Evertible membrane catheter and method of use

A catheter for medical or veterinary use is provided which is especially adapted for gentle and pristine introduction into a body cavity or vasculature. The catheter includes an outer and inner tube with a cylindrical membrane connecting distal ends of the two tubes. A fluid may be introduced into an annular space between the tubes to inflate the membrane, which may have a variable thickness to inflate into various configurations within the body cavity. The catheter may be advantageously provided with a guide wire for directing the catheter during insertion into the body cavity by diverting the distal end of the outer tube. The invention hereof also includes a method of using the catheter including the steps of inserting, directing and locating the catheter, extending inner tube beyond the outer tube, isolating the body cavity or vessel and then withdrawing the catheter from the body cavity or vessel.

Background of the Invention 
1. Field of the Invention 
This invention relates to an evertible membrane catheter for insertion into 
a body cavity which may be used to perform a variety of diagnostic and 
treatment functions. The catheter hereof may be adapted for use as a 
bronchial or endotracheal tube, in the lung, heart, artery or vein, in the 
gastrointestinal tract, biliary tract, urinary tract, uterine cervix or in 
a fallopian tube. The invention also includes a method for use of the 
catheter hereof. 
2. Description of the Prior Art 
Catheters are well known in the field of medicine as a tool for 
transmission of fluids such as urine in the case of a urinary catheter or 
air in the case of an endotracheal tube. More recently, the use of 
catheters as diagnostic and treatment tools have been explored and 
expanded, using catheters to obtain tissue and culture samples or to 
introduce medication into a specific body cavity or vessel. 
It has been previously recognized that catheters are especially useful in 
acquiring a pristine culture or biopsy of cells, introducing a fluid, 
dilating a stricture, applying a material or medicament to a plaque or 
stricture, or aspirating a fluid. Examples of these uses and procedures 
include introducing the catheter into the urinary tract to determine and 
differentiate kidney infections from the bladder or urethral infections, 
using the catheter for a urinary retention problem solution, introducing 
the catheter into the uterus in the first trimester of pregnancy via the 
cervix to avoid risks associated with amniocentesis in prenatal diagnosis 
and-other procedures, introducing a catheter into the coronary artery to 
dilate a stricture or area of atherosclerotic plaque or stenosis or to 
treat clotting, and introducing a catheter into the aorta or pulmonary 
artery to assist the heart to beat by alternately inflating and deflating 
a balloon or membrane connected to the catheter, as well as introducing a 
catheter into the tracheobronchial tree to investigate bronchial 
infections such as pneumonia or using a large diameter catheter as an 
endotracheal tube. 
Because the catheter must past through an entry portion of a body cavity or 
organ, for example, the skin, nasopharynx or vagina, prior to reaching the 
portion to be studied, the sterility of the catheter may be compromised 
and the sample rendered valueless. Further, it is often necessary for a 
catheter to pass through a body cavity or vessel which has been injured or 
narrowed by disease, and the entry of the catheter may produce further 
damage or even perforation which may result in morbidity and mortality. 
The potential transmission of disease by catheter has slowed the 
acceptance of chorionic villus sampling as an alternative to amniocentesis 
as a diagnostic procedure in high risk pregnancies. In addition, the 
difficulty of maintaining a pristine sample from the desired culture area 
has heretofore been difficult, inasmuch as the sampling device used in the 
catheter may have been exposed to various and sundry organisms during the 
transit from the body cavity to the location to be sampled. 
When investigating the bronchial tree, a surgical technique known as 
transtracheal aspiration, in which an incision is made which bypasses the 
pharynx, has been developed in an effort to overcome this problem and 
obtain uncontaminated lung or transpharyngeal bronchial samplings. 
However, transtracheal aspiration is often a dangerous procedure 
presenting the risks of cutaneous emphysema and hemoptysis. Physicians are 
often hesitant to make use of transtracheal aspiration, especially in 
immune compromised patients. 
Entry to body cavities or vessels is often made difficult by the presence 
of narrow passages because of scarring or obstruction. Tracts often become 
tortuous with age or the presence of disease pathology. Gaining access 
through tortuous tracts or narrowed passages can be difficult and even 
risk perforation when conventional catheters are used, with or without a 
balloon tip. 
