TECHNICAL FIELD

The invention relates to endotracheal and tracheostomy tubes which are vital medical devices used to provide reliable airway in both humans and animals in many critical medical and surgical conditions. It provides many advantages in terms of monitoring the pressure of the cuffs in the tubes.

BACKGROUND OF THE INVENTION

In the medical treatment of patients in need of respiratory support, the placement of tubes into the trachea through the mouth or nose (endotracheal tube) or through a surgically formed opening (tracheostomy tube) is an increasingly common intervention in critical situations. Endotracheal tubes (ETT) are used more often. In human and animal surgery, they are utilized to deliver anesthetic gases safely to the lungs and to provide safe respiration. The standard ETT has at least one cuff in its distal part. To observe the intra-cuff pressure, there is at least one pilot balloon in the proximal portion of the ETT. When the tube is inserted, the cuff or cuffs are inflated and they provide sealing to minimize the risk of aspiration. The pressure in the cuff should be high enough to perform these primary functions, but not to stop the blood flow in the trachea. There are two traditional techniques to inflate ETT’s cuffs. The first is the assessment of the pressure based on the palpation of the pilot balloon. The second is that it is inflated by a volume of air adjusted to the size of the selected tube. These methods have been shown to cause some errors. The measured pressure in the cuff is shown to be very close to the value applied to the tracheal wall. If it comes into contact with the inner wall of the trachea with high pressure, normal blood flow in the mucosa is disrupted by the pressure on the capillaries in the contact portion. It may result in insufficient blood flow and tissue ischemia. Prolonged ischemia can cause various degrees of damage, such as erosion of the mucosa, destruction of tracheal cartilage rings or tracheal dilatation and segmental tracheomalacia. Intubation related complications include sore throat, hoarseness, tracheal rupture, tracheal necrosis, tracheal stenosis and recurrent laryngeal nerve palsy. In the several studies, it has been shown that cuff pressure values exceeding 30 cm H ₂ 0 are risky and some damages can occur in a very short time such as 15 minutes [Acta Otolaryngol 1976; 345 (Suppl.345): l-7., BMJ.1984; 288(6422): 965-8., Intensive Care Med. 20l3;39(4):575-82., Respiratory Care. June 2014 Vol 59 No 6: 933-956.]. The low pressure of the ETT cuffs may result in the aspiration pneumonia by the leakage of oropharyngeal secretions. In some studies, the incidence of ventilator-associated pneumonia (VAP) has been shown to be higher in patients with consistently low ETT cuff pressure below 20 cm H ₂ 0 (Am J Respir Crit Care Med. 2011 Nov 1; 184(9): 1041-7, Ann Intensive Care. 2015 Dec; 5(l):43.).

Although there is no consensus on the value of the cuff pressure to be ideal, it is generally recommended to keep the pressure between 20 and 30 cm H ₂ 0. Abnormal pressures are encountered, although both over and under-inflated cuffs cause increased morbidity, mortality and costs. Common ways of predicting ETT cuff pressure are the palpation of the pilot balloon by hand or fingers, evaluation of stiffness, or listening to the sound generated by air leakage during patient ventilation. Even experienced people can make mistakes in these methods (AANA J. 2003; 7l(6):443-7., Prehosp Emerg Care. 2007; l l(3):307-l l. Anaesth Intensive Care 2016 Sep; 44(5):599-604.). Therefore, some devices and methods have been developed to provide a safe, objective ETT cuff pressure (US patent no; 8721589, 6647984, 5318021, US patent applications no; 20130098363, 20120215074, 20120204884, 20120188084, etc.). These and similar innovations seem useful in many situations. However, studies on cuff pressure in intubations performed in pre-hospital settings have shown to be inflated at highly hazardous levels (Ann Emerg Med. 2006 Jun; 47(6):545-7., Am J Emerg Med. 2007; 25(l):53-6.). Many patients are intubated in a pre-hospital setting by emergency medical teams. If the cuff pressure is high in the time passed until it is delivered to the hospital, it may be long enough to cause damage to the tracheal mucosa. Despite all these realities, the high rate of abnormal pressures continues. Because the health care personnel who intervened at the scene, should be aware of the many factors that need to be taken care of, and the fact that they had to solve many problems in a short time with few staff. In addition, some ambulances were found to have no equipment to measure cuff pressure (Emerg Med J. 2013 Oct; 30(l0):851-3). It is thought that these devices haven’t accepted among the priority apparatus to be carried by the medical units which have narrow space such as ambulances, and it is troublesome to carry these devices in pre-hospital settings.

