Patent Application
20110213264
The present disclosure relates generally to medical devices and, more particularly, to airway devices, such as tracheal tubes.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Tracheal tubes are often placed in the airway of a patient in medical situations that necessitate protection of the airway from possible obstruction or occlusion. For instance, tracheal tubes may be used in emergency situations, such as when a patient experiences cardiac or respiratory arrest. The underlying condition that necessitates intubation of the patient may also cause a drop in aortic pressure, leading to low blood flow to non-critical organs, such as the respiratory tract, to compensate for an increased need for blood flow to critical organs, such as the brain. A decrease in blood flow to the respiratory tract may be detected by assessing the level of blood gases and/or blood analytes present in the tracheal mucosa.
Some traditional systems measure the level of blood gases and/or blood analytes in the respiratory tract by introducing a sensor into the trachea and contacting the tracheal mucosa. However, critically ill patients are already intubated with a tracheal tube, and an introduction of an additional sensing device can be uncomfortable and burdensome.
Accordingly, systems that deploy the sensor from the tracheal tube already in place in the respiratory tract have been developed. However, such systems often fall short of expectations since they may compromise one or more of the functions of the tracheal tube. For example, some traditional systems may compromise the sealing properties of the cuff coupled to the tracheal tube. Accordingly, there exists a need for improved systems that measure blood gases and/or blood analytes in the respiratory tract without interrupting the proper functioning of the tracheal tube.
Advantages of the disclosed techniques may become apparent upon reading the following detailed description and upon reference to the drawings in which:
One or more specific embodiments of the present techniques will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
As described in detail below, embodiments of an endotracheal tube (ETT) having a sensor disposed on a non-sealing portion of a cuff are provided. The ETT may include a lumen in which one or more support cables may be positioned to facilitate a bidirectional exchange of data, power, and so forth between the sensor and an external support system. The tracheal tube may be disposable rather than reusable, capable of sensing one or more indicators of blood flow characteristics, capable of conveying gas to and from a patient, and capable of deploying one or more sensors during intubation. During use, the sensor on the cuff may be configured to deploy upon inflation of the cuff and adapted to return to its predeployment position upon deflation of the cuff. Furthermore, when deployed, the sensor may be adapted to abut the tracheal mucosa of a patient or not contact the tracheal wall at all. Nevertheless, the sensor is configured to measure a presence or amount of at least one blood gas and/or blood analyte, such as carbon dioxide, oxygen, or pH, in the trachea during deployment. In this way, embodiments of the disclosed ETT may be used to indirectly monitor the cardiac state of a patient by monitoring the level of blood gases and/or blood analytes in the respiratory tract. That is, measurements of such gas and analyte levels in the trachea may be used to determine parameters relating to cardiac output, such as blood flow, and may provide insight into possible cardiac pathologies, such as perfusion failure.
The devices and techniques provided herein may enable the ability to sense blood gases and or blood analyte levels while maximizing the sealing capabilities of the cuff because the sensor is associated with the non-sealing portion of the cuff. That is, while the sensor may be disposed on or coupled to the cuff, the placement of the sensor is such that deployment of the sensor does not affect the seal between the cuff and the tracheal wall. For example, in certain embodiments, the cuff may be a tapered cuff, and the sensor may be located on the tapered portion of the cuff, which is not adapted to seal against the tracheal wall. The tapered portion of the cuff may be located toward the proximal or distal end of the tracheal tube, and the sensor may be appropriately positioned so as not to interfere with the seal between the cuff and the trachea. In additional embodiments, the tracheal tube may include a sealing cuff and a deployment cuff, and the sensor may be coupled to the deployment cuff. The foregoing features may have the effect of maintaining the functionalities of traditional tracheal tubes (e.g., providing an unobstructed airway path) while endowing the tracheal tubes with new functionalities (e.g., measuring blood gases and/or blood analytes).
It should be noted that the provided tracheal tubes and methods of operating the tracheal tubes may be used in conjunction with auxiliary devices, such as airway accessories, ventilators, humidifiers, and so forth, which may cooperate with the tracheal tubes to maintain airflow to the lungs of the patient. For instance, the tracheal tubes may be placed in the trachea and coupled to a ventilator to protect the airway from possible obstruction or occlusion in emergency situations, such as when a patient experiences cardiac or respiratory arrest, For further example, the tracheal tubes may be coupled to an interface circuit and/or a monitor that is configured to receive data from the sensor, process such data, and display the processed data to an end user (e.g., medical technician, doctor, nurse, etc.).
Furthermore, although the embodiments of the present invention illustrated and described herein are discussed in the context of endotracheal tubes, it should be noted that presently contemplated embodiments may include a sensor located on a non-sealing portion of the cuff associated with any of a variety of suitable airway devices. For example, the sensor may be coupled to the non-sealing portion of a cuff associated with a tracheostomy tube, a Broncho-Cath™ tube, a specialty tube, or any other airway device with a cuff. Indeed, any device with a cuff designed for use in an airway of a patient may include a sensor disposed on the non-sealing portion of the cuff. Furthermore, as used herein, the term “tracheal tube” may include an endotracheal tube, a tracheostomy tube, a Broncho-Cath™ tube, a specialty tube, or any other airway device.
