Abstract:
Apparatus and methods for withdrawing nasopharyngeal fluid samples from a patient are disclosed. A kit including a catheter and a manual suction device is disclosed, wherein the catheter can be self-navigating and define aspiration holes through which aspiration fluid can be emitted and nasopharyngeal fluid samples can be withdrawn. The catheter may also include an insertion depth scale to ensure patient comfort and optimum sample quality. The methods for obtaining nasopharyngeal fluid samples include the steps of inserting the catheter into a patient&#39;s nasopharynx, and aspirating the nasal pharynx to withdraw a specimen.

Description:
[0001]     This application claims the benefit of Provisional Application No. 60/634,702 filed Dec. 9, 2004, the disclosure of which is incorporated by reference herein.  
         [0002]     This invention relates generally to methods and apparatus for gathering samples used for diagnosing viral and bacterial infections in mammals, particularly humans. More particularly the present invention relates to methods and apparatus for collecting nasopharyngeal specimens quickly and with reduced patient discomfort. 
     
    
     BACKGROUND OF THE INVENTION  
       [0003]     Diagnosing viral and bacterial pathogens such as influenza, respiratory syncytial virus (RSV), and pertussis, requires culturing or using rapid tests of specimens gathered from a patient&#39;s throat or nasal cavity.  
         [0004]     Studies show that nasopharyngeal aspiration provides specimens that are superior to those obtained by nasal swabs, nasal washes or throat swabs. See: Schmid et al.,  Prospective comparative study of culture specimens and methods in diagnosing influenza in adults,  BMJ 1998;316:275; Stensballe, et al.,  Comparison of nasopharyngeal aspirate and nasal swab specimens for detection of respiratory syncytial virus in different settings in a developing country,  Tropical Medicine and International Health 2002;7:4:317-321; and Friedman, et al.,  Development of a Rapid Diagnostic Test for Pertussis: Direct Detection of pertussis Toxin in Respiratory Secretions,  J. of Clinical Microbiology 1989;27:11:2466-2470. Nonetheless, nasopharyngeal aspiration is considered by most practioners to be overly invasive and causing considerable patient discomfort. Further obtaining such specimens is difficult for even skilled practioners because the catheters, suctions, or IV tubing used to collect the specimens are not intended for obtaining such samples.  
         [0005]     One prior sample collection apparatus is a tracheal suction catheter. Such a device connects to a wall-mounted suction unit with an in-line sputum trap to collect a specimen. The catheter is inserted into the nasal cavity, a specimen is withdrawn using suction rinsed or aspirated with saline. The sputum trap contents form the sample to be lab tested.  
         [0006]     Modified tracheal suction catheters can be large and traumatic upon insertion in the nasal cavity making such a device painful for the patient, particularly children. This makes tracheal catheters unreliable because they do not always reach the nasopharynx due to the discomfort experienced by the patient with insertion. This typically results in a “less than ideal” nasal specimen rather than a nasopharyngeal specimen thereby compromising the specimen results. Tracheal catheters are also complicated in preparation and expensive due to all the components required for the collection with wall suction.  
         [0007]     Another device used to collect nasopharyngeal specimens is a modified intravenous (IV) tube. Health care personnel typically cut off the tube end; attach it to a syringe or suction; and insert into the nasal cavity to withdraw a specimen. In addition to the catheter stiffness causing discomfort, the modified IV catheter can irritate sensitive nasal linings during insertion because the leading end has been cut and has relatively sharp edges. Similar to the tracheal suction catheter, this commonly results in a nasal rather than a nasopharyngeal specimen, thereby compromising the specimen integrity.  
         [0008]     The open leading end of the IV tube can also be sealed against the nasal lining when fully inserted occluding the catheter and prolonging or preventing the sample collection.  