In studies performed in patients who were intubated in emergency centers, hospitals, operating theaters and intensive care units, a high rate of abnormal cuff pressures were found. It was found that high cuff pressures were detected at 62% even in intensive care units, and cuff pressures were not routinely measured in 75% of intensive care units. (Anaesthesia. 2002; 57(3):275-7, Am J Emerg Med. 2009; 27(8):980-2., Int J Pediatr Otorhinolaryngol. 2012 Jan; 76(l):6l-3., West J Emerg Med. 2016 Nov; l7(6):72l-725.). These studies suggest that medical personnel have difficulties in regulating cuff pressure in stressful environments, they raise them to highly dangerous levels, they are in short time, they are distracted by other problems that require attention.

In the transport of critically ill patients, aeromedical transport has an important place. Various air transport vehicles (fixed wing air ambulance, helicopter, and commercial airline) are used. Commercial airlines often pressurize their cabinets, but provide high-altitude transportation. Helicopters fly at lower altitudes but do not apply pressurization. At high altitudes, the ambient pressure can be reduced and there may be a large increase in pressure in the air-filled space. It has been shown that, even with moderate increases in the altitudes, the pressures in air filled cuffs may rise above the critical perfusion pressure of the tracheal mucosa. It has been reported that cuff pressures vary dangerously in the ascending and descent periods of the flight, and it is necessary to continuously monitor and adjust the cuff pressures during the flight, especially in helicopter transports (Emerg Med J. 2007 Aug; 24(8): 605., Ann Emerg Med. 2010 Aug; 56(2) :

89-93., Pediatr Emerg Care. 2011 May; 27 (5) : 367-70., Prehosp Emerg Care. 2013; 17 (2): 177- 80.). Simple and reliable methods are needed to monitor the pressures in this very noisy and stressful transport environment. The cuff pressure is a dynamic event. It can change continuously. Different factors lower or increase them. Coughing, changing the position, making some interventions such as aspiration, some anesthetic agents are factors that cause changes in the cuff pressures (Anesth Analg. 2013 Mar;l l6(3):609-l2., Rev Bras Enferm. 2017 Nov-Dec;70(6): 1145-1150., Aust Crit Care. 2017 Sep;30(5):267-272.). The cuff pressures should be measured and corrected at regular intervals in the patients under anesthesia and in the intensive care unit, also.

In some centers, different devices and techniques are used to measure and monitor the cuff pressures. In some studies, it is concluded that air leakage is caused when connecting to pilot balloon for measurement, many devices have different results compared to each other and some of them are laborious. Some studies concluded that cuff pressure leads to an increase in the risk of tracheal ischemic lesion during the measurement by these devices. Some studies suggested that the time required for use is longer, they are expensive and cumbersome, they are not sensitive enough, and new regulations and apparatus are required (Respir Care. 2004 Feb;49(2): 166-73., Rev Bras Ter Intensiva. 20l4;26(4):367-72., J Intensive Care. 2014 Jan 3l;2(l):7., BMC Anesthesiol. 2015 Oct 15;15: 147., Ann Intensive Care. 2015 Dec;5(l): 54.).

As can be seen from the above literature, it is understood that most of the existing apparatuses give different results from each other, there aren’t any apparatus for this purpose in some ambulances. In some cases, it has been shown that some personnel are untrained in their usages, and they find them insensitive and time-consuming or they used the methods with high error margin. In some studies, it has been found that they may reduce the cuff’s air during measurement, or they may increase to dangerous levels in some cases. In conclusion, it is has been suggested that there is a need for a new solution that provide the pressures to be in normal limits. Especially in some cases, it is understood that there is a need for a practical method which is easy to learn and time saver, and also works in a noisy environment. These features are more important for the mobile healthcare team that is in charge of the patients at the scene, and for the transport personnel.

