U.S. patent number 3,709,210 [Application Number 05/110,045] was granted by the patent office on 1973-01-09 for bed patient isolation system.
This patent grant is currently assigned to Environmental General Corporation. Invention is credited to Frank E. Matthews.
United States Patent |
3,709,210 |
Matthews |
January 9, 1973 |
BED PATIENT ISOLATION SYSTEM
Abstract
A bed patient isolation unit for isolating infection-susceptible
patients from their environment or vice versa has a rigid frame of
specially-formed beams supporting an enclosure including flexible
side walls of transparent plastic sheeting equipped with
pseudopodal sleeve-glove arms by means of which sterile manual
access to the interior isolation area of the unit is provided. A
filter-pump device at one end of the unit has air inlet and air
outlet areas in the end wall providing a laminar flow of filtered
air from the outlet area at a slight positive pressure with respect
to the ambient, so that external contaminated air cannot enter the
isolation area.
Inventors: |
Matthews; Frank E. (Reston,
VA) |
Assignee: |
Environmental General
Corporation (Alexandria, VA)
|
Family
ID: |
22330941 |
Appl.
No.: |
05/110,045 |
Filed: |
January 27, 1971 |
Current U.S.
Class: |
600/21;
128/205.26; 312/3; 108/143; 312/1 |
Current CPC
Class: |
A61G
10/005 (20130101) |
Current International
Class: |
A61G
10/00 (20060101); A61b 019/00 () |
Field of
Search: |
;128/1R,1B,191
;312/1,3,4 ;5/70,332 ;108/137,143 ;160/84,330,346 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truluck; Dalton L.
Claims
I claim:
1. a. Isolation unit for bed patients comprising
b. a bed compartment provided with support means and having top,
bottom, and end walls and side members of material impervious to
air attached thereto,
c. a service corridor compartment formed by top, bottom and side
walls adjacent one of the side walls of the bed compartment and
having a common wall therewith, and having also a service access
opening between one end of the service compartment and the foot end
of the bed compartment, and an exit access opening at the other end
of the service corridor for access of service personnel to the
outside of the unit from the service corridor,
d. the side walls of the bed compartment being at least partly of
flexible sheet plastic material having flexible sleeve and glove
devices incorporated thereinto for providing a bacterially
impervious means of manual access to the interior of the bed area
from outside of the bed area,
e. means for maintaining a pressure differential between the air in
the bed area and the ambient air, including the air in the service
corridor,
f. a service unit attached to said support means and movable from a
position over the bed area into a position adjacent said access
opening where it can be reached by personnel in said service
corridor compartment without entering said bed compartment.
2. The invention according to claim 1, said unit also including a
rigid framework of readily dissemblable members supporting the wall
and side members of the unit, said framework comprising rigid
horizontal beams at the upper portion of the framework, said
horizontal beams containing in the underside thereof a deep
downwardly opening valence slot having a guide track therein for
slidably supporting the upper edge of said flexible plastic wall
material in pleated condition, said slot providing a deep valence
skirt on either side of the upper edge of the flexible wall to
retard the passage of air from one side of the flexible wall to the
other side while permitting the pleated flexible wall material to
slide laterally for a limited distance on said guide track within
said slot so that the glove and sleeve devices can be moved
laterally to service an extended area within said bed area.
3. The invention according to claim 2,
said framework comprising individual lengths of rigid extrusions
held together with removable fasteners for rapid assembly and
disassembly.
4. The invention according to claim 3, said rigid extrusions having
a cross-section including track means for supporting drapery
sliders to retain said walls of flexible material.
5. a. Isolation unit for bed patients comprising
b. a rigid framework and flexible plastic wall curtains supported
by said framework and providing two adjacent enclosed areas, one
serving as a bed area and the other serving as a service corridor
alongside the bed area, there being an access opening between the
foot end of the bed area and said service corridor providing free
access between the service corridor and bed area,
c. flexible glove and sleeve devices incorporated into part of the
plastic material of said wall to provide a bacterially impervious
means of manual access to the interior of the bed area from outside
the bed area,
d. means for maintaining a pressure differential between the air in
the bed area and the ambient air to bacterially isolate the bed
area from the ambient area;
e. said framework comprising rigid horizontal beams at the upper
portion of the framework, said horizontal beams containing in the
underside thereof a deep downwardly opening valence slot having a
guide track therein slidably supporting the upper edge of said
flexible plastic wall material in pleated condition, said slot
providing a deep valence skirt on either side of the upper edge of
the flexible wall to retard the passage of air from one side of the
flexible wall to the other side while permitting the pleated
flexible wall material to slide laterally for a limited distance on
said guide track within said slot so that the glove and sleeve
devices can be moved laterally to service an extended area within
said bed area,
f. at least one of the slot walls having a weakening groove
extending axially therealong so that it can be deformed toward the
other wall to provide a close fit for one edge of the pleated
curtain wall.
