Isolator for use in surgery or as a clean room and method of using the same

An isolator and method of using it for providing a contamination-free atmosphere in which a surgical procedure can be performed or equipment that is sensitive to environmental contamination can be assembled. The isolator includes an inflatable bag of flexible material through which filtered air is circulated. For use in surgery, a portion of the lower side is made of an elastic surgical drape material to allow a body member upon which a surgical procedure is to be performed to be pulled into the work space of the bag. A portion of the top side of the bag is made of a relatively stiff, optically transparent, material through which the surgeon or the assembly worker can view the work area. A plurality of open-ended sleeves are attached to the bag through which the hands and arms of the surgeon and his assistants or the worker can extend into the work space.

This invention relates to an isolator for providing a contaminant-free 
atmosphere in which a surgical procedure can be performed or equipment 
sensitive to environmental contamination can be assembled and to a method 
of using the same. 
A large amount of effort is spent in the avoidance of contamination of 
surgical wounds by disease organisms in the operating room. All 
instruments and dry goods coming into contact with the surgical field are 
sterilized, either in an autoclave or with chemicals. Chemicals are used 
to sterilize the patient's skin in the area of the surgery. The surgical 
team scrub their hands and arms for at least five minutes after which 
hands and arms are bathed in alcohol. Sterilized gowns, caps, and masks 
that filter the team's exhaled air are worn by the surgical team along 
with sterile gloves that cover their hands. Thereafter, the surgical team 
avoids contact with non-sterilized objects. Further, the air in the 
operating room is constantly changed and filtered. 
Even with all this preparation and attention to sterilization, a 
significant percentage of supposedly clean operations result in wound 
infections, which means that operating aseptically on man remains only a 
concept and not an accomplished procedure. 
One of the problems is that disease organisms are ubiquitous in operating 
room air, on the patient's skin, in his gastrointestinal tract, and in the 
exhalations of all persons in the room. Also, the individuals of the 
surgical team shed disease organisms as they move around the operating 
room during the surgery For example, it has been determined that 30,000 to 
60,000 particles are shed each minute from each person in the operating 
room. Foreign particles that have been shown to cause granuloma, a type of 
infection, include lint, wood fibers, talc dust and related agents. These 
particles come from drapes, gloves, wrapping materials and other items 
found inside the operating room (OR). Bacterial contaminants are released 
into the atmosphere from the skin and hair, by breathing and passing gas, 
and from the urinary tracts of the surgical team and the patient. 
There are certain types of surgery that experience a higher than normal 
rate of infection. It is these surgeries where the use of the isolator of 
this invention is most important. Surgeries involving the implantation of 
a prosthetic device or artificial organ is a common example. The dose of 
bacteria necessary to invade the wound and cause an infection is reduced 
when foreign matter, such as an implanted device, is introduced into the 
body. Repeated experimental and clinical studies have proven that the mere 
presence of a foreign body can seriously impede the human body's immune 
system. Over 50,000 bacteria may be required to cause a surgical wound 
infection in normal operations whereas only 100 bacteria can cause 
infection when an implant device, even though inert, is introduced. In 
some implant surgeries, it has been theorized that a single bacterium may 
be all that is necessary to cause a deep wound infection. 
Certainly many wound infections can be attributed to endogenous (patient) 
causes It is generally agreed, though, that airborne contamination during 
surgery contributes in some degree to the number of infections. Indeed, 
there is much empirical evidence and many major comprehensive studies that 
suggest it as the prime contributor. The complications that develop from 
wound infection can be very serious and it is a continuing problem that 
plagues the operating community as well as the patient The isolator of 
this invention will provide surgeons and patients with an extra 
preventative measure against surgical wound infections. 
Therefore, it is an object of this invention to provide an isolator and a 
method of using the isolator that includes a tent or bag of flexible, 
impervious material for placing on the area of the patient where the 
surgery is to be done and pumping a continuous stream of filtered air that 
flows from one side of the bag across the surgical wound to exhaust ports 
on the opposite side of the bag to maintain the bag inflated at a pressure 
above atmospheric and to constantly change the air in the isolator. 
It is a further object of this invention to provide such an isolator and a 
method of using the isolator where the instruments and other material used 
during the surgery is moved into and out of the bag through a door in the 
side where the exhaust ports are located so the air is always moving in a 
direction to keep any contaminants outside the bag from entering the bag 
while the door is open. 
It is a further object to provide such an isolator and method in which the 
instruments and other material are moved into and out of the bag through 
an air lock, the doors of which have exhaust ports through which most of 
the air flows to the outside. 