In the existing measuring and monitoring systems, there is an extra apparatus connected to the pilot balloon. In intensive care units and operating rooms, they occupy some volume as an extra device. Extra volume causes a kind of image pollution. It distracts attention and makes patient monitoring difficult. In intensive care units, it is desirable to monitor many patients in the same time and at a sufficient distance. However, it is necessary to approach to the patient to read the indicators of these devices. Remote recognition is not possible. Personnel responsible for the cuff pressures should come in contact with the patients in order to measure them. In this case, the risk of infection increases. In addition, an extra device in intensive care units and operating rooms may be another factor that increases the risk of infection.

SUMMARY OF THE INVENTION

Another method of providing artificial airway is the process of making a hole in the trachea with the use of percutaneous or surgical methods called tracheostomy. The tracheostomy tube and tracheal cannula are the apparatuses that pass through this artificial opening in the trachea and which provide air passage through the space/passage through them. The general structure of these apparatus is very similar to the EET. In the structure of both, there is at least one cuff (2) and at least one pilot balloon (1) connected to this cuff (2) or cuffs. The complications of the cuff pressure and normal pressure values related to EET are valid for the cuffs of tracheostomy tubes. The cuff (2)/cuffs remaining in the body is/are inflated after the EET, tracheostomy tube and tracheal cannula are placed in larynx and trachea at desired distance. The pressure is very difficult to measure therein directly. Pilot balloon (1) outside the body and connected to the cuff (2) is in balance with the intra-cuff pressures and are similar. The most practical way to get an idea about the pressure of the said cuff (2) is to assess the pressure of the said pilot balloon (1). In the system we have developed, all or some of the pilot balloon (l)/balloons of the EET, tracheostomy tube and tracheal cannula and/or the conduit (3)/conduits providing connection to the cuff (2)/cuffs change/changes color depending on its/their internal pressure, and thus provide information on pressures of the cuff (2)/cuffs to which they are connected. This color production and change provides information on both the pilot balloon (1) and in-cuff (2) pressure value. It can be understood both if it is at a sufficient level and if it has reached to dangerous levels. In the same time, it also provides a warning for re-adjustment if it moves away from the desired value during use. In order to achieve color reproduction and color change properties according to the pressure, mechanochromic and piezochromic materials are used in the structures of the pilot balloon (1) and/or of the conduit (3) which provides connection to the said cuff (2). To provide the features of color production and color change according to the pressure, the mechanochromic and piezochromic materials have been included/incorporated in/into these components (the pilot balloon (1) or balloons, the conduit (3) or the conduits) in the manufacturing stage. As alternative embodiments, the mechanochromic and piezochromic materials are adhered (glued) and/or coated and/or assembled (bonded/mounted) after the production process. The mechanochromic and piezochromic material is the matter that produces color or change color suddenly (simultaneously) and reversibly in response to the pressure. Thank to the system we have developed, it is now possible to monitor simultaneously the pressures of the cuff/cuffs during the inflation and the subsequent pressure instantly.

Some patients are very sensitive to high pressures of the cuff/cuffs. There are some clinical conditions that should not be applied to high pressure even for a short time. For such critical cases and places where illumination is poor, it is arranged to generate light at certain pressure levels and provide warning. In this context, the materials that generate light depending on pressure (piezoluminescent and mechanoluminescent materials) are used in the structures of all or some of the said pilot balloon (1) and/or of the conduit (3) which provides connection to the said cuff (2). To provide the features of light according to the pressure, the piezoluminescent and mechanoluminescent materials have been included/incorporated in/into these components (the pilot balloon (1) or balloons, the conduit (3) or the conduits) in the manufacturing stage. As alternative embodiments, the piezoluminescent and mechanoluminescent materials are adhered (glued) and/or coated and/or assembled (bonded/mounted) after the production process. This piezoluminescent and mechanoluminescent material provides warnings by producing light at certain critical levels of the pressure.

