Respiratory filter apparatus with patient enclosure and method

A respiratory filter apparatus having a patient enclosure which includes a respiratory filter apparatus with a face cone for use by a patient in communication with a filter and with air drawn through the face cone and a thin, plastic, transparent, supported, disposable patient enclosure adjacent the filter apparatus about the upper portion of the patient's body with the face cone within the patient enclosure whereby a patient's respiratory effluent is contained within the enclosure and the patient enclosure maybe discarded after use.

BACKGROUND OF THE INVENTION 
It has been reported that extensive airborne tuberculosis transmission is 
associated with the treatment of patients in the process of sputum 
induction. In particular, extensive TB transmission has been associated 
with the employment of pentamadine aerosol treatments. HIV-infected 
patients tend to be at an increased risk of reacting to tuberculosis by 
virtue of aerosol airborne transmission. The transmission of the diseases 
to unsuspecting infected patients and to medical staff is enhanced by the 
coughing induced by aerosol treatments, such as pentamadine, wherein a 
nebulizer is connected to a free standing air compressor to generate 
aerosol particles of the chemical. In addition, aerosols produced by 
sputum induction, bronchoscopy and suctioning patients with artificial 
airways also may lead to the airborne transmission of diseases to other 
persons and staff breathing the same air. Therefore, it is desirable to 
remove an infectious aerosol produced by patients and also to remove 
airborne drug particles which may be produced which patients are treated 
with aerosolized forms of drugs. Typically, the medical treatments 
involving enhanced coughing or aerosol drug treatment of patients is 
carried out in rooms of adequate fresh air ventilation so as to decrease 
the probability of transmission. However, adequate ventilation alone 
cannot eliminate the risk of airborne transmission. Other techniques 
include carrying out the procedures in high level, ventilated areas with 
the air exhausted safely to the outside with negative room air pressure 
relative to the outside together with properly installed and maintained UV 
lights and with extensive and regular treatments and testing of the staff 
for airborne disease infection. 
The hazards of airborne transmission and the occupational exposure for 
example to hepatitis B virus in human immunology and to other viruses has 
been recognized as a growing problem in occupational medicine, since the 
transmission of hepatitis or AIDS through sputum and saliva of a patient. 
One technique for reducing the risk of airborne transmission of disease is 
to provide a booth approach, such as an enclosed chamber, designed to 
remove any infectious aerosols produced by the coughing of a patient which 
booth usually comprises an enclosed chamber having a seat for the patient 
and a back panel wall against which the patient sits and includes a 
prefilter, a blower and a high efficiency particulate filter. The back 
panel includes on its back portion a UV tube light to enclose a duct-like 
space and whereby on activation of the air blower, the air is drawn 
through the prefilter into the chamber while the patient is undergoing the 
aerosol treatment up over the back panel and through the duct-like space 
and exposed to the UV rays and through the hepafilter and then discharged 
into the environment. 
While the booth approach may be satisfactory in some respects, the booth 
approach is not portable, thus it cannot be used for bedside or 
non-ambulatory patients, and further is more expensive. More particularly, 
after treatment of the patient the booth still remains contaminated and 
thus there must be a period of time before the next patient can enter the 
enclosed booth. 
It is therefore desirable to provide for a high efficiency, portable, 
quickly reusable respiratory filter apparatus and method. 
SUMMARY OF THE INVENTION 
The invention relates to a respiratory filter apparatus and method for 
reducing the risk of airborne disease transmission from the respiratory 
effluent of a patient. In particular, the invention concerns a high 
efficiency, particulate, portable respiratory filter apparatus employing a 
disposable face cone used by a patient undergoing nebulizer treatment 
which is likely to lead to enhanced coughing of a patient, the face cone 
within a disposable, supported patient enclosure. 
