Abstract: A bite block for an endotrachial tube includes a hollow body extending between open ends to receive an endotrachial tube such that opposing ends of the tube protrude through the open ends of the bite block. The bite block includes a tether to retain the bite block to the tube to prevent unwanted separation or movement of the tube within the bite block. The tether consists of a flexible arm which protrudes rearwardly from the bite block towards the inlet end of the tube and terminates in a ring configured to encircle the endotrachial tube, thereby effectively tethering the bite block to the tube. The arm and ring are configured such that the arm flexes in an arc when tethering the tube, thereby permitting the ring to engage the tube when fitted to thereto.

Abstract: A cleaning apparatus including an elongate tubular member utilized by extending into an endotracheal tube. A cleaning assembly provided at a distal end of the elongate tubular member radially expands to engage the interior wall of the endotracheal tube, for cleaning thereof by an outer periphery, achieving an effective cleaning engagement. A fluid impervious bladder portion provides an effective seal preventing fluid seepage during cleaning withdrawal. Further, a ventilator coupling connects to the endotracheal tube, a first inlet port couples to a ventilator assembly to supply air to a patient, and a second inlet port receives the elongate tubular member there through into the endotracheal tube. Also, a bypass coupling assembly connects between the channel of the elongate tubular member and the ventilator assembly directing air into the channel of the elongate tubular member and out the distal end upon occlusion of airflow.

Abstract: The present disclosure describes systems and methods that utilize a tracheal tube adaptor system. The tracheal tube adaptor system includes a tracheal tube adaptor and/or a flaring jig. A proximal end of a tracheal tube may be flared and the tracheal tube adaptor may be coupled to the proximal end of the tracheal tube. The tracheal tube adaptor may be configured to easily attach and detach an end connector. The end connector may be used to couple a variety of medical devices such as a ventilator, a manual respirator, a nebulizer, a vaporizer, suctioning equipment, and so forth, to the tracheal tube. The use of the tracheal tube adaptor system and methods enables the rapid detachment and attachment of various end connectors, thus allowing the coupling of the tracheal tube to a variety of medical devices.

Abstract: A conventional respiratory nebulizer has an emergency medication dose storage system delivering the stored medication dose directly to the nebulizing chamber with a single impulse of manual force to a simple mechanical delivery system, thereby making the nebulizer useable in two steps: (a) opening the medication capsule with a simple opening action; and (b) inhaling the nebulized medication. The nebulizer can be operated without disassembling the nebulizer housing so as to expose the nebulizing chamber and without manually opening the liquid medication container and, without spillage and without manual pouring of the liquid medication directly into the nebulizing chamber, and without reassembling the nebulizer housing before positioning the inhaler mouthpiece in the mouth so as to inhale the nebulized medication. The delivery system includes a pressure burstable seal at one end of the capsule, which is burst by the application of force against the opposite end of the capsule.

Abstract: Methods and devices are disclosed for manipulating the airway, such as to treat obstructive sleep apnea. An implant is positioned within the body with respect to the airway. The spatial orientation of the airway is manipulated, directly or indirectly, to affect the configuration of the airway. In general, the implant is manipulated to displace the trachea in an inferior direction, resist superior displacement of the trachea and/or to alter the tracheal wall tension. The implant restrains the trachea in the manipulated configuration.

Abstract: A device for maintaining an airway in a patient. This device includes a mask having a resilient conformable peripheral portion that is shaped such that the mask forms a seal with the larynx when the mask is positioned in the laryngo pharynx to thereby prevent ingress of extraneous fluids into the larynx. The peripheral portion of the mask define at least one cavity for providing fluid communication to the esophagus when the mask is inserted into the laryngo pharynx. An airway tube is connected to or formed with the mask for passing gas to the larynx when the mask is properly inserted into the laryngo pharynx. The airway tube preferably is curved as it leaves the mask.

Abstract: A method of operating a ventilator assembly having inhalation and exhalation passages communicating with one another, and a respiration assembly that can perform repetitive respiratory cycles. The method includes (a) connecting the conduit with an open end of an endotracheal tube positioned within the trachea so that the open end leads into the airway below the vocal cords, (b) repetitively cycling the respiration assembly so that during the inhalation phase, gas in the inhalation passage flows through the endotracheal tube and into the airway, and during the exhalation phase, an exhalation valve is maintained relatively closed and the exhaled gases flow pass the vocal cords and out of the mouth thereby facilitating the patient's ability to speak, and (c) monitoring ring the pressure within at least one of the passages during both phases for determining the pressure within the patient for use in operating the ventilator assembly.