As these materials are generally expensive, the cheaper embodiment is developed. In this application, materials that produce or change colors according to pressure (piezochromic and mechochromic materials) and light-generating materials according to pressure (piezoluminescent and mechanoluminescent materials) are used only in the valve (4) of the pilot balloon (1). The pilot balloon (1) or balloons, the conduit (3) or conduits and valve (4) or the valves of the pilot balloon (4) are easily visible. They can be seen from all sides (delivers image from 360 degrees). It is possible to view and monitor from a distance. There is no need to approach or contact to the patient. Since they don’t occupy extra space, they don’t cause visual pollution. As they aren’t any extra matter/substances, they won't be a source of infection. They don't require an external energy and manual interventions. Thus, they allow health care personnel to take the time on the other important tasks. Color change and color or light productions are reversible. Thus, they give instant information. The pressure can be displayed instantly from the beginning of the inflation of the cuff to the end. They provide the striking view/images. They are easily visible. They can be seen even in low lighting. They are simple to use. They aren’t exhausting. They don’t require much attention. No extra effort is required to detect the warning. Color change and color or light productions can be made sensitive to every pressure level. Thus, it enables the recognition of both high and low values. They also function in noisy environments. All these features can solve many of the problems encountered in the use of the other apparatuses and provide additional advantages. When our system displays a warning, it allows it to be confirmed by the other systems. Moreover, our system works with the other apparatus that monitor the pressures.

Description of the Figures Figure 1: Schematic drawing of the general structure of the endotracheal tube

Figure 2: Schematic drawing of the general structure of the tracheostomy tube

Description of the reference numbers given in the figures

1 : Pilot balloon for endotracheal and tracheostomy tubes

2: Cuff of the endotracheal and tracheostomy tubes

3 : The conduit (pipe) of the endotracheal and tracheostomy tubes

4: The valve of pilot balloon for endotracheal and tracheostomy tubes 5: The structure (formation) located on the pilot balloon, which contains the materials that provide color production and color change according to the pressure (mechanochromic and piezochromic materials) and the materials that generate the light according to pressure (mechanoluminescent and piezoluminescent materials).

6: The structure (formation) located on the proximal part of the conduit (closer to the pilot balloon), which contains the materials that provide color production and color change according to the pressure (mechanochromic and piezochromic materials) and the materials that generate the light according to pressure (mechanoluminescent and piezoluminescent materials).

7 : The structure (formation) located on the distal part of the valve for the pilot balloon (closer to the pilot balloon), which contains the materials that povide color production and color change according to the pressure (mechanochromic and piezochromic materials) and the materials that generate the light according to pressure (mechanoluminescent and piezoluminescent materials).

DETAILED DESCRIPTION OF THE INVENTION

In the system we have developed, the pilot balloon (1) and/or valve (4) and/or the conduit

(3) are provided with the ability to produce and change color or to generate the light according to the pressure inside the cuff (2). They are made capable of the showing the pressure. In this context, the pilot balloon (1) or balloons, the conduit (3) or the conduits or the valve (4) or the valves are manufactured entirely or partly by using the mechanochromic and/or piezochromic and/or piezoluminescent and/or mechanoluminescent materials. As alternative embodiments, the mechanochromic and/or piezochromic and/or piezoluminescent and/or mechanoluminescent materials are adhered (glued) and/or coated and/or assembled (bonded/mounted) after the production process. In an alternative embodiment to provide the stability and durability and lower the costs, the use of the said materials (mechanochromic and/or piezochromic and/or piezoluminescent and/or mechanoluminescent materials) is limited to certain parts. They are placed in the specific sections of the said equipments. In an example, the said materials are located on the larger part (5) of the pilot balloon (1). In another example, the said materials are located on the proximal part (6) of the conduit (3). In another embodiment, the said materials are located on the distal part (7) of the valve (4) for the pilot balloon (1). It is possible to deploy the preferred parts differently for various situations. All settlements are in a position to display the main functions and are easily visible.

