Patent Publication Number: US-11033703-B2

Title: System and method for emergency apneic oxygenation

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit as a divisional of application Ser. No. 14/602,991 filed Jan. 22, 2015 which claims benefit as a continuation-in-part of PCT Application No. PCT/US2013/51739 filed Jul. 23, 2013, which in-turn claims the benefit of Provisional Appln. 61/674,414, filed Jul. 23, 2012, under 35 U.S.C. § 119(e). Additionally, application Ser. No. 14/602,991 filed Jan. 22, 2015 claims benefit of Provisional Appln. 61/930,043, filed Jan. 22, 2014, under 35 U.S.C. § 119(e). 
    
    
     STATEMENT OF GOVERNMENTAL INTEREST 
     This work was supported by the U.S. Department of Veterans Affairs, and the Federal Government has certain rights in this invention. 
    
    
     BACKGROUND 
     Apnea refers to suspension of external breathing. During apnea there is little or no movement of the muscles of respiration and the volume of the lungs essentially remains unchanged. Severe tissue damage, brain damage and death can result. Oxygenation during apnea is called apneic oxygenation. Continuous apneic oxygenation delivered to the lower end of the trachea has been found to maintain trauma patients for up to one hour following injury. Despite these findings, there has yet to be an apneic oxygenation catheter developed for use in the field by emergency medical technicians (EMTs) or the military. 
     A cricothyrotomy is an incision through the cricothyroid membrane above the cricoid cartilage readily evident just above the trachea, and is considered less invasive than an incision through the trachea (tracheotomy) and to have fewer complications. Cricothyrotomy ventilation is often necessary to secure the airway in injuries requiring apneic oxygenation. When there is an obstruction in the airway and endotracheal intubation is not possible, an immediate solution is to insert a tube through a hole in the cricothyroid membrane. In some cases the bypass will allow the patient to breathe on their own. In other instances the bypass will provide an entry way for assisted ventilation and/or drug delivery. 
     Generally, the devices available to perform emergency cricothyrotomies require a skilled practitioner and require many steps to secure the airway. One example device and procedure are described in U.S. Pat. No. 4,677,978. There, a derivative of the Seldinger method is used making the installation of this device labor intensive. First, a scalpel is used to make an incision into the cricothyroid membrane. Next, an over-the-needle catheter is entered into the airway with a syringe. The syringe and needle are then removed, leaving the catheter in place. Following that, a guide wire is inserted into the catheter, and the catheter is removed. Finally a dilator is inserted over the guide wire and the guide wire is removed. 
     Other devices such as those described in U.S. Pat. No. 4,869,718 do not use the Seldinger method and therefore require fewer steps. However, these devices only provide a small opening for the catheter and are limited to high frequency jet ventilation. 
     SUMMARY 
     Techniques are provided for emergency apneic oxygenation, including devices that provide a more sustainable opening through the cricothyroid membrane. 
     In a first set of embodiments, a cannula for emergency apneic oxygenation includes a longitudinal inner passage having an inner diameter. A distal portion of the cannula is made of shape memory material shaped to bend in a first direction along the inner passage, and has a first outer diameter greater than the inner diameter. The cannula includes a cannula base having a second outer diameter greater than the first outer diameter. A distance from a distal end of the cannula to a proximal end of the distal portion of the cannula is less than a distance from a surface of a throat of a target subject to a distal surface of an airway of the target subject. 
     In some of embodiments of the first set, the first outer diameter is less than 10 millimeters. 
     In a second set of embodiments, a catheter for emergency apneic oxygenation includes a distal portion having a first outer diameter and a first longitudinal inner passage of a first inner diameter less than the first outer diameter. The catheter also includes a proximal portion configured at a proximal end for attachment to a fluid supply and having a second longitudinal inner passage in fluid communication with the first longitudinal inner passage. The catheter still further includes padding at the distal end of the distal portion configured to disperse fluid flow and to prevent damage to a lining of an airway of a target subject. 
     In some embodiments of the second set, the first outer diameter is less than 10 millimeters. 
     In some embodiments of the second set, the catheter includes a mark or a collar configured to be placed around the catheter at a particular distance to the proximal side from the distal end of the distal portion. The particular distance is approximately equal to a distance from an entry point into the airway of the target subject to a sub-segmented bronchus of the target subject. In some of these embodiments, the particular distance is in a range from about 5 centimeters to about 15 centimeters. 
     In a third set of embodiments, a trocar for emergency apneic oxygenation includes a distal portion comprising a tapered cutting edge and a penetration portion disposed proximal to the distal portion and having a diameter less than 10 millimeters. The trocar also includes a stop lip disposed proximal to the penetration portion and having a diameter greater than the diameter of the penetration portion. A distance from a distal end of the stop lip to a distal end of the distal portion is less than about a distance from a surface of a throat of a target subject to a distal surface of an airway of the target subject. 
     In a fourth set of embodiments, a system for emergency apneic oxygenation includes a cannula and a trocar. The cannula includes an inner passage of an inner diameter, a distal portion and a cannula base. The distal portion has a first outer diameter greater than the inner diameter, and is made of shape memory material shaped to bend in a first direction along the inner passage. The cannula base has a second outer diameter greater than the first outer diameter. The trocar includes a distal portion that includes a cutting edge, a penetration portion and a stop lip. The penetration portion is disposed proximal to the distal portion and has a diameter about equal to the inner diameter. The stop lip is disposed proximal to the penetration portion and has a diameter greater than the diameter of the penetration portion. The trocar is configured to engage the cannula by passing through the inner passage and straightening the bent distal portion of the cannula. When the trocar is engaged, a distance from a distal end of the distal portion of the trocar to a proximal end of the distal portion of the cannula is less than a distance from a surface of a throat of a target subject to a distal surface of an airway of the target subject. 
     In some embodiments of the fourth set, the system also includes a system base that has a system base opening that has a diameter about equal to the first outer diameter. The system base has an area outside the system base opening that is sufficient to inhibit the cannula base from passing into the airway of the target subject. 
     In some embodiments of the fourth set, the system also includes a catheter. The catheter is configured to pass through the inner passage of the cannula and be directed by the direction of the bent distal portion of the cannula down the airway of the target subject, after the cannula passes into the airway of the target subject and the trocar is removed. 