Turning now to the drawings,
As illustrated, a tapered cuff 24 configured to be inflated to seal against the walls of a body cavity (e.g., the trachea) may be attached near the distal end 16 of the tubular body 12, or along the body. The cuff 24 may be inflated via an inflation lumen 26 terminating in an inflation tube 28 connected to a fixture 30 located at the proximal end 14 of the tubular body 12. A first shoulder 32 of the tapered cuff 24 secures a non-tapered end 34 of the cuff 24 to the tubular body 12. Likewise, a second shoulder 36 of the cuff 24 attaches a tapered end 38 of the cuff 24 to the tubular body 12, In some embodiments, the first shoulder 32 and/or the second shoulder 36 may be folded up inside the cuff 24.
The tubular body 12 and the cuff 24 may be formed from materials having desirable mechanical properties (e.g., puncture resistance, pin hole resistance, tensile strength, and so forth) and desirable chemical properties (e.g., biocompatibility). In one embodiment, the walls of the cuff 24 may be made of a polyurethane (e.g., Dow Pellethane® 2363-80A) having suitable mechanical and chemical properties. In other embodiments, the walls of the cuff 24 may be made of a suitable polyvinyl chloride (PVC). In certain embodiments, the cuff 24 may be generally sized and shaped as a high volume, low pressure cuff that may be designed to be inflated to pressures between about 15 cm and 30 cm of water.
A sensor 40 is disposed on a non-sealing portion of the cuff 24. That is, the sensor may be located anywhere on the cuff 24 that is not configured to provide the seal desired between the body of the tube and the body tissues (e.g., directly contact the body cavity, such as the tracheal wall), during inflation of the cuff 24. For instance, in one embodiment, the sensor may be positioned at the tapered end 38 of the cuff as shown in
In the embodiment illustrated in
In further embodiments, such as in the embodiment of
While in the embodiments of
Furthermore, although the illustrated embodiments show a tapered cuff, further embodiments may feature one or more sensors located on a non-sealing portion of a non-tapered cuff in accordance with aspects of the present invention. In the presently contemplated embodiments, the sensor may contact the tracheal mucosa directly to obtain a blood gas or blood analyte measurement or may obtain the measurement via equilibration with gases or analytes located in the tracheal cavity adjacent the mucosa and/or the tracheal wall tissue. Accordingly, the sensor may be any suitable carbon dioxide, oxygen, pH, or other gas or analyte sensor, such as an electrochemical sensor, a fluorometric sensor, or a mid-infrared sensor. Furthermore, the sensor may be configured to simultaneously or sequentially measure more than one gas or analyte level.
As before, the dedicated lumen 42 and conduit 44 may couple one or more devices or systems to the sensor 40 during intubation. That is, the sensor 40 and dedicated lumen 42 may be positioned within the trachea 50 of the patient 46 during intubation while the conduit 44 may be externally located. In the illustrated embodiment, the external conduit 44 is communicatively coupled to an interface circuit 54 that is configured to receive and process measurement data acquired by the sensor 40. The interface circuit 54 is coupled to a power supply 56 that provides power for the sensor 40 and any electronics associated with the sensor 40. The interface circuit 54 may also facilitate the transfer of power to the sensor 40 in some embodiments. The power supply 56 is further coupled to a monitor 58 that is adapted to interpret and display the measurements received from the sensor 40 via the interface circuit 54. To that end, the monitor 58 may include a memory, a display, code configured to provide a specific output, and so forth. For example, the monitor 58 may include software adapted to integrate measurements taken at preset intervals over a predetermined period of time and/or to average or otherwise process measurements taken from multiple positions within the trachea 50. The monitor 58 may be connected to a ventilator 60 that supplies air to the patient 46 through connector 18.
Still further, in other embodiments, the sensor 40 may be adapted to unidirectionally or bidirectionally communicate with one or more external devices via wireless communication. That is, in some embodiments, the sensor 40 may not be coupled to the external devices via the conductors. In such embodiments, the sensor 40 may wirelessly communicate with devices such as a monitor, ventilator, mobile phone, PDA, or central communications point. Further embodiments may feature a single conductor that couples the sensor 40 to the power supply 56, while data communication occurs via a wireless route.
A recess 74 is located in the tubular body 12 between the first shoulder 32 and the fourth shoulder 72. The recess 74 is configured to receive a sensor 76 that is shown in a deployed position in
It should be noted that in further embodiments, the sensor 76 may be coupled to the tubular body 12 at the first shoulder 32 and adapted to rotate into sensing position against the non-tapered end 34 of the cuff 24. In this embodiment, the sensor 76 deploys to a vertical position against the cuff 24 such that the sealing function of the cuff 24 is not compromised by measurement acquisition. In this embodiment, the cuff 64 may still be coupled to the tubular body 12 to create a cavity between cuff 24 and cuff 64 and/or to facilitate sensor alignment when deployed. Still further, in embodiments in which the sensor 76 is coupled to the shoulder 32 and the cuff 24, the second cuff 64 may be eliminated.
As before, the sensor 76 is connected to the dedicated lumen 42 terminating in the conduit 44 and support cables may be positioned in the lumen 42 to facilitate bidirectional communication between the sensor 76 and an externally located support system. The external conduit 44 communicatively couples the interface circuit 54 to the sensor 76. The interface circuit 54 in turn couples the power supply 56 with the sensor 40, In this way, the interface circuit 54 facilitates the transfer of power and data to and from the sensor 76. The power supply 56 is also coupled to the monitor 58 that is adapted to interpret and display the measurements received from the sensor 76 via the interface circuit 54. The monitor 58 is connected to the ventilator 60 that supplies air to the patient 46 through the connector 18.
While the disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the embodiments provided herein are not intended to be limited to the particular forms disclosed. Rather, the various embodiments may cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims.