Piezochromic property means that color change is produced by applied pressure, mechanical strain, tension, stress. For the occurrence of the mechanochromic or piezochromic effect, the reflection spectrum and/or the emission spectrum and/or the reflection wavelength of the light on the material should be changed depending on the pressure. The occurrence of this effect in the visible light spectrum makes it possible to see it directly. In some materials, the color density is directly related to the amount of pressure applied. In some of the materials that produce or change color according to pressure, with the disappearance of the pressure, the color is lost or returned to its original state. This feature is defined as a reversible color change. Different methods, systems and materials are utilized for this color production and change. It is possible to utilize any material which is suitable to the conditions of the use (temperature, heat, humidity, etc.) and sensitive to the desired pressure range (minimum 5 cm H ₂ 0 - maximum 150 cm H ₂ 0) and isn’t harmful to the body and the environment. Some examples of the materials that can be used in our invention are given below. The materials and applications used in the scope of the determination of pressure based on color change or production in our system are not limited to these examples. Our system is suitable for the use of any material (natural or artificial) that produces and changes color instantly and reversibly according to the pressure, and is convenient for the methods wherein the said materials are used. In a preferred embodiment, piezochromic material is in a liquid crystal state. The most well-known materials suitable for adaptation in our system are those described as liquid crystals. When pressure is applied over, the change of alignment in the liquid crystals results in color change. Color reproduction or change in some liquid crystals is caused by compressible helix structure. Thus, the pitch length is changed by a decrease or increase in pressure. In our invention, various liquid crystal forms and their mixtures are used in order to achieve the piezochromic effect.

The term polymer includes homopolymer, copolymer and oligomer. Polymer can be made in various shapes such as fiber, membranes, gels, film by the different methods such as extrusion, coating, and molding. All these shapes are suitable for use in various arrangements of our system. These are the forms that are utilized for the functions to be reached within the scope of our system. Due to the conformation of the monomers forming the polymer chain and the positions of the bonds between them, rotation angles are formed. As a result, the polymer chain acts as a spring on nanoscale scale. The spring constant corresponds to the elastic modulus of the polymers. The integration of a cholesterol structure within a cross-linked polymer network with soft elastic properties provides the intended piezochromic behavior. In a good piezochromic material, the liquid crystal and chiral optically active substances are distributed in a matrix of a polymer or copolymer. As a similar application, piezochromic material is made up of a cholesteric mixture embedded in a cholesteric elastomer matrix that has mesogenic side chains with similar molecular structure. Various combinations of components such as poly [3-(l- dodecyl) thiophene-2, 5-diyl], poly (3-dodecylthiophene), cholesteryloleylcarbonate, cholesterylchloride and cholesterylnonanate have been used. Our invention is not limited to the components in these examples. Any suitable mixtures of the pressure-sensitive liquid crystal cholesterol esters and the other organic polymer materials may be utilized in our system.

As an alternative application, a piezochromic composite material is formed in which a layer of piezochromic material is embedded between two polymer films. In this embodiment, any suitable mixture of pressure-sensitive liquid crystal cholesterol esters can be used. There are many mixtures that differ in color and physical properties. The examples include a mixture of cholesteric liquid crystals such as cholesterol nonanoate, cholesteryl chloride, cholesteryl oleyl carbonate, cholesterol 2, 4-dichlorobenzoate. Forming the piezochromic composite materials by using a mixture of pressure sensitive liquid crystal cholesterol esters is planned and included in our system.