It is a further object and feature of this invention to provide an isolator 
having an air lock that can be severed from the isolator when the surgery 
is completed to protect the instruments that have been used during the 
surgery from the air in the operating room so the instruments will be 
readily available, if needed, during the period between the completion of 
the surgery and the moving of the patient from the operating room. 
The first surgical isolators were developed for use in gnotobiotics where 
germ-free laboratory animals were obtained by delivering such animals from 
their parents by Caesarean section directly into an aseptic environment. 
Later a plastic isolator for use on humans was designed by Levenson, et al 
and described in an article entitled "A Plastic Isolator for Operating in 
a Sterile Environment" American Journal of Surgery, 104, 891-899, 1962. A 
subsequent isolator was developed by McLauchlan, et al and described in an 
article entitled "The Surgical Isolator", British Medical Journal, 1(903): 
322-4, 23 Feb., 1974. Both of these isolators are discussed in "Air 
Contamination Control in Hospitals" by Joseph R. Luciano, Copyright 1977, 
Plenum Press, New York, pages 355-359. 
Both the Levenson and McLauchlan isolators included bags of thin, flexible, 
plastic material inflated with sterile air. Both have jackets or sleeves 
that extend into the bag and that cover the surgeon and his assistant's 
arms during the surgery. The jackets and sleeves are closed at their ends 
by the gloves that the surgeons wear. This makes it very difficult for the 
surgeons to change gloves during the surgery should one of the gloves 
tear. Also, should it be necessary to remove the isolator and complete the 
surgery without it, the surgeon would have to be regloved before he could 
proceed. Another disadvantage of this arrangement, is that since the 
gloves are attached to their ends, the sleeves or jackets extend into the 
work area of the isolator to the same extent as the arms of the surgical 
team and tends to partially obscure the vision of the surgeon, as well as 
just being somewhat in the way of the surgical team as it works. 
It is therefore an object of this invention to provide an isolator having 
sleeves through which the surgical team can extend their pregloved hands 
and arms into the work space with the open end of the sleeves engaging 
their arms above the elbow and held in place by elastic so that the 
sleeves fold in upon themselves or intussuscept as required to allow the 
arm to which it is attached to move freely into and out of the bag and 
into and out of the work space of the isolator above the surgical wound of 
the patient. 
The isolators of both Levenson and McLauchlan had clear plastic in the top 
through which the surgical team could view the surgical field, but the 
plastic was flexible and would change shapes depending upon the air 
pressure in the isolator and would tend to balloon away from the surgical 
field. 
Therefore, it is an object of this invention to provide an isolator 
comprising an inflatable bag having side and end walls of flexible 
material and an upper side, a portion of which is of flexible material and 
a portion of which is of a relatively stiff, optically transparent 
material, that is designed so that when the bag is inflated, it will 
assume a position a predetermined distance above the surgical field and 
remain substantially in that position throughout the operation giving the 
surgeon and assistants a clear and unlimited view of the surgical field 
and ample room inside the bag in which to work. 
It is another object of this invention to provide a surgical isolator 
comprising an inflatable bag of flexible material that is impervious to 
disease organisms that includes a section in the upper wall of relatively 
stiff, optically transparent, material that will assume a position when 
the bag is inflated that is substantially straight along the longitudinal 
axis of the bag and slightly convex or V-shaped along the transverse axis 
of the bag to provide a window through which the surgeon has a clear view 
of the surgical field. 
It is a further object of this invention to provide an improved arrangement 
for filtering the air being pumped into the bag to decrease the 
possibility of contaminating the sterile isolator when the bag is 
connected to the blower supplying the air to the bag. 
It is a further object of this invention to provide a blower-air filter 
assembly for providing filtered air under pressure to the bag of the 
isolator in which any leakage will be of filtered air back to the suction 
side of the blower to keep non-filtered air from entering the bag. 
It is a further object of this invention to provide an isolator having a 
bag that is inflated with sterile air from a blower-filter assembly that 
passes through another filter located in the sterile air duct between the 
blower-filter assembly and the bag so that the connection between the 
sterile air duct and the blower-filter assembly is made upstream from this 
filter to entrap any contaminants that are introduced into the air duct 
when the connection is made. 
It is a further object of this invention to provide an isolator comprising 
an inflatable bag of flexible material a portion of the lower side of 
which is made of an elastic material through which a body member upon 
which a surgical procedure is to be performed, can be pulled into the work 
space in the bag through an incision in the elastic material that is 
smaller than the member to cause the stretched elastic material to tightly 
surround the member and isolate the body member from the environment 
outside the work space. 