U.S. Pat. No. 4,023,559 to Gaskell is an example of a catheter designed to 
be inserted into a body cavity for sampling, irrigating, or draining a 
portion of the cavity while preventing the contamination of the sampling 
or drain portion by microorganisms residing in entry portions of the 
cavity. The catheter there consists of an outer tube surrounding an inner 
tube and having a normally closed, distal end. The distal end has 
incisions which open under the pressure resulting from the axial movement 
of the inner tube. The inner tube remains retracted and the incisions 
closed as the catheter is passed into a body cavity so that the inner tube 
may remain sterile while the outer tube is thereby contaminated. When the 
distal end of the catheter reaches the desired portion of the body cavity, 
the still sterile inner tube is advanced through the incisions as the 
rounded distal end of the outer tube so that it may drain or introduce 
fluid. Optionally, a sterile sampling means may be inserted through the 
lumen of the inner tube. 
The Gaskell catheter, however, has several shortcomings. First, since the 
outer tube walls must have sufficient resilient strength to firmly 
maintain the incisions in closed condition during entry and exit, the 
outer tube must therefore be made of a relatively heavy gauge tubing. This 
limits the catheter's flexibility. Secondly, because the outer edges of 
the incisions are contaminated with extraneous micro-organisms during the 
transit through the cavity, the previously sterile inner tube also becomes 
contaminated as it is extended through and contacts the incisions during 
use. The inner tube is, of course, again contaminated as it is withdrawn 
past and contacts the incisions after use. As a result, any sampling or 
culture taken will be contaminated by the inner tube and provide invalid 
results. 
My prior U.S. Pat. No. 4,324,262 discloses a catheter which is provided 
with a reflective membrane which protects the sampling tip contained 
therein during the passage to the sampling area. The catheter of my 
previous patent discloses the use of an evertible membrane having a brush 
for collecting samples from the desired zone, as well as a guide wire 
which provides only a degree of stiffness for control during insertion. 
One problem with these prior catheters has been their inability to 
negotiate the tortuous paths of certain bronchial, urinary or vascular 
restrictions. When sharp corners or turns were encountered during 
insertion of the catheter, substantial injury to the walls of the vessel 
was possible when attempting to force the catheter through these turns. 
Another difficulty presented by the structure of the prior catheters was 
the inability to provide a membrane with a balloon at the end of the 
catheter which could be presented in various shapes or degrees of 
inflation according to the particular vessel or cavity being sampled or 
treated. Another problem of the prior catheters has been the inability to 
control the amount of air pressure within the balloon to ensure that the 
membrane of the balloon did not rupture. Finally, the structure of these 
prior catheters limited their utility to sampling or fluid transmission 
catheters, rather than in direct treatment by light or heat to a body 
cavity obstruction. 
SUMMARY OF THE INVENTION 
The problems outlined above are in large measure solved by the evertible 
membrane catheter in accordance with the present invention. That is to 
say, the catheter hereof is designed to negotiate restricted passageways 
of the body and conform to the walls of the vessel or cavity, and not only 
obtain a pristine sample from the desired cavity location, but also to 
provide a means of treatment of restricted coronary passages through the 
use of thermal or laser energy. It is another object of the present 
invention to provide a protruding pristine tip in a blood vessel and 
alternately increase and decrease the pressure and expansion of said tip 
in order to provide for propulsion of blood or other bodily fluids such as 
spinal fluid in the brain or assist peristalsis in the gastrointestinal or 
biliary tract. 
Other objects of the invention include providing a protruding pristine tip 
which will provide for a toposcopic mapping between points along the 
cavity or vessel of interest to correspond to points along the pristine 
tip or membrane extension or expansion, and to provide a method for 
isolating a portion of a body cavity in a pristine environment. The 
present invention also provides a pristine introducer device, an 
aspirating culture catheter, provides a protruding tip in association with 
an insemination straw for inseminating an ovum in a uterus and provides a 
protruding tip for a flow-directed and venous infusion port catheter 
obviating the need for a central venous pressure line or a sidearm 
introducer whereby the tip incorporates a thermistor. 
It is another object of the present invention to provide a method of 
acquiring a pristine sample from a body cavity or tract, a method of 
tracheal or transtracheal intubation, directing, aspiration, isolation, 
mapping and/or culture. It is a further object of the present invention to 
provide a method of cervical and transcervical intubation, aspiration, 
isolation, mapping, laser treatment and/or culture. 
