TB Infection Control

Dear IC experts,
This is just a lead question from Gael's mail (sorry for deviating a bit). Would it be safer to have the TB wards designated in reverse order i.e. lowest for MDR-TB and top-most for smear negative cases. This would probably reduce mixing of MDR-TB cases with others and solve the problem of IC in elevator. The elevator could also have an entrance in open/ well ventilated place.
 
Thanks for sharing your inputs on this.
 
Vineet Bhatia

Dear All,

I think best thing is to do a quick air movements / directions study and then take a call.

Regards,

Raveendra

That s an interesting discussion. I think that it might be safer to have the wards in reserve order assuming there won't be a lot of patients movement from one ward to another. It hard to imagine proper ventilation in the elevator. I m wondering if UV lights properly installed and monitored cannot help.
Other thoughts
Best,

Bazile
Sent from my BlackBerry® smartphone

I have a suitable device for the lifts, happy to donate it to you guys and
tell you how to look after it.

e mail me dimensions of lift and I will see if it will fit ( could fit)

Regards

Paul Bushnell.

I was trying not to comment on this discussion, but the introduction
of "devices" requires comment.

Despite my enthusiasm for upper room UVGI, this is probably not a
problem that should be solved by "devices" alone, but rather primarily
by administrative measures, and respiratory protection.

My primary point is that even a slow elevator adds a very short
exposure to ongoing exposure in the hospital, mostly from patients,
staff, or visitors with UNSUSPECTED TB and UNSUSPECTED drug
resistance. Persons with known TB on EFFECTIVE therapy (based on known
drug susceptibility) are unlikely to be infectious regardless of smear
status. Undue attention to the elevator situation is almost certainly
less important that active cough surveillance at all entrance points,
rapid diagnosis of TB and of drug resistance, and the prompt
introduction of EFFECTIVE treatment. When that is done, the elevator
problem is mostly solved.

I say mostly solved because there may still be missed cases who escape
cough surveillance, if in place, and missed drug resistance for many
reasons, including the lack of availability of rapid molecular
diagnostics.

Another administrative control is to transport any coughing patient on
the elevator with just one attendant who is wearing a well-fitted
respirator - not ...

I was trying not to comment on this discussion, but the introduction
of "devices" requires comment.

Despite my enthusiasm for upper room UVGI, this is probably not a
problem that should be solved by "devices" alone, but rather primarily
by administrative measures, and respiratory protection.

My primary point is that even a slow elevator adds a very short
exposure to ongoing exposure in the hospital, mostly from patients,
staff, or visitors with UNSUSPECTED TB and UNSUSPECTED drug
resistance. Persons with known TB on EFFECTIVE therapy (based on known
drug susceptibility) are unlikely to be infectious regardless of smear
status. Undue attention to the elevator situation is almost certainly
less important that active cough surveillance at all entrance points,
rapid diagnosis of TB and of drug resistance, and the prompt
introduction of EFFECTIVE treatment. When that is done, the elevator
problem is mostly solved.

I say mostly solved because there may still be missed cases who escape
cough surveillance, if in place, and missed drug resistance for many
reasons, including the lack of availability of rapid molecular
diagnostics.

Another administrative control is to transport any coughing patient on
the elevator with just one attendant who is wearing a well-fitted
respirator - not a surgical mask. There is no reason to pack the
elevator with other patients, visitors, or other staff. Strict rule:
coughing patients ride with just one other person who is protected.
Perhaps a sign on and in the elevator would help with adherence.

If the ceiling height is above 7 feet, it should be possible to
install a properly designed UVGI fixture for air disinfection. I
would NOT use a UV fixture or any device as an excuse to pack an
elevator with a coughing patient plus visitors, other patients, and
staff. In close quarters, no air disinfecting device may work quickly
enough to prevent exposure. Likewise a fan/UV or fan/filtration device
could be used IN THEORY, because the volume of the elevator is small.
However, it has been our experience all over the world that these
devices are often poorly designed to move substantial volumes of air
without short-circuiting (reprocessing the same air) and can be
reassuring without real efficacy. Paul Jensen has found devices with
blue light but no UV, fans but no little air movement, and filters or
UV that are completely ineffective for lack of maintenance.

SUMMARY: 1) get coughing persons diagnosed and on effective
treatment, 2) transport coughing patients with only one attendant who
has a properly fitted respirator, 3) consider properly designed upper
room UVGI or an independently-tested room air cleaner (properly sized
for the room) to reduce risk between rides. Be highly skeptical of
devices unless thoroughly checked out by an independent expert - not
the salesman!