     In a fifth set of embodiments, a kit for emergency apneic oxygenation includes a cannula, a trocar, a base and a catheter. The cannula includes an inner passage of an inner diameter, a distal portion, and a cannula base. The distal portion has a first outer diameter greater than the inner diameter, and is made of shape memory material shaped to bend in a first direction along the inner passage. The cannula base has a second outer diameter greater than the first outer diameter. The trocar is configured to engage the cannula by passing through the inner passage and straightening the bent distal portion of the cannula. The system base has an opening about equal to the first outer diameter and is configured to be placed with the opening centered on an appropriate entry site on a target subject for the trocar engaged with the cannula. The catheter is configured to pass through the cannula after insertion of the cannula into the entry site by the engaged trocar and subsequent removal of the trocar. The catheter has a length that is at least a sum of a first distance from the entry site to a sub-segmented bronchus of the target subject and a second distance from the entry site to a supply of fluid. 
     In some embodiments of the fifth set, the first outer diameter is less than 10 millimeters. 
     In a sixth set of embodiments, a method for emergency apneic oxygenation includes cutting an opening of diameter less than 10 millimeters into an airway of a target subject at an entry site. The method also includes passing a distal end of a catheter through the opening and down the airway of the target subject to a sub-segmented bronchus of the target subject. The method further includes connecting a distal end of the catheter to a supply of oxygen and providing oxygen from the supply to the target subject at a rate sufficient to sustain life of the target subject. 
     In a seventh set of embodiments, a system for emergency apneic oxygenation is provided. The system includes a cannula that has an inner passage of an inner diameter and a distal portion with a first outer diameter. The distal portion is shaped to bend in a first direction along the inner passage. The system also includes a trocar configured to engage the cannula by passing through the inner passage. Additionally, the system includes a system base comprising a panel with an opening of a diameter about equal to the first outer diameter. The system base also includes a bumper with an arcuate surface shaped to be received by a recess formed by a cricothyroid membrane so that the opening is centered on the cricothyroid membrane to provide an entry point for the trocar engaged with the cannula. 
     In an eighth set of embodiments, a method is provided for emergency apneic oxygenation. The method includes moving an arcuate surface of a system base along a surface of a throat of a target subject. The method also includes receiving the arcuate surface in a recess formed by a cricothyroid membrane along the surface. The method further includes aligning an opening in the system base with an entry point in the cricothyroid membrane based on the receiving step. The method further includes engaging a trocar with a cannula by passing the trocar through an inner passage of the cannula and straightening a bent distal portion of the cannula. The method further includes inserting the engaged trocar and cannula through the opening in the system base and the entry point in the cricothyroid membrane and into an airway of the target subject. 
     Still other aspects, features, and advantages of the invention are readily apparent from the following detailed description, simply by illustrating a number of particular embodiments and implementations, including the best mode contemplated for carrying out the invention. The invention is also capable of other and different embodiments, and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
         FIG. 1A  through  FIG. 1D  are block diagrams that illustrate example components of a apnea oxygenation kit, according to an embodiment; 
         FIG. 2A  through  FIG. 2D  are block diagrams that illustrate example use of the components of  FIG. 1A  through  FIG. 1D , according to an embodiment; 
         FIG. 3A  through  FIG. 3E  are block diagrams that illustrate example variations to the kit of  FIG. 1A  through  FIG. 1D , including a protective casing according to various embodiments; 
         FIG. 4  is a block diagram that illustrates an example distal face of the system base  330 , according to some embodiments; 
         FIG. 5A  through  FIG. 5H  are block diagrams that illustrate example variations in catheters from that depicted in  FIG. 1D , according to various embodiments; 
         FIG. 6A  and  FIG. 6B  are respective front and side views of a cricothyroid membrane in a target subject; 
         FIG. 7A  through  FIG. 7D  are block diagrams that illustrate an example variation in the system base from that depicted in  FIG. 1C  and  FIG. 4 , according to an embodiment; 
         FIG. 8A  and  FIG. 8B  are block diagrams that illustrate another example variation in the system base from that depicted in  FIG. 1C , according to an embodiment; 
         FIG. 9  is a block diagram that illustrates an example use of the components of  FIG. 1A ,  FIG. 1B ,  FIG. 1D  and  FIG. 7A  through  FIG. 7D , according to an embodiment; and 
         FIG. 10  is a flow diagram that illustrates an example of a method for providing emergency apneic oxygenation, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A method, apparatus, system and kit are described for emergency apneic oxygenation. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention. 
     Some embodiments of the invention are described below in the context of an emergency, such as a trauma caused by natural disasters, accidents, or acts of war or terror, suffered by an adult. However, the invention is not limited to this context. In other embodiments the procedure or device is employed on children and in clinical or hospital settings, such as in first aid, preparation for or recovery from surgery, or response to power failures in the operating room, or wherever cardiopulmonary resuscitation (CPR) or automated defibrillator is employed, such as for response to heart attack, pulmonary embolism, significant overwhelming infection, and choking. 
     As used herein, a “proximal” end or face shall be construed as the end or face that is closest to the user when the device is in use. As defined herein, a “distal” end or face shall be understood as the end or face that is closest to, or deepest inside, the patient, and farthest from the user, when the device is in use. As used herein, diameter refers to a shortest distance through an object, whether the object has a circular cross section or not. As used herein, a subject is a person or animal, and a target subject is a subject that is to receive apneic oxygenation. In some embodiments, the target subject is an individual person; in some embodiments, the target subject is a population of individuals, such as adults or sub-teenaged children. In such embodiments, the values of characteristics (such as values of airway diameter and length) of the target subject are an average or range of characteristics of the population. As used herein, a fluid means any material that flows at ambient temperatures, including liquids (e.g., medications) and gases (e.g., oxygen gas). 
     Although processes, equipment, and data structures are depicted in  FIG. 1  as integral blocks in a particular arrangement for purposes of illustration, in other embodiments one or more processes or data structures, or portions thereof, are arranged in a different manner, on the same or different hosts, in one or more databases, or are omitted, or one or more different processes or data structures are included on the same or different hosts. 
