Patent Publication Number: US-2015080797-A1

Title: Device for checking indwelling site

Description:
FIELD 
     The present invention relates to a device for checking indwelling site, which checks the indwelling site of a medical tube indwelled in the digestive tract, such as the stomach and the duodenum. 
     BACKGROUND 
     Persons whose food intake function has decreased due to, for example, advanced age or disease, “patients,” must be assisted through some sort of means in taking in nutrition required to maintain life. One conventional example of such is a medical tube that is inserted orally or intranasally and indwelled in the digestive tract, such as the stomach and the duodenum, to administer nutrition (so-called feeding tube). Such a medical tube is designed to be indwelled in the digestive tract, such as the stomach and the duodenum, by inserting the tip into the esophagus side. In some cases, however, the tip is mistakenly inserted into the respiratory tract side, and consequently the medical tube is mistakenly indwelled in the lower respiratory tract, such as the bronchi or lungs. 
     In such cases, if the patient is an ordinary patient, they often either cough or vomit to prevent erroneous indwelling. If such a medical tube is inserted into a patient who is of advanced age or unconscious, however, such living body reactions as coughing or vomiting might not necessarily occur. Therefore, some sort of means or methods is necessary in order to check the indwelling site of a medical tube. Generally, the following means are used: checking by means of the air bubble generated when air is injected into the stomach, checking based on whether or not the stomach contents can be sucked in (including visual observation), checking based on the pH of the stomach contents sucked in and collected from the stomach, checking by means of X-ray radiography, or checking by means of an endoscope mounted on the tip of the tube. 
     For example, in a publication titled Healthcare Safety Information. “No. 8: Preventing Accidental Erroneous Insertion or Injection of Intranasal Feeding Tubes,” the Japanese Nursing Association recommends that the indwelling site of a feeding tube be checked every time when giving nutrients or the like through an inserted feeding tube by determining whether or not the gastric juice (stomach contents) can be sucked in and whether or not the air bubble sounds can be detected by means of radiography or litmus paper. 
     In addition to the above, a technique has been disclosed for checking the indwelling site of a feeding tube by means of gastric juice pH are disclosed (for example, see Japanese Kokai Patent Publication No. 62-298331). A technique has also been disclosed for checking the indwelling site of a tube indwelt, in the respiratory tract by means of carbon dioxide (for example, see U.S. Pat. No. 5,124,129). 
     In a technique such as described in Japanese Kokai Patent Publication No. 62-298331, an attempt to suck in gastric juice from the stomach of a patient might fail depending on how gastric juice accumulates in the patient. A technique such, as described in U.S. Pat. No. 5,124,129 requires mounting and dismounting a carbon dioxide detection device instead of a syringe, which makes the technique cumbersome. When an indwelling site is checked by means of air bubble sounds, instead of directly collecting the gastric juice, the indwelling site is checked just by indirectly listening to sounds which include considerable noise, making it difficult to accurately determine the indwelling site. Therefore, such a technique lacks reliability. 
     Although radiography increases the level of reliability, such a method is not desirable from the standpoint of decreasing exposure to medical radiation as much as possible. Radiography also requires large-scale equipment, which is inconvenient, and not cost-effective when checking each time. The method using litmus paper requires dripping suctioned gastric juice onto litmus paper, which makes the technique cumbersome. Using an endoscope mounted on the tip of the medical tube increases the level reliability, but such a method requires large-scale equipment and a high level of operator expertise. 
     Moreover, the indwelling site of a medical tube cannot be accurately checked by any one method alone. The indwelling site of a medical tube cannot be accurately checked even using X-ray. In addition, although combining a plurality of checking methods is said to be standard procedure, using the equipment and tools needed for a plurality of checking methods makes the equipment bulky and the checking procedure complicated. On the other hand, considering future rising demand for medical tubes, it will be increasingly important to be able to carry out a plurality of checks without requiring large-scale equipment or a high level of specialization. 
     SUMMARY 
     In accordance with one or more aspects, the present invention can provide a device for checking indwelling site capable of carrying out a plurality of operations for checking the indwelling site of a medical tube by simple techniques using a single device. 
     In accordance with one or more aspects, the device for checking indwelling site of the present invention can check the indwelling site of the tip of a medical tube, provided with a barrel for connecting to the medical tube, a first plunger having a hollow torso member and a first tip member disposed on the tip of the torso member and having a hole formed communicating between the inner cavity of the torso member and the inner cavity of the barrel, and disposed capable of pushing into or pulling out of the barrel, a second plunger having a second tip member and that is disposed capable of pushing into or pulling out of the torso member of the first plunger, and a carbon dioxide detecting member that is arranged inside the torso member and closer to the tip than to the second tip member, wherein the first plunger is restricted from moving towards the tip at a location where the first tip member does not contact the inner wall of the barrel on the tip side, and has a space having a predetermined volume formed between the tip face of the first tip member and the inner wall of the barrel on the tip side. 
     In accordance with one or more aspects, the device for checking indwelling site of the present invention can carry out a plurality of checking operations using a single device and by simple techniques, and thus can greatly improve the reliability of checking whether or not the tip of a medical tube has been indwelled appropriately. 
    