6. a. A patient isolation unit comprising
b. a rigid framework defining the walls and top of an isolation
unit,
c. said unit having a bed area and a narrow service corridor area
with internal access at one end thereof to the bed area, and
external access at the other end thereof to the exterior of said
unit, and an inner wall of flexible transparent material between
said two areas,
d. an outer wall made at least partly of flexible transparent
material suspended from said rigid framework,
e. said inner and said outer wall each containing a pair of
flexible glove and sleeve devices providing bacteria-impervious
sterile manual access to all parts of the bed area from outside the
bed area,
f. one end wall of said unit comprising an air filtration unit
having an inlet area and an outlet area, both areas communicating
with the interior of the unit, and means for drawing ambient air
from the interior of the unit in through said inlet area, then
through a filter, and expelling said filtered air through said
outlet area into said isolation unit at a positive pressure with
respect to the ambient air pressure,
g. and means for reversing the direction of flow of air from the
filtration unit with respect to the bed area so as to maintain the
bed area optionally at a higher or lower air pressure than the
ambient air outside of the unit.
7. The invention according to claim 6,
h. wall fastening means for optionally moving said inner wall into
either of two positions within said unit between said inlet area
and said outlet area of the end wall so that said bed area is in
one of said positions of the wall under positive pressure so as to
isolate the bed area from the ambient environment,
i. and in the other position of the inner wall the bed area
includes said outlet area and is under a slight negative air
pressure.
8. a. For use in a patient isolation unit having an enclosed bed
compartment containing a bed area and a service corridor and
supplied with a laminar flow of bacteria-free air under a slight
positive pressure from a pressure source at one end of the
compartment, over the bed in the compartment, to an access opening
at the other end of the compartment, beyond the foot end of the
bed,
b. the improvement comprising a patient service unit above the bed
and movable over the bed from a position near the head end of the
bed to a position adjacent said access opening,
c. said service unit being provided with compartments for holding
patient supplies and needs,
d. said service unit having a top covering said compartments and
serving as a bed tray,
e. and hinge means for said top for swinging it into an upright
position to provide access to said compartments,
f. slide guide means for sliding said top on said service unit
transversely of said bed,
g. whereby said top can be slid on the service unit partially into
said access opening for supplying a patient in the bed without
entering said compartment.
9. The invention according to claim 8,
h. and fixed overhead track means in said isolation unit above the
bed area of the unit,
i. service unit suspension means slidably mounted on said track
means and supporting said patient service unit above the bed.
10. The invention according to claim 8,
h. said slide guide and hinge means comprising a tubular element
fitted to said service unit and having a longitudinal slot along
its entire length,
i. a hinge pin lying within said slotted tubular element and
projecting beyond it at both ends,
j. a short arm fixed at one end to said flat top and at the other
end to the projecting end of said hinge pin, there being one short
arm at each end of the hinge pin, at least one said short arms
being slidable within the slot of said tubular element when said
top is slid on the surface unit.
11. The invention according to claim 10,
k. said hinge pin having a maximum thickness greater than the width
of the slot in said tubular element so that it can be slid along
the slot but not pulled through it.
12. The invention according to claim 11,
l. and a mirror fastened to the underside of said top.
Description
This invention relates to a bed patient isolation system having
walls of transparent plastic sheeting surrounding a bed, in which a
differential atmospheric pressure is maintained between the bed
area and the outside area so as to prevent contamination of one
area by the other. This is accomplished by means of a known air
filtration and pump system, and pseudopodal sleeve-glove
arrangements are provided by means of which a person on the outside
of the sterile area can administer to the needs of the patient. The
unit is divided by an interior partition of plastic sheeting, which
is preferably pleated or draped, especially in the pseudopal areas,
so as to provide considerable lateral movement of the pseudopods;
this provides a bed space and a corridor having access to the bed
space at one end of the corridor and access to the exterior at the
other end. This partition can be moved as a whole with respect to
the inlet and outlet areas so as to change the direction of airflow
in the bed area and thus isolate an infection-susceptible patient
from the ambient environment in one position of the partition or
isolate the environment from a contagious patient in another
position of the partition wall. For serving the patient in either
condition with supplies and materials, an over-bed table is
provided which is arranged to move in a fixed path along the length
of the bed and is equipped with a top which can be slide from one
side to the other so as to make it accessible to a nurse or doctor
by partially projecting it into the corridor so that sterile
supplies can be placed on it, the slidable top can also be swung up
to uncover a multi-storage compartment for personal effects, and a
small sink provided with sterile water for washing. The rigid frame
is formed with drapery slide means for supporting the flexible
plastic wall sheeting and valence means for obstructing the flow of
air from one side of the curtain to the other over the top or
bottom of the sheet wall are also provided.