       FIG. 1A  through  FIG. 1D  are block diagrams that illustrate example components of an apnea oxygenation kit, according to an embodiment. In the illustrated embodiment, the components of the kit are shown with circular cross sections; however, in other embodiments other cross sections are used, such as oval cross sections, polygonal cross sections, lens shaped cross sections, and rectilinear cross sections. 
       FIG. 1A  is a block diagram that illustrates an example cross section through a cannula  110  with an inner passage of inner diameter  116  configured for passing one or more catheters. The cannula  110  is configured to be inserted through a wall at the front of the target subject&#39;s airway, e.g., above the cricoid cartilage, and into the target subject&#39;s airway. Thus it extends from the skin surface of a throat of a target subject into the airway. 
     A distal portion  112  of the cannula is made of a shape memory material and is bent in a first direction (downward in the illustrated view) as one progresses through the inner passage from a proximal end to a distal end. The distal portion  112  has an outer diameter  117 , larger than the inner diameter  116 . At the proximal end of cannula  110  is a cannula base  114 , with an outer diameter greater than the outer diameter  117  of the distal portion  112  of the cannula. In some embodiments, there is a straight portion  115  of the cannula between the bent distal portion  112  and the cannula base portion  114 . Suitable shape memory materials are known in the art, for example, titanium, thin stainless steel, and nickel titanium alloy (also called Nitinol). When in place in the wall of a target subject&#39;s airway, the downward bend of the distal portion  112  of the cannula directs a catheter threaded through the cannula downward in the subject&#39;s airways toward the lungs. This downward bias provides a very advantageous control when an operator is working in unguided and difficult conditions, such as darkness. The larger outer diameter of the cannula base  114  prevents the cannula  110  from falling through a hole with a diameter closely matching the outer diameter  117  of the distal portion  112  of the cannula, while allowing the entire distal portion  112 , and in some embodiments, a straight portion  115  to pass into the hole. The cannula base  114  has thickness  118  and is made of any suitable rigid or semi-rigid material including the same materials as the distal portion or separate materials such as stainless steel, titanium, nitinol, plastics or other types of polymers, or some combination. 
     It is also desirable that the bend in the cannula take place within the airway of the target subject without contacting or penetrating the back wall of the airway. Thus, it is advantageous for a distance  119  from a distal end of the cannula to a proximal end of the distal portion  112  of the cannula to be less than a distance from a surface of a throat of a target subject to a distal surface of an airway of the target subject. In some embodiments, the length of the distal portion  112  is so constrained. In some embodiments in which the distal face of the cannula base  114  is flush with the skin of the target subject, the distance from the distal face of cannula base  114  to the distal end of the cannula is advantageously less than the distance from a surface of a throat of a target subject to a distal surface of an airway of the target subject to avoid damaging or perforating the back wall of the airway. 
     Currently, apneic oxygenation uses holes into the airway which are a centimeter (10 millimeters) or more. Preferably, smaller incisions are made to reduce blood loss and chances for complications such as infection. By passing catheters attached to an oxygen supply, a smaller opening can be used. Thus, in various embodiments, the outer diameter  117  of the distal portion of the cannula is less than 10 millimeters and preferably in a range from about 3 millimeters to about 4 millimeters. The inner diameter  116  is sufficient to pass at least one catheter to supply oxygen and is preferably in a range from about 2 millimeters to about 3 millimeters. Larger inner diameters are used for bigger catheters or for multiple catheters, in various embodiments. 
       FIG. 1B  is a block diagram that illustrates an example trocar  120 , according to an embodiment. Trocar  120  (also called an obturator) is used to cut a hole from the skin of the throat into the airway of the target subject without damaging the back wall of the airway of the target subject. The trocar is made of any suitable rigid material, such as stainless steel, carbon steel, titanium, cobalt chrome, plastics or other types of polymers, or some combination. The trocar  120  is further configured to leave the cannula in place in the hole so cut. In the illustrated embodiment, the trocar includes a tapered piercing tip  124  at a distal end and a penetration portion  122  disposed proximal to the distal portion  124  and having a diameter  123  about equal to an inner diameter  116  of the cannula  110 . Thus the diameter  123  is less than about 10 millimeters and preferably less than 4 millimeters, and most preferably for use with a single catheter in a range from about 2 millimeters to about 3 millimeters. The piercing tip  124  is generally conical in shape. However, in some embodiments the piercing tip has more than one cutting edge. The trocar  120  also includes a stop lip  128  disposed proximal to the penetration portion and having a diameter greater than the diameter of the penetration portion. The stop lip  128  is configured to keep a cannula  110  from sliding along the trocar during insertion. In some embodiments, proximal to the stop lip is a handle  126  that is more easily grasped by an operator. 
     To keep from damaging a back wall of the airway of the target subject, a distance  127  from a distal end of the stop lip  128  to a distal end of the distal portion is less than a distance from a surface of a throat of a target subject to a distal surface of an airway of the target subject. In some embodiments, in which the cannula  110  with base of thickness  118  is disposed distal to the stop lip, a distance  127  minus thickness  118  is constrained to be less than the distance from the skin of the throat to the back wall of the airway. In some embodiments, in which the cannula  110  with base of thickness  118  and system base of thickness  134  is disposed distal to the stop lip and cannula base  114 , a distance  127  minus thickness  118  and minus thickness  134  is constrained to be less than the distance from the skin of the throat to the back wall of the airway. In various embodiments, depending on the target patient, the distance  127  is selected in a range from about 5 millimeters to about 35 millimeters, and preferably about 25 millimeters. The trocar  120  is configured to engage the cannula  110  by passing the piercing tip  124  of the trocar through the inner passage of the cannula base  114  and thence into the inner passage of the bent distal portion  112 , and straightening the bent distal portion  112  of the cannula. 