    
     
       BRIEF EXPLANATION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing the overall configuration, of a device for checking indwelling sites according to Embodiment 1 of the present invention. 
         FIG. 2  is an enlarged schematic view showing an enlargement of a part of the device for checking indwelling sites according to Embodiment 1 of the present invention. 
         FIG. 3  is a schematic view showing the overall configuration of a device for checking indwelling sites according to Embodiment 2 of the present invention. 
     
    
    
     Embodiments of the present invention will be described hereinafter using the attached drawings as a reference. 
     DETAILED DESCRIPTION 
     Embodiment 1 
       FIG. 1  is a schematic view showing the overall configuration of a device for checking indwelling site of Embodiment 1 of the present invention (hereafter, referred to as the device  100 ).  FIG. 2  is an enlarged schematic view showing an enlargement of a part of the device  100 . The device  100  will be described using  FIGS. 1 and 2  as a reference. It will be noted that the relative size of the parts may differ from the actual size of the parts in the drawings, including  FIG. 1 .  FIG. 2  also omits the scale  44  on the barrel  40 . 
     The device  100  is a medical device used when inserting a medical tube  10  orally or intranasally to indwell a tip  10   a  thereof in the digestive tract, such as the stomach or duodenum, and thereby administer nutrition or cause the contents of the digestive tract to be discharged from the digestive tract. The device  100  can inject air for listening to and checking air bubble sounds when inserting the medical tube  10  or administering nutrients, allowing at least checking operations to be carried out using a single device; namely, detecting and checking body fluids, and detecting and checking carbon dioxide. Specifically, the more checking operations that are carried out, the more likely it is to detect erroneous insertion and indwelling of the tip  10   a . The device  100  can achieve a plurality number of checking operations using a single device, and thus enhances the reliability of determining the indwelling site of the tip  10   a.    
     Configuration of Device  100   
     As exemplarily shown, in  FIG. 1 , the device  100  can comprise the medical tube  10 , a syringe  50 , a detecting member such as a carbon dioxide detecting member  60  (hereafter, simply referred to as the detecting member  60 ), an adaptor  70 , and a connector  75 . In the following explanation, the side to be inserted into the patient (the patient side) is called the tip side or tip end, and the side to be operated by the operator (the operator side) is called the base side or base end. 
     Medical Tube  10   
     The medical tube  10  is typically a flexible tubular material, and may be formed of a synthetic resin such as, for example, polyurethane or polyvinyl chloride. The medical tube  10  has a tip  10   a  and a base  10   b . The tip  10   a  is designed to indwell in the digestive tract, such as the stomach or the duodenum, and the base  10   b  is designed to be connected to the adaptor  70 . The shape of the tip  10   a  is not specifically limited, but it, should be a shape that does not damage the part of the medical tube  10  to be inserted. The tip  10   a  also functions as a weight to facilitate inserting the medical tube  10  through peristaltic movements. An opening, through which fluid passes when supplying nutrients or sucking in the content, inside the digestive tract, can be formed on the tip  10   a . The base  10   b  can have a shape capable of connecting to the adaptor  70  (for example, a shape capable of inserting into the adaptor  70  shown in  FIG. 1 ). 
     A guide wire for facilitating insertion into the digestive tract may be inserted into the inner cavity of the medical tube  10  beforehand in a manner allowing later withdrawal. When inserting the guide wire into the inner cavity of the medical tube  10 , the tip of the guide wire is typically positioned to the inside of the tip  10   a  of the medical tube  10 . The guide wire can assist in inserting the medical tube  10  into the digestive tract such as the stomach and the duodenum. The guide wire may be inserted into the inner cavity of the medical tube  10  through the adaptor  70 . The base of the guide wire may be fixed by the adaptor  70  or may protrude from the adaptor  70 . 
     Although Embodiment 1 was described for an example in which the medical tube  10  is a feeding tube, the medical tube is not limited to a feeding tube, and the medical tube  10  may be a tube other than a feeding tube (for example, a drain tube) to be indwelt in the digestive tract. Although a drain tube and a feeding tube typically have different diameters, the method for indwelling these tubes in the digestive tract is similar. 
     Syringe  50   
     The syringe  50  typically has at least a barrel  40  attached by a connector  75  to a tip member  41  and through which a first plunger  20  is pushed in or pulled out from the base side. The first plunger  20  is typically disposed to be capable of freely pushing into or pulling out of the barrel  40 . A second plunger  30  is typically disposed to be capable of freely pushing into or pulling out from within the first plunger  20 , for example, the inside of a torso member  21 , and a space-forming member  26  disposed on the tip of the first plunger  20  and designed to assure a space of a predetermined volume between the inside of the barrel  40  and a first tip member  22 . 
     First Plunger  20   
     The first plunger  20  typically comprises the hollow torso member  21  having the second plunger  30  disposed inside capable of freely pushing in or pulling out, and the first tip member  22  disposed on the tip of the torso member  21  and having a hole  23  formed communicating between the outside, specifically, the inner cavity of the barrel  40 , and the inner cavity of the torso member  21 . When force applied by the operator is transmitted through the torso member  21 , the first plunger  20  typically is pushed into and pulled out of barrel  40  so as to vary the pressure in the barrel  40 . For example, the first plunger  20  can suck fluids (liquids (digestive fluids such as gastric juice), gasses (gasses such as carbon dioxide), or mixtures thereof) into the barrel  40  when pulled by the operator; and drain the fluids in the barrel  40  when pushed. 
     The torso member  21  can serve to transmit force applied by the operator. It comprises a clear synthetic resin, for example, in a manner so that the cross-section thereof is circular or polygonal (such as a hexagon or octagon). Embodiment 1 shows an example in which the cross-section of the torso  21  is circular. As exemplarily shown in  FIG. 2 , a scale  24  may be disposed on the outer wall of the torso member  21 . If provided, the scale  24  is helpful in determining the volume of the fluid (gas) sucked into the torso member  21 . Although the drawings show an operating member  25 , for assisting the operation of pushing in or pulling out the first plunger  20 , provided on the periphery on the base of the torso member  21 , the operating member  25  is optional, and is not essential. 