The objects and advantages of the isolator of this invention in solving the 
problem of infections in surgical procedures have been described above. 
The isolator of this invention also has utility in industry. It can 
replace the "clean rooms" now used to provide a contamination-free 
atmosphere in which equipment is assembled that is especially sensitive to 
environmental contamination, such as dust. A typical clean room has an 
atmospheric-control system that rigidly controls temperature and humidity 
and bars entrance, by means of filters, of all but the tiniest mote of 
dust. Walls and ceilings are of one-piece plastic with no cracks where 
dust might collect and are washed and vacuumed daily. Maintenance cannot 
be done within the room: plumbing, wiring, and lighting are so arranged 
that maintenance can be handled in crawl spaces above the ceiling. The 
room has no sharp corners; they are rounded off to forestall dust 
collection. 
Before entering, workers don special clean suits, including head covering 
and boots, and pass under an "air shower" that removes all loose particles 
of matter. The parts that make up the assembly are thoroughly cleaned and 
polished before delivery to the clean room, which they enter through an 
air lock. 
With the isolator of this invention, much of the elaborate equipment, 
special room design, and special clean suits can be eliminated greatly 
reducing the cost of a clean room operation.

The isolator shown in the drawings is described below as it is used in a 
surgical procedure. As explained above, it can be used as a clean room for 
industrial purposes equally as well. 
The isolator shown in FIGS. 1-5 and generally indicated by the number 10, 
is essentially a bag that is inflated in use. It is made of materials 
through which disease organisms cannot pass. Most of the bag, in the 
preferred embodiment, is made of a clear, flexible acrylic resin plastic 
except for optical window 12 in the top portion of the isolator and a 
portion of the bottom side of the isolator, where a special material is 
provided for certain surgical procedures that will be described below. 
Window 12 is made out of a relatively stiff, optically clear, plastic 
material, such as the thermoplastic carbonate-linked polymer produced by 
reacting bisphenol A and phosgene and sold under the trademark "Lexan" by 
the General Electric Co. It provides the surgical team with a clear, 
undistorted, view of the surgical field. In addition, the window, being 
relatively stiff compared to the acrylic material used for the rest of the 
bag, will cause the inflated bag to assume a more or less elliptical shape 
in cross-section as shown in FIG. 3. In the embodiment shown in FIGS. 1-5, 
the window is substantially straight along the longitudinal axis of the 
bag and slightly convex along the transverse axis. It is also a stable 
window that will assume a position relative to the bottom of the bag and 
substantially maintain that position even though the pressure in the bag 
may change slightly during the time it is in use. Further, it will not 
undulate or balloon under the pressure, which could distort the view 
through the window. 
Side walls 10a and 10b of the isolator are provided with openings that 
connect to open ended sleeves 14-21 attached to the side wall of the 
isolator. In this embodiment, four sleeves are provided on each side of 
the isolator. The sleeves are open ended, but are held substantially 
closed, when not in use, by rubberized elastic attached to the sleeves 
adjacent the ends. In use, the surgeon will extend his arms through the 
openings in, for example, sleeves 14 and 15, as they are held open by an 
assistant, until the elastic band of the sleeves is somewhere above his 
elbow. Then as the surgeon extends his arms into the working space between 
the bottom of the isolator and window 12, the sleeves will turn inwardly 
on themselves or intussuscept as required to allow the arms to which they 
are attached to move freely into the isolator. In FIG. 5, for example, the 
surgeon has his arms sufficiently inside the isolator to perform his 
surgery, yet sleeves 14 and 15 are outside of the working space of the 
isolator so as not to interfere with the movement of the surgeon's hands 
or arms or interfere with his vision of the surgical field. 
In this arrangement, the surgeon is gloved outside the isolator. If he 
needs to change gloves during the surgery, he can simply pull his arms out 
of sleeves 14 and 15, be regloved, and reinsert his hands and arms back 
into the isolator through sleeves 14 and 16. This can be done quickly and 
easily. 
Further, if for some reason, it is necessary to remove the isolator before 
the surgery is completed, the surgeon can remove his arms from the 
sleeves, remove the isolator, and immediately continue without having to 
be regloved as is the case with the prior art isolators. Some air leaks 
out through sleeves 14 and 15 both when the surgeon has his arms in the 
sleeves and also when they are not in use. This positive flow of air along 
the sleeves of the surgeon and out through the opening end of the sleeves 
through which the surgeon's arms extend, prevents disease organisms from 
the surgeon from entering the isolator to contaminate and infect the 
surgical wound. 