It is another object of the present invention to provide a method of 
fallopian tube intubation, aspiration, isolation, mapping, stinting, laser 
treatment and/or culture. 
It is another object of the present invention to provide a method of 
lacrimal duct intubation, aspiration, isolation, mapping, stinting, laser 
treatment and/or culture. 
It is another object of the present invention to provide a catheter for 
blood vessel intubation, guiding, tapping, isolation, stinting, dilation, 
laser treating and/or culture. 
It is another object of the present invention to provide a method of 
gastrointestinal tract intubation, mapping, isolation, dilation, laser 
treating, tamponating, and/or culture. 
It is another object of the present invention to provide a gastrostomy tube 
for gastrostomy patients. 
It is another object of the present invention to provide a method of 
urinary tract intubation, mapping, isolation, dilation, laser treating or 
heating, tamponating, stinting, aspiration and/or culture. 
The catheter in accordance with the present invention broadly includes a 
pair of concentric tubes adapted for slidable movement therebetween, a 
membrane connecting the distal end of the two tubes. When the inner tube 
is withdrawn into the outer tube, the membrane is thus reflected, 
presenting a pristine chamber to protect against contamination of the 
inner tube and any structure carried therewithin. There exists an annular 
space between the inner tube and the outer tube whereby fluids such as air 
or liquids may be introduced under pressure to "inflate" the membrane. The 
inner and outer tubes are adapted to be resilient and flexible, so that a 
guide wire may be connected to the distal end of the outer tube for 
manipulation of the outer tube at its distal end. A guide wire extends 
roughly the length of the outer tube so that it may be pushed or pulled 
thereby causing deflection of the inner and outer tube at the distal end. 
In preferred embodiments, the catheter may include a conductor for the 
transmission of thermal or laser energy to the distal end of the catheter. 
The conductor may be a metal, such as copper or stainless steel adapted to 
carry thermal energy for heat treatment of plaque on coronary walls, or 
alternately a fiber optic filament employed to direct laser energy to an 
obstruction in a vessel of the body. The conductor may be wrapped in 
helical fashion around the inner tube in order to supply radiant energy, 
or alternately a straight filament for directing laser energy from the 
distal end thereof. 
In particularly preferred forms, the catheter hereof may include a 
Y-connector provided with a connection for attachment of a conventional 
surgical syringe. The syringe may be used to inflate the membrane into a 
"balloon" for dilation of restricted passages of a vessel or cavity, for 
partially inflating the membrane to ease passage of the catheter through a 
body vessel, or for pressurizing the "balloon" of the catheter when the 
membrane is fully everted. The Y-connector is preferably provided with a 
over-pressurization check valve which is in communication with the annular 
space surrounding the inner tube so as to prevent over pressurization and 
thus rupture of the membrane. Alternately, the membrane may be provided 
with a series of small perforations which will sufficiently dilate when 
the membrane is over inflated or pass a treating fluid therethrough. The 
Y-connector may also be provided with a separate medicating catheter 
running the length thereof, whereby medicaments can be separately 
introduced to various parts of the vessel or body cavity through ports in 
the outer tube. 
The catheter hereof may also be provided with a flexible connector near the 
distal end of the outer tube. The outer tube may thus be separated into 
two parts and joined by the flexible connector so as to enable greater 
deflection of the outer tube by the guide wire during transit through a 
body cavity or vessel. 
The inner tube of the catheter may be separated into separate canals within 
the inner tube, so that separate actions may be performed by single 
insertion of the catheter. Thus, a sample operation could first be 
performed, followed by treatment using a medication or cold injectate 
supplied through the perforations or a port, or by thermal or laser 
treatment by the conductor, or temperature differential recorded by 
temperature probe or thermistor. 
The method of the invention involves the insertion of a catheter into a 
body cavity or vessel. As the outer wall of the closed, double wall of the 
pristine or sterile chamber becomes contaminated by germs residing in the 
entry portions of the body, the inner wall of the chamber remains sterile. 
As the reflected end of the pristine chamber, which is also the distal tip 
of the outer catheter, reaches the desired portion of the body cavity or 
vessel, the inner tube is advanced with respect to the outer tube. The 
inner tube passes through the area previously occupied by the reflected 
resilient membrane and is preceded by the reflected inner wall of the 
pristine chamber until the inner wall is completely extended. The membrane 
is thereby fully everted and the pristine chamber is extinguished. If the 
user wishes to retract the inner tube, the respective motions are 
reversed. 