     The first tip member  22  typically is mounted on the periphery of the tip of the torso member  21  through fitting, screwing, adhering, or welding, and the peripheral surface thereof contacts the inner wall of the barrel  40 . When force is transmitted by the operator to the first plunger  20 , the first plunger  20  typically is pushed or pulled so that the peripheral surface of the first tip member  22  slides on the inner wall of the barrel  40 . An example of the material comprising the first tip member  22  is a gasket or the like. The hole  23  for communicating between the inside of the barrel  40  and the inside of the first plunger  20  is formed in the approximate center of first tip member  22 . When equipped with a hydrophobic filter, the hole  23  prevents fluids from flowing into the torso member  21 . 
     Because the second plunger  30  (to be described later) keeps the inside of the torso member  21  airtight, the inside of the barrel  40  can be kept airtight even when the hole  23  is formed on the first tip member  22 . 
     The tip of the torso member  21  may be covered by the first tip member  22 , and a cylindrical member passing through the hole  23  formed on first tip member  22  may disposed on the tip of the torso member  21 . If the cylinder member is provided, the torso member  21  needs to have a bottom of a cylindrical shape, on the tip of which a through hole is formed. The cylinder member may also be formed so as to protrude from the center of the bottom. The first tip member  22  may be formed so as to be integrated with the torso member  21 . Although the material comprising the first tip member  22  is not specifically limited, considering contact with the inner wall of the barrel  40 , this material is preferably a flexible material; for example, an elastomer such as a rubber or a synthetic resins. 
     Second Plunger  30   
     The second plunger  30  typically comprises a stick-like member  31  disposed capable of pushing in or pulling out of the inside of the torso member  21  of first plunger  20 , and a second tip member  32  disposed on the tip side. When force applied by the operator is transmitted through the stick-like member  31 , the second plunger  30  is either pushed into or pulled out of the inside of the torso member  21  of the first plunger  20 . The second plunger  30  can suck in fluids (gasses) inside the torso member  21  of the first plunger  20  when pulled by the operator, and drain the fluids inside the torso member  21  of the first plunger  20  when pushed by the operator. 
     The stick-like member  31  typically serves to receive the force applied by the operator, and this member may be constituted with a synthetic resin, etc. Although not specifically limited in cross-sectional shape, the stick-like member  31  need not be hollow inside, unlike the torso member  21  of the first plunger  20 , which must be hollow inside. 
     Although the drawings show an operating member  35 , for assisting the operation of pushing in or pulling out the second plunger  30 , provided on the periphery on the base of the stick-like member  31 , the operating member  35  is optional, and is not essential. 
     The second tip member  32  typically is mounted on the periphery of the tip of the torso member  31  through fitting, screwing, adhering, or welding, and the peripheral surface thereof contacts the inner wall of the torso member  21  of the first plunger  20 , making the inside of the torso member  21  of the first plunger  20  airtight. When force is transmitted by the operator to the second plunger  30 , the second plunger  30  is pushed or pulled so the peripheral surface of the second tip member  32  slides on the inner wall of the torso member  21  of the first plunger  20 . An example of the material comprising the second tip member  32  is a gasket or the like. The second tip member  32  may also be formed integrated with the stick-like member  31 . Although the material comprising the second tip member  32  is not especially limited, considering contact with the inner wall of the torso member  21  of the first plunger  20 , the material is preferably a flexible material; for example, an elastomer such as a rubber or a synthetic resins. 
     Barrel  40   
     The barrel  40  typically is a cylinder having an inside that can be visually checked, a through hole formed on the tip member  41 , and a bottom. The barrel typically is linked to the medical tube  10 , which can be freely mounted or dismounted through the connector  75  and the adaptor  70 . The barrel  40  comprises, for example, a clear synthetic resin, and is formed into a shape of which the cross-sectional plane is circular or polygonal (such as a hexagon or an octagon). Embodiment 1 of a barrel  40  having a circular cross section. 
     A cylinder  42  typically is formed so as to project from the central portion of the tip member  41  of the barrel  40  and capable of freely mounting or dismounting by means of a connector  75 , which is fit or screwed on. Embodiment 1 shows an example of the cylinder  42  formed in the central portion of the tip member  41 . However, the location where the cylinder  42  is formed is not specifically limited, and the cylinder  42  may be formed at a different location from the central portion of the tip member  41 . 
     As exemplarily shown in  FIG. 1 , a scale  44  may be disposed on the outer wall of barrel  40 . If provided, the scale  44  is helpful for determining the volume of the fluid (gas, liquid, or a mixture of both) sucked into the torso member  21 . The drawings show an operating member  43 , for assisting the operation of pushing in or pulling out the first plunger  20  and projecting peripherally, provided on the periphery on the base opposite the tip member  41  of the barrel  40 . This operating member  43  coordinates with the operating member  25  and the operating member  35  to contribute to the operations by the operator. The operating member  43  is optional, however, and is not an essential member. 
     Space-Forming Member  26   
     The space-forming member  26  typically is provided on the tip of the first plunger  20 , or more specifically on the tip face of the first tip member  22 , so as to protrude towards the tip side, and forms a space  55  of a predetermined volume between the inner wall of the barrel  40  (hereafter, referred to as the inner wall  41   a ) on the tip side and the tip face of the first tip member  22 . The space-forming member  26  can in some cases also function as a stopper that restricts the movement of the first plunger  20  towards the tip side at a predetermined location (a location at which the first tip member  22  does not contact the inner wall  41   a  of the barrel  40  on the tip side; specifically, at a location that assures a predetermined volume capable of storing the liquid fraction of the sucked-in fluid). Providing the space-forming member  26  allows the liquid fraction of the fluid sucked into the barrel  40  to be stored in the space  55 , and enables intake of just the gas fraction into the torso member  21  of the first plunger  20 . 