Ed

In the first place I think we have to establish if it is a real problem/risk. Do we have multiple patients on a regular base in the lift? Is the lift overcrowded? Can we use stairs for staff and lift for patients? I see much bigger problems at fire escapes between the floors, this is normally the place where inpatients and staff encounter and circulate between the floors, as these have to be accessible at all times and can't be closed.

Most elevators have a form of ventilation, extraction into the lift shaft and in this way reducing the problem to an extent. UVGi, I would not recommend as the actual air movement in a full lift is very limited because of all people standing close to each other. Furthermore most lifts have stainless steel walls and reflexion of UV rays might be very difficult to control.

I have seen set ups in the former Russian states of using exposed UVGI when the lift is not in occupied. This will disinfect the lift to a certain extent, but doesn't solve the problem when the lift is occupied. So this set up is also questionable if really effective ...

In the first place I think we have to establish if it is a real problem/risk. Do we have multiple patients on a regular base in the lift? Is the lift overcrowded? Can we use stairs for staff and lift for patients? I see much bigger problems at fire escapes between the floors, this is normally the place where inpatients and staff encounter and circulate between the floors, as these have to be accessible at all times and can't be closed.

Most elevators have a form of ventilation, extraction into the lift shaft and in this way reducing the problem to an extent. UVGi, I would not recommend as the actual air movement in a full lift is very limited because of all people standing close to each other. Furthermore most lifts have stainless steel walls and reflexion of UV rays might be very difficult to control.

I have seen set ups in the former Russian states of using exposed UVGI when the lift is not in occupied. This will disinfect the lift to a certain extent, but doesn't solve the problem when the lift is occupied. So this set up is also questionable if really effective.

Best results I see again with administrative controls as suggested by Edward Nardell

Hans Mulder

In the first place I think we have to establish if it is a real problem/risk. Do we have multiple patients on a regular base in the lift? Is the lift overcrowded? Can we use stairs for staff and lift for patients? I see much bigger problems at fire escapes between the floors, this is normally the place where inpatients and staff encounter and circulate between the floors, as these have to be accessible at all times and can't be closed.

Most elevators have a form of ventilation, extraction into the lift shaft and in this way reducing the problem to an extent. UVGi, I would not recommend as the actual air movement in a full lift is very limited because of all people standing close to each other. Furthermore most lifts have stainless steel walls and reflexion of UV rays might be very difficult to control.

I have seen set ups in the former Russian states of using exposed UVGI when the lift is not in occupied. This will disinfect the lift to a certain extent, but doesn't solve the problem when the lift is occupied. So this set up is also questionable if really effective ...

In the first place I think we have to establish if it is a real problem/risk. Do we have multiple patients on a regular base in the lift? Is the lift overcrowded? Can we use stairs for staff and lift for patients? I see much bigger problems at fire escapes between the floors, this is normally the place where inpatients and staff encounter and circulate between the floors, as these have to be accessible at all times and can't be closed.

Most elevators have a form of ventilation, extraction into the lift shaft and in this way reducing the problem to an extent. UVGi, I would not recommend as the actual air movement in a full lift is very limited because of all people standing close to each other. Furthermore most lifts have stainless steel walls and reflexion of UV rays might be very difficult to control.

I have seen set ups in the former Russian states of using exposed UVGI when the lift is not in occupied. This will disinfect the lift to a certain extent, but doesn't solve the problem when the lift is occupied. So this set up is also questionable if really effective.

Best results I see again with administrative controls as suggested by Edward Nardell

Hans Mulder

ALL THE PROTOCOLS ARE FINE IN AN IDEAL WORLD. THE PROBLEM IS AFRICA IS NOT
AN IDEAL WORLD WHEN IT COMES TO COMPLIANCE AND DILLIGENCE.

ACTIVE COUGH SURVEILLANCE ALL GOOD, BUT ON BUSY DAYS OR WHEN 8 PEOPLE GO
THROUGH A DOORWAY AT ONCE, AND ALL GET INTO THE LIFT?

YOU CANNOT CONTROL THE AMOUNT OF PEOPLE GOING INTO A LIFT AT ONE TIME, NOT
POSSIBLE IN AFRICA, THAT I CAN ASSURE YOU.

MASKS / RESPIRATORS ETC ARE OFTEN OUT OF STOCK AS WELL, SO BEST IS TO
INSTALL A DEVICE THAT HAS BEEN TESTED FOR EFFICACY, HAS A KNOWN CADR / e
ACH, AND THAT LETS YOU KNOW WHEN IT IS NOT EFFECTIVE ANYMORE BY SWITCHING
ITSELF OFF.

PAUL.