The specific nature of the invention, as well as other objects and
advantages thereof, will clearly appear from a description of a
preferred embodiment as shown in the accompanying drawings, in
which:
FIG. 1 is a perspective schematic view of the unit as a whole;
FIG. 2 is a schematic plan view showing the air flow with the
interior partition positioned for reverse isolation;
FIG. 3 is a similar view showing the partition and air flow in the
position for direct isolation;
FIG. 4 is a schematic perspective view of the over-bed unit;
FIG. 5 is an end view of the over-bed unit;
FIG. 6 is a transverse sectional view taken on line 6--6 of FIG. 1
showing the detail construction of a beam element;
FIG. 7 is a similar sectional view showing a modified beam
element;
FIG. 7a is a transverse sectional view of a joining bar used for
connecting two of the elements shown in FIG. 7;
FIG. 8 is a transverse sectional view of a sealing gasket used in
connection with the beams of FIGS. 6 and 7; and
FIG. 9 is a transverse sectional view of a corner of the unit
showing the manner in which the beams are assembled.
FIGS. 1, 2 and 3 show the general arrangement of the system. A
framework of rigid beam-like members 2, 2a, which can be assembled
in place by suitable fastening means, as will be shown in more
detail below, supports exterior walls 4, 4a, which are preferably
of flexible sheet plastic material and, together with end wall 6
define an enclosed space. Although some of the exterior walls could
be of rigid material, the walls defining the actual bed space of
the unit should be flexible, preferably transparent sheeting, since
access by means of pseudopodal sleeve-glove devices is required, in
order to allow movement of the glove ports so as to enable all
parts of the interior to be reached.
Beams 2 may support a roof 3 preferably of translucent rigid
plastic panels, or, as in the case where a hospital is especially
designed for this type of isolation unit, the beams 2 may extend to
(or depend from) the ceiling of the room in which the unit is
located.
The enclosed space of the unit is itself divided into two areas 7
and 8, of which the first is for a bed, while area 8 is a corridor
area having an access opening 9 to the bed area 7, and another
access opening 11 to the exterior of the unit. The dividing wall 12
between the corridor and the bed area is also of flexible
transparent plastic sheeting, preferably draped or pleated so that
glove-sleeve pseudopods 13, which extend from suitable armports in
the sheeting, can have considerable lateral freedom of movement
whereby all of the bed length can be reached from the corridor side
by a nurse or doctor's hands thrust into the pseudopods. The
remaining area of the bed space can be reached by similar
pseudopods in the opposite wall 4a of the unit. The other two walls
4 and 9 of the unit need not be heavily pleated or transparent, as
they do not contain pseudopods, but can be stretched fairly flat if
desired, or be of rigid material.
A standard hospital bed 16 is ordinarily located in the bed area,
which is typically about five feet wide, while the corridor is
about 2 feet in width, and the entire unit about 7 by 10 feet. The
dimensions should be such that all of the bed area can be reached
by the pseudopods 13 and 14, although if desired, more than one
pair of pseudopods can be provided in each wall. The two service
walls in which the pseudopods are located are preferably loosely
draped or pleated, and are suspended from the frame members on
slidable hangers so that the pseudopods can be moved a considerable
distance laterally, i.e., along the length of the bed area, so that
all parts of the bed area can be reached for servicing from the
outside of the bed area.