     The space  55  typically has a predetermined volume allowing storage of the liquid fraction of the sucked-in fluid. Specifically, the space  55  has a larger volume than when the inner wall  41   a  on the tip side of the barrel  40  contacts the tip face of first tip member  22 . In the device  100 , the space-forming member  26  typically is provided on the tip face of the first tip member  22  so as to protrude further towards the tip side, thus assuring the space  55 . The space  55  typically serves to store the liquid fraction of the fluid sucked into the barrel  40 , and make it easier to intake gas into the torso member  21  of the first plunger  20 . Without the space  55 , it is more likely that all of the fluid sucked into the barrel  40  will be sucked into the torso member  21  of the first plunger  20  and contact the liquid. Consequently, the carbon dioxide might not be detected. The space-forming member  26  does not close the cylinder member  42 , inside the barrel  40 , or the hole  23  of the first tip member  22 . 
     The space-forming member  26  may take any shape capable of exhibiting the above functions. For example, the space-forming member  26  may comprise a cylinder having walls completely surrounding the hole  23  of the first tip member  22 , or may comprise a shape having a plurality of legs longitudinally in the axial direction. As shown in  FIG. 2 , the contacting member  26   a , which contacts the inner wall  41   a  on the tip side of the barrel  40 , may be disposed on the tip side of the space-forming member  26 . The materials comprising the space-forming member  26  and the contacting member  26   a  are not specifically limited, and these members may comprise, for example, a synthetic resin. 
     Although the example is shown of a configuration in which the space-forming member  26  is disposed to the space  55 , the space need not necessarily be provided by disposing the space-forming member  26  so long as the space  55  is formed between the inner wall  41   a  on the tip side of the barrel  40  and the tip face of the first tip member  22 ; that is, as long as the first tip member  22  of the first plunger  20  is prevented from contacting the inner wall  41   a  on the tip side of the barrel  40 . For example, a stopper may be provided on the base side of the torso member  21  so as to assure a space of a predetermined volume between the inner wall  41   a  on the tip side of the barrel  40  and the tip face of the first tip member  22 . In such a case, it is convenient to have the operating member  25  function as a stopper to stop the first plunger  20  moving towards the tip side by causing the operating member  25  to contact the base edge of the barrel  40 . 
     Detecting Member  60   
     The detecting member  60  typically is arranged inside the torso member  21  of the first plunger  20  at a location closer to the tip side than the second tip member  32  of the second plunger  30 , and discolors when it reacts with carbon dioxide. For example, when the fluid (gas) sucked into the torso member  21  of the first plunger  20  is carbon dioxide, the detecting member  60  reacts with the carbon dioxide and discolors. The detecting member  60  may use any conventional technique capable of detecting carbon dioxide. For example, the detecting member  60  may comprise a sheet-like material that discolors when it contacts carbon dioxide. The detecting member  60  should be located inside the torso member  21 . The detecting member  60  can detect even a small volume of carbon dioxide, however, if located close to the suction inlet of the torso member  21 ; specifically, close to the hole  23  of the first tip member  22 . 
     Adaptor  70   
     The tip of the adaptor  70  typically is connected to the base  10   b  of the medical tube  10 , and the base thereof is connected to the connector  75 , thus functioning to connect the medical tube  10  to the syringe  50  through the connector  75 . The adaptor  70  typically is connected to the connector  75  in a freely mountable and dismountable manner, allowing the medical tube  10  to be easily mounted and dismounted through the adaptor  70 .  FIG. 1  shows an example in which the diameter of the adaptor  70  becomes smaller towards the tip.  FIG. 1  also shows a configuration in which a cap  71  is disposed on the base of the adaptor  70 . 
     The adaptor  70  may comprise a clear synthetic resin allowing the flow of fluid to be easily recognized. Although  FIG. 1  shows an example in which the base  10   b  of the medical tube  10  is connected to the tip of the adaptor  70 , the medical tube  10  may remain in a freely mountable and dismountable manner. The connecting method between the medical tube  10  and the adaptor  70  is not specifically limited. Although the adaptor  70  is not an essential member of device  100 , it is provided that the adaptor can improve operability. If the adaptor  70  is not provided, the medical tube  10  may be connected to the tip of the connector  75 . The cap  71  typically functions to prevent liquid dripping from the adaptor  70  when the adaptor  70  is removed from the connector  75 . The cap  71  is not an essential member. Although the explanation provided herein discusses a configuration in which the adaptor  70  and the medical tube  10  are separate members, the adaptor  70  may be configured so as to be integrated with the medical tube  10 . 
     Connector  75   
     The tip of the connector  75  typically is connected to the adaptor  70 , and the base typically is connected to the cylinder  42  of the barrel  40 , thus functioning to connect the medical tube  10  to the syringe  50 . As shown in  FIG. 1 , when the tip side of the connector  75  comprises a catheter-tip shape, the adaptor  70  can be more easily mounted and dismounted. This also prevents erroneous connections. Although  FIG. 1  shows an example in which the base side of the connector  75  is screwed onto the periphery of the cylinder  42  of the barrel  40 , the shapes of the tip and the base of connector  75  are not limited to the shapes shown in  FIG. 1 , and may take a lure-like shape. In such a case, the base of the adaptor  70  and the cylinder  42  typically also may take either a male lure shape or a female lure shape. 
     The connector  75  preferably comprises a clear synthetic resin allowing the flow of the fluids to be easily seen. Although the connector  75  is not an essential part of device  100 , providing the connector can improve operability. If the connector  75  is not provided, the adaptor  70  is connected to the cylinder  42 . If neither the adaptor  70  nor the connector  75  is provided, the base  10   b  of the medical tube  10  may be directly connected to the cylinder  42 . 
     Techniques Utilizing Device  100   
     An exemplary explanation regarding the techniques utilizing device  100  is provided below. 