After insertion of the catheter to the desired location within the vessel 
or body cavity, a fluid such as air may be supplied through the annular 
space to the resilient membrane in order to isolate or dilate the various 
surrounding membrane. Air is supplied to the annular space by attachment 
of a conventional syringe as a pressurized air source. The inner tube or 
reflected membrane therefore need not come in contact with the 
contaminated outer wall at any time since the reflection formed by the 
pristine inner wall membrane never makes contact with the contaminated 
outer wall since the reflection formed by the pristine inner wall membrane 
never makes contact with the outer tube surface, whether or not the inner 
tube is advancing through it. 
The catheter hereof could also be used as an endotracheal tube, wherein the 
inner tube is a breathing tube while the inflated membrane acts to seal 
the trachea against the escape of air. The catheter could also be used as 
a vaginal speculum, wherein the inner tube is a cervical viewing device 
while the inflated membrane acts to seal the vagina. The inflated membrane 
might also be used to dilate the cervical canal or gain general access to 
the uterus for culture or other intervention such as instilling or 
withdrawing fluid. 
The catheter could also be used as an inner ear speculum, wherein the inner 
tube is a viewing cannula or introducer while the inflated membrane acts 
to seal the ear canal. The catheter hereof could also be used to gain 
gentle access to the inner ear by everting through the bony and membranous 
eustachian tube for culture or other intervention. The catheter hereof is 
also useful as an anal speculum, wherein the inner tube is a viewing 
cannula or introducer while viewing rectal mucosa wherein the inflated 
membrane acts to seal the anal canal mucosa. An anal stricture may be 
dilated by the inflated everted membrane to permit, e.g., an anal polyp to 
be investigated or removed. The catheter hereof could also be used as an 
esophageal speculum, wherein the inner tube is a viewing.RTM. cannula or 
introducer while viewing the esophageal mucosa. The inflated everted 
membrane thereby acts to seal and dilate the esophagus. Strictures within 
the esophagus may be dilated, other pathology investigated and/or mapped, 
or the stomach entered in pristine and gentle fashion. The duodenum might 
also be entered. 
The present catheter could also be used as a bladder speculum, wherein the 
inner tube is used for gentle access in viewing of the bladder mucosa 
wherein the inflated membrane acts to seal the urethra. Bladder infections 
can be differentiated from kidney or urethral infection, and either 
urethra dilated or isolated for culture. It is also contemplated that the 
catheter of the present invention may be used to tamponade bleeding or to 
dilate strictures in any tract or canal where it may be used in the method 
of the invention. 
In various alternative embodiments, the outer wall of the membrane may be 
perforated to permit fluid introduced by the syringe to escape. Upon inner 
tube extension, this perfusate is allowed to escape along the outside 
extended membrane as the pristine or sterile chamber is extinguished. The 
escaping fluid, which is introduced via the annular space or perfusate 
passage may be a buffered local anesthetic, topical buffered antibiotic, 
or any other fluid desired by the operator. A diagnostic or therapeutic 
medicament can also act as a membrane lubricant for aiding membrane 
extension and retraction. Additional passages and ports may be supplied to 
permit introduction of additional medicaments at various locations along 
the outer tube as in a venous infusion port or thermodilution catheter. 
The apparatus of the invention may further include a sampling means such as 
a brush or swab located on the lumen of the inner tube. Alternatively, a 
method of ablation of lesions may include a laser prope extendable from 
the inner tube or in helical fashion upon the surface of the inner tube, 
as in the conductor previously described. Irrigating fluid or other fluid 
may be passed through the lumen of the inner tube to wash the cavity or 
tract, or fluid may be drained therefrom. 
The catheter may also include a lock ring on the operator end of the inner 
tube and an annular gasket between the inner and outer tube affixed to the 
outer tube. The operator can therefore ensure the full extension of the 
inner tube by examination of the position of the lock ring with respect to 
the hub and gasket of the Y-connector apparatus of the outer tube. 