The head end wall of the unit, 6, is of solid construction and
contains an air pump and filter unit, the details of which are not
per se a part of the present invention except to note that the air
enters the unit at the inlet grill 18 and is discharged through a
porous grill or screen wall 19, which occupies most of the rest of
the head wall area, in such manner as to produce an essentially
laminar flow of air from the outlet base at a slight positive
pressure with respect to the ambient pressure outside the unit,
from the head end of the bed area to the foot end, with the
corridor wall 12 placed as shown in FIG. 2. With the corridor wall
placed as shown in FIG. 3, the bed area will be at a slight
negative pressure, in order to insure that no contamination can
pass from the patient to the ambient air. Means are provided
between the air inlet and outlet openings to clean the air of any
deleterious organisms such as baterial, molds, pollen, etc., so
that the air emerging from the outlet is essentially sterile. Such
cleaning means are known in the art and do not per se form a part
of the invention; one such cleaning means successfully used in
practice may be a mechanical filter, such as a HEPA filter,
commercially available; these are tested to remove in excess of
99.97 of particles over 0.3 microns in size. However, in place of,
or in addition to these filters, other suitable means such as
electrical precipitators, ultra-violet sterilizers, etc. may also
be used.
The necessary motor, pump and other mechanical equipment of the air
unit may be conveniently located in housing 21 on top of the unit,
and suitable lighting means for the interior may be provided either
within or without the bed space, or both, although it is noted that
external lighting is easier to maintain. The unit as a whole must
be provided in small enough component sub-units so that they can be
readily transported and carried through an ordinary doorway, in
order that the isolation unit may be set up in any ordinary
room.
In the case where the patient must be bacterially isolated from the
outer world, all supplies and materials furnished him must, of
course, be sterile, which is readily possible with known
techniques, but entering such supplies and materials into the bed
area in an antiseptic manner is more of a problem. In order to
accomplish this needed function, a special over-bed table 23 is
provided, which is arranged to be moved in a fixed path along the
length of the bed. This could be done by means of a pedestal on
wheels or casters, but a preferred arrangement is to suspend the
table over the bed by means of tracks 24, provided in overhead
beams 26 (FIG. 4), and hangers 27 extending downwardly from the
rollers 28 riding in the tracks and supporting table 23 at the
lower end of the hangers so that the table can be readily moved
from a position at the head end of the bed, where it can serve the
patient, to a position where it is opposite the access opening 9
which leads into the corridor 8. The table is provided with a
bottom portion 29 which is deep enough to accommodate a
multi-storage compartment having recesses as at 31 and a shallow
sink 32, preferably of molded plastic, which is supplied with
sterile water from a tank 33 and flexible rubber tubes 34.
The top of the table has a flat cover 36 which can be swung up on a
hinge arrangement 37 into the position shown in dotted lines in
FIG. 5, to provide access by the patient to the storage
compartments 31 and the water sink 32. The underside of the top may
contain a mirror 38a for the patient's use when the top 36 is swung
up. Alternatively, the top 36 may be slid out to either side of the
bed as shown in FIGS. 2 and 4, so that part of it projects into the
service corridor 8 from which sterile supplies can be put by a
nurse or attendant onto the table top. It will be noted that this
is done at the point where the air stream turns and reverses
direction, so that the sterile articles are unwrapped or uncovered
and placed on the table in the reverse airstream of the corridor,
so that there is no chance of contamination from the attendant or
from the unsterile outer containers reaching the patient or
contaminating the table top if sterile procedures are used. On the
other hand, if the environment is to be kept from contamination by
the patient (e.g., in the case of a contagious disease), as will be
shown below, the airflow would be coming from the back of the
attendant into the bed area across the table top.
If desired, one or more additional small shelves may be provided
above the table top as shown at 35.
The special sliding hinge arrangement 37 which makes the
above-described use of the table top 36 possible is shown in more
detail in FIG. 5, and comprises a tubular hinge member 38, shown as
a square tubular member, but which could equally well be round, and
which has a narrow axial slot 39 on the side facing the patient. A
hinge pin 41 lies in the tube 38 and has a maximum diameter greater
than the width of the slot 39 so that it cannot be pulled through
the slot. The ends of the hinge pin extend out beyond the ends of
the tube 38, and from these ends project rodlike members 42 which
are fixed, as by welding, to the table top 36; members 42 (or at
least one of them) are dimensioned so that they can pass freely
into the slot 39 when the table top 36 is to be slid transversely
into the service corridor, and the one member which is in the slot
when the tray top 36 is slid partially into the service corridor
also serves to prevent the top from being inadvertently swung up,
which would cause articles to fall off it, and also enables objects
to be put on the projecting end of the tray top 36 without its
falling off due to unbalance. However, when the top 36 is in its
normal position on the table 23, the members 42 are clear of
tubular hinge member 38 and the top 36 can be hingedly swung up
into the position shown by the dotted line in FIG. 5, with the top
36 resting against members 27, uncovering the storage compartments
31 and basin 32, while presenting the mirror 38a in a position
where it can be used by the bed patient.