Abstract: An airway device is provided that may track the flow of respiratory gases through the device with sensing elements at a plurality of locations along the gas flow path of the device. Such a device may be useful for assessing a variety of clinical states, for adjusting patient ventilator settings, or for determining whether or not an airway device has been properly inserted into a patient airway.

Abstract: Methods, apparatus, and kits for enhancing breathing in patients suffering from chronic pulmonary obstructive disease are described. The methods and apparatus rely on increasing flow resistance to expiration in a manner which mimics “pursed lip” breathing which has been found to benefit patients suffering from this disease. In a first example, a device is implanted in a trachea or bronchial passage to increase flow resistance, preferably selectively increase resistance to expiration relative to inspiration. In a second embodiment, a mouthpiece is provided, again to increase resistance to expiration, preferably with a lesser increase in flow resistance to inspiration. In a third embodiment, the patient's trachea or bronchial passage is modified by the application of energy in order to partially close the lumen therethrough.

Abstract: A laryngeal mask airway installation kit includes a laryngeal mask airway having a gastric access tube and includes a stylet capable of being inserted into the gastric access tube from the inlet end. When bent, the stylet changes the original shape of the laryngeal mask airway, thus facilitating the installation of the laryngeal mask airway.

Abstract: The present invention relates to methods and systems for resuscitation of an infant which maintains healthy blood oxygen saturation values in the infant by titration of supplemental oxygen concentrations.

Abstract: An assembly structure to facilitate the cleaning of an interior endotracheal tube including an elongated tubular member dimensioned to pass within and along the length of the endotracheal tube. A cleaning assembly is connected adjacent the distal end of the tubular member and is structured to be disposed in an expanded position and a non-expanded position, wherein the expanded position defines a cleaning orientation of the cleaning assembly relative to the interior surfaces of the endotracheal tube. The distal end of the tubular member includes an enlarged tip portion disposed on and at least partially defining the distal end, wherein the exterior surface of the enlarged tip peripherally includes a curved and/or at least partially domed configuration structured to assume a protective orientation relative to the cleaning assembly at least when the cleaning assembly is in the non-expanded position.

Abstract: Dry powder inhalers include: (a) a first generally planar spiral travel path in an inhaler body, wherein the first spiral travel path has a plurality of adjacent curvilinear channels forming lanes with upstanding sidewalls, including an inner lane and an outer lane; and (b) a plurality of discrete sealed microcartridges with substantially rigid bodies disposed in the first travel path, each comprising a pre-metered (typically dose) amount of dry powder, the microcartridges being configured to slidably advance along the first travel path toward an inhalation chamber that merges into an inhalation output port. In operation, at least one microcartridge is held in the inhalation chamber to release the dry powder therein during inhalation.

Abstract: A tracheotomy tube apparatus includes an outer cannula having first and second ends, a fenestration along the length of the outer cannula between the first and second ends, and a first inner cannula sized for insertion into the outer cannula. The first inner cannula includes a resilient region which lies adjacent the fenestration when the first inner cannula is properly oriented within the outer cannula, and a valve operatively associated with the first inner cannula. A region between the resilient region and the valve provides a passageway between the first inner cannula and the outer cannula when the first inner cannula is properly oriented within the outer cannula.

Abstract: A handle assembly and method of its use which facilitates the cleaning of the interior of an endotracheal tube. The handle assembly comprises a body structured to be held and manipulated by a hand of a user and is structured to removably retain an inflation device. A tubular member is connected to the body and is dimensioned to be inserted within and pass along an interior length of the endotracheal tube to facilitate the cleaning thereof. A calibration assembly is movably connected to the body and structured to determine an accurate or appropriate length of the tubular member to be inserted within the endotracheal tube to avoid over insertion of the tubular member. A positioning member associated with the calibration assembly is connected to the restricting portion and is movable along the length of the body to position the positioning/stop member adjacent the proximal end of the endotracheal tube for alignment and determination of the accurate length of the tubular member to be inserted.