The invention relates to a high efficiency, respiratory filter apparatus 
which is designed to reduce the risk of airborne disease transmission, 
such as hepatitis or tuberculosis, induced from the respiratory effluent 
of a patient, such as by enhanced coughing of a patient during aerosol 
nebulizing treatment. The respiratory filter apparatus comprises a housing 
having an air inlet and an air outlet and which housing includes a motor 
blower designed to draw air into the air inlet and to discharge air from 
the air outlet. The apparatus includes a high efficiency, particulate 
filter and optionally as well an absorbent type filter, such as a charcoal 
filter, to absorb chemicals, such as aerosol drugs or liquid droplets, and 
a particulate material within the housing with one or more filters 
positioned within the housing to filter air between the air inlet and the 
air outlet. The filter apparatus also includes a tube, typically a 
flexible tube, say two to four inches in diameter, having a one and an 
other end with the one end in an air passage in communication with the air 
inlet in the housing. A disposable face cone, such as a paper or plastic, 
truncated face cone, is employed and secured either by clamping or fitting 
over the other end of the tube, and with the base of the cone extending 
outwardly from the other end of the tube and of sufficient size and shape 
to generally encompass the face of the patient using the filtering 
apparatus so as to gather any patient effluent, so that any respiratory 
effluent from the patient whose face is positioned in the face mask is 
drawn by the air stream from the face cone into the air inlet and through 
the filters to the air outlet to discharge safely into the environment. 
The respiratory filter apparatus of the invention is also designed to 
include the employment with the face cone of a nebulizing system, and in 
particular, as a nebulizing chemical holder device as has been determined 
in many patients, particularly elderly patients, find it difficult to hold 
the nebulizing chemical holder while employing the nebulizer. The 
nebulizer holder may include an extending rod and nebulizer container 
holder in which to put the chemicals to be nebulized, and with the 
nebulizing system adapted to fit within the face cone so that during the 
nebulizing aerosol treatment of the patient, which tends to induce 
coughing, on coughing the sputum or respiratory effluent from the patient 
will be drawn by the air flowing stream into the disposable face cone and 
the aerosols into the hepafilter and the housing. Typically, nebulizing 
systems employ an air compressor with a connecting tube extending into the 
nebulizing solution and if desired, the air compressor in use with the 
nebulizing system may be used or may also be placed within the housing for 
use to make a compact package. 
Typically, the face mask comprises a truncated cone made of a disposable, 
inexpensive material, such as paper, non-woven fibrous material, such as 
polypropylene or polyethylene, which may be coated or uncoated or a solid, 
thin plastic type material, all of which should be inexpensive and 
disposable and capable of being sanitized. Typically, the short end of the 
face cone may be slipped on the other end of the tube with a tight fit, or 
as desired may be clamped. However, desirably, the inner surface of the 
face cone should extend slightly inwardly and about the interior surface 
of the tube so as not to contaminate the inlet tube. Optionally and 
desirably the respiratory filter apparatus may include a right angle or 
angled swivel connector connecting the air inlet in the housing to the one 
end of the flexible tubing so that the flexible tubing elbow may be swung 
around and positioned to meet the patient's need, either sitting or at 
bedside. Further, the filter apparatus typically has casters that roll so 
it may be easily removed and operated at the bedside of a patient. 
In one embodiment, a respiratory filter apparatus is employed with a 
patient enclosure. The patient enclosure is adapted to surround generally 
all or a portion of the patient and typically comprises a disposable, and 
optionally and preferably, a transparent, thin, plastic material which is 
supported in its upper section by a supporting means secured to the 
respiratory filter apparatus, and which patient enclosure after use by a 
patient may be discarded, thus avoiding the problems associated with the 
employment of rigid chambers which are more expensive and must be 
continually disinfected after the use of each patient. The respiratory 
filter apparatus with the patient enclosure may comprise the filter 
apparatus as described with a face cone, which face cone is provided to be 
inserted within the patient enclosure, or may comprise for example any 
other respiratory filter apparatus with a transparent, disposable, 
inexpensive, supported patient enclosure as desired. The patient enclosure 
includes a support means typically secured to the respiratory filter 
apparatus and generally to the housing thereof. 
