BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to a system and related assembly for inflating and electronically monitoring pressure within a retaining or pressure cuff such as, but not limited to, the type used to effectively maintain the position of an endotracheal tube within the trachea. In addition to the inflating structure of the assembly, control circuitry is cooperatively structured with other operative components of the assembly to include multilevel sampling capabilities dependent, at least in part, on a time basis and a pressure stability within the retaining cuff. The assembly may also be structured for single or limited use monitoring sessions and preferably includes a self-contained power source.

DESCRIPTION OF THE RELATED ART

The use of endotracheal tubes is well known in the medical profession. In practice, the tube is inserted through the mouth, nose or tracheotomy of the patient into the trachea and is structured, when properly positioned, to facilitate ventilation from a ventilator or the like.

As conventionally used, the endotracheal tube and/or tracheostomy tube includes a coupling structure at the proximal or outer end thereof which connects the lumen of the endotracheal and/or tracheostomy tube to the source of ventilation. The endotracheal and/or tracheostomy tube commonly includes an inflatable, pressure or retaining cuff which is generally disposed in surrounding relation to the distal end of the tube. In use, the cuff is inflated and thereby serves to secure or stabilize the position of the tube as it expands radially outward into confronting relation to the walls of the trachea. As a result, the inflated cuff serves to stabilize the position of the endotracheal tube and also establishes a seal within the trachea. As conventionally structured, a conduit is associated with the endotracheal tube and includes an interior lumen used to inflate the cuff when the endotracheal tube is properly positioned within the trachea. Dependent on the structure and use of the endotracheal tube, the inflating line or conduit may be integrally formed on or within the primary wall of the tube itself. As such, the cuff is manually inflated by an appropriate inflation assembly such as, but not limited to, a separate, removable syringe connected in fluid communication with the outlet lumen. Moreover, the cuff is inflated to a pressure which accomplishes the above noted seal with the interior of the trachea, as well as effect the aforementioned stabilization of the endotracheal and/or tracheostomy tube.

The importance of under inflation, over inflation and/or excessive pressurization of the retaining cuff is well recognized, due to the potential of resulting injury and/or trauma to the patient. Accordingly, when the pressure within the cuff is too low, the sealing function thereof cannot be fully achieved resulting in possible leakage of saliva, air, etc. into the trachea. However, an over pressurization of the cuff may result in reduced blood flow to tracheal tissue, tracheal ischemic conditions, and cause ulcers, bleeding and tracheal stenosis or tracheomalacia after removal of the tube, which can lead to the need for tracheal repair surgery or even a tracheal transplant. Accordingly, it is important to maintain the inner pressure of the cuff, depended on its structure and design, within predetermined ranges in order to affect both the above noted fluid seal with the trachea as well as stabilization of the endotracheal tube within the trachea.

Known attempts to overcome problems of the type set forth above have resulted in the provision of various types of pressure gauges or other pressure monitoring devices connected in fluid communication with the outlet lumen and with the pressure or retaining cuff itself. However, many of these known or conventional attempts to accurately monitor cuff pressure have resulted in less than accurate or satisfactory results. Accordingly, while known monitoring devices may be at least minimally effective for their intended function, they have been found to be relatively bulky, cumbersome, costly, and/or less than efficient. Indeed, because of these factors, monitoring devices are often not available at the bed side and ET cuff pressure monitoring is often inadequately addressed, both initially as well as after the patient is intubated.

Moreover, even if a one time, initial pressure identification is achieved, such is inadequate because the pressure can change over time, such as when the patient is moved or the endotracheal tube is repositioned, or when ventilation settings are adjusted. As a result, there is a need in the medical profession for an assembly structured to properly inflate and adequately monitor the pressure within a retaining or pressure cuff of an endotracheal and/or tracheostomy tube. Further, the inflating and monitoring functions of a proposed monitoring assembly should preferably be carried out by a single unit which may be incorporated within the endotracheal tube assembly or alternatively may be connected thereto. As such, the monitoring of the pressure within the retaining cuff should be effectively accomplished by a mere visual observation of the preferred assembly, without requiring repeated attachment and removal of a pressure monitor and/or inflating device. In addition, such a preferred monitoring and inflating assembly should be easily operable, and in certain preferred embodiments may be structured to be used as a single use device, which is not integrated into the endotracheal tube, but readily connectable to an inflation lumen of the tube and subsequently detachable there from, but further wherein reconnection of the monitoring assembly is prevented so that reuse of the device is prevented to avoid cross-contamination of infection from patient to patient.