Paul,

A "there is no other solution but my solution" response is not
helpful. Even in Africa protocols can be enforced if necessary. In
the early days of HIV treatment, cynics said that patients could never
take medications on time, that they had no watches, that it was
Africa. This has proven to be untrue. First and foremost,
administrative controls!

I know you offered to donate the device, but can I presume that you
are marketing that product?

Just a thought on this question...

Putting the TB wards on the first floor increases the likelihood
that air from wards will reach the other wards on floors higher up.
Air always goes vertically in buildings, in spite of careful design
intended to prevent it from doing so. Elevators are actually one of
the drivers of the flow of air between floors, with the elevator car
(cabin) acting like a piston and pumping air up an down as it moves.
But warm air rises, so warm air within a building finds pathways
between lower floors and upper floors. The flow may not be large
and, therefore, important. But this would be something to confirm if
the TB wards are located on one of the lower floors.
- hal levin


"In theory, there is no difference between theory and practice. But in practice, there is."
- Yogi Berra

SINCERELY NOT INTENDED AS SUCH, AND I AGREE WITH ADMINISTRATIVE CONTROLS
FIRST.

I LIVE HERE, AND KNOW MAPUTO WELL. WHILST GETTING PEOPLE TO ADHERE, SIMPLY
SUGGESTING A RATHER SAFE THAN SORRY APPROACH.

PRODUCTS ARE MINE YES, BUT I WOULD NOT USE THIS FORUM AS MKTNG PLATFORM,
MERELY TRYING TO HELP.

HAPPY TO DONATE TO ANY OF THESE TYPE OF SITUATIONS WITHIN REASON, ONLY IF I
KNOW THEY WILL BE EFFECTIVE IN THE SPECIFIC ENVIRONMENT.

THE OFFER SHOULD NOT BE PERCEIVED AS MARKETING PLEASE.

RGDS

Taking into account this stack effect mentioned by Hal, as part of the reconstruction of 5 floor TB hospital building in Vladimir, Russia we moved the highest TB transmission risk department (ward) for MDR TB patients to the mechanically ventilated UPPER floor, with separated areas (1st - very high risk - for patients during first days of SLD treatment, 2nd - medium risk - for patients on SLD for more than 1 week, 3rd - low risk - for staff). No patients without DST based treatment will stay on this floor. All technological vertical channels ( including gaps and any openings between every floor of the building) are sealed. 

Still we have one stairway and one lift for all admitted patients, but it is separated by positive pressure anteroom (sluice). I think the role of TB transmission in elevators and stairs is overestimated, because they are usually (or should be) very well naturally ventilated and time spent there is very limited, so they are not the highest priority in the overall complex of TB IC measures in the facility. 

Absolutely agree with Ed that adequate administrative controls may be absolutely enough for elevators. Because of very limited height of elevator cabin upper room UVGI fixture probably can ...

Taking into account this stack effect mentioned by Hal, as part of the reconstruction of 5 floor TB hospital building in Vladimir, Russia we moved the highest TB transmission risk department (ward) for MDR TB patients to the mechanically ventilated UPPER floor, with separated areas (1st - very high risk - for patients during first days of SLD treatment, 2nd - medium risk - for patients on SLD for more than 1 week, 3rd - low risk - for staff). No patients without DST based treatment will stay on this floor. All technological vertical channels ( including gaps and any openings between every floor of the building) are sealed. 

Still we have one stairway and one lift for all admitted patients, but it is separated by positive pressure anteroom (sluice). I think the role of TB transmission in elevators and stairs is overestimated, because they are usually (or should be) very well naturally ventilated and time spent there is very limited, so they are not the highest priority in the overall complex of TB IC measures in the facility. 

Absolutely agree with Ed that adequate administrative controls may be absolutely enough for elevators. Because of very limited height of elevator cabin upper room UVGI fixture probably can not be safely installed. Unshielded UVGI for whole volume switched on while the cabin is not occupied may be an option, but it requires reliable automation. The effect of air cleaners recirculating air is usually so low, that their effect during few seconds occupants stay inside may be only psychological, obstructing more important organizational measures. 

There are no engineering controls installed in our elevators.  
 
Dr. Grigory V. Volchenkov 

Chief Doctor
Vladimir Oblast TB Dispansery

Sudogodskoe shosse, 63
Vladimir 600023 RUSSIA

phone/fax work: +7(4922)323265
mobile +7 9206253227; +7 9190189226

PPlease don't print this e-mail unless you really need to. Thank you!

Few simple measure could help as well. Like health education of patients about covering mouth, while cough. Some poster may be displayed near elevators as well. Masks may be use by patients out side the room.