     First, an operator prepares the device  100 . Subsequently, the operator measures the approximate length of the medical tube  10  to be inserted (specifically, the length reaching the stomach). If a guide wire is utilized, whether the tip of the guide wire has been inserted correctly to reach the tip member  10   a  of the medical tube  10  must be checked. When a guide wire is utilized, the medical tube  10  is preferably inserted with the medical tube  10  and the adaptor  70  removed from the connector  75 . The base of the guide wire is preferably fitted inside the adaptor  70 . 
     Subsequently, the operator applies an anesthetic lubricant (for example, lidocaine gel, etc.) on medical tube  10  from tip member  10   a  thereof to a location 15 cm to 20 cm down from, the tip to lubricate medical tube  10 , and then starts inserting the tube into oral cavity or the nasal cavity. The operator causes tip member  10   a  of medical tube  10  to reach the target digestive tract such, as the stomach or duodenum, etc. After tip member  10   a  of medical tube  10  has reached the target digestive tract of the patient, the guide wire is removed from medical tube  10 . Subsequently, the operator removes cap  71  of adaptor  70 , and connects syringe  50  to the base of adaptor  70  through connector  75 . 
     In order to check whether or not tip member  10   a  of medical tube  10  has reached the target digestive tract, the operator injects air by pushing first plunger  20 , and then checks the presence of air bubble sounds by means of a stethoscope (the first checking operation). If the air bubble sounds are confirmed, the operator can determine that tip member  10   a  of medical tube  10  might have reached the target digestive tract. As stated above, device  100  is capable of injecting the air that is necessary to conduct the first checking operation without utilizing another device. The device  100  is capable of conducting the second checking operation while the injection of air is going on; in other words, even when the device remains connected to medical tube  10 . 
     Subsequently, the operator pulls first plunger  20  to reduce the pressure within barrel  40  and eventually to suck in the body fluid from tip member  10   a  of medical tube  10 . Subsequently, the operator checks whether or not first plunger  20  has been pulled; in other words, whether or not the body fluid has been successfully sucked in (the second checking operation). If the body fluid is successfully sucked in, the operator is able to determine that the likelihood of tip member  10   a  of medical tube  10  having reached the target digestive tract is furthermore increased. At this time, the operator also visually checks whether or not the body fluid has been successfully sucked in. It is unknown at this stage whether or not the sucked in body fluid is a digestive fluid. The pH of the fluid that has been sucked into barrel  40  may be checked by means of litmus paper, BTB solution, pH meter, etc. If the resulting pH indicates a value showing the properties of the digestive fluid that is secreted from the target digestive tract, for example, the operator is able to determine that the likelihood that the medical tube has reached the target digestive tract is further increased. 
     However, even when air bubble sounds are confirmed in the first checking operation, and even when the fluid suction is confirmed in the second checking operation, it is still not certain that tip member  10   a  of medical tube  10  has reached the target digestive tract. Thus, device  100  is further capable of conducting the third checking operation, in addition to the air injection necessary to conduct the first checking operation as well as the second checking operation. That, is, the more checking operations that are conducted, the higher the likelihood that erroneous indwelling of the tip member  101  will be noticed. Thus, the device  100  can carry out a plurality of checking operations using a single device. 
     The operator pulls second plunger  30 , reduces the pressure within torso member  21  of first plunger  20 , and causes only the gas fraction of the fluid, which has been sucked into barrel  40 , to be sucked in torso member  21  of first plunger  20 . Subsequently, the operator checks whether or not detecting member  60 , which is provided on torso member  21  of first plunger  20 , reacts (the third checking operation). If detecting member  60  reacts, the operator is easily able to confirm in a visual manner that the sucked-in gas is carbon dioxide, and thereby is able to determine that tip member  10   a  of medical tube  10  has reached not the target digestive tract, but rather the lower airway, such as the bronchi or the lungs. On the other hand, if detecting member  60  does not react, the operator is able to determine that the likelihood that tip member  10   a  of medical tube  10  reached the target digestive tract is furthermore increased. 
     If any of the checking operations, namely the confirmation of air bubble sounds through the first checking operation, confirmation of the body fluid through the second checking operation, and detection of carbon dioxide through the third checking operation, does not confirm that tip member  10   a  of medical tube  10  has been indwelt at an appropriate location, the operator is then able to determine that the likelihood is high that tip member  10   a  of medical tube  10  reached not the target digestive tract, but rather the lower airway such as the bronchi or the lungs; in other words, that tip member  10   a  has been erroneously indwelt. In such case, medical tube  10  needs to be immediately removed, and re-inserted. By conducting all of the checking operations from, the first to the third, it becomes possible to increase the reliability of the judgment regarding whether or not tip member  10   a  of medical tube  10  has been indwelt at an appropriate location. 
     On the other hand, if a high likelihood that tip member  10   a  of medical tube  10  has been indwelt at an appropriate location is confirmed in all of the checking operations from the first, to the third, the operator is then able to determine that the likelihood is very high that tip member  10   a  of medical tube  10  has reached the target digestive tract. In such case, medical tube  10  is fixed with a surgical tape and the like, and the series of operations for inserting the medical tube  10  is completed. 
     Thus, if nutrients are provided through the medical tube  10 , the syringe  50  and the connector  75  are both removed from the adaptor  70 , and a tube for providing nutrients can be connected to the adaptor  70 . When draining the contents of the digestive tract through the medical tube  10 , the syringe  50  and the connector  75  are both removed from the adaptor  70 , and a draining tube connected to a suction device such as a negative pressure generator or the like can be connected to the adaptor  70 . If not carrying out feeding or draining, the cap  71  is preferably mounted on the adaptor  70 . 