Abstract: According to various embodiments, methods and systems for determining pressure in the lungs may employ tracheal pressure measurements. The tracheal pressure measurements may be obtained through a pressure monitoring lumen associated with a tracheal tube. Such systems may include a purging or flushing mechanism to keep the pressure monitoring lumen free of any obstructions. The flushing mechanism may utilize fluids delivered through the pressure monitoring lumen at a predetermined point in the breathing cycle and/or at a predetermined pressure relative to the respiratory gases. The resulting pressure measurements may be used to determine a more accurate estimate of lung pressure, which in turn may be used to control a ventilator and provide breathing assistance to a patient.

Abstract: An airway adapter suitable for use with patients having low tidal volumes, e.g., neonates, which minimizes deadspace in the airway and promotes smooth flow of gases through the adapter. The adapter includes a first portion adapted to couple to a tubular adapter, such as an endotracheal tube adapter, and a second portion adapted to couple to a ventilation tube. A longitudinally compressible member is coupled to the first portion to minimize deadspace in the adapter. A portion of the compressible member resiliently contacts and seals against a tubular adapter upon assembly of the airway adapter therewith.

Abstract: A supraglottic airway of the type used to facilitate lung ventilation and the insertion of endo-tracheal tubes or related medical instruments through a patient's laryngeal opening where the shield is designed to have an internal increase in pressure during assisted inhalation such as positive-pressure ventilation.

Abstract: An improved Guedel Oral Airway for providing an air passage to a patients trachea. The oral airway includes a tubular member which is generally elliptical in cross section and having a straight section and a curved section with the tubular member having a curved lower wall member extending from the center of the bottom wall portion of the tubular member outwardly and away from the tubular member. The cross-section of the lower wall member is generally an inverted V-shape in cross-section with the side edges thereof being positioned outwardly of the end wall portions of the tubular member.

Abstract: An apparatus for maintaining a surgical airway and method for the same includes an elongated body insertable orally into a patient. The elongated body defines leading and trailing ends. An opening is defined through the leading and trailing ends, such that surgical equipment may be insertable through the opening of the elongated body. A securing member is connected to the trailing end. The securing member holds the elongated body in a position such that an airway remains open to treat the patient, while supporting oxygen flow to the patient.

Abstract: A voice prosthesis dilator and sizer device is provided including an elongated member having a first end with a tip and a flange and a second end with a stop portion. The elongated member includes an intermediate portion with a measuring area disposed adjacent to the flange and including measuring indicia thereon and having a dilation area adjacent to the second end. The elongated member also includes a recessed region adjacent to the flange to receive the flange in a folded position upon insertion into the non-dilated fistula. The dilation area has a larger diameter than the measuring area.

Abstract: According to various embodiments, a tracheal tube ventilating device includes a sealing portion near a distal end of the tube. The sealing portion has an electroactive polymer configured to undergo a clinically effective change in volume, thickness, or both upon application of an electrical potential. Such a change in volume, thickness, or both enables sealing of the device against an inner surface of a trachea while permitting the free passage of ventilating gas through the tube. In addition, at least one electrical conductor is coupled to the electroactive polymer and is configured to apply the electrical potential.

Abstract: The volume of a hyperinflated lung compartment is reduced by sealing a distal end of the catheter in an airway feeding the lung compartment. Air passes out of the lung compartment through a passage in the catheter while the patient exhales. A one-way flow element associated with the catheter prevents air from re-entering the lung compartment as the patient inhales. Over time, the pressure of regions surrounding the lung compartment cause it to collapse as the volume of air diminishes. Residual volume reduction effectively results in functional lung volume expansion. Optionally, the lung compartment may be sealed in order to permanently prevent air from re-entering the lung compartment.

Abstract: According to various embodiments, an endotracheal tube ventilating device with a sealing cuff includes an anchoring device. The anchoring device may be secured to the tube above the sealing cuff and extend outwardly from the tubular body. In addition, the anchoring device may be configured to be positioned completely within the hypopharynx of a patient, in contact with the piriform fossa and a laryngeal surface of the epiglottis without creating an airtight seal of the hypopharynx or the esophagus.

Abstract: The invention relates to a silicone catheter including chlorhexidine gluconate, methods of making this catheter, and methods of using it. The method of making the catheter includes contacting a silicone catheter with a liquid containing chlorhexidine gluconate. Chlorhexidine gluconate is stably incorporated into the silicone catheter. The invention also relates to a silicone medical device or article including chlorhexidine gluconate and methods of making this such a medical device or article.