Polymers can undertake many new tasks due to the mesogenic structures that have photogenic, electronic and ionic functions. In some polymers, mesogenic units are formed by non-covalent interactions. On the other hand, some polymers show the liquid crystallinity by the nanosegregation of aromatic and aliphatic moieties. These configurations make piezochromic features more precise and comprehensive. Certain polymers can exhibit piezochromism themselves; the interaction of an embedded piezochromic additive results in a piezochromic effect. The interactions of the polymers with non-piezochromic additives also can have a piezochromic effect. Some examples for the substances which show changes in conformation or structural rearrangements depending to the pressure applications include crystals of toluene sulfonate diacetylene polymers and copolymers containing (diacetylene) or poly (silylates). In an alternative embodiment in the scope of our invention, the polymers themselves were transformed into piezochromic materials and these properties were utilized in our system. Taking into account the targeted pressure range and duration of use according to the clinical situation, some polymers and copolymers which show changes in conformation or structural rearrangements depending to the pressure applications are used in our innovation.

Combination of piezochromism with other chromogenic properties, especially thermochromic or thermotropic effects is planned and included in our system. For example, the pressure-indicating material may be a thermochromic material sensitive to temperature change. It is possible to obtain the temperature that activates this thermochromic material indirectly by transmitting it from another material which changes the temperature depending on the applied pressure. In this example, the piezochromic material is thermochromic and responds to the temperature increase resulting from the applied pressure. Any formulation containing thermocromic or thermotropic materials which provide the current health and safety requirements can be used in our system. These configurations also are planned to be utilized in our innovation.

In another embodiment, the pressure indicating material can be sensitive to a change in the electric current generated by a piezoelectric material. In this case, the pressure indicating material will show an optical response (for example; a color production or modification) within the pressure range formed. This pressure range is probably raised or lowered and is not affected by the temperature range that is routinely subjected to. These types of systems are composed of piezoelectric materials that can convert mechanical and electrical energy into one another. Some polymers such as polyvinylidene fluoride are piezoelectric. Today, one of the most commonly used piezoelectric materials is lead-zirconate-titanate. Any formulation containing piezoelectric materials which provide the current health and safety requirements can be used in our system. These configurations also are planned to be utilized in our innovation.

In other alternative embodiments, proximity dye based polymers are used. These pressure sensitive polymers are formed by taking advantage of the properties of some dye molecules that change color depending on their proximity to other dye molecules. In this design, the pressure or tension causes the dye molecules within the polymer to approach each other. This approach causes the emission properties of the dye molecules to change. This change appears as an optically distinct color. Proximity dye -based polymers have been used to determine the pressures are utilized in our system.

In another embodiment, plasmonic shift is used in relation to the movement of gold nanoparticle chains in polymer matrix as a result of plastic deformation. It is advantageous for the polymeric materials which contain colloidal nanoparticles to exhibit viscous flow depending on the intensity and duration of the pressure. The displacements in the distance between particles cause the alterations in the plasmon coupling resulting in color change. By modifying the elasticity of the polymer matrix (for example, by adding plasticizers) the viscosity/ flexibility is changed. Thus, plasmonic shift and colorimetric changes occur and the desired pressure sensitivity range is reached. The plasmon excitation can be widely tuned by arranging the multiple nanoparticles. In this context, the other plasmonic metals (silver, gold, platinum, copper, etc.) can be utilized. Properties of colloidal nanoparticles, interactions between particles and structural order provide wide range of use. They may also function in the polymer composite film for similar purposes. The applications of our system include also the plasmonic shift. The materials which use plasmonic changes for pressure-induced color change were also used in our innovation.

In an alternative embodiment as a piezochromic indicator, nanometer powders are utilized. It has been shown that some nanometer particles can undergo color change as their sizes change due to the fact that the particle dimensions are in the proximity or far small wavelengths of the visible rays. It has been discovered that the nanometer voids formed by the inorganic nanometer powder mixtures can cause the color changes at very low pressure range and their piezochromic sensitivity is better than the traditional polymeric materials. In addition, the piezochromic process is usually gradual and reversible. In our system, the nanometer powder mixtures that can form the nanometer voids are used for situations that need to be very sensitive.