Gradations may be provided on the inner tube to gauge partial extension of 
the membrane.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawing, a catheter 10 in accordance with the present 
invention broadly includes an outer tube 12, a connector 14, an inner tube 
16 and a membrane 18. The inner tube 16 is disposed within and slidable 
with respect to outer tube 12 so that the inner tube 16 may be extended 
and withdrawn with respect to outer tube 12. An annular space 20 is 
defined by the difference in diameters of the inner tube 16 and the outer 
tube 12. Connector 14 is preferably a Y-connector, adapted to receive a 
conventional syringe 22 in airtight, locking engagement. 
As shown in FIG. 1, the syringe 22 includes barrel 24, plunger 26 slidably 
engaged within barrel 24 and sealed with respect to the barrel in order to 
permit pressurization of fluid within the barrel 24 by depressing the 
plunger 26. Syringe 22 also includes a tip 28 adapted to be received 
within Y-connector 14 and locking ring 30 for positive engagement with 
branch 32 of Y-connector 14. A one-way valve mechanism may be contained 
within branch 32 so that syringe 22 including barrel 24 might be removed 
after repressurization without loss of pressurization. Branch 32 is 
tubular and fluidically communicates with the annular space 20 between 
outer tube 12 and inner tube 16. Branch 32 is also provided with a check 
valve 34 to prevent overpressurization of membrane 18. The check valve 34 
is fluidically connected to annular space 20 and includes cap 36 which is 
threadably engaged on branch 32 and defines an air passageway 38 opposite 
branch 32. Cap 36 covers spring 40 which is biased against ball 42 which 
in turn covers opening 44 through branch 32 and permits excess air to flow 
around ball 42 and out through air passageway 38. 
Outer tube 12 includes generally a distal end 46 and a user end 48. Distal 
end 46 is located remote from user end 48 and adapted for insertion into a 
body cavity. User end 48 is preferably connected to Y-connector 14. 
Outer tube 12 may also be provided with one or a plurality of channels 54 
transmitting fluids, and especially medications to various locations along 
the outer tube. The channels 50 are generally located within the annular 
space 20 between inner tube and outer tube and terminate in port 52 for 
dispensing fluids at desired locations along the length of the catheter 
10. It is to be understood that the channel 50 enters the outer tube at 
the user end 48 through Y-connector 14 as shown in FIG. 1 or through the 
outer wall of the outer tube 12, and transits the length thereof. Channel 
50 may be provided with a plurality of tubes or ports 52 for dispensing 
fluids along the length of the outer tube 12. 
As shown in FIG. 1, the Y-connector contains a series of lock rings 54, 56 
and 58 in axial alignment with the outer tube 12. Lock ring 54 is 
essentially in the nature of a connector which is both externally and 
internally threaded in order to mount on Y-connector 14 and to receive 
lock ring 56. Lock ring 56 is also internally and externally threaded, and 
is adapted to secure inner tube 16 to outer tube 12 and to receive lock 
ring 58. 
Lock ring 56 is better shown in FIG. 2, where it may be seen that lock ring 
56 is provided with a series of internal threads 60 for threadable 
engagement with lip 62 of lock ring 54. As may be appreciated from an 
examination of FIG. 2, lock ring 56, although rotatable about inner tube 
16 and gasket 64, is not movable longitudinally with respect thereto. 
Thus, since lock ring 54 is in fixed longitudinal relationship to outer 
tube 12, inner tube 16 may be locked relative to outer tube 12 only when 
the inner tube is fully extended with respect to outer tube 12. When 
locked in position, the distal end 66 of inner tube 16 is outside outer 
tube 12, and is lockable only when in this fully extended position. In the 
embodiment shown in FIGS. 1 and 2, a filament 68 is located within inner 
tube 16 and extends therethrough, with filament 68 having a tip 70 at its 
distal end and being connected to lock ring 58 at its user end. It is to 
be understood that the catheter hereof contemplates that a variety of 
different filaments 68 may extend from lock ring 56, and that in fact a 
plurality of such filaments may extend therefrom, the types of which will 
be discussed hereinafter. Additionally, filament 68 as defined herein may 
be a hollow tube, permitting the insertion of successively narrower tubes 
or lumens therethrough. 
