Surgery – Respiratory method or device – Means for protecting user from pressure wave or flame...
Reexamination Certificate
2000-12-08
2002-05-07
Lewis, Aaron J. (Department: 3761)
Surgery
Respiratory method or device
Means for protecting user from pressure wave or flame...
C128S207140, C128S207150, C128S202220
Reexamination Certificate
active
06382207
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device for preventing ignition of an endotracheal tube during laser surgery. More particularly, the present invention involves detection of impingement of the laser on the endotracheal tube, and communication between the endotracheal tube and the laser in order to modulate the intensity of the laser beam impinging the endotracheal tube, and prevent ignition of the endotracheal tube.
BACKGROUND OF THE INVENTION
An endotracheal tube is a tube within or passing through the trachea which opens an unobstructed airway for a patient to breathe. These tubes have numerous applications in surgical procedures, particularly in surgical procedures of the ears, nose or throat of a patient. Recently, medical advances have included the use of laser beams in surgical procedures. However, in surgical procedures of the throat, close proximity exists between the area of the patient being operated upon and the endotracheal tube. Hence, when lasers are used in such procedures, there is a real possibility of accidental impingement of the endotracheal tube with the laser beam and ignition of the endotracheal tube. Such accidental ignition can cause substantial injury to the patient. As a result, efforts have been made to minimize the potential of igniting the endotracheal tube during laser surgery.
On such effort involves providing a fire suppression and prevention assembly to the endotracheal tube, wherein the tube is surrounded by a flexible sheath that can be inflated with a non-inflammable fluid. Consequently, if the sheath is accidentally impinged with laser radiation, the airway carrying gases to the patient, e.g., oxygen, is protected and the non-inflammable fluid helps extinguish any fires before they can injure the patient. However, such a method possesses inherent limitations. In particular, the volume of the throat is extremely small. Thus, a sheath surrounding the endotracheal tube may well take up valuable space within the throat and obstruct the medical provider's view of the area of the throat upon which is being operated.
Another method for minimizing the possibility of igniting the endotracheal tube involves a device wherein the endotracheal tube is surrounded with an airtight flexible metal tube, which is resistant to laser radiation. Such a device may also comprise an upper fluid-inflatable polymeric cuff and a lower inflatable polymeric cuff, which are inflated with a fluid (liquid) that is passed through a conduit which passes through the tube, so that the upper and lower cuffs are in fluid communication. As a result, the metal tubing protects the gas being passed to the patient from the laser, and the upper cuff protects the lower cuff from the laser beam. However, this type of a device suffers from drawbacks similar to those set forth above, i.e., it takes up a large volume in the patient's throat obstructing the medical provider's view, and constrains the flexibility of the endotracheal tube.
Other methods of ameliorating the possibility of ignition of the endotracheal tube include wrapping the tube in laser beam resistant material, or in a metal foil, which reflects any stray laser radiation from the endotracheal tube. The tube can also be wrapped with a material having pores of a diameter or thickness ranging from ⅕ to ⅓ of the wavelength of a laser beam used in a laser surgical procedure. However, such methods suffer from inherent limitations. For example, they limit the flexibility of the endotracheal tube. Also, these wrappings can dislodge or unwrap from the tube during surgery, leaving the endotracheal tube exposed for possible impingement by the laser beam. Another problem with such methods, particularly the metal foil wrappings, is that laser radiation reflected from the endotracheal tube can readily strike areas of the throat, injuring the patient.
Accordingly, what is needed is a new and useful device and method for preventing ignition of an endotracheal tube, wherein the device senses the impingement of laser radiation on the endotracheal tube, and then modulates the intensity of the laser radiation, preventing ignition of the endotracheal tube.
The citation of any reference herein should not be construed as an admission that such reference is available as “Prior Art” to the instant application.
SUMMARY OF THE INVENTION
There is provided, in accordance with the present invention, a new, useful, and unobvious device for preventing ignition of an endotracheal tube during laser surgery. Such a device grants the medical provider an unobstructed view of the patient's throat and modulates the intensity of laser radiation entering the patient's throat after the laser radiation has been detected impinging the endotracheal tube.
Broadly, the present invention extends to a device for preventing ignition of an endotracheal tube during laser surgery, wherein the device comprises a sensor which is associated with the endotracheal tube, which senses impingement of a laser beam onto the endotracheal tube. A device of the invention also comprises a controller which modulates the intensity of the laser beam, wherein the controller and the sensor are in communication. When the sensor senses impingement of the laser beam on the endotracheal tube, the sensor instructs the controller to modulate the intensity of the beam impinging the endotracheal tube, which prevents ignition of the endotracheal tube. In a particular embodiment, the controller impedes the laser beam.
Numerous sensors have applications in a device of the present invention. For example, a sensor of a device of the invention can comprise a wire associated with the endotracheal tube, wherein the wire is electrically connected to a power source and a microprocessor. The microprocessor is also electrically connected to the controller. The power source can produce either direct current (DC) or alternating current (AC). When an electrical parameter of the wire, e.g, resistance, voltage, current, capacitance, impedance, etc., changes due to impingement of the laser beam onto the wire, the microprocessor measures the change in the electrical parameter, and communicates that change to the controller. The controller in turn modulates the intensity of the laser beam based upon this change in the electrical parameter.
For example, in situations where the power source is supplying direct current (DC) to the sensor, the sensor can comprise a wheatstone bridge electrically connected to a wire that is associated with the endotracheal tube, wherein the wire is also electrically connected to the power source. An electrical parameter of the wire changes when the wire is impinged with the laser beam. The association of the wire can include locating the wire on the outer surface of the tube, within the lumen of the tube, within the material that forms the tube, and/or wrapping the wire around the outer surface of the tube, wherein the wire is electrically connected to the power source. The sensor can also comprise a microprocessor that is electrically connected to the wheatstone bridge and the controller. When an electrical parameter of the wire is modulated due to impingement of the laser beam on the wire, the microprocessor measures this modulation and instructs the controller modulate the intensity of the laser beam impinging the endotracheal tube. As a result, ignition of the endotracheal tube is prevented. The electrical parameter of the wire can be voltage, resistance, current, etc. One of ordinary skill in the art can readily program the microprocessor to measure a modulation in any of these parameters using routine programming techniques.
Naturally, numerous materials can be used in a wire of a device as described above. Particular examples of such materials include, but certainly are not limited to Nichrome, a composition of 80% Ni, and 20% Cr by weight, and a resistivity of 108X
10
8
ohm*meter.
Likewise, a large variety of lasers have applications with a device of the invention, including CO
2
and excimer lasers, to name only a few
Barbetta Joseph
Giuffre Kenneth
Gibbons Del Deo Dolan Griffinger & Vecchione
Hackensack University Medical Center
Lewis Aaron J.
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