The described embodiment comprises a support means of a telescopic rod 
having a one and the other end, one end secured to the housing and with 
the telescopic rod adapted to be telescoped between a compact, stored 
position adjacent the housing when not in use and an upward, extended, 
supporting position. The other end of the rod includes for example 
U-shaped or rectangular rod extending arms pivotably swivelable at the 
other end of the rod, so that in the compact, stored position the 
extending arms or U-shaped rods are generally planar with the plane of the 
telescoping rod and may be compactly stored adjacent or one side of the 
housing. In the use position, the extending rods or U-shaped arms are 
swung outwardly generally perpendicularly from the stored plane, then 
locked in position, such as by the insertion of a stud in an aligned hole 
through the material and the swivel bracket after the telescoping rod has 
been extended to the desired height to provide the desired height of the 
patient enclosure. 
The disposable patient enclosure typically comprises a thin, flexible 
plastic, such as a polyethylene or a transparent polyvinyl chloride, 
inexpensive, disposable patient enclosure forming a generally box-like 
space having a top, three sides, a bottom and an open side with an 
extending bib portion, which bib portion is adapted to fit around the 
front of the patient and help enclosure the open side. Typically, the bib 
portion would comprise an extending portion from the bottom portion having 
a circular hole therein for the insertion of the patient's head, with the 
bib portion extending from the patient's chin downwardly. The top section 
of the patient enclosure is provided for a means from which to be 
supported on the extended supporting arms and for example may comprise in 
one embodiment a double panel at the top, so that the extending arms may 
be slipped within the panel and extend generally the full length of the 
top panel to provide a hanging, supporting structure for the patient 
enclosure. While U-shaped arms may be used, generally rectangular rod 
formed support is preferred to provide better strength and support about 
the full periphery of the top section. Typically, the patient enclosure 
will contain a means so that a face cone may be inserted at one side of 
the patient enclosure for use by the patient in a generally sealed fashion 
often with the use of adhesive tape within the enclosure, with the patient 
typically seated, such as by the employment of a prior cross slit in one 
side and typically opposite the bib enclosure, so that the face cone may 
be inserted as required and be snugly taped in position in a sealed 
manner. 
The patient enclosure as described protects the technician or medical 
personnel attending to the patient by providing a disposable, inexpensive 
patient enclosure which after use may be merely removed from the extending 
supporting arms and the neck of the patient, rolled up and then discarded 
as biomedical waste material. The transparent nature of the material 
permits the patient to be observed by the technician. In use, the air 
flows from the patient in the patient enclosure into the face cone, so 
that no respiratory effluent is discharged from the slightly open end of 
the patient enclosure. The supporting means may comprise any variety of 
support means, but the support means as described and particularly used is 
moved from a compact, stored position generally adjacent one side of the 
housing of respiratory filter apparatus to an extended position wherein 
the telescoping rod is extended to the desired height, locked in place, 
such as by a threaded tightening arrangement, and then the extended arms 
extended generally perpendicularly and then locked in place, such as with 
a locking stud or a threaded enclosure, then the patient enclosure slipped 
onto the extending arms, the face cone inserted through the precut 
opening, then the bib placed about the neck of the patient and the patient 
seated in position within the enclosure. 
In use, the patient, who is subject to coughing, places his face within the 
disposable face cone within the patient enclosure typically while seated 
during the coughing spells and the motor blower is turned on so as to blow 
the aerosol contaminated sputum into and toward the hepa-type filter. In 
addition, a patient being treated with an aerosol nebulizing system 
employing the nebulizing solution within the face mask, so that as the 
nebulizing solution induces coughing by the patient, the air flow draws 
the aerosol particles away from the outside environment and into the other 
end of the tube into the hepa-type filter. After treatment and use, the 
patient enclosure is removed from the supporting arms, rolled up and 
discarded. 