         [0009]     Therefore, there is a need for methods and apparatus for collecting nasopharyngeal specimens that are simple for practitioners to use and have less discomfort to patients.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention is directed to improve nasopharyngeal aspiration methods and apparatuses. The methods and apparatus are relatively simple for practioners to perform and have less discomfort to patients than prior art methods and apparatus for obtaining such samples. Such improved methods and apparatus result in better samples being obtained for testing, and therefore provide more reliable results that lead to better patient treatment.  
         [0011]     A nasal aspiration kit for obtaining a nasopharyngeal sample in accordance with the present invention includes: a manually operable suction device; and a catheter for connection to the manually operable suction device for navigating to the nasopharynx. The kit can include a lubricant for application to the catheter, a specimen container, and/or instructions that further the ease with which the kit is used. The catheter may also have a depth insertion scale for accurately reaching the nasopharynx.  
         [0012]     The present invention also includes a method for obtaining a nasopharyngeal sample from a patient, the method comprising the steps of: positioning the patient properly, inserting a catheter into the nasal cavity of a patient, injecting a saline solution into the patient&#39;s nasal cavity; and withdrawing a specimen from the patient&#39;s nasal cavity using a manually operable suction source. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is an aspiration kit using a syringe as a manually operated suction device in accordance with present invention;  
         [0014]      FIG. 2  is an alternate embodiment of an aspiration kit in accordance with the present invention using a bulb aspirator as a manually operated suction device;  
         [0015]      FIG. 3  is a side view of a Luer catheter for use in the present invention;  
         [0016]      FIG. 4  is a bulb aspirator with a friction-fit catheter in accordance with the present invention;  
         [0017]      FIG. 5  is a partial perspective view of a catheter in accordance with the present invention;  
         [0018]      FIG. 6  is a partial side view of the catheter tip in  FIG. 5 ;  
         [0019]      FIG. 7  is a cross-sectional view of a catheter taken along line  7 - 7  in  FIG. 6 ;  
         [0020]      FIG. 8  is a partial perspective view of a catheter tip in accordance with the present invention;  
         [0021]      FIG. 9  is a side view of a catheter with a depth insertion gauge in accordance with the present invention;  
         [0022]      FIG. 10  is a side view of a Luer catheter with a depth insertion scale in accordance with the present invention;  
         [0023]      FIG. 11  is a side view of a catheter with a depth insertion scale and a bulb aspirator in accordance with the present invention;  
         [0024]      FIG. 12  is a series of instructions for performing a method in accordance with the present invention; and  
         [0025]      FIG. 13  is a partial cross-section of a nasal cavity having in it a catheter in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     In the following detailed description of the preferred embodiments, the same reference numerals will be used to identify the same or similar elements in each of the figures.  
         [0027]     Referring generally to FIGS. I and  2 , there is depicted a nasal aspiration kit  20  in accordance with the present invention, including a catheter  22 , a manually operable suction device  24 , a lubricant  26 , a vial  28  ( FIG. 2  only) of aspiration fluid, and a specimen container  30 .  
         [0028]     The combination of these components in the kit  20  enables health care users to obtain consistently reliable nasopharyngeal specimens from patients while causing relatively little discomfort compared to previous apparatus for obtaining nasopharyngeal specimens. The kit  20  includes all that is necessary for obtaining and storing a specimen. It is packaged in a sealed container to ensure that it is sterile before use. Given the relatively low cost of the kit  20 , it is also disposable after use.  
         [0029]     The kit  20  includes instructions that explain the simple usage of the kit  20  components so that consistent samples can be obtained even by inexperienced medical personnel.  
         [0030]     The catheter  22  is preferably flexible enough to minimize patient discomfort, yet rigid enough to be navigated through the nose and nasal cavity to obtain a specimen from the desired nasopharyngeal location.  
         [0031]     The catheter  22  includes a leading end  40 , shaft  42 , and connector  44  for connecting to the manually operable suction device  24 . The catheter  22  also preferably includes a depth of insertion scale  50  ( FIGS. 9, 10 ,  11 ) that can be monitored as the catheter  22  is inserted into and guided through the nasal cavity.  