       FIG. 1C  is a block diagram that illustrates an example system base  130 , according to an embodiment. System base  130  has diameter  131  and includes a system base opening  132  of diameter about equal to the outer diameter  117  of cannula  110 . As shown in  FIG. 2A , system base also has thickness  134 . The system base  130  has an area outside the system base opening  132  that is sufficient to inhibit the cannula base  114  from passing into the airway of the target subject. The system base  130  also provides an advantage of locating the entry point incision on the throat of the target subject as a center of the opening  132 . The system base  130  is made of any suitable rigid or semi-rigid material, including molded plastic, other types of polymers, stainless steel, titanium, or cobalt chrome, or some combination. In various embodiments, the system base has a diameter in a range from about 5 millimeters to about 15 millimeters. Although appearing circular in  FIG. 1C , in various other embodiments, the system base  130  has a different shape, such as a rectangle or shape to match the contours of the neck of the target subject. 
       FIG. 1D  is a block diagram that illustrates an example catheter  140 , according to an embodiment. Catheter  140  is a long tube  142  of flexible non-toxic and sterile material, such as silicon plastic or other types of polymers with a fitting  144  for attachment to fluid supply, such as an oxygen supply or a medicine supply. A tube with outer diameter of 2 to 3 millimeters was found suitable for delivering sufficient oxygen to a target subject without exposing the subject to the risks associated with a larger opening, including excessive bleeding, infection and loss of life. The inner diameter is selected in a range from about 1 millimeter to about 2 millimeters. A distal portion is configured to be inserted into an airway of the subject patient and a distal end open to allow free fluid flow, for example into a sub-segmented bronchus of the target subject. A proximal end is configured for attachment to a fluid supply such as an oxygen supply or medicine supply. A proximal portion connects an entry point into the airway of the target subject to the proximal end and also comprises a second inner and outer diameter that are the same as in the distal portion in some embodiments, and different in other embodiments. The second longitudinal inner passage is in fluid communication with the first longitudinal inner passage. 
     In other embodiments, the kit includes additional or fewer components. For example, in some embodiments, the cannula base  114  has an outer diameter sufficient to prevent falling into any opening for the distal portion  112 , and the system base is omitted. In various other embodiments, other components are added, such as those described in more detail below. 
       FIG. 2A  through  FIG. 2D  are block diagrams that illustrate example use of the components of  FIG. 1A  through  FIG. 1D , according to an embodiment. As shown in  FIG. 2A , a cross section of the throat of a target subject is illustrated by skin  210 , front wall  212  of airway, and airway  220  having width  222 . The system base  130  of thickness  134  is laid on the skin  210  of the subject to expose in the opening  132  an entry point  230  for the incision. A distance  224  extends from the distal face of the system base  130  to the back wall of the airway; and a distance  223  extends from the proximal face of the system base  130  to the back wall of the airway. 
     The trocar  120  has engaged the cannula  110  and straightened the bent distal portion. The proximal face of the cannula base  114  is flush with the distal face of the stop lip  128 . The incision is made by driving the trocar engaged with the cannula in the direction of the open arrow. 
     As shown in  FIG. 2B , the trocar  120  cuts through the skin  210  and front wall  212  of the target subject airway  220  with the cannula  110  in place. The back wall of the airway is not disturbed so long as the distance  127  from the distal end of trocar to the stop lip minus the thickness  118  of the cannula base minus the thickness  134  of the system base is less than the distance from the skin  210  to the back wall of the airway  220 . In some embodiments, markings on cannula base  114  indicate the direction of bending of the cannula with the trocar disengaged. This mark is oriented so that the cannula  110  will bend downward when the trocar is removed. 
     As shown in  FIG. 2C , the trocar  120  is removed from the entry site by pulling on the handle  126  in the direction of the open arrow. In some embodiments, the base  114  of cannula is held in place while the trocar  120  is removed. The system base  130  prevents the base  114  of cannula  110  from entering the hole made by the piercing tip  124  of the trocar  120 . With the trocar disengaged, the distal portion of cannula  110  assumes its original shape, and points downward in the airway towards the lungs of the target subject, as desired. 
     As shown in  FIG. 2D , a catheter  140  is inserted through the inner passage of the cannula  110  and is automatically directed downward inside the airway toward the lung because the cannula has remembered its downward bent shape. 
       FIG. 3A  through  FIG. 3E  and  FIG. 4  are block diagrams that illustrate example variations to the kit of  FIG. 1A  through  FIG. 1D , including a protective casing, according to various embodiments. In some embodiments the device further comprises a protective casing  350 . Once the body cavity is penetrated, as shown in  FIG. 3B , the trocar  320  and optional protective casing  350  may be removed. The cannula  310  and base  330  remain in place. In these embodiments, the trocar includes a locking disk  321  that has a diameter larger than stop lip  328 . The diameter and length depend on dimensions of any securing mechanism  352  and  354  on the protective casing. The preferred dimensions fix locking disk  321  into the securing mechanism  352  and  354  when in place. 
     Referring to  FIG. 3C , the protective casing  350  comprises an outer casing  351 , a securing mechanism  352 ,  354  for the locking ring of the trocar  320 , and one or more fasteners  356 . Outer casing  351  is made of a generally rigid material, such as metal, plastics or other types of polymers, and has an outer diameter of between about 0.5 centimeters to about 4 centimeters. The interior diameter of outer casing  351  is between about 0.49 centimeters and about 3.99 centimeters. The length of outer casing  351  is between about 0.5 centimeters to about 4 centimeters. Securing mechanism  352  and  354  is located somewhere along the interior surface of the outer casing  351 . Securing mechanism  352  and  354  may cover the entire circumference of the outer casing  351  or there may be one or more parts spaced around the circumference of the outer casing  351 . The purpose of the securing mechanism is to fix the locking ring of the trocar in place when the trocar tip is inserted into the subject. The securing mechanism also serves as a safety mechanism to prevent the user from pressing the trocar too far into the subject. 
     In some embodiments the securing mechanism  352  and  354  is located at different locations on the outer casing interior surface to conform to different patient sizes. In other embodiments, the locking ring is fixed by the securing mechanism  352  and  354  before the snaps of the cannula are fixed to the base. For these embodiments, the cannula is preferably manually fixed after the trocar and protective casing are removed. It is contemplated that this embodiment will provide for a longer cannula without risking unwanted damage by the trocar. 