The invention will be described for the purposes of illustration only in 
connection with certain preferred embodiments; however it is recognized 
that various changes, modifications, additions and improvements may be 
made to the respiratory filter as illustrated, all falling within the 
spirit and scope of the invention.

DESCRIPTION OF THE EMBODIMENTS 
With reference to the drawings, there is shown a hepafilter portable 
nebulizer apparatus having a housing 10 having an upper chamber 12 and a 
lower chamber 14 with an outlet 16 for exhaust, provided with a filter 18 
and a blower 20 for blowing air out of the outlet 16 and drawing air into 
the upper chamber 12. The respiratory apparatus includes a plurality of 
wheels 22 positioned on the base of the lower chamber 14 for the portable 
movement of the apparatus to a bedside location in a patient's room, and 
the upper chamber 12 is connected to the lower chamber by a plurality of 
hinges 24 for movement between a closed filtration position in air-tight 
cooperation with lower chamber 14 and an open filter removal position to 
permit access to the interior space of the upper chamber 12 wherein a 
hepafilter of corrugated construction barrier type filter is removably 
disposed extending across the width of the upper chamber 12. 
The upper chamber includes a swivel base 30 fitting disposed in the central 
top portion thereof for rotatably connecting an upwardly extending elbow 
28 of hollow tubular construction, having a 90.degree. bend, formed of 
resilient material having a one end engaged in the swivel base 3 and an 
other end for receiving a flexible tube 32 formed of accordion type vacuum 
hose having an outlet end and an inlet end, the inlet end having a flange 
34 being adapted to engage the conically shaped disposable face cone 36 
within which is disposed a nebulizer 38. 
The face cone 36 is constructed of a barrier metal or plastic material, is 
conically shaped having a small diameter end for engaging the flange 34 
and a large diameter end for receiving the nebulizer mounted on a 
separate, spaced apart holder 46. A thin, plastic, disposable, truncated 
face cone insert 48 is used within the face cone means, which insert is 
disposed after use as biomedical waste. A supply of the disposable face 
cone inserts and disposable bags to contain the used inserts may be 
secured to the sides of the housing. The nebulizer is constructed to 
produce an aerosol, medication-containing mist responsive to compressed 
air being introduced at the bottom of said nebulizer via a flexible air 
line 42 connected to an air compressor 40 located remotely to the 
respiratory filter apparatus and which supplies air under pressure to the 
nebulizer to create an aerosol to be inhaled by the patient. 
The respiratory filter apparatus with the patient enclosure of the 
invention includes a patient enclosure which provides a disposable, 
transparent patient enclosure about the upper portion of the body of the 
patient using the respiratory filter apparatus and which patient enclosure 
is disposable and provides further protection for the medical personnel 
attending the patient. The patient within the patient enclosure is 
enclosed on three sides, on the top and the bottom and has bib section to 
protect the patient on the open forward section. However, the air is drawn 
inwardly in the open forward section into the face cone and through the 
respiratory filter apparatus so that there is no discharge of respiratory 
effluent of the patient outside the patient enclosure. 
The patient enclosure may be used with the described respiratory filter 
apparatus or with other filter apparatus and comprises a telescopic-type 
support rod 60 secured to the back section of the housing 10 through a 
pair of brackets 62 which secures the lower section of the telescopic 
support rod 60. At one end of the rod, there is a generally tubular, 
rectangular support frame 64 of defined size which is pivotably secured to 
the one end of the support rod 60 by a pivotable block elbow 66 which may 
be locked in position through the insertion of a stud (not shown), when 
the rectangular support frame 64 is pivoted up to a rectangular position, 
as shown for example in FIGS. 1 and 5. FIGS. 1, 4 and 5 show the patient 
enclosure in a supported, in-use position. FIGS. 2 and 3 show the 
apparatus in a compact, non-supported position. 