Abstract: The present disclosure describes systems that may extend the proximal length of a tracheal tube. A tracheal tube extension system may be provided that includes secure attachment features used to securely couple a tracheal tube to a tracheal tube extension. The tracheal tube extension may be attached to the proximal end of the tracheal tube and includes an upper end connector. The upper end connector may be used to couple the tracheal tube extension to a variety of medical devices such as a ventilator, a manual respirator, a nebulizer, a vaporizer, suctioning equipment, and so forth. The use of the tracheal tube extension enables an increase in working space in the area in front of the tracheal tube, thus allowing for the convenient and rapid access to the various connectors that may be coupled to the patient.

Abstract: A thermoplastic polymeric composition having a xanthene or xanthenes-based compound as a plasticizer, a method to modify the thermoplastic polymeric materials to increase their relative plasticity while maintaining good strength or “toughness” characteristics, and various articles of manufacture that can be made using the polymer composition are described.

Abstract: According to various embodiments, methods and systems for determining pressure in the lungs may employ tracheal pressure measurements. The tracheal pressure measurements may be obtained through a pressure monitoring lumen associated with a tracheal tube. Such systems may include a purging or flushing mechanism to keep the pressure monitoring lumen free of any obstructions. The flushing mechanism may utilize respiratory gases diverted from the airway stream and regulated to flush the lumen at relatively low pressures. The resulting pressure measurements may be used to determine a more accurate estimate of lung pressure, which in turn may be used to control a ventilator and provide breathing assistance to a patient.

Abstract: An oral airway for providing an air passage to a patient's trachea. The oral airway includes a curved section and a straight section with the curved section having spaced-apart curved upper and lower members and the straight section having spaced-apart planar upper and lower members with the same width. The curved upper member has the same width as the planar upper member with the curved lower member having a greater width than the width of the lower planar member. The width of the curved lower member is greater than the width of the planar lower member and the distance between the curved upper and lower members is greater than the distance between the planar upper and lower members. The curved lower member has a generally inverted V-shaped cross-section.

Abstract: A waterproof structure of a respiratory tube is provided. The waterproof structure comprises a hollow body and a lid. The hollow body has a first opening end and a second opening end opposing to the first opening end. The lid pivots onto the hollow body at the first opening end. Before the lid is immersed into liquid, the gravity of the lid can keep the lid at a certain position so that the respiratory tube is well-ventilated. After a part of the lid is immersed into the liquid, the buoyancy provided by the liquid forces the closing surface thereof to substantially seal the first opening end and prevent liquid from going into the tube.

Abstract: A respiratory therapy facemask configured to be positioned against a patient's face and adjacent the patient's mouth, includes a face plate configured for attachment to the patient and defining an opening, the face plate including a laterally extending track defining a slot. A tube rest assembly is configured for being slidably engaged in the slot and for securely accommodating an endotracheal tube. The tube rest assembly is configured for directly engaging the track for lateral movement in the opening.

Abstract: Some embodiments include oral airway assemblies that can include a body having an opening extending from a first end of the body to a second end of the body with the body having upper and lower portions in one cross section. A flange can be included that extends from the first end of the body and outwardly from the opening. An upper member extending from the upper portion of the second end of the body and outwardly from the opening away from the lower portion can be provided. The assemblies can include a lower member slidably engaged with the body, with at least a portion of the lower member extending outwardly from the lower portion of the second end of the body and away from the upper portion when engaged with the body. In accordance with other embodiments a member can be provided to slidably engage with the body, and include a tab at one end, with the tab being pivotably coupled to the member.

Abstract: According to various embodiments, a tracheal tube may include an integral humidification system. The tracheal tube may be formed at least partially from a material that is permeable to water vapor but substantially impermeable to respiratory gases. The water vapor may be actively provided to the tracheal tube or may be passively transferred from a patient's surrounding airway space.

Abstract: A medical apparatus that holds open a mouth of a patient. The apparatus contains a passage through which the patient can breathe by mouth. The apparatus contains a port to which an oxygen line is connected and which delivers oxygen to the passage for inhalation by the patient. The apparatus contains a sampling port which samples air in the passage and delivers sampled air to a monitoring device. The latter measures, for example, carbon dioxide content in the sampled gas, and issues a warning if carbon dioxide concentration is out-of-bounds. Phosphor material can be added to the apparatus, to make the apparatus glow in a darkened operating room, to allow technicians to easily find the patient's mouth and to insert tools, tubing, instruments and the like in the patient's mouth.