     Referring to  FIG. 3C , one or more fasteners  356  are located at the base of the protective casing. The fasteners  356  are used to secure the protective casing  350  to the base  330  as depicted in  FIG. 3A  and  FIG. 3B . In one embodiment, the protective casing  350  is removed from the base by rotating the protective casing  350 . In this example the rotation frees the one or more fasteners  356  from the base. Other types of fasteners may be used instead. For example, the fasteners  356  may snap into the base. 
       FIG. 3D  depicts a proximal face of the system base  330 . The base  330  comprises a generally disk shaped surface. Base  330  further comprises one or more notches  332  for the fasteners of the outer casing. The shape of the notches  332  depends on the configuration of the protective casing fasteners. In one example embodiment the notches  332  are L-shaped to allow for the release of the protective casing when the protective casing is rotated. In some embodiments, the base  330  also comprises one or more notches  333  which receive one or more snaps  312  of the cannula  310  as depicted in  FIG. 3E . The specific configuration of notches  332  and  333  may vary in other embodiments. In consideration of the teaching provided herein, one having ordinary skill in the art would recognize other configurations that while not specifically identified, are still within the overall spirit and scope of this invention. 
     Referring again to  FIG. 3D , in some embodiments the system base  330  is attached to a strap  336  that wraps around the neck of the target subject, and is held in place by complementary buckle  338   a  and clasp  338   b . In some embodiments, strap  336  is attached to system base  330  by eyelets that form part of base  330 . In the illustrated embodiment, the system base  330  includes an inner annulus  334  that is slightly recessed for accepting the distal face of cannula base  114 . 
       FIG. 4  depicts a distal face of the system base  330 , according to some embodiments. In the illustrated embodiment, the distal face is contoured with one or more contours  339  so that the system base  330  settles most securely when the opening of the system base is properly positioned over a preferred entry point. Thus, a system base is configured with a shape that follows contours of a throat of the target subject so that the system opening is centered on a location appropriate as an entry point for a catheter for emergency apneic oxygenation. 
       FIG. 5A  through  FIG. 5H  are block diagrams that illustrate example variations in catheters from that depicted in  FIG. 1D , according to various embodiments.  FIG. 5A  is a block diagram that illustrates an apneic oxygenation catheter  500  according to an embodiment. Catheter  500  comprises an elongated shaft  501 , having a proximal end  519  and a distal end  509 . Catheter  500  further comprises one or more ventilation ports called apertures  506  at the distal portion of the shaft and a connection element  514  at the proximal end. The connection element  514  is depicted connected to a fluid supply tank  518 , such as an oxygen supply tank. Apertures  506  may be located in any pattern desirable. For example, in some embodiments a plurality of apertures are located within a particular distance of the distal end of the distal portion, where each aperture is configured to permit fluid flow between the first longitudinal inner passage and an outside of the catheter. In some of these embodiments, the particular distance is less than a distance from a sub-segmented bronchus of the target subject to a mainstem bronchus of the target subject. 
     In some embodiments, the catheter  500  includes a collar  516  to mark the particular distance  507  of the catheter to be inserted through the cannula and into the airway of the target subject. The collar is configured to be placed around the catheter at a particular distance  507  to the proximal side from the distal end of the distal portion, wherein the particular distance  507  is approximately equal to a distance from an entry point into the airway of the target subject to a sub-segmented bronchus of the target subject. In some embodiments, the particular distance is in a range from about 5 centimeters to about 15 centimeters. In some embodiments, the collar is movable along that range. In some embodiments, gradation marks are included along the shaft in addition to or instead of the collar  516 . An advantage of the collar  516  is that the collar presents a physical stop when it encounters the cannula. This physical stop allows an operator to detect, without having to look at the catheter, when sufficient length has been inserted into the airway. In some embodiments, the inner and outer diameter of the catheter have one set of values on a distal portion  502  to the distal side of the collar  516 , and another set of values on a proximal portion  512  to the proximal side of the collar  516 . 
     Oxygenation catheter  500  advantageously includes padding  504  at the distal end. Padding  504  in various embodiments includes, for example, a balloon, a sponge, or other attachment that would help prevent injury to the trachea or bronchi during insertion or dispense air in 360 degrees or both, in some combination. In some embodiments, a dissolvable capsule at the distal end is used to reduce the risk of injury when the device is inserted, alone or in combination with the padding. 
     Catheter  500  may further comprise one or more balloons  508  along the shaft  502 . The purpose of balloon  508  is to secure the device in the patient, in some embodiments; or to concentrate the oxygen to a certain area of the lungs, in some embodiments. The one or more balloons  508  may be located at various locations along the length of shaft  502  depending on the particular needs. Balloon  508  may be inflated using the oxygen source or it may have a separate lumen in which a separate inflation device is attached. 
     The apneic oxygenation catheter may have more than one lumen.  FIG. 5B  depicts a quadruple lumen embodiment  520  having a drug delivery lumen  522   a  and an oxygen delivery lumen  522   b  inside catheter sheath  524  with apertures  526  into the lumen  522   b . In an embodiment, the lumen  522   b  is configured with a connector  525  for connecting to a fluid supply tank  518 , such as an oxygen tank. In other embodiments, the catheter may have one, two, three or more lumens. The proximal end of drug delivery lumen  522   a  is configured to be readily attached to containers  526  of drugs. Catheter  520  in some embodiments further comprises a fenestrated diaphragm  528  inside drug delivery lumen  522   a . Diaphragm  528  enables small drug particle dispersion for better lung absorption. Example drugs that may be used include, but are not limited to, epinephrine, atropine, and lidocaine. Thus, each of the first longitudinal inner passage in a distal portion and the second longitudinal inner passage in a proximal portion is divided into a plurality of lumens, each lumen in the first longitudinal passage in fluid communication with a corresponding lumen in the second longitudinal passage. 
     The oxygenation catheter may also have a bifurcated or trifurcated distal end, below a catheter sheath, to provide for additional oxygenation.  FIG. 5C  is a block diagram that illustrates an example trifurcated catheter  530  with three lumens  532   a ,  532   b  and  532   c , each configured with connectors  535   a ,  535   b ,  535   c , respectively, for connecting to a fluid supply tanks, such as an oxygen tank.  FIG. 5F  is a block diagram that illustrates an example trifurcated catheter  544  deployed in a lung  590 . The branch may be located at the base of the trachea or further down in the lung  590 .  FIG. 5F  depicts trachea  592  and a branch in one mainstem bronchus, with each different lumen  542   a ,  542   b ,  542   c , located in a different sub-segmented bronchus of bronchi  593   a ,  593   b ,  593   c , respectively. 