It is another advantage and feature of this invention to make a portion of 
the bottom of the isolator out of a surgical drape of resilient material. 
This allows a body member, upon which a surgical procedure is to be 
performed, to be pulled into the work space of the isolator through an 
incision in the drape that is smaller than the body member. The stretched 
elastic material tightly engages the member to reduce the chances of 
disease organisms from entering the work space from the outside. Any air 
that leaks through the opening in the drape will tend to carry such 
organisms away from the work space. This feature, of course, is 
advantageous where the body member is of such shape and size that it can 
be pulled into the work space conveniently so as to isolate it from the 
outside environment and from the body of the patient itself. For example, 
a foot, a knee, a whole leg, or a portion thereof, hands, arms, head, and 
genitalia are examples of body members that could be so handled. 
In FIG. 2, drape portion 30 is positioned so that the patient's genitalia 
can be pulled through an incision in the drape and isolated from the 
outside during a surgical procedure, such as the implantation of a penile 
prosthesis. 
Air conduit 36 is integrally attached to the isolator and sterilized along 
with the isolator before it is placed in use. In the operation room, the 
end of conduit 36 is attached to filter 38 connected to the outlet of 
blower 40. Filter 38 is of the type that will filter out disease organisms 
to prevent them from entering the isolator. The filter and blower are 
supported on table 42 located adjacent operating table 43. 
In most cases, the outlet side of filter 38 will not be as sterile as is 
desired for use with the isolator. Even if sterile, someone has to make a 
connection between conduit 36 and the outlet of the filter and this can 
introduce disease organisms into the conduit when the connection is being 
made. The connection usually consists of slipping the end of conduit 36 
over outlet to 38a and clamping or taping the conduit in place. 
It is another feature and advantage of this invention to provide conduit 44 
that has conical filter 46 installed in the conduit downstream from its 
end, as shown in FIG. 5. Filter 46 will prevent any disease organisms that 
are introduced into the conduit, while it is being connected to the 
blower, from reaching the isolator Filter 38, described above, is 
classified as a high efficiency particle air (HEPA) filter. Conically 
shaped filter 46, in the embodiment shown in FIG. 4, is made of thin 
plastic membrane like material having a porosity of several million pores 
per square inch that can filter bacteria out of the moving air stream. One 
such material is marketed by E.I. duPont de Nemours & Co. under the 
trademark "REMAY", Style 2016, and is made of a spun bound polyester. 
One end wall of the isolator includes rather large flap 50 that is held in 
the closed position by tape. Instruments and the like are moved into and 
out of the isolator through this flap. Suction tubes, cautery, and the 
like can be inserted through smaller flap 52 at the other end. Air 
continuously leaks out of the isolator through the flaps and the sleeves. 
This is desirable since there should be a continuous flow of sterile air 
over the surgical wound, not a blast of air, of course, but steady 
movement. The elastic holding the sleeves closed can function to regulate 
pressure in the isolator. As it increases, it will open the sleeves 
letting out more air and vice versa. 
An alternate embodiment of the surgical isolation system of this invention 
is shown in FIGS. 6-11. It includes inflatable bag or bubble 60, which is 
generally rectangular in cross-section, having side walls 62 and 64, end 
walls 65 and 66, top 67, and bottom 68. The bag in FIG. 6 is shown 
inflated and resting on operating table 70. There is a patient between the 
bag and the operating table, but for the sake of clarity, the patient is 
not shown. It is understood that the bag is resting on top of the patient 
although some part of the patient may be pulled inside of the bag, if the 
surgery is on a portion of the body that can be pulled inside the bag. 
Filtered air is supplied to the bag from blower-filter assembly 72 through 
duct 73 that is connected to an opening in end wall 66. Air travels the 
length of the bag and is exhausted through exhaust ports in end wall 65. 
It is very important that the air in the bag be changed continuously. In 
one embodiment of the invention, the blower-filter assembly provided ten 
times the volume of the bag every minute. To maintain the bag properly 
inflated with an adequate flow of air through the bag, a volume of air 
equal to at least double the volume of the bag should be supplied to the 
bag every minute. 
In the embodiment shown, air lock 74 is attached to end 65 of the bubble. 
The air lock is used to pass instruments, materials, and prostheses into 
and out of the bubble. It also serves as the conduit through which most of 
the air is exhausted from the bag. 