Returning again to FIG. 1, the catheter hereof is advantageously provided 
with a guiding mechanism 72. Guiding mechanism 72 extends along 
substantially the entire length of outer tube 12 and includes sheath 74 
surrounding guide wire 76. As shown in FIG. 1, guide wire 76 extends from 
sheath 74 near the user end 48 of outer tube 12. Guide wire 76 attaches 
ring 78 for ease in manipulating guide wire 76. Guide wire 76 is 
preferably of flexible, stainless steel of sufficient strength and 
thickness to enable it to be manipulated by both pushing and pulling on 
ring 78. Guide wire 76 continues along outer tube 12 until it extends from 
sheath 74 at a location proximate but not adjacent to distal end 46 of 
outer tube 12. Guide wire 76 is securely attached to distal end 46 by a 
metallic clamp 80. 
In one embodiment of the present invention, as shown in FIG. 1, the sheath 
74 terminates at flexible connector 82. Flexible connector 82 is adapted 
to join together remote section 12a and proximate section 12b of outer 
tube 12 and is in the form of a corrugated sleeve through which guide wire 
76 and inner tube 16 extend. Corrugated sleeve 82 enhances the ability of 
distal end 46 to deflect in response to manipulation of guide wire 76, and 
employs a corrugated sleeve much the same as that found in the toy 
POPOIDS. 
Turning now to FIG. 3, the distal end of the catheter 10 is shown with the 
distal end of the inner tube 16 withdrawn inside outer tube 12. Membrane 
18 is shown in a first, reflected position, and it may be appreciated that 
clamp 80 serves to positively connect both the cylindrical, tubular 
membrane and the guide wire 76 to the distal end 46 of outer tube 12. The 
reflected membrane 18 is also connected to the distal end 66 of inner tube 
16 by clamping means, which in the embodiment shown in FIG. 3 is helically 
wrapped element 86, with membrane 18 being stretched over annuli 88, which 
is preferably made of copper. In the reflected position shown in FIG. 3, 
membrane 18 consists of an outer cylindrical wall 90 and inner annular 
wall 92, resulting in a double walled annular membrane defining a pristine 
chamber 94 within inner wall 92. As shown in FIG. 3, the area between 
outer wall 90 and inner wall 92 is in fluidic communication with annular 
space 20 and is therefore able to receive fluid under pressure from 
annular space 20. It may also be appreciated that the provision of fluid 
under pressure from annular space 20 will cause inner wall 92 to seal 
against itself at junction 96 to thereby seal against the introduction of 
foreign matter into pristine chamber 94 when the distal end 66 of inner 
tube 16 is withdrawn within outer tube 12. 
It may be seen from FIGS. 3 and 4 that the catheter hereof may be provided 
with a brush laser probe, thermistor or swab at tip 70 which is connected 
to a lumen 98 of sufficient length to permit tip 70 to extend beyond the 
distal end 66 of inner tube 16. Tip 70 would have a brush or swab for 
culture sampling, a laser lens for laser surgery, or a bead-type 
thermistor for sensing or monitoring the temperature in a body cavity. 
Lumen 98 may be advantageously connected to end cap 58 if it is desired to 
limit the amount of extension of lumen 98 or may extend through the user 
end 100 of inner tube 16 as shown in FIG. 2 as filament 68. Alternately, 
filament 68 may represent the user end of a conductor such as helically 
wrapped element 86 in which case filament 68 would be connected to a 
source of electromagnetic energy such as, for example, a source of heat or 
light amplitude by stimulated emission of radiation. When used principally 
to conduct heat, helically wrapped element 86 would normally be a 
stainless steel metal wire extending through inner tube 16 to filament 68, 
which could also be stainless steel or copper if the resistance through 
the inner tube prior to reaching the helically wrapped element was desired 
to be reduced. Helically wrapped element 86 could also be a quartz fiber 
adapted for receiving light amplification by stimulated emission of 
radiation. Similarly, helically wrapped element 86 could also be a fiber 
optic element of plastic or other suitable material adapted for carrying 
light amplification by stimulted emission of radiation. 
As shown in FIG. 4, membrane 18 is especially adapted to be of variable 
thickness from clamp 80 to annuli 88. The variable thickness membrane 18 
would ordinarily be no thicker than the thickness of the outer tube 12 and 
could be of gossamer thinness. The variation in thickness is especially 
useful in adapting the catheter hereof to various body cavities, and 
especially vascular passageways of various sizes. The thickness of the 
membrane can be arranged as a gradient, as shown in FIG. 4 or 
alternatively of stepped variations in thickness, as desired. 