The housing 10 also includes a pair of hooks 70 to support a chair 80 which 
patient uses so that the chair may travel with the portable respiratory 
filter apparatus. On either side of the housing 10 there are hooks 72 for 
a supply of biomedical hazardous waste disposal bags 76, while on the 
other side of the housing 10, there are hooks 74 to suspend a plurality of 
thin plastic cone inserts 48 for use within the face cone 36 and which 
cone inserts 48 are disposed of through the use of the disposal bag 76. In 
addition, the housing 10 includes a holder 90 for a spray can of 
disinfectant which may be used to disinfect the area, particularly the 
face cone 36 prior to the insert of another face cone insert 48. The 
housing 10 would also include handles 92 on either side of the housing to 
aid in moving portable respiratory filter apparatus as desired. 
The patient enclosure 68 comprises a disposable, thin, transparent, such as 
a polyvinyl chloride, plastic patient enclosure which forms a generally 
box-like enclosure space within which the patient sits. The patient 
enclosure 68 includes a bib section 84 which is placed against the front 
chest of the patient and which includes a head opening 86 for the 
insertion of the head of the patient. The patient enclosure 68 also 
includes a pair of cross slits 88 opposite the bib section so that the 
face cone 36 fits snugly through the cross slit area, as shown in 
particular in FIG. 5, and then if desired even taped into place to provide 
a more effective seal. The patient enclosure includes a double panelled 
top section 82 of the transparent material with the one end of the double 
top open so that the rectangular support frame 64 when placed in the use 
position with the telescopic rod 60 extended, may be slipped between the 
opposing double top section 82 of the patient enclosure 68 to provide for 
a full periphery support of the patient enclosure 68. While the support of 
the patient enclosure has been illustrated by the particular use of a 
rectangular support frame 64 and the use of a double panelled top 82, it 
is recognized that there are many ways in which the patient enclosure 68 
may be supported and retained in position other than the preferred 
illustration as described. 
As shown, a compact, portable filter apparatus with the patient enclosure 
and containing the telescopic support rod 60 and the rectangular support 
frame 64 in a compact, stored position adjacent the back end of the 
housing 10 and with the chair 80 hooked onto the chair hook 70, the 
respiratory filter apparatus may be rolled to a position where needed, 
then the chain 80 removed for use by the patient, and thereafter, the 
telescopic support frame extended to the desired height, and then the 
rectangular support frame 64 swung out on the block elbow 66 and then 
supported in position by the insertion of a stud or by threaded locking 
nut or knob. While the support frame is retained in the extended position 
through a threaded locking knob 96, it is more particularly illustrated 
thereafter the face cone 36 is inserted through the cross slits 88, the 
head opening 86 placed over the head of the patient and the pump started 
to draw air. As particularly illustrated, the housing 10 also includes 
various pressure and air gauges, monitoring controls and valves and the 
faces thereof 94. 
Responsive to blower 20 exhausting air through outlet 16, air is drawn in 
(see arrows) passing along the walls of the disposable, conical shaped 
face cone 36 and insert 48, hence along the interior passage provided by 
flexible tube 32 and elbow 28 into upper chamber 12, thence be drawn 
through the corrugated hepafilter element 26 thereby depositing 
contaminant thereon, thence into lower chamber 14 from which the air is 
thence exhausted through filter 18 having charcoal filter element 
constructed to be symmetrical with outlet 16 and adapted to provide an air 
tight fit with the peripheral edge thereof. 
After use by the patient, the used cone insert 48 is removed and placed in 
the hazardous waste disposal bag 76, while the patient enclosure 68 is 
also removed and disposed of in a waste bag. Typically, the bib section 84 
is removed from the patient and then rolled forward, while the double top 
section 82 and the enclosure 68 are slid off the support frame 64, and the 
enclosure rolled up with the comtaminated surfaces placed inwardly. A 
spray disinfectant, such as an aerosol spray, is then removed from the 
holder 90 and used to disinfect the face cone 36 and area prior to 
inserting a new face cone insert 48 and using a new patient enclosure 68. 
The respiratory filter apparatus as thus shown and described provides an 
effective, compact, portable apparatus for use by patients and provides 
protection for medical personnel attending the patient.