         [0032]     Preferably, the catheter leading end  40  is rounded and closed as illustrated in  FIGS. 3, 4 ,  5 ,  6 , and  8 . Such a configuration minimizes nasal lining irritation and, importantly, helps enable the catheter  22  to be “self-navigating.” When used properly by a medical professional, the closed and rounded leading end  40  can glance off the patient&#39;s middle and lower turbinate and otherwise slide along sensitive nasal tissue toward the back of the nasal cavity without extra manipulation. Such a self-navigating feature results in increased patient comfort and more reliable gathering from the nasopharynx.  
         [0033]     To instill aspiration fluid from the catheter  22 , there is at least one aspiration hole  48  defined in the catheter shaft  42  as illustrated in  FIGS. 5 and 6 . In the illustrated embodiments, there are two such aspiration holes  48  on opposite sides of the shaft  42  from each other. The aspiration holes  48  can be any shape and in any number, but are preferably the oval shape illustrated to allow more aspiration fluid to exit and enter the catheter  22  and quickly obtain nasal fluid specimens. Oval holes also allow larger openings without sacrificing catheter strength during insertion of the catheter  22 . The side position of the opening prevents occlusion of the catheter during aspiration compared to an end opening.  
         [0034]     In one preferred embodiment illustrated in  FIGS. 5 and 6 , each aspiration hole  48  is approximately oval in shape, as illustrated, and are approximately 0.110 inches long (plus or minus 0.015 inches) and 0.040 inches wide (plus or minus 0.015 inches).  
         [0035]     Also preferably, the aspiration holes  48  are spaced up the catheter shaft  42  from the leading end  40  a distance X ( FIG. 6 ) to prevent weakening of the leading end  40 . A preferred spacing X from the extreme end of the leading end  40  is approximately 0.185 inches, but preferably ranges from 0.020 inches to 0.300 inches.  
         [0036]     Generally, the aspiration holes  48  must be close enough to the leading end  40  to allow adequate aspiration without a substantial amount of aspirate to be required in the pool  47  or be left behind after the procedure. See:  FIG. 13 .  
         [0037]     Preferred catheter  22  designs include material durometer (softness) and sidewall thickness to provide sufficient rigidity for reliable insertion while being flexible enough to minimize patient discomfort. In addition, the catheter  22  must not collapse during forceful aspiration. A catheter  22  cross-section is illustrated in  FIG. 7 . Pebax 3533-SA-01 with a 0.100 inch outside diameter and a 0.065 inch inside diameter is the preferred catheter material and cross-sectional size. Outside diameters up to 0.250 inch and down to 0.030 inch as well as inside diameters from 0.165 inch and down to 0.020 inch could also be used. In addition many durometers could be used from 35-70 Shore D.  
         [0038]     Another feature of the present invention is illustrated in  FIGS. 9, 10 , and  11 . The catheter  22  preferably includes an anatomic nasopharyngeal depth calibration scale  50 . Using this scale  50 , a health care provider can monitor the catheter&#39;s insertion depth before beginning aspiration. Studies of using Cat and MRI scans have been performed on patients ranging from newborns to adults.  
         [0039]     Average distances from nasal openings to the back (posterior) nasopharyngeal wall were measured and plotted to derive the preferred insertion depth scale by age illustrated in  FIG. 9 . Such a scale is preferably pad printed on the catheter shaft  42  to provide a reliable insertion depth measurement without guesswork or external measuring devices. The scale  50  ensures proper insertion depth for the catheter  22  without unnecessary patient discomfort. In particular, such a scale spares the patient and health care provider from using patient discomfort levels or guesswork as a guide to insertion depth.  
         [0040]     In addition, the scale  50  reduces the chance that the catheter  22  will be inserted beyond nasopharynx to the oropharynx. Over-insertion of the catheter  22  could result in aspiration of saline, coughing, and choking during the procedure.  