     As stated above, according to the device  100  of Embodiment 1, the following excellent effects are obtained. According to the device  100 , a plurality of checking operations can be carried out using a single device by simple techniques. Therefore, according to the device  100 , because the indwelling sites of the tip member  10   a  of the medical tube  10  are checked through a plurality of checking operations, the reliability of judging whether or not the tip of the medical tube has been indwelled appropriately is greatly improved. According to the device  100 , unlike methods using radiography or endoscopy, because the indwelling sites of the tip member  10   a  of the medical tube  10  are checked through simple techniques, no large-scale equipment is necessary, and no high level of expertise is required from the operator. Therefore, the device  100  is extremely superior in terms of versatility and cost effectiveness. 
     Embodiment 2 
       FIG. 3  is a schematic view exemplarily showing the overall configuration of a device for checking indwelling site (hereafter, referred to as the device  100 A) of Embodiment 2 of the present invention. The device  100 A will be described using  FIG. 3  as a reference. Like the device  100  of Embodiment 1, the device  100 A is a medical device that is used to insert a medical tube  10  orally or intranasally to indwell the tip  10   a  thereof in the digestive tract, such as the stomach or the duodenum, and thereby administer nutrition or cause the contents of the digestive tract to be discharged from the digestive tract. Embodiment 2 will be primarily described in terms of the differences from embodiment 1, and an explanation regarding the portions that are the same as Embodiment lis omitted by assigning the same reference numerals to such portions. 
     The device  100 A can carry out three of the following checking operations in a single device: when inserting the medical tube  10  or administering nutrients, air for checking air bubble sounds can be injected, body fluids can be detected and checked, carbon dioxide can be detected and checked, and the pH of the body fluid can be checked. Specifically, the device  100 A can carry out checking the pH of the sucked-in body fluid (a fourth checking operation) in addition to the second and third checking operations of Embodiment 1. That is, the more checking operations that are conducted, the more likely it is to detect the erroneous insertion and indwelling of the tip  10   a . The device  100 A can carry out a plurality of checking operations using one device, and thus enhances the reliability of determining the indwelling site of the tip  10   a.    
     Configuration of Device  100 A 
     The basic configuration of the device  100 A is similar to the device  100  of Embodiment 1 shown in  FIG. 3 . The device  100 A differs from the device  100  in having a body fluid retrieving member  80  mounted on the barrel  40 , and a connecting tube  85  connected to the body fluid retrieving member  80 . Otherwise, the configuration of the device  100 A is the same as the configuration of the device  100  in Embodiment 1. 
     Body Fluid Retrieving Member  80   
     The body fluid retrieving member  80  can have a nearly cylindrical casing  81 , a cylindrical connector  82  arranged projecting from the tip side of the casing  81 , and a linking member  83  arranged on the base side of the casing  81 . 
     The casing  81  typically comprises a synthetic resin or the like, is nearly cylindrical, and has openings on the tip side axially (on the side of the barrel  40 ) and on the rear edge side (the side of the connecting tube  85 ). The cylindrical connector  82  is arranged projecting from the tip of the casing  81 , and is nearly coaxial with the casing  81 . The inner cavity of the casing  81  communicates with the inner cavity of the barrel  40  through the cylindrical connector  82 . The body fluid retrieving member  80  may be fixed onto the barrel  40  through the cylindrical connector  82 , or remain freely mountable and dismountable. 
     The tip of the cylindrical connector  82  typically is connected to the barrel  40 , and the base typically is connected to the casing  81  to communicate between the inner cavity of the barrel  40  and the inner cavity of the casing  81 . The diameter and the length of the cylindrical connector  82  are not specifically limited, as long as the cylindrical connector  82  communicates between the inner cavity of the barrel  40  and the inner cavity of the casing  81 . The tip of the cylindrical connector  82  may be mounted on a part of the wall of barrel  40 , or alternatively cylindrical connector  82  may be formed so as to be integrated with barrel  40 . The casing  81  may be mounted in a freely mountable or dismountable manner onto the base of cylindrical connector  82 , which is connected to barrel  40 ; alternatively, cylindrical connector  82  and casing  81  may be formed so as to be mutually integrated. 
     Linking member  83  typically is provided on the base of casing  81 , and it provides the linkage to the tip of connecting tube  85  shown additionally in  FIG. 3 . To prevent the inner cavity of barrel  40  from, being accidentally linked, to the outer air through the inner cavity of casing  81  when connecting tube  85  is not linked, linking member  83  preferably has a closure member such as a septum (a flexible member such as rubber), cap, and the like.  FIG. 3  shows an example in which septum  83   a  is provided on linking member  83 . In such a case as the above in which septum  83   a  is provided, it is necessary to form a space that is capable of accommodating the septum, on either linking member  83  or casing  81 . If septum  83   a  is provided, a slit that allows casing  81  and connecting tube  85  to mutually link must be formed on septum  83   a.    
     Connecting Tube  85   
     Connecting tube  85  typically comprises tip linking member  86 , which provides a linkage to linking member  83 ; tube main body  87 , which is connected to tip linking member  86 ; body fluid stopper  88 , which is provided on the base of tube main body  87 ; and pH detecting member  89 , which is provided in the inner cavity of tube main body  87 . 
     Tip linking member  86  typically is provided on the tip side of tube main, body  87 , and typically is constituted, so as to be linkable to linking member  83  of body fluid retrieving member  80 . The constitution of tip linking member  86  is not specifically limited, as long as it is constituted to be linkable to linking member  83  of body fluid retrieving member  80 . For example, tip linking member  86  may be constituted as a male connector, and linking member  83  of body fluid retrieving member  80  may be constituted as a female connector so that these members are fit or screwed, together to be connected. The male/female assignments may be reversed. Specifically, tip linking member  86  may be constituted by utilizing general connectors. 