     Referring now to  FIG. 5D  and  FIG. 5F , one possible deployment method for the trifurcated system is a pull string. In  FIG. 5D  separate lumen  542   a ,  542   b ,  542   c  with connectors  545   a ,  545   b ,  545   c , respectively, are controlled at the distal end by pull string ring  546  connected to pull strings  547 . When pulled, the strings  547  retract a sheath  544  of the catheter, exposing each lumen in succession. By feel, the operator may leave one lumen near each of different sub-segmented bronchi. In  FIG. 5E , separate lumen  552   a ,  552   b ,  552   c  with connectors  555   a ,  555   b ,  555   c , respectively, within sheath  554 , are controlled at the distal end by pull string ring  556  connected to pull strings  557 . When pulled, the strings  557  retract each lumen in succession. Here, each of one or more distal ends (branches) is connected to a pull string  557  to coordinate the deployment of each distal end of lumen  552   a ,  552   b ,  552   c.    
       FIG. 5G  is a block diagram that illustrates an example alternative securing mechanism to the balloon  508  of  FIG. 5A . Catheter  570  includes a shaft  572  and expandable device  574   a  connected by guide wire  577  to ring  576 . When ring  576  is pulled, expandable device  574   a  expands. Expandable device  574   a  is used to anchor the catheter  570  in the airway of the target subject, as depicted in  FIG. 5H .  FIG. 5H  is a block diagram that illustrates an example location of catheter shaft  572  and expanding device  574   b  in an expanded configuration in a lung  590  of a target subject. The distal end of shaft  572  is located in sub-segmented bronchus  593   b  of sub-segmented bronchi  593   a ,  593   b ,  593   c . In an example embodiment, expandable device  574   a  is made of nitinol. However, other biocompatible materials, such as metals, plastics or other polymers, or some combination, are used in other embodiments. In some embodiments, expandable device  574   a  is a silicon balloon or similar type feature is used. Catheter  570  further comprises a guide wire channel in some embodiments. 
     Thus various embodiments include an anchoring device disposed outside the catheter at a particular distance proximal to the distal end of the distal portion of the catheter, wherein the anchoring device is configured to assume a first shape of small cross sectional area and a second shape of larger cross sectional area sufficient to fill the airway of the target subject outside the catheter. 
     Various combinations of the devices described above may be combined into a kit for emergency use. In addition to the oxygenation catheter and a cannula-trocar crycothyrotomy intubation assembly, a kit may further comprise an oxygen source. It is contemplated that an oxygen tank capable of containing enough oxygen to maintain an average sized patient for at least an hour would be preferable. However, larger or smaller tanks may be used in the kit. A person having ordinary skill in the art would be capable of determining the most appropriate tank size. In some example embodiments, vials of drugs such as, for instance, epinephrine, atropine, or lidocaine are provided with the kit. 
     A method is described for providing apneic oxygenation, according to some embodiments. Although steps are described as integral steps in a particular order for purposes of illustration, in other embodiments, one or more steps, or portions thereof, are performed in a different order, or overlapping in time, in series or in parallel, or are omitted, or one or more additional steps are added, or the method is changed in some combination of ways. A method for emergency apneic oxygenation includes cutting an opening of diameter less than 10 millimeters into an airway of a target subject at an entry site. The method also includes passing a distal end of a catheter through the opening and down the airway of the target subject to a sub-segmented bronchus of the target subject. The method still further includes connecting a distal end of the catheter to a supply of oxygen, and providing oxygen from the supply to the target subject at a rate sufficient to sustain life of the target subject. 
     In some embodiments, cutting the opening further comprises inserting at the entry site a trocar engaged with a cannula comprising a distal end of shape memory material, wherein the cannula without trocar engaged is bent in a first direction. The trocar is inserted so that the first direction is directed downward in the airway of the target subject. The step further includes removing the trocar while leaving the cannula inserted at the entry site. 
     In some embodiments, inserting the trocar engaged with the cannula at the entry site further includes placing a system base on a throat of the target subject so that an opening of the system base is centered on the entry site, and inserting the trocar engaged with the cannula through the opening in the system base. 
     In some embodiments, passing the distal end of the catheter through the opening further comprises passing the distal end of the catheter through the cannula. 
     In some embodiments, the opening into the airway of the target subject is in a range from about 2 millimeters to about 3 millimeters. 
       FIG. 6A  and  FIG. 6B  are respective front and side views of a cricothyroid membrane  630  along a throat surface of a target subject  600 , according to an embodiment. The cricothyroid membrane  630  is positioned above the trachea  625  and the cricoid cartilage  620  and below the thyroid cartilage  610 . As depicted in  FIG. 6B , a recess  640  is formed by the cricothyroid membrane  630  between the thyroid cartilage  610  and the cricoid cartilage  620 . In one embodiment, the recess  630  has a depth  650  within a range of 8-12 millimeters, such as 10.4 millimeters, for example. In another embodiment, the recess  630  has a length  660  within a range of 7-9 millimeters, such as 8.2 millimeters, for example, along the surface of the throat. As appreciated by one skilled in the art, the cricothyroid membrane  630  is a relatively soft pliable tissue, relative to the more rigid tissue that forms the thyroid cartilage  610  and the cricoid cartilage  620 . The cricothyroid membrane  630  is located below the Adam&#39;s apple  607  in a male target subject and is also located below the hyoid cartilage  605 . 
       FIG. 7A  through  FIG. 7D  are block diagrams that illustrate a variation in the system base from that depicted in  FIG. 1C , according to an embodiment. The system base  700  includes a panel  702  with a system base opening  706  that has a diameter  708  about equal to the first outer diameter of the cannula and in a range of about 0.25 to about 2.5 centimeters. In an embodiment, the panel  702  is a disc-shaped panel with a length or diameter  720  in a range of about 5 to about 20 millimeters and a thickness  717  in a range of about 0.7 to about 2 millimeters. Although the embodiment of  FIGS. 7A through 7D  depict that the panel  702  as a disc-shaped panel, the panel may take any shape that is capable of facilitating the emergency apneic oxygenation procedure discussed herein. 