The membrane shown in FIG. 4 is also provided with a plurality of 
perforations 102 extending through the membrane 18. The membrane 18 is 
preferably of sufficient resiliency such that perforations 102 would 
normally be closed except when, as shown in FIG. 4, inner tube 16 is 
extended beyond the distal end 46 of outer tube 12 and fluid has been 
introduced under pressure to annular space 20 in order to inflate membrane 
18. When fluid has been introduced under pressure to inflate membrane 18, 
perforations 102 dilate to sufficient diameters to permit the passage of 
fluid therethrough. As shown in FIG. 4, the membrane 18 is thicker 
adjacent clamp 80, causing it to expand less under pressure than the inner 
portions of the membrane proximate annuli 88. 
An alternate embodiment of the inner tube 16 is shown in FIGS. 5 and 6, 
whereby inner tube 16 is a channel tube 104 which includes at least one 
wall 106 separating channel tube 104 into a plurality of separate chambers 
108 and 110. As may be seen from FIG. 5, the chambers 108 and 110 are 
adapted to receive separate members inserted therethrough. For example, a 
conductor such as a fiber optic wick 112 for conducting and directing a 
beam of electromagnetic energy such as light or light amplification by 
stimulated emission of radiation waves therefrom is shown in first chamber 
108. The second chamber 110 is provided with pipe 114 carrying lumen 84 
and tip 70. As noted previously, pipe 114 carrying lumen 84 therewithin as 
well as wick 112 may emerge from user end 100 of inner tube 16 in the 
manner of additional filaments 68. As may be seen in FIG. 6, channel tube 
104 is essentially concentric with outer tube 12, as is the case with 
other inner tubes 16. It is to be understood that the chambers of the 
channel tube may be of proportionately different sizes, and one channel 
might remain empty for the passage of fluid therethrough. 
Inasmuch as the catheter 10 hereof may be inserted into various body 
cavities, such as a lung, a uterus, an anal canal, a uterine cervical 
canal or endocervix, a fallopian tube, an endotracheal canal including an 
esophagus, stomach or duodenum, a biliary tract or gall bladder, a 
urethral canal including a urethra, bladder or vagina, or an artery, vein 
or chamber of the heart, or the trachea or a bronchial passage in the case 
of its use as an endotracheal tube, the outer tube 12 and inner tube 16 
are preferably resiliently flexible according to the particular diameter 
of the catheter 10 and intended use. For example, the diameter of the 
outer tube 12 of the catheter 10 would be substantially greater when used 
as an endotracheal tube than when used as an arterial catheter. Therefore, 
it is preferred that the catheter hereof be made of resilient synthetic 
plastic material in order to easily traverse restricted body passages. 
Similarly, metallic components of the catheter such as guide wire 76 and 
optionally helically wrapped element 86 should be of a small diameter in 
order to be sufficiently flexible to negotiate narrow passages within the 
body. The inner and outer tubes may be made of teflon or polyvinylchloride 
to permit smooth axial movement of the inner tube within the outer tube 
16, and either tube may be provided with a lubricant to enhance its 
sliding ability. 
When performing the method of the present invention, the distal end 46 of 
the outer tube of the catheter 10 will normally be inserted through a body 
orifice or through an incision into a body organ or cavity. Such cavities 
may include, for example, a blood vessel such as a vein, artery or chamber 
of the heart, a trachea, bronchial passage or portion of the lung, a 
vagina, uterus or fallopian tube, a urethra or bladder, the trachea or the 
esophagus, stomach or duodenum, the anal canal, or the biliary tract 
including the gall bladder. 
The catheter 10 as disclosed herein includes outer tube 12, inner tube 16 
and an annular space 20 therebetween, and a cylindrical membrane forming a 
sleeve between the distal end 46 of the outer tube 12 and the distal end 
100 of the inner tube 16. The catheter 10 also preferably includes means 
for directing the distal end of the outer tube 12 such as guiding 
mechanism 72. The user then employs guide wire 76 to direct the distal end 
of the outer tube of the catheter 10 into the desired portion of the body 
cavity by pulling on ring 78 to cause the distal end 46 of the outer tube 
12 to deflect transversely to its axial orientation and in the direction 
of guiding mechanism 72, or alternatively pushing on ring 78 to cause the 
distal end 46 of outer tube 12 to deflect away from guiding mechanism 72. 