Hi Grigory,

wrt recirculating devices, consider the following;

if a lift is 2.8 x 1.3 x 1.3 ( guesstimate) volume is 4.7 m3

If lift has 3 - 4 occupants, volume decreases to probably 3.5 m3

If a device moves 100 m3/h and has 100% kill rate, it has effectively 30
ac/h .one every two minutes.

Assuming people are in the lift together for 30 seconds per trip, it
provides close to 25% certainty

Not tested figures but indicative.....

Paul,

It takes 13 seconds for me to get to the fifth floor, with 30 ACH mixing in the cabin the infection aerosol concentration may be reduced by 17% IF the air is perfectly mixed and there is NO continuing aerosol generation. 

But without administrative controls high concentrations can be generated just in the breathing zone. Looks like risk reduction can be zero. 

So I would insist on administrative controls as the most (or may be even only) effective intervention in such settings.  
 
Dr. Grigory V. Volchenkov 

Chief Doctor
Vladimir Oblast TB Dispansery

Sudogodskoe shosse, 63
Vladimir 600023 RUSSIA

phone/fax work: +7(4922)323265
mobile +7 9206253227; +7 9190189226

PPlease don't print this e-mail unless you really need to. Thank you!

I will not recommend UVGI or some kind of "*device*" in an elevator and
forward the following idea:

All elevators normaly come with extraction fans as standard equipment in
the cars. Install a fan that can provide 15 ACH per hour.

The elevator shaft will be open at the top and the motor room will have
forced air extraction ventilation for cooling and fresh air provision.
Increase the motor room's ACH to 30 and make sure that the air supply
louvre openings are sufficient.

There may be an argument that the "infected air" from the elevator cars
could infect the elevator maintenance personnel while they are in the
motor room. This can be discarded for practical reasons because by
improving the ACH, the environmental conditions are improved and can
only be better than the original.

Dries Meyer

This is not only an "Africa" problem. It is a general world wide problem.

Provision must be made for the conditions that exist and to compliment
administrative controls.

Dries Meyer.

I agree with Grigory that the room air circulating devices will not
work. I tested some units and calculated the air flow potential of
several units in a room with now other means of air movement. I found
that they were for all practical purposes and in spite of suppliers
claims, useless.

Dries Meyer.

Is the 100m³ the nominal rating of the fan ? If so, what is the flow
rate at the outlet grill of the unit ?

I found the units advertised with 80m³/h fans only had a flow rate from
4 to 6m³/h at the outlet grill. Some of these units included 65W HO UV-C
lamps whereas a 9W UV-C lamp would have been sufficient to deactivate TB
bacteria because of the low flow rate.

The situation can not vary much to the above if a 100m³m/h fan is used,
especialy when the air movement caused by the travel of the elevator car
is included in the calculation.

Dries Meyer.

A very generalised and loosely held comment Dries.

Do the sums on what effect a device measuring output 100-120 cmh would have
in a lift. I think you will find it difficult to convincingly argue that
they are useless. What would you prefer to install, should the wish be that
some form of protection be installed? Put one in a lift and do a smoke
test....simplist way of visible proof.

No more on this for me.

Paul.

"No more of this for me" will not solve the problems caused by these
inefficient units.

The low efficacy of this type of unit has been proved many times. I also
made smoke tests with several of these "devices" and have the flow meter
test results and fotos to proof my statement.

I also find it strange that the manufacturers of these units always
quote the nominal rating of the fans and never the static pressure or
the actual flow rate at the outlet grill. These small fans normally
deliver a negligible static pressure the main reason for the low airflow
rate at the outlet grill.

I am also 100% sure that the extraction fan in the elevator car will
have an higher air flow rate than the actual air flow delivered by your
unit.

Were your claims validated by an approved test Authority ? I am sure a
validation test could be carried out by the CSIR to put this matter to
rest. You could contact Faatima at +27 844 088 860 for the procedure to
arrange the validation test.

Dries Meyer.

I gave you the figure Dries. 100 cm/h at output.
rated 300.output 100.

This flow rate could be uncomfortable for occupants of the elevator.

Did you test the air flow pattern in the elevator car with the cars
extraction fan on. The cars extraction fan will affect the units air
flow because it should exceed 100m³m/h.

What is the applied UV-C dose of the unit, or the deactivation dose in
µWs/cm² ?

Where is the unit installed in the elevator car. Against the side (at
what height ) or the roof.

How do you control the air flow if there is for instance 6 people in the
elevator car.

Dries Meyer.

As moderator I would like to close this discussion and take further
exchanges off line. There is broad consensus among many who commented
that the short time spent on an elevator, and the possibility of
administrative controls, both suggest that it would not be a priority
to do air disinfection on elevators.

Ed