     The system base  700  also includes a bumper  704  with an arcuate surface  710  that is shaped to be received by the recess  640  formed by the cricothyroid membrane  630  between the thyroid cartilage  610  and the cricoid cartilage  620  of the target subject  600 . When the arcuate surface  710  of the bumper  704  is received by the recess  640 , the system base opening  706  is centered on the cricothyroid membrane  630  to provide an entry point for the trocar engaged with the cannula. In one embodiment, the bumper  704  is a cylinder and the arcuate surface  710  is the rounded outer surface of the cylinder. A diameter or thickness  716  of the bumper  704  is in a range of about 4 to about 8 millimeters, such as 5 millimeters, for example. The bumper  704  is made from a material which maintains its shape as it is moved over the throat surface of the target subject and is a material that is capable of sliding over the skin surface of the throat surface. In one embodiment, the bumper  704  is made from any suitable rigid or semi-rigid material, including molded plastic, other types of polymers, stainless steel, titanium or cobalt chrome or some combination. In some embodiments, the plate  702  and bumper  704  are made of the same material, and in some embodiments are formed as an integral unit. In some of these embodiments, the plate  702  constitutes a broadened and flattened upper side of the bumper  704  opposite from the surface that settles into recess  640 . 
     As depicted in  FIGS. 7B and 7C , the bumper  704  is oriented such that a longitudinal axis  718  of the bumper is orthogonal to an axis  707  of the system base opening  706  that extends through an opening  705  in the bumper  704 . In one embodiment, the opening  705  in the bumper  704  is aligned with the system base opening  706  and has a diameter that is about equal to the diameter  708  of the system base opening  706 . As further depicted in  FIG. 7C , a length  722  of the bumper  704  is about equal to the diameter or length  720  of the panel  702 . In one embodiment, the length  722  of the bumper  704  is in a range of about 5 to about 10 millimeters. Although  FIG. 7C  depicts that the length  722  of the bumper  704  and the diameter or length  720  of the panel  702  are approximately equal, the length of the bumper may be greater than or less than the length of the panel. In some embodiments, the bumper  704  is configured to rotate relative to the plate  702 , so that the bumper can be rolled along the skin into the recess  640 . 
     As depicted in  FIG. 7B , in one embodiment of the system base  700 , a portion of the panel  702  includes a lighted material  724  that illuminates the system base opening  706  in a dark environment or in an absence of visible light, to assist a user of the system base  700  to locate the system base opening  706  in a dark environment. In another embodiment, a top surface of the panel  702  includes the lighted material  724  or notches, to indicate the orientation of the panel  702  to the user in a dark environment. In one embodiment, the lighted material  724  is a florescent paint that coats a perimeter of the system base opening  706  and is configured to illuminate the perimeter of the system base opening  706  in the visible spectrum, in response to an excitation frequency outside of the visible spectrum, such as infrared (IR) radiation or ultraviolet (UV) radiation, for example. Examples of such fluorescent paints include, but are not limited to, Luminescent Carbon, Fluorescent Silicon, or Low IR emitters such as trivalent chromium. In another embodiment, the lighted material  724  is one or more illumination devices, such as a light emitting diode (LED) that illuminates the system base opening  706 . In one example, the illumination device is a low-level infrared emitter that emits infrared radiation in response to a remote control device (not shown), such as at a wavelength in a range between 875 nanometers and 950 nanometers, for example, and a user observes the radiation using low red or infrared goggles. In an additional embodiment, the fluorescent material is a florescent paint that coats an inside surface of the system base opening  706 , to illuminate the system base opening  706  in a dark environment. In some embodiments, lighted material  727  is provided on the panel  702 , to indicate an orientation of the downward direction of the trachea or a direction of axis  718  of the bumper or both. 
     To use the system base  700 , the bumper  704  is initially positioned with the arcuate surface  710  in contact with the throat surface at a sternal notch (i.e., below the trachea  625  in  FIG. 6 ) or just below the chin (i.e., above the hyoid cartilage  605  in  FIG. 6 ). The bumper  704  is initially oriented such that the longitudinal axis  718  is orthogonal to the throat or torso of the target subject. The bumper  704  is then slid over the skin surface of the throat in a direction of the cricothyroid membrane  630  until the arcuate surface  710  is received in the recess  640  formed by the cricothyroid membrane  630 . In one embodiment, the arcuate surface  710  of the bumper  704  is slid along the surface of the throat. In another embodiment, the bumper  704  is rotatable relative to the panel  702  such that the bumper  704  is configured to rotate over the skin surface until the arcuate surface  710  is received within the recess  640 . 
       FIG. 8A  and  FIG. 8B  are block diagrams that illustrate a variation in the system base from that depicted in  FIG. 1C , according to an embodiment. The system base  800  depicted in  FIG. 8A  and  FIG. 8B  is similar to the system base  700  of  FIG. 7A  through  FIG. 7D , with the exception that the bumper  804  has a cross section that is an elongated triangle with rounded edges  810  between adjacent sides  812 ,  814  of the elongated triangle. In one embodiment, the bumper  804  includes an opening  805  that is aligned with the system base opening  806 . The arcuate surface of the bumper  804  that is slid along the throat surface of the target subject is one of the rounded edges  810 . In one embodiment, the rounded edges  810  are shaped, based on the depth  650  and the length  660  of the recess  640  formed by the cricothyroid membrane  630 . Although  FIG. 8A  and  FIG. 8B  depict that the bumper  804  is an elongated triangle with rounded edges, the bumper can be any elongated polygon with any number of sides, provided that the rounded edges of the elongated polygon are shaped to fit in the recess  640  formed by the cricothyroid membrane  630 . In some embodiments the upper side of the bumper  804 , opposite from the rounded edge  810  formed to contact recess  640 , is a broadened and flattened surface to serve as an integrated plate  802 . 