Abstract: An oral airway for providing an air passage to a patient's trachea including two embodiments. In both embodiments, the oral airway includes a curved section and a straight section with the curved section having spaced-apart curved upper and lower members and the straight section having spaced-apart planar upper and lower members with the same width. In the first embodiment, the curved upper member has the same width as the planar upper member with the curved lower member having a greater width than the width of the lower planar member. In the second embodiment, the width of the curved lower member is greater than the width of the planar lower member and the distance between the curved upper and lower members is greater than the distance between the planar upper and lower members.

Abstract: The present invention concerns a tracheostomy cannula comprising a cannula tube, wherein the cannula tube has a bend with a radially inward and a radially outward side of the cannula tube and a tube lumen and a tube wall and an axis extending parallel to the tube wall in the tube lumen and a distal and a proximal end and on the radially outward side of the bend a first window region having one or more openings in the tube wall. To provide a tracheostomy cannula having a cannula tube, with which talking is made possible and the entry of air into the tissue is prevented even when the position of the tracheostomy cannula in the trachea or the anatomical conditions change, it is proposed in accordance with the invention that the cannula tube has in axially displaced relationship with the first window region at least one further window region having one or more openings in the tube wall.

Abstract: An endotracheal tube securing device having a securing device body that is operatively engaged to a biased plunger for securing an endotracheal tube to the securing device body is disclosed. The securing device body defines a chamber in communication with opposing front and rear openings with a top opening in transverse relation to the front and rear openings. A plunger biased by a spring is slidably disposed inside the chamber through a top opening and includes a channel that communicates with first and second opposed openings that become aligned with the front and rear openings of the securing device body when the user depresses the plunger and inserts the endotracheal tube through the aligned plunger. The endotracheal tube becomes secured to the securing device body when the user releases the biased plunger, thereby engaging the endotracheal tube between the plunger and the securing device body.

Abstract: The invention relates to methods and devices related to improvements in the use of a medical breathing tube. In some embodiments, the invention reduces injuries, diseases and death associated with the use of said breathing tube. In preferred embodiments, said breathing tube reduces the risk of inadequate inflation in the lungs.

Abstract: Consists of positioning, through the orifice or tracheostoma -9-, a cannula for permanent implant -1-, in a fully aligned manner with the help of an inserter -6-, whereby the inner end or suprastomal extension -4- of the cannula -1-, upon withdrawing the inserter -6- vertically positioned in the supra-ostial area -10- of the trachea -8-, allowing, once the aforementioned permanent cannula -1- has been permanently positioned, the introduction of a perforated cannula -11- having a characteristic curvature therethrough, oriented, through the lower aperture -3- of the permanent cannula -1-, towards the interior of the lungs in order to allow insufflation of air from the exterior, while the exhaled air is derived through the vertical extension -4- towards the larynx through the orifices -13- disposed in the curvature elbow thereof.

Abstract: The present invention relates generally to the field of laryngeal mask airway devices. The invention provides for dual passageways in a laryngeal mask which permits a physician to effectively isolate the trachea from the esophagus. In one embodiment, the physician separately inserts an instrumentality (e.g., an endotracheal tube) into a patient's esophagus in order to isolate the stomach from the lungs, respectively. In another embodiment, the physician inserts an instrumentality (e.g., an endotracheal tube) into the trachea and inserts another instrumentality (e.g., a drainage tube) in the second passageway within the laryngeal mask in order to remove particles or fluids contained in the laryngeal mask that may cause problems if allowed to flow through the patient's trachea to the lungs.

Abstract: A delivery device for and method of delivering substance, the delivery device comprising: a delivery outlet (7) from which substance (S) is in use delivered; a gas chamber (17) containing a gas and being of reducible volume, wherein a reduction in the volume of the gas chamber (17) to a predeterminable volume acts to pressurize the contained gas to a predeterminable pressure; a seal element (11) disposed between the gas chamber (17) and the delivery outlet (7); and an opening mechanism configured, on reduction of the volume of the gas chamber to a predeterminable volume, to open the seal element (11), whereupon a gas flow from the gas chamber (17) acts to deliver substance (S) from the delivery outlet (7).