In order to determine the pressure by the color changes, the materials called as mechanophores also are used in our system. Mechanophore is defined a component that exhibits a chemical or physical detectable structure change such as production or change of color when exposed to the pressure. They are generally mechanically sensitive chemical groups. When exposed to a certain force, special chemical reactions are triggered. As a result of this reaction, color production or change occurs. They usually have a ring structure chemically. When exposed to the stress or pressure, the ring opens and gives color. When the stress or pressure disappears, it usually closes again and the color returns to its former state. In order to make better use of the mechanophores in determining the pressure, a variety of applications are used to place them in the center of the polymer chains that have different characteristics. In order to provide the color production and change according to the pressure, the materials in which the polymer chains are used together with mechanophores are utilized in some embodiments of our system.

In its most common form, the mechanophores include molecules called spiropyran which can make distinct color changes when subjected to mechanical stress. The spiropyrans are generally colorless. When exposed to mechanical stress at certain levels, their colors change, for example, such as red or purple. The color and tone of the color changing structures can be altered by the materials which are transparent or different colors on the floor. The mechanophore may alternatively comprise an organic mechanochromic material that may be chosen from pyrans, oxazines, fulgides, fulgimides, diarylethenes, lactone dimers, imidazole dimers, and mixtures thereof. The mechanophores used in our system contain many organic mechanochromic molecules with similar properties.

Another method for taking advantage of mechanophores is the use of compositions containing mechanophores as the coating or undercoating materials. The mechanochromic coating compound is dispersed in the binding compound mentioned without chemical bonding. The binder compositions may be polyurethane, polyester or acrylic polymers. For similar purposes, it is possible to use mechanochromic dyes. In addition, similar features can be obtained in organic mechanochromic materials that can be polymerized, such as naphthoxazines. The use of the mechanophores in the primer coating or undercoating materials, or in the mechanochromic dyes, or in the the polymerizable organic mechanochromic materials is planned and included in our system.

In order to determine the pressure by the color changes, polarized materials are used in our system. In this application, the pieces of polarized material are placed such that their planes of polarization are at some angles (for example, 90°) to each other. Or, some polarizers are oriented parallel to each other. When these planes of polarizations and polarizers move due to the pressure, a color change occurs. These applications are also included in our innovation.

The piezochromism is also found in some solid inorganic materials. Depending on the pressure changes, the absorption and emission spectra are also changed in palladium and some other metal complexes (like nickel, platinum etc.). The feature of the piezochromism in solid inorganic materials is also used in our system.

It has been shown that the refractive index of some materials changes due to the pressure applied. One example of these materials is the aromatic solvents containing poly (N-methyl acrylamide). These materials also are utilized in our system. Leuco dyes are relatively easy to cover, print or participate in the main structure. They are applicable for pressure sensitive materials. In the scope of our invention, some leuco dyes (triphenylmethane, fluorane, phenothiazine, auramine etc.) also are utilized due to their ease of use in some alternative regulations.

In an alternative embodiment to determine the pressure by the color changes, the pilot balloon (1) or balloons, the conduit (3) or the conduits, the valve (4) or the valves are arranged by at least two distinct layers, and one of them is more flexible. At least one layer comprises optically contrasting pigment particles or crystals. At least one layer is transparent or different color. Upon compression or elongation of the layers, the density and/or the orientation of the pigment particles changes; this results in a reversible visible color production or change, given the optically contrasting property of the pigment particles. These structures function as a visual marker by designing specific colors according to certain pressures to produce or change them. Within the scope of the pressure detection, the formation of multiple layers with different elasticity and colors is used in our system