In the embodiment shown, the air lock includes a rigid framework of angle 
iron connected to form rectangular end frames 75 and 76 that are held 
upright by struts 77 extending between the corners of the end frames. The 
outside of the framework is covered by the same clear, flexible plastic 
used for the bag except for window 78 in the top that is made of the same 
rigid optically transparent material used for window 67 in the top of the 
bag. 
End frame 76 is connected to an opening in end wall 65 of the bag. To 
function as an air lock, doors or the like are located at each end, one to 
allow material to be moved into and out of the air lock from the outside. 
The other to allow material to be moved into and out of the air lock from 
the bag. In the embodiment shown, these door functions are provided by end 
flaps 80 and 81. The flaps include rectangular sheets 82 and 83 of clear, 
flexible plastic that are connected along the lower edge to the bottom of 
the end frames. The opposite sides of the flaps are connected to rigid 
support members 84 and 85. The flaps are held in position closing the air 
lock by L-shaped latch members 86 and 87 attached to the middle of the 
flaps opposite support members 84 and 85 and extend through slots in upper 
end frame members 75a and 76a, as shown in FIG. 9. Either end of the air 
lock can be opened by removing the latch member from the slot, allowing 
the flap to collapse to the bottom of the air lock. 
Openings 88 are provided in the flaps to serve as exhaust ports through 
which air can flow out of the bag through the air lock into the operating 
room. It is intended for most of the air exhausted from the bag to flow 
through these openings. Therefore, the size and member of openings are 
chosen to allow the air to flow out of the bag at about the rate that air 
is pumped into the bag with the pressure drop across the flaps being 
sufficient to maintain the desired inflation pressure in the bag. Due to 
the pressure drop across the flaps, rigid members 89 and 90 are attached 
to the flaps across the middle to engage the end frames and support the 
flaps. 
Blower-filter assembly 72 includes housing 92 that is divided into blower 
compartment 93 and filter compartment 94 by plenum 95. In this embodiment, 
the plenum is a rectangular box having openings on opposite sides Mounted 
on one side to pump air into the plenum is blower 96. Mounted on the other 
by bolts 97 is HEPA filter 98. Mounting flanges 99 support the blower, 
filter, and plenum in the housing. Appropriate seals are located between 
the blower and the plenum and the plenum and the HEPA filter to keep 
unfiltered air from entering filter compartment 94 and air duct 73. Should 
any of the seals leak, however, with the arrangement described above, 
since the pressure in filter compartment 94 is greater than the pressure 
outside housing 72 and the pressure in blower compartment 93, filtered air 
will leak out of filter compartment 94, but unfiltered air cannot enter 
the compartment and contaminate the air entering the bag. 
Conical filter 100 serves the same purpose as conical filter 46 described 
above in connection with FIG. 5. 
In this embodiment, the bag has three sleeves 102, 103, and 104 on one side 
and three sleeves 105, 106, and 107 on the other side. Air lock 74 has one 
sleeve 108. These function in the same manner as the sleeves described 
above in connection with the embodiment shown in FIGS. 1-5. They are 
constructed differently, however, being formed of four, flat triangular 
pieces of plastic connected at their edges to each other and the side wall 
of the bag. 
Smaller sleeves 109 and 110 in end wall 66 allow the passage of suction and 
electrocautery connections to the outside of the bag. The elastic around 
the openings in these sleeves provides a substantially airtight seal 
around the arms of the surgical team and the electrical cables and 
pneumatic hoses extending through the sleeves 
In operation, the air lock can be supported by a separate table, such as 
table 112. This allows the air lock to be disconnected from the bag after 
the surgery is completed and the surgical instruments have been moved back 
into the air lock. It can be disconnected simply by cutting it from wall 
65 leaving it intact on table 112. The bag can then be removed and the 
patient prepared for removal from the operating room. While this is going 
on, the instruments will be somewhat protected from the air in the 
operating room and be available should the need arise. 
From the foregoing it will be seen that this invention is one well adapted 
to attain all of the ends and objects hereinabove set forth, together with 
other advantages which are obvious and which are inherent to the apparatus 
and structures. 
It will be understood that certain features and subcombinations are of 
utility and may be employed without reference to other features and 
subcombinations. This is contemplated by and is within the scope of the 
claims. 
Because many possible embodiments may be made of the invention without 
departing from the scope thereof, it is to be understood that all matter 
herein set forth or shown in the accompanying drawings is to be 
interpreted as illustrative and not in a limiting sense.