Abstract: A supraglottic airway of the type used to facilitate lung ventilation and the insertion of endo-tracheal tubes or related medical instruments through a patient's laryngeal opening where the shield is designed to have an internal increase in pressure during assisted inhalation such as positive-pressure ventilation.

Abstract: There is provided herein methods, apparatus and systems for evaluating carbon dioxide (CO2) concentration in a subject's breath, for example in subjects ventilated with High Frequency Ventilation (HFV), the method includes inserting to a trachea of a subject an endotrachial tube (ETT), sampling breath from an area in the trachea located in proximity to a distal end of the endotrachial tube (ETT) and evaluating one or more CO2 related parameters of the sampled breath.

Abstract: Novel compositions, as well as related methods, coatings, and articles, are disclosed.

Abstract: The present invention is directed to a novel device and method for providing a disposable endotracheal intubation device for use with an auxiliary passageway serving as a guide for the placement of an orogastic or other enterally directed device in a patient. The present invention pertains to a combination intubation device comprising an endotracheal tube and a catheter proximate the endotracheal tube to guide the path of an enteral tube. In a preferred embodiment, the endotracheal tube is capable of defining an arcuate path in a first geometric plane between its proximal end and its distal end to facilitate introduction of the tube into the trachea of a patient. In a preferred embodiment, the catheter employs a fenestration to facilitate removal of the intubation device from the patient without removal of any enteral device previously directed therethrough into the patient.

Abstract: The present invention provides a method and apparatus for treating obstructive sleep apnea by using negative oral pressure to a patient. The present apparatus includes a vacuum unit for controlling and maintaining negative pressure of an oral cavity of the patient, a tube with one end thereof connecting to the vacuum unit to suck out air in the oral cavity to generate the negative pressure therein, and a mouthpiece connecting to the other end of the tube and fitting into and sealing the patient's mouth to prevent the oral cavity from air leakage. By using negative pressure in the oral cavity, the patient's soft palate is pulled toward the oral cavity and the patient's tongue is pulled toward an upper palate so as to maintain the patient's nasal air passageway open.

Abstract: An improved endotracheal tube is provided which is adapted to optimally and safely accommodate the nasopharyngeal airway during nasopharyngeal intubation. The endotracheal tube includes a body having a nasopharyngeal section adapted to sealably enclose and contain a spirally-wound coil longitudinally therealong. The nasopharyngeal section integrally transposes into a rigid section which extends longitudinally from the nasopharyngeal section and terminates at a lower end of endotracheal tube. The nasopharyngeal section with incorporated spirally-wound coil allows for multiple positioning of nasopharyngeal section about a face of a patient, thereby minimizing pressure sores, abrasions, and ulcerations, and further allows for quick, easy, and efficient surgical access to the nasopharyngeal airway without requiring removal of the endotracheal tube.

Abstract: A kink resistant silicon endotracheal tube includes an inflatable cuff for positioning the endotracheal tube in a patient's trachea. The cuff is folded over onto itself to provide a cavity for accumulating bacteria and secretions that are then removed by suction. The cuff in the lower part of the endotracheal tube is also folded over onto itself for centering the endotracheal tube in the center of an airway. A suction catheter is also positioned in a portion of the tube under tension as opposed to a portion under compression to reduce the likelihood of kinking. A kink resistant endotracheal tube also includes a thickened and/or reinforced area of the curved portion of the endotracheal tube in an area under compression.

Abstract: According to various embodiments, a tracheal tube may employ sensing techniques for determining a distance between the inserted tube and an anatomical structure such as a carina. The distance information may provide an indication as to whether or not the tracheal tube is properly placed within the trachea. Because a tracheal tube may rotate within the trachea, the sensing information may be gathered from multiple locations on the tracheal tube for a rotation-independent measurement technique.

Abstract: An oral airway for providing an air passage to a patient's trachea. The oral airway includes a curved section and a straight section with the curved section having spaced-apart curved upper and lower members and the straight section having spaced-apart planar upper and lower members with the same width. The curved upper member has the same width as the planar upper member with the curved lower member having a greater width than the width of the lower planar member. The width of the curved lower member is greater than the width of the planar lower member and the distance between the curved upper and lower members is greater than the distance between the planar upper and lower members. The curved lower member has a generally inverted V-shaped cross-section.