, 21 , comprises an insertable tube, 11, and a snap fitting (sealing means), 24, for a swivel connector (not shown).

FIG. 6a shows a side view in section wherein a dead space eliminator, 21 , in use during ventilator treatment, thus eliminating techical dead space of an ETT, 1, is illustrated, wherein the trachea, 31, of a patient, an endotracheal tube, 1, having the distal end, 8, in the trachea, 31, a swivel connector, 2, a dead space eliminator, 21, comprising an insertable tube, 11 , and a snap fitting (sealing means), 24, for a swivel connector, 2, at the proximal end, 23, the insertable tube, 11, and the dead space eliminator, 21 , having the distal end, 22, in the trachea, 31 , an inflated cuff, 6, a part of an expiratory limb, 5, to ventilator (not shown), and a part of an inspiratory limb, 4, from ventilator are disclosed.

FIG. 6b shows a view in perspective into the opening at the distal end, 8, of the endotracheal tube, 1 , with a dead space eliminator, 21, in use position, showing the distal end, 22, of the of the insertable tube, 11 , of the dead space eliminator,21 and the inflatable cuff, 6.

FIG. 6c is a schematic wiev showing a ventilator, 41 , a third position, 44, to measure pressure in expiratory limb, 5, and a fourth position, 45, to measure pressure in inspiratory limb, 4, both positions, 44 and 45, being inside the ventilator, 41 , during ventilator treatment with a dead space eliminator, 21, in a use position. A trachea, 31 , of a patient is also shown.

FIG. 7 shows a diagram disclosing pressure recordings from a pressure receptor in the inspiratory limb and a pressure receptor in the expiratory limb, wherein the inspiratory limb pressure and expiratory limb pressure are plotted during inspiration and expiration. By alternating pressure receptors through the breathing cycle, a true tracheal pressure can be measured continuously through the breathing cycle independent of endotracheal tube resistance or resistance of a insertable tube of a dead space eliminator.

MODES FOR CARRYING OUT THE INVENTION The following examples illustrate, but in no way limit the invention.

Example 1 A dead space elimination is achieved by using a narrow flexible tube, 11 , that can be introduced (inserted) into a standard endotracheal tube (ETT), 1 , to achieve an peripheral lumen which is limited by the interior wall of the ETT, 1 , and the exterior wall of the inserted tube, 11. In this example this lumen is preferably used for expiration, and the lumen of the inserted tube, 11 , is preferably used for inspiration. The insertable tube, 11, is dimensioned so that the resistance of the two separate lumina have equal resistance to airflow or that the expiratory resistance is less than the inspiratory resistance. The consequence of the insertion of the flexible tube, 11, and connecting it to the inspiratory limb, 4, of the breathing system of the ventilator and connecting the outer lumen to the expiratory limb, 5, of the breathing system is that the Y-piece, 3, is moved from its normal position outside the patient at the ventilator end of the ETT, 1, to the wind pipe, 31, of the patient at the patient end, 8, of the ETT, 1 , decreasing the dead space with a volume equal to the volume of the ETT, 1, and all connectors to the normal Y-piece, 3.

An insertable inner tube, 1 , of 5.5 mm outer diameter has been developed to be fitted in a standard 8 mm ID endotracheal tube, 1 , which resulted in a substantial decrease in alveolar CO₂ levels, especially at low - protective - minute ventilation. The main advantage of double lumen ventilation is that it can be implemented in patients with a standard 8 mm ID ETT, 1, by applying an insertable inner tube, 11. Double lumen ventilation necessitates an increase in driving pressure of the ventilator, but no formation of intrinsic PEEP (positive end expiratory pressure) at tidal volumes of <_600 ml, l:E ratio of < 1:1 and compliance < 35 ml/cm H₂O was seen. Compared to TGI this ventilatory technique is safe and easy to apply and no need for electronic synchronisation is at hand. With the use of double lumen tube technique, protective ventilation can be achieved without excessive augmentation of carbon dioxide levels.

The effect of minimizing dead space can be obtained by moving the Y-piece, 3, from the proximal, 9, to the distal (tracheal) end, 8, of the endotracheal tube (ETT), 1. A 5.5/4.5 mm outer/inner diameter (OD/ID) teflon tube, 11 , has been developed that can be inserted into a standard 8 mm ID endotracheal tube, 1, through a swivel connector, 2, eliminating all ETT and Y-piece dead space by locating the Y-piece, 3, in the trachea, 31.

Example 2

The pressure in the breathing system described above in Example 1 is measured with two pressure receptors, one receptor in the inspiratory limb, 4, and the other receptor in the expiratory limb, 5, of the breathing system. The pressure receptors can be positioned inside a ventilator, 41. The pressure below the tube, 11, in the wind pipe, 31, of the patient is measured with the pressure receptor in the expiratory limb, 5, during inspiration and with the pressure receptor in the inspiratory limb, 4, during expiration. By alternating pressure receptors through the breathing cycle in this way true tracheal pressure can be measured continuously through the breathing cycle independent of ETT or the insertable tube resistance. This methodology can be used in standard breathing system to measure Y-piece pressure from the ventilator, 41.

Claims

1. A dead space eliminator (21) for an endotracheal tube (1) or a tracheostomy tube the endotracheal tube (1) or the tracheostomy tube both having a proximal end (9) and a distal end (8) characterized in that the dead space eliminator (21) comprises a tube (11) insertable into an endotracheal tube (1) or a tracheostomy tube the insertable tube (11) having a proximal end (23) and a distal end (22), the insertable tube (11) having sealing means (24) at the proximal end (23).

2. A dead space eliminator (21) according to claim 1 characterized in that the distal end (22) of the insertable tube (11) generally coincides with the distal end (8) of the endotracheal tube (1) or the tracheostomy tube, when the insertable tube (11) is in an inserted position into the endotracheal tube (1) or the tracheostomy tube.

3. A dead space eliminator (21) according to either of claim 1 and 2 characterized in that the insertable tube (11), when inserted into an endotracheal tube (1) or a tracheostomy tube, together with the endotracheal tube (1) or the tracheostomy tube form a double lumen endotracheal tube or a double lumen tracheostomy tube.

4. A dead space eliminator (21) according to either of claim 2 and 3 characterized in that the sealing means (24) are sealing.

5. An endotracheal tube (1) or tracheostomy tube characterized in that the endotracheal tube (1) or the tracheostomy tube comprises a dead space eliminator (21) according to any of claims 1 to 4.

6. A method for eliminating the dead space in an endotracheal tube (1) or a tracheostomy tube characterized by the use of a dead space eliminator (21) according to any of claims 1 to 4.