       FIG. 9  is a block diagram that illustrates an example use of the components of  FIG. 1A ,  FIG. 1B ,  FIG. 1D  and  FIG. 7A  through  FIG. 7D , according to an embodiment. A system  900  is provided for emergency apneic oxygenation. The system  900  is similar to the system of  FIG. 2A  through  FIG. 2D , with the exception that the system base  700  has replaced the system base  130 . The system  900  includes a cannula  910  that is similar to the cannula  110 . The cannula  910  has an inner passage of an inner diameter and a distal portion with a first outer diameter greater than the inner diameter. The cannula  910  is shaped in the distal portion to bend in a first direction  940  along the inner passage. In one embodiment, the distal portion is made of shape memory material. The cannula  910  further includes a cannula base  914  with a second outer diameter greater than the first outer diameter. As illustrated in  FIG. 9 , the system  900  also includes a trocar  920  configured to engage the cannula  910  by passing through the inner passage and straightening the bent distal portion of the cannula  910 . The system base  700  is initially moved along the throat surface  210  until the arcuate surface  710  of the bumper  704  is received within the recess  640  at the cricothyroid membrane  630 , as previously discussed. The system base opening  706  and the bumper opening  705  are then aligned with the cricothyroid membrane  630 . The engaged trocar  920  and cannula  910  are then inserted through the system base opening  706  and bumper opening  705  and through the throat surface  210  at the cricothyroid membrane  630 . 
     As illustrated in  FIG. 9 , a portion of a distal end of the trocar  920  is coated with a lighted material  926  configured to illuminate the distal end of the trocar  920  in an absence of visible light. To assist the user inserting the trocar  920  into the system base opening  706  in a dark environment, the lighted material  926  on the distal end of the trocar  920  and the lighted material  724  on the panel  702  illuminate the distal end of the trocar  920  and the system base opening  706 . In one embodiment, the lighted material  926  is a fluorescent paint that is used to coat the distal end of the trocar  920 . Examples of such fluorescent paints include, but are not limited to, Luminescent Carbon, Fluorescent Silicon, or Low IR emitters such as trivalent chromium. As further illustrated in  FIG. 9 , a portion of the cannula base  914  is coated with a lighted material  930  configured to illuminate the first direction  940  in an absence of visible light. In one embodiment, when the user inserts the engaged trocar  920  and cannula  910 , the user verifies that the illuminated fluorescent material  930  is oriented in the first direction  940  or the downward direction along the airway  220 . When the trocar  920  is subsequently removed from the cannula  910 , the cannula  910  remains in the airway  220  and the distal portion of the cannula  910  bends in the first direction  940 , to accommodate passing a catheter through the cannula and into the airway  220  in the first direction  940  for emergency apneic oxygenation. 
     As further illustrated in  FIG. 9 , upon inserting the engaged trocar  920  and cannula  910  through the cricothyroid membrane  630  and into the airway  220  of the target subject, a distance  927  from a distal end of the trocar  920  to a proximal end of the cannula  910  minus a thickness  918  of the cannula base, minus a thickness  717  of the panel  702  and minus a thickness  716  of the bumper  704  is less than a distance from a surface  210  of a throat of the target subject to a distal surface of an airway  220  of the target subject. In one embodiment, the distance  927  depicted in  FIG. 9  is longer than the distance  127  depicted in  FIG. 2B , by the thickness  716  of the bumper  704 . In one embodiment, a distance  929  from the throat surface  210  to a center of the airway  220  is in a range of 19-29 millimeters, such as 24 millimeters, for example. In another embodiment, a diameter  931  of the airway  220  at the cricothyroid membrane  630  is in a range of 18-22 millimeters, such as 20 millimeters, for example. 
       FIG. 10  is a flow diagram that illustrates an example of a method  1000  for providing emergency apneic oxygenation, according to an embodiment. In step  1001 , the arcuate surface  710  of the bumper  704  is moved along the throat surface. As previously discussed, in one embodiment, the arcuate surface  710  initially contacts the throat surface at or near the sternal notch and is moved or rolled superiorly upward toward the cricothyroid membrane  630 . In step  1003 , upon the arcuate surface  710  sliding over the throat surface and moving into the recess  640  formed by the cricothyroid membrane  630 , the arcuate surface  710  is received in the recess  640 . In step  1005 , when the arcuate surface  710  of the bumper  704  is received in the recess  640 , the system base opening  706  is aligned with an entry point in the cricothyroid membrane  630 . 
     In step  1007 , the trocar  920  engages the cannula  910  by passing the trocar  920  through the inner passage of the cannula  910 . In step  1009 , the engaged trocar  920  and cannula  910  are inserted through the system base opening  706  that is aligned with the cricothyroid membrane  630  and pass through the cricothyroid membrane  630  into the airway  220  of the target subject. In some embodiments in which the bumper  704  is rolled into place, the trocar also punctures the bumper  704  to produce an opening through the bumper aligned with the system base opening and the cricothyroid membrane  630 . During step  1009 , lighted material  926  on a distal end of the trocar  920  and lighted material  724  around the system base opening  706  are used to assist a user inserting the trocar  920  into the system base opening  706  in a dark environment. In step  1011 , after the engaged trocar  920  and cannula  910  are inserted into the airway  220 , the trocar  920  is rotated to align the trocar and cannula so the cannula will bend downward into the trachea upon removal of the trocar. 
     In step  1013 , the trocar is removed while leaving the cannula  910  inserted at the entry point in the cricothyroid membrane  630  bent in a first direction  940  (i.e. downward direction) along the airway  220 . During step  1011 , the engaged trocar  920  and cannula  910  are inserted in a manner, so that the distal portion of the cannula  910  is configured to bend in the first direction  940  (i.e. downward direction) along the airway  220  when the trocar  920  is removed in step  1013 . In one embodiment, the lighted material  930  on the cannula base  914  is oriented in the first direction  940  during step  1009 . 
     In the foregoing specification, embodiments of the invention has been described with reference to specific examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. Throughout this specification and the claims, unless the context requires otherwise, the word “comprise” and its variations, such as “comprises” and “comprising,” will be understood to imply the inclusion of a stated item, element or step or group of items, elements or steps but not the exclusion of any other item, element or step or group of items, elements or steps. Furthermore, the indefinite article “a” or “an” is meant to indicate one or more of the items, elements or steps modified by the article.