         [0041]     Referring back to  FIGS. 3 through 4 , there is illustrated two possible catheter connector  44  designs although other connectors not illustrated could be used in the present invention. The connectors  44  are used to quickly and reliably connect the catheters  22  to the manually operably suction devices  24 . In  FIGS. 1, 3  and  10 , there is illustrated a Luer catheter  54 , having a “Luer lock”  56 . Such a lock  56  is a standard in the medical industry, so medical personnel are familiar with its operation and confident in its reliability.  
         [0042]     Another catheter connector  44  is illustrated in  FIG. 4  as being a simple friction fit over a nipple  58  that uses the resiliency of the catheter  22  to connect to a manually operable suction device  24  such as the pipette  60  illustrated. This connection is simple and reliable.  
         [0043]     Manually operable suction devices  24  are illustrated in  FIGS. 1 and 2 . In  FIG. 1  the suction device  24  is a syringe  64 , and is preferably a control syringe having a connector  66  to mate with a luer lock  56 , as described above in relation to  FIG. 3 .  
         [0044]     A control syringe  64  as illustrated in  FIGS. 1 and 13  includes a thumb hole  68  on the plunger  70  and finger holes  72  on the syringe  64  to provide improved control over the procedure using one hand quickly and comfortably.  
         [0045]     Another embodiment of a manually operable suction device  24  in accordance with the present invention illustrated in  FIGS. 2 and 11  includes a bulb aspirator  78 , which are smaller and more compact than syringes. Bulb aspirators  78  such as pipettes or other flexible bulbs provide adequate control of the procedure, and yet has less aspiration force compared to a syringe. The bulb aspirator  78  can be used as an aspirant or as the saline container. When the pipette or bulb aspirator  78  is used it may be pre-filled with aspirant (such as saline solution.) When such a design is used it could be provided with a twist off, cuttable or pull off section just outside of a lure lock fitting which is molded onto the pipette  78 . This provides an even more simple system of a lure catheter, pipette, lubricant, and a cap.  
         [0046]     Other manually operable suction devices can be used with the present invention.  
         [0047]     The kit  20  may also include lubricant  26  for the catheter  22  and may include aspiration fluid  28  such as saline solution. Also, the kit  20  preferably includes a specimen container  30  that is sized to hold the nasal fluid specimen. When either a syringe  64  or pipette  78  is used as the manually operable suction device  24 , the syringe  64  or bulb aspirator  78  itself can be used as a specimen container, and no additional containers need be provided. Optionally, more than one container  30  can be provided when multiple tests may be performed on the sample.  
         [0048]     The kit  20  also preferably includes an instruction label  32  or insert as illustrated in  FIG. 12 . The instructions  32  describe the necessary steps as: having a patient lie on his or her back (supine position); extending the patient&#39;s neck to allow pooling of the aspirate in the nasopharynx; drawing into the catheter  22  sufficient aspiration fluid  28 , lubricating the catheter; instructing the patient to hold his or her breath; advancing the catheter until the appropriate insertion depth is noted on the depth insertion scale  50  or until resistance is met by the nasopharynx, quickly pushing the plunger  70  (or squeezing the aspiration bulb  78 ) and then pulling the plungers  70  (releasing pressure from the aspiration bulb  78 ) to withdraw a specimen (preferably about 1 cc); disconnecting the catheter  22  from the manually operable suction device  24  to retain the specimen in the suction device  24  or otherwise depositing the specimen in the specimen container  30  for transport to an appropriate lab for testing.  
         [0049]     A kit in accordance with the present invention is available from M-Pro, LLC located at 5255 East River Road, Suite 210, Fridley, Minn. 55421, phone (763) 258-8170.  
         [0050]     Modifications to the foregoing detailed description of the preferred embodiments will be apparent to those skilled in the art and no unnecessary limitations there from should be read into the following claims.