Further, in addition to its applicability within the pressure or retaining cuff associated with an endotracheal tube, it is also recognized that such a structure would be highly beneficial for use within a variety of different medical devices, including the pressure or retaining cuffs, often referred to as balloons or bladders, used in balloon kyphoplasty, balloon sinuplasty, coronary or vascular balloon angioplasty and/or the delivery of stents, balloon esophageal dilation, and the dilation of strictures and sphincters, balloon dilatation of the nephrostomytract, and/or Swan Ganz catheters, among other medical devices.

SUMMARY OF THE INVENTION

The present invention is directed to a system and an attendant assembly for inflating a retaining cuff to an intended and/or predetermined pressure and monitoring the pressure thereof, once inflated. As used herein, the term “retaining cuff” is meant to primarily include a pressure or retaining cuff for an endotracheal tube. However, the system and assembly of the present invention may be used with a variety of pressure or retaining cuffs structured for use in different medical procedures or instrumentation.

In more specific terms, the system and assembly of the present invention includes a housing having an interior pressure chamber and an inlet and an outlet disposed in direct fluid communication with the pressure chamber. The inlet is structured for connection to a fluid pressure source such as, but not limited to, a syringe-like structure including a plunger and a delivery nozzle or portion which may comprise a male lure connector. When so structured, the male lure connector should be dimensioned and configured to be inserted in the inlet of the pressure chamber. The outlet of the pressure chamber is structured for connection with a fluid communicating connection with the retaining cuff by virtue of a conduit, outlet lumen, pilot balloon, etc., connected to the retaining cuff.

Control circuitry is connected to or defines at least a part of the housing and includes a micro processor, a pressure sensor, as well as other operative components associated with the intended features of the monitoring function of the present invention. The pressure sensor is preferably in the form of a sensor module and the pressure sensor or sensor module is disposed in fluid communication with the pressure chamber. As such, the sensor module and the cooperative components of the control circuitry are cooperatively structured to determine and monitor pressure within the pressure chamber. Further, due to the aforementioned fluid communicating connection between the pressure chamber and the retaining cuff, the pressure within the pressure chamber is substantially the same as that within the retaining cuff. As a result, the determination and/or monitoring, by the sensor module, of the pressure within the pressure chamber will result in a determination, monitoring and indication of the same pressure within the retaining cuff.

Yet additional structural and operational features of the system and assembly of the present invention include the control circuitry comprising sufficient memory or memory capabilities to facilitate it storing calibration values or “calibration parameters”. More specifically, the assembly of the present invention is self-calibrating and the corresponding calibration values will be stored in the non-volatile memory and then be placed in a “no-power state”. Accordingly, the assembly is shipped from the factory with no power applied to the control circuitry. The control circuitry remains in this “no-powered” mode until the monitoring assembly of the present invention is first activated. Upon a first or initial activation electrical energy, such as from a self-contained power source, is directed to the control circuitry, microprocessor, etc. to facilitate the first or initial activation. Immediately subsequent to the initial or first activation and from that point on, the control circuitry or more specifically the microprocessor, pressure sensor or sensor module and possibly other operative components associated therewith, will be either in a “sleep mode” or “sensor power mode”.

In addition, when in the sleep mode certain “low power” components operatively associated with control circuitry including, but not limited to the display device may draw relatively small amounts of current until fully activated. However, the pressure sensor or sensor module draws a relatively greater amount of current and as such will be maintained in a “power-off” mode when not activated, such as when the pressure is not being monitored. As a result of the above, the operable life of the self-contained power source or battery is extended.