     However, linking member  83  of body fluid retrieving member  80  may be constituted to be linkable to tip-side linking member  86 . As shown in  FIG. 3 , if septum  83   a  is provided on linking member  83  of body fluid retrieving member  80 , linking tube  86   a , which can be inserted into the slit formed on septum  83   a , needs to be provided. The connection constitution of body fluid retrieving member  80  and connecting tube  85  is not limited to the constitution shown in  FIG. 3 , and connection constitutions that are widely utilized may be used. 
     Tube main body  87  typically allows the body fluids retrieved by body fluid retrieving member  80  to pass through. Tube main body  87  may be constituted with a synthetic resin such as polyvinyl chloride, which is a flexible tube material and does not contain polyurethane or plasticizers. The length and diameter of tube main body  87  are not specifically limited, and commonly-utilized tubes may be utilized to constitute tube main body  87 ,  FIG. 3  shows an example in which clamp  87   a  is provided on tube main body  87 . Clamp  87   a  closes and opens the inner cavity of tube main body  87  in a freely closeable/openable manner. Clamp  87   a  is not an essential member, and the operator may close and open the inner cavity of tube main body  87  by utilizing their fingers. 
     Body fluid stopper  88  typically is provided on the base of tube main body  87 , and can prevent the body fluid coming out of tube main body  87  from flowing out of connecting tube  85 . Body fluid stopper  88  may be constituted with a hydrophobic filter and the like which allows only gases to pass through. Other members of different connection constitutions may be connected to body fluid stopper  88 . In such case, a balloon, syringe, negative pressure generator, and the like may be connected to body fluid stopper  88  as examples so that the body fluid that has been sucked into barrel  40  is sucked to the side of body fluid retrieving member  80 . 
     pH detecting member  89  typically reacts with the body fluid guided into tube main body  87 , thereby to detect the pH of the body fluid. pH detecting member  89  may be constituted with any material, as long as it can be accommodated within tube main body  87  and is capable of detecting pH. For example, pH detecting member  89  may be constituted with litmus paper. 
     Techniques Utilizing Device  100 A 
     An exemplary explanation regarding the techniques utilizing device  100 A is provided below. The techniques for the first to the third checking operations are similar to those discussed for device  100  in embodiment 1. 
     When it has been confirmed through the second checking operation that the body fluid has been sucked in, the operator retrieves the body fluid, which has been sucked into barrel  40 , into body fluid retrieving member  80 , for example, by means of specific gravity or sucking force. Subsequently, the operator connects connecting tube  85  to body fluid retrieving member  80 . When connecting tube  85  becomes connected to body fluid retrieving member  80 , the inner cavity of tube main body  87  is opened to transfer the body fluid, which has been retrieved into body fluid retrieving member  80 , to the side of connecting tube  85 . Subsequently, the operator supplies the body fluid to pH detecting member  89 , which is provided on tube main body  87 , and checks the pH of the body fluid through the operations of pH detecting member  89  (the fourth checking operation). 
     If the pH that is detected by pH detecting member  89  is a value that indicates the properties of the digestive fluid secreted from the target digestive tract, for example, the operator is then able to determine that the likelihood of tip member  10   a  of medical tube  10  having reached the target digestive tract is furthermore increased. The fourth checking operation may be conducted in parallel with the third checking operation discussed in embodiment 1, subsequent to the third checking operation, or prior to the third checking operation. Specifically, the more checking operations that are conducted, the more likely it is to detect the erroneous insertion and indwelling of tip  10   a . Device  100 A enables a multiple number of checking operations in a single device, and thus it enhances the reliability of determining the indwelling site of the tip  10   a.    
     If there is any of the checking operations, namely the confirmation of air bubble sounds through the first checking operation, confirmation of the body fluid through the second checking operation, detection of carbon dioxide through the third checking operation, or confirmation of the pH of the body fluid through the fourth checking operation, that does not confirm that tip member  10   a  of medical tube  10  has been indwelt at an appropriate location, the operator is then able to determine that the likelihood that tip member  10   a  of medical tube  10  has reached the lower airway such as the bronchi or lungs, instead of the target digestive tract-namely, that it has been erroneously indwelt, is high. By conducting all of the checking operations from the first to the fourth, it becomes possible to increase the reliability of the judgment regarding whether or not the tip member  10   a  of the medical tube  10  has been indwelt at an appropriate location. On the other hand, if the high likelihood of the tip member  10   a  of the medical tube  10  having been indwelt at an appropriate location is confirmed in all of the first to the fourth checking operations, the operator can then determine that the likelihood that the tip member  10   a  of the medical tube  10  has reached the target digestive tract is very high. In such a case, the medical tube  10  is fixed with a surgical tape or the like, and the series of operations for inserting the medical tube  10  is completed. 
     As stated above, according to the device  100 A of Embodiment 2, the following excellent effects can be obtained. According to the device  100 A, a plurality of checking operations can be carried out using a single device by simple techniques. Therefore, according to the device  100 A, because the indwelling site of the tip member  10   a  of the medical tube  10  is checked through one more additional checking operation in addition to the two checking operations that can be carried out by the device  100  of Embodiment 1, the reliability of judging whether or not the tip of the medical tube has been indwelled appropriately is furthermore improved. According to the device  100 A, unlike methods that utilize radiography or endoscopy, because the indwelling site of the tip member  10   a  of the medical tube  10  is checked through simple techniques, no large-scale equipment is necessary, and no high level of expertise is required from the operator. Therefore, the device  100 A is extremely superior in terms of versatility as well as cost effectiveness. 
     In the embodiments, an example is provided in which medical tube  10  is inserted by utilizing a guide wire. However, the embodiments are not limited to the above, and the medical tube  10  may be inserted without utilizing a guide wire. 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Listing of the Reference Numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                   
                  10: Medical tube 
               