The catheter 10 is then placed so that the distal end 46 of the outer tube 
12 is located adjacent the desired portion of the body cavity. It is then 
contemplated that the inner tube will be extended so that the distal end 
100 of the inner tube 16 is beyond and outside the distal end 46 of the 
outer tube 12, thereby everting membrane 18. 
The desired portion of the body cavity would thereafter be isolated by 
introducing a fluid under pressure into the annular space 20 so as to 
inflate the membrane 18. The desired portion of the body cavity could then 
be sampled by use of a brush or swab as tip 70 when extended beyond the 
distal end 100 of inner tube 16, or the area could alternately be treated. 
Such treatment could include the provision of fluid medication to the 
portion of the body cavity adjacent the membrane by aspirating fluid 
through the perforations 102. Such fluid could include, for example, a 
polar solvent such as saline, and a lyophilized powder could be dissolved 
in such saline solution. Alternatively, for treatment in an area such as 
the biliary tract, a nonpolar solvent such as an oil based medication may 
be used to dissolve gallstones lodged therein, or chenodeoxycholic acid 
used to dissolve accumulated cholesterol in atherosclerotic plaques in 
blood vessels. 
Once located adjacent the desired portion of the body cavity, the catheter 
10 can also be used to treat obstructions of the vascular system. For 
example, membrane 18 could be alternately inflated and deflated in 
synchrony with the closing of the aortic valve or an EKG tracing while the 
inner tube 16 is contained within the distal aorta or pulmonary artery so 
as to assist the heart by propelling blood through circulation. The 
catheter 10 hereof could also be used to thermally ablate a lesion or 
collection of plaque in an artery by applying heat to filament 68. The 
heat applied to filament 68 is conducted along the filament and to 
helically wrapped element 86 for, in essence, melting plaque or an 
occlusion in the artery. In another type of heat treatment, helically 
wrapped element 86 is a quartz fiber capable of receiving light 
amplification by stimulated emission of radiation. When such light is 
introduced at filament 68 at the proper wavelength for plaque absorption, 
and air or a polar solvent such as normal saline solution introduced into 
annular space 20 by syringe 22, the heat of tissue vaporization generated 
by such light through helically wrapped element 86 passes through the air 
or saline solution without affecting it and passes through membrane 18 or 
perforations 102 to be absorbed by the plaque material within the artery 
and vaporized. Portions of all of the plaque material may be vaporized. 
The helically wrapped element 86 forms a lasing medium, or active medium 
which refers to the solid, liquid or gas responsible for determining the 
wavelength of the laser emission within the annular space. The laser used 
is classified by output power, whether continuous wave or pulsed, and 
wavelength. 
Yet further, it may be appreciated that, in accordance with the invention 
hereof, light amplification by stimulated emission of radiation may be 
supplied directly through, e.g., filament 68 to wick 112 or tip 70 when a 
laser lens fitment is used as tip 70. Such laser radiation may be focused 
into a particularly occluded region of a body cavity by focusing the beam 
through a lens fitment to appropriate spot size with the beam centered by 
inflated membrane 18 or to conduct laser surgery in a body cavity, 
restricted passageway, or vessel by converting radiant energy to heat to 
vaporize tissues, photocoagulation by converting radiant energy into heat 
so as to increase the tissue temperature to denature protein or nonthermal 
application called photoradiation therapy. One possible source of laser 
for connecting to filament 68 is the Model 20 from HGM Medical Laser 
Systems of Salt Lake City, UT. 
The check valve 34 of the present invention is particularly useful in 
preventing the overinflation of the membrane 18 which might cause it to 
rupture. When excessive fluid pressure builds up in annular space 20, 
fluid is forced through opening 44 past ball 42 and out through passageway 
38. Because cap 36 is threadably engaged on Y-connector 14, the tension in 
spring 40 is adjustable and thus the pressure at which ball 42 will be 
unseated from opening 44 may be adjusted to desired pressures. 
Additionally, under substantial loosening of cap 36, the fluid may be bled 
off under pressure while withdrawing the distal end of the inner tube to 
reflect the membrane, or at any other time it is desired to deflate 
membrane 18.