The aforementioned calibration parameters will be directly associated with and/or at least partially dependent on intended utilization of the system and assembly; the length of an intended monitoring session; cooperative structuring and operation of the various components and/or other operative features of the system and assembly. However, all of the aforementioned calibration parameters or values needed for the accurate determination and display of pressure readings and/or determination and maintenance of pressure values of the retaining cuff and pressure chamber, will be stored prior to a first use or first activation of the assembly. More specifically, when the assembly is being structured, assembled and/or programmed for use and prior to its initial use or activation, all of the calibration parameters and data are stored into the non-volatile memory of the control circuitry.

Further, the memory is structured to store and/or maintain the calibration parameters, wherein the control circuitry is then placed in the aforementioned in the “no-powered mode”, as set forth above, during shipment and prior to its first or initial activation. Moreover, upon an initial or first activation when the assembly is ready for use, the calibration parameters relating to the intended monitoring capabilities of the monitoring assembly will be implemented. Accordingly, there is no need to calibrate the control circuitry and/or other operative components of the assembly after it has been initially activated for its first use in a monitoring session.

The housing of the inflating and monitoring assembly may also include the aforementioned display device preferably, but not necessarily, in the form of a display screen having “touch activation” features operative to selectively activate and control operation of the display device and in certain embodiments activation of other components of the monitoring assembly. In use, the display device will provide a visual indication of the pressure values or pressure readings of the retaining cuff. As further noted, the display device is operative on a very “low power” basis and as such may draw a small amount of current when it and the microprocessor, associated with the control circuitry, are in the “sleep mode” after a first or initial activation of the monitoring assembly. It is again emphasized that before the initial or first activation or use of the monitoring assembly, the operative components, including the control circuitry, are in the aforementioned “no-powered mode”, in that no power is applied to the control circuitry during assembly or shipping.

In at least one embodiment, cooperative structuring between the display device and control circuitry facilitates the powering-up of the microprocessor upon a selective activation of the display device, such as by utilizing the aforementioned touch activation of the display device. In contrast, even when not performing a monitoring, reading or display of a pressure value of the retaining cuff, the display device will normally remain in an active state even when the microprocessor and the pressure sensor or sensor module are in the sleep mode. This is due in part to the fact that the display device operates on extremely low power. Accordingly, the difference between the “sleep mode” and the “sensor power mode” is that the pressure sensor and the microprocessor are running and active during the “sensor power mode”. In contrast, when in the “sleep mode” the pressure sensor or sensor module and the microprocessor are virtually powered off, at least to the extent that only a few exceptionally low power functions are operable.

Other operative features associated with one or more preferred embodiments of the present invention are also directly associated with the conservation of power in order to extend the operable life of the self-contained power source. Accordingly, the control circuitry and microprocessor are operatively structured with the sensor module to include “multilevel sampling capabilities” which is effective to accomplish power modulation to the pressure sensor or sensor module. More specifically, the multilevel sampling capabilities comprise a sampling or monitoring of the pressure of the retaining cuff at different rates or frequencies. Therefore, the multilevel sampling capabilities include at least a high rate sampling mode and a low rate sampling mode. Further, the high rate sampling mode includes a sampling frequency sufficient to determine substantially real-time pressure values of the retaining cuff and may occur at multiple times per second such as, but not limited to, 4 times per second. In contrast, the low rate sampling mode comprises a sampling frequency of generally about once every 1-2 seconds. Therefore, power to and consumed by the pressure sensor or sensor module varies, so as to conserve energy of the self-contained power source or battery associated with the monitoring assembly. As such, during the high rate sampling mode, the pressure sensor will maintained in the “sensor power mode” a sufficient amount of time to obtain pressure readings at the higher sampling rate. Therefore, more power will be consumed by the pressure sensor during this high rate sampling mode. In contrast, the pressure sensor will be allowed to assume the “sleep mode” and thereby consume less energy during the low rate sampling mode. This is due, as set forth above, to the fact that the sensor module may be activated only about once every 1-2 seconds, rather than multiple times per second as is the case during the high rate sampling mode. It is therefore again emphasized that the variation in sampling rates, as well as the overall capability of placing the microprocessor and the pressure sensor in either the “sleep mode” or “sensor power mode” serves to effectively save energy delivered by the self-contained power source.