The beams 2, 2a, of which the framework of the unit is made are
preferably of a special construction as shown in FIGS. 6-8. The top
and bottom horizontal beams which hold the flexible plastic curtain
walls are shown in FIG. 6. At one edge of the beam 2 is a groove 43
adapted to frictionally retain a rubber or soft plastic extrusion
such as is shown at 44, which has a hollow center portion 46 which
may be used to conceal electrical wiring for light and power, and
also has a groove 47 for the reception of the edge of a panel 3,
which may be a translucent fiberglass plastic panel forming the
roof or ceiling of the isolation unit. The beam 2 (or 2a) also has
at least one and preferably two longitudinal slots 48 which can
serve as tracks to retain rollers 28 of the bed table unit, and
also serve to retain connecting bars 49 (FIGS. 7 and 7a) whereby
two beams may be connected end-to-end to form a single longer beam.
At the bottom of the beam is a very deep slot 51 having at its end
tracks 52 for the reception of drapery-type sliders or rollers 53
carrying hooks 54 on which the flexible plastic sheets 4, 4a are
supported. These may be stretched fairly tight horizontally and
vertically to form those walls of the unit which are not carrying
pseudopods, or left in pleated condition as above explained for
those walls which carry pseudopods and which must be capable of
considerable lateral movement.
At least one of the skirts 56 of slot 51 is preferably provided
with a longitudinal weakening groove 57 so that it may be bent
inwardly as indicated by the dotted line so as to reduce the width
of the aperture at the bottom of the slot 51 to a minimum so that
the flow of air from one side of the unit 4 (or 4a) to the other is
reduced, thus tending to reduce the amount of blower power required
to maintain the desired pressure differential on both sides of the
wall.
Where the beam is not used to support a curtain wall, e.g., the
center beams which support only the roof and the bed table, the
lower skirt portion may be omitted as shown in FIG. 7, which is, in
effect, only the upper half of the beam shown in FIG. 6. It will be
understood that the lower beams of the framework, as at 2b, which
hold the lower edge of the plastic curtain wall are the same as
shown in FIG. 6, except that they are inverted, with the slot 51
facing up and retaining the bottom edge of the curtain wall. For
those beams of the type shown in FIG. 7, which do not support the
edge of a roof panel 3 but instead support it at some intermediate
location, extrusions 58 or 59 may be used, and these are also used
at the bottom of the frame to seal the crack between it and the
floor, the form shown at 59 (FIG. 9) being particularly useful
where the floor is irregular or uneven.
The framework members may be connected together in any suitable
fashion, but a preferred typical form of interconnection is shown
in FIG. 9, where two beams 2 are joined to a vertical beam 60 by
means of threaded bolts 61 and a cover plate 62 covers the ends of
the beam 2 and the bolt 61, while the vertical space between 60 and
62 below the beams 2 serves to contain the ends of the curtain wall
4 so as to combine a neat appearance with an effective closure for
retaining the desired pressure differential.
FIG. 2 shows the condition of so-called "reverse isolation," in
which the air in the bed area is maintained at a slight positive
pressure, to insure that the patient is not subjected to
contaminated external air. FIG. 3 shows how, by a very simple
change, the unit can be adapted to isolate the patient, in the case
of contagious diseases, so that air contaminated by the patient is
always filtered before it can mix with external air. In order to
accomplish this, the partition 12 of FIG. 2 is reversed and moved
to the position 12a of FIG. 3, so that the corridor is now at 8a,
and is supplied with air from a part of the exhaust grill 19, while
the bed area now includes the inlet grill 18 and a part of the
exhaust grill 19. Since the inlet grill 18 must take in as much air
as is exhausted from the entire outlet grill 19, it is clear that
there will now be a net diminution of atmospheric pressure within
the bed area, and that air must be brought in through opening 9a
from the corridor 8a in order to supply this deficiency. Therefore,
the net flow of air in the bed area will be through the filter unit
18, and any air reaching the exterior from the bed area will have
passed through the filter system. It will be apparent that the
entire arrangement involves only re-hanging of the transparent
plastic sheeting and can be accomplished in a few minutes.
A small portable toilet 9a' is also provided, being preferably
placed in the corner as shown in FIG. 1, at the inner end of the
corridor, so that it is always in an airstream of the proper
direction to provide the desired protection. This corner is
preferably provided with opaque drapes, not shown, in order to
provide privacy for the user.
* * * * *