Luminescence is a general term used for electromagnetic radiation generated by the excitation of an atom or molecule by an external energy. Luminescent materials can absorb energy, store some of it, and convert it into light. The light emitted usually covers wavelengths in visible light zones. However, the other wavelengths such as infrared and ultraviolet can also be emitted. Mechanoluminescence is defined as the light emission resulting from any mechanical action on a solid. Piezoluminescence is considered to be a species of mechanoluminescence and defined as a type of luminescence formed by pressure upon certain solids. Some crystals and irradiated salts, such as NaCl, KC1, and KBr have been shown to exhibit piezoluminescence properties upon the application of pressures. It has also been discovered that ferroelectric polymers exhibit piezoluminescence upon the application of stress. In order to determine and monitor the pressures of the cuff (2), the pilot balloon (1) the conduit (3) and the valve (4) are formed by the utilizing the materials which generate the light according to the pressures (the mechanoluminescent and piezoluminescent materials). With this feature, the pressure in the cuff provides a striking and easily noticeable warning due to the light generated by the pressure at predetermined values depending on the patient's condition. In an alternative arrangement that allows the appearance of colors and lights produced from every angle (from all directions), the said piezochromic, mechanochromic, piezoluminescent and mechanoluminescent materials used in the pilot balloon (1) the conduit (3) and the valve (4) are dispersed in a matrix. This matrix is a binder that acts as a support for the chromic and luminescent materials. This matrix consists of a polymeric binder mixed with at least one solvent, a plasticizer and a dispersing agent. Such a matrix may be a polyurethane, acrylic, polysilane family, silicone, epoxy, polyamide, cellulosic system or any other polymeric system combining the specific features required for the said components of the endotracheal and tracheostomy tubes.

In another embodiment that makes them to be more robust and effective, the said piezochromic, mechanochromic, piezoluminescent and mechanoluminescent materials are used in combination or separately, in certain amounts, in the form of ink, dye, dye crystals, polymers, mechanophores, pigment or pigment crystals, or in combination with some substrates. These materials are also utilized in the shape of microencapsulated in certain sizes, films, coatings, disc, plate style, and are placed in the microcellular frameworks or in the polymeric structures. The features of the color changes and light productions according to the pressures are modified to provide quantitative and precise information in situations where it is necessary to be very sensitive. The shapes of the parts where the color changes and light productions according to the pressures occur are designed in a manner to indicate the numbers of pressure values (40, 30, 25, 20, 18, 15, 14, 5 etc. cm H ₂ 0) and/or sign, color, letter, emblem, or symbol that correspond to a certain pressure. Since these numbers are of clinical significance, they provide great convenience to health personnel. In a more improved embodiment to provide the detailed in formations, pluralities of piezochromic, mechanochromic, piezoluminescent and mechanoluminescent materials are used to provide multiple stimuli sensitive to multiple thresholds.

To observe easily the color change and light production, different colors such as white, orange, yellow, blue, purple, red, green, or combinations or tones of these colors are provided in the system. When the pressure drops below normal, these colors change. When the pressure is normal, they return to the original colors. In addition, they can get also a different color, when the pressure rises above normal.

According to the condition of the patient (blood pressure, hydration, etc.), the type of disease, the intervention and treatment (such as medications), sometimes the pressure rise in the cuff is more risky, sometimes the pressure drop is more dangerous. For the conditions where the high pressure is a greater risk, our system is designed so that the color will be lost at low pressure and some colors are formed at high pressure. When low pressure is a greater risk, color will be lost at high pressure and some colors are formed at low pressure. Sometimes the patient's condition, illness, and the type of intervention and treatment require a large number of data to be monitored. To be advantageous in these cases, the color will be lost at normal limits and some colors are formed at abnormal pressures. In some cases, our system is designed so that the color will be lost at abnormal pressures and some colors are formed at normal pressures.

The features of the color change and color or light production according to the pressure can be used together and functions comparably when gases and liquids apart from air are used to inflate the cuffs. In addition, when our system displays a warning, it allows it to be confirmed and used with other systems. All novelties that are presented in this reference and mentioned above can be applied or adapted to all tubes (single, double, multiple, grooved, corrugated, non-adhesive, water- swellable, accordion, curved, etc.) that are used on humans and all similar cuff types, and in addition, all tubes that have aspiration (suction) or monitorization equipments, the tubes that are spiral, ringed, double-lumen and the like, the tubes that allow to administer medications, and the tubes that are used in veterinary medicine individually or in combination. In addition, they are also sterilizable, washable, and reusable as well as being disposable.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the inventions will become apparent to persons skilled in the art upon the reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.

Method of application of the invention to industry; all components that we have explained under the heading ‘Safe endotracheal and tracheostomy tube’ are suitable for serial manufacturing.