In addition, the multilevel sampling capabilities include dynamic operating characteristics comprising automatic changes of sampling rates or frequencies, dependent at least in part on a “time basis” as well as the pressure stability of the retaining cuff. Accordingly, when the pressure within the retaining cuff remains substantially stable over a period of time, for example two minutes, the dynamic operating characteristics of the multilevel sampling capabilities will automatically change the frequency of sampling from the high rate sampling mode to the low rate sampling mode. In addition, the sampling rate or sampling frequency will automatically be changed back from the low rate sampling mode to the high rate sampling mode upon the determination of an actual change in the pressure or retaining cuff or the occurrence of one or more predetermined external events.

As also described in greater detail hereinafter, the occurrence of a predetermined external event may also cause the dynamic operating characteristics to automatically change the sampling rate or frequency from the low rate sampling mode to the high rate sampling mode when any event occurs which would appear to affect the pressure within the retaining cuff. By way of example only, a manual adjustment or inadvertent manipulation of the fluid communicating connection of the retaining cuff with the outlet of the pressure chamber may be interpreted by the control circuitry as an attempt to remove the retaining cuff from its intended fluid communication with the pressure chamber. In order to assure a real-time evaluation of the pressure within the retaining cuff during an external event, the high rate sampling mode will be established in order to accurately determine the pressure of the retaining cuff. However, the external event such as, purposefully or inadvertently, manipulating the fluid communicating connection may in fact not result in a reduction of the pressure within the retaining cuff.

Yet additional features of one or more preferred embodiments of the system and assembly include “limited use capabilities” comprising structuring the control circuitry for permanent deactivation after use. Moreover, the limited use capabilities may comprise operative features which allow the assembly to be a single use device or alternatively capable of being used for a limited or predetermined number of monitoring sessions. In accordance therewith, a switching assembly may be connected to the housing and directly associated with the outlet of the pressure chamber. When so disposed or otherwise operatively positioned, the switching assembly is structured to deactivate the control circuitry upon the removal of the aforementioned fluid communicating connection from the outlet. The switching assembly may also be structured to activate the control circuitry upon the introduction or establishment of the fluid communicating connection with the outlet. This initial activation may occur when the retaining cuff is initially connected in fluid communication with the interior of the pressure chamber by virtue of the outlet. As set forth above, the control circuitry may normally or initially be disposed in a sleep mode and will not be activated. However additional structural and operative features associated with the switching assembly may include an automatic activation of the control circuitry upon establishment of the fluid communicating connection of the retaining cuff with the outlet.

As set forth above, one or more embodiments of the assembly may include the aforementioned limited use capabilities. As a result the removal of the fluid communicating connection of the retaining cuff with the pressure chamber, through the outlet, may in turn result in the assembly being incapable of being used after such removal. However, in order to overcome any inadvertent manipulation, handling or external event which would be perceived by the control circuitry as an attempt to disconnect the fluid communicating connection, the control circuitry includes a “time delay facility”. The time delay facility is operatively connected to the control circuitry. The time delay facility is structured to delay deactivation of the control circuitry for a predetermined time period upon an at least partially disconnection of the fluid communicating connection. Therefore, any inadvertent contact or manipulation with the fluid communicating connection which would be interpreted by the control circuitry as an attempt to disconnect the fluid communicating connection will not, at least for a period of time, result in the prevention of utilizing the repeated use of the monitoring assembly. Such predetermined time period associated with the time delay facility may be as little as a few seconds or as long as one or more minutes, before the remainder of the monitoring assembly is rendered inoperable and incapable of a repeated use. This time delay will allow a user to reconnect the fluid communicating connection or make other adjustments which will prevent the control circuitry from becoming inoperable.

These and other objects, features and advantages of the present invention will become clearer when the drawings as well as the detailed description are taken into consideration.