               
                   
                  10a: Tip 
               
               
                   
                  10b: Base 
               
               
                   
                  20: First plunger 
               
               
                   
                  21: Torso member 
               
               
                   
                  22: First tip member 
               
               
                   
                  23: Hole 
               
               
                   
                  24: Scale 
               
               
                   
                  25: Operating member 
               
               
                   
                  26: Space-forming member 
               
               
                   
                  26a: Contacting member 
               
               
                   
                  30: Second plunger 
               
               
                   
                  31: Stick-like member 
               
               
                   
                  32: Second tip member 
               
               
                   
                  35: Operating member 
               
               
                   
                  40: Barrel 
               
               
                   
                  41: Tip member 
               
               
                   
                  41a: Inner wall 
               
               
                   
                  42: Cylinder 
               
               
                   
                  43: Operating member 
               
               
                   
                  44: Scale 
               
               
                   
                  50: Syringe 
               
               
                   
                  55: Space 
               
               
                   
                  60: Carbon dioxide detecting member 
               
               
                   
                  70: Adaptor 
               
               
                   
                  71: Cap 
               
               
                   
                  75: Connector 
               
               
                   
                  80: Body fluid retrieving member 
               
               
                   
                  81: Casing 
               
               
                   
                  82: Cylindrical connector 
               
               
                   
                  83: Linking member 
               
               
                   
                  83a: Septum 
               
               
                   
                  85: Connecting tube 
               
               
                   
                  86: Tip linking member 
               
               
                   
                  86a: Linking tube 
               
               
                   
                  87: Tube main body 
               
               
                   
                  87a: Clamp 
               
               
                   
                  88: Body fluid stopper 
               
               
                   
                  89: pH detecting member 
               
               
                   
                 100: Device for checking indwelling site 
               
               
                   
                 100A: Device for checking indwelling site