Help make working with anesthetics safer

[Janet Hoff]

Good day,

I work in medical research with mice and rats. My work often involves anesthetizing rodents with isoflurane (the same type of gas anesthetic that is used in human medicine). The animal is placed in a small box and isoflurane and oxygen is introduced to the box. In a short time the box is filled with enough gas to put the animal to sleep. The animal is removed from the box and his nose placed in a cone where isoflurane and oxygen are delivered at a controlled rate. The problem lies in opening the box. Each time the box it opened, isoflurane escapes into the room. Typically, animals are anesthetized in groups, so the exposure can become dangerous.

At this time, there is nothing on the market that removes the gas actively from the box before opening the lid. I would like to come up with something, for myself and others who are in this situation.

The box is either 4 x 4 x 4 for mice or 8 x 4 x 4 for rats, has two one inch openings, one where the gas and oxygen is introduced and the other where the gas (passively) is removed and collected into a canister containing activated charcoal. I have purchased a 1 inch (computer) fan and placed it in line between the box and the canister to provide some suction, but it's not quite strong enough.

I have ordered a larger, 4 inch fan, that is used in duct work.

Do you think a larger fan will provide the force needed to help remove the gas from the box?

Will it add pressure to the flow when I change the dimension of the line (starting at the 1 inch connection on the box, building to the 4 inch fan, then narrowing again to the other 1 inch connection (to the charcold filter).

Do you anticipate any fire hazards when working around oxygen this closely?

Thanks in advance.

jhLVT

 

[mgb_phys]

Can you open the box under a fume hood? Either a full chemical lab type or just a simple extractor fan that vents to the outside air.

100% O2 is a fire risk, especially if it is allowed in contact with materials for a long time - clothes can become saturated with it and very difficult to extinguish if they catch fire. However small flow rates of O2 in a room with a regular atmosphere aren't likely to build up high concentrations.
This is one of the reasons that "Oxygen" cylinders used in aircraft and most non-medical breathing gas uses are only 80% O2, the other reason is that prolonged breathing of 100% O2 is toxic.

 

[Uncle Al]

Janet Hoff wrote:
>
> Good day,
>
> I work in medical research with mice and rats. My work often involves
> anesthetizing rodents with isoflurane (the same type of gas anesthetic
> that is used in human medicine). The animal is placed in a small box
> and isoflurane and oxygen is introduced to the box. In a short time
> the box is filled with enough gas to put the animal to sleep. The
> animal is removed from the box and his nose placed in a cone where
> isoflurane and oxygen are delivered at a controlled rate. The problem
> lies in opening the box. Each time the box it opened, isoflurane
> escapes into the room. Typically, animals are anesthetized in groups,
> so the exposure can become dangerous.
>
> At this time, there is nothing on the market that removes the gas
> actively from the box before opening the lid. I would like to come up
> with something, for myself and others who are in this situation.
>
> The box is either 4 x 4 x 4 for mice or 8 x 4 x 4 for rats, has two one
> inch openings, one where the gas and oxygen is introduced and the other
> where the gas (passively) is removed and collected into a canister
> containing activated charcoal. I have purchased a 1 inch (computer)
> fan and placed it in line between the box and the canister to provide
> some suction, but it's not quite strong enough.
>
> I have ordered a larger, 4 inch fan, that is used in duct work.
>
> Do you think a larger fan will provide the force needed to help remove
> the gas from the box?
>
> Will it add pressure to the flow when I change the dimension of the
> line (starting at the 1 inch connection on the box, building to the 4
> inch fan, then narrowing again to the other 1 inch connection (to the
> charcold filter).
>
> Do you anticipate any fire hazards when working around oxygen this
> closely?[/color]

Isoflurane is hepatotoxic. Chronic exposure is inadvisable. The best
idea is to vent the box into a dump line by flushing with plain or
enriched air. Ptherwise, open and vent in a laminar flow hood with an
external exhaust line. Isoflurane (mw = 184.5) 2% in oxygen is 1.2X
the density of air. Suck the fumes down and out. Second best is a
fume hood with external exhaust. Charcoal scrubbing is notoriously
unreliable starting 24 hrs after the seal is breached - and a really
bad idea in enriched oxygen.

Oxygen above 30% concentration is a flammability hazard. Always use
oxygen-certified hardware and lines for 100% oxygen. Dilute dumps
with airflow. Tygon tubing conducting oxygen burns like a fuse.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

 

[Andy Resnick]

Janet Hoff wrote:

> Good day,
>
> I work in medical research with mice and rats. My work often involves
> anesthetizing rodents with isoflurane (the same type of gas anesthetic
> that is used in human medicine). The animal is placed in a small box
> and isoflurane and oxygen is introduced to the box. In a short time
> the box is filled with enough gas to put the animal to sleep. The
> animal is removed from the box and his nose placed in a cone where
> isoflurane and oxygen are delivered at a controlled rate. The problem
> lies in opening the box. Each time the box it opened, isoflurane
> escapes into the room. Typically, animals are anesthetized in groups,
> so the exposure can become dangerous.[/color]
<snip>

I second Uncle Al's recommendations, and I'll add a couple other
suggestions. First, a purge with dry air instead of pure O2 is highly
desireable. Second, what about connecting the outflow to a vacuum line?
We have "house vacuum" ports in the wall and you may be able to simply
purge into that with plastic valves and tubing: I would avoid all moving
metal + electrical parts around O2.

--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University

 

[Janet Hoff]

Thanks for the replies.

Looking around on the internet, I found this nifty vaccum: http://www.mini-vac.com/instructions.html

I was thinking of getting two of these small vacuums, and use one as a blower to push fresh air into the box by placing it, in line, between the fresh gas/oxygen supply and the box, then using a second Mini vac to create a vacuum in line with the activated charcoal (waist gas collection canister). I don't know of any alternatives to the activated charcoal for portable waist gas collection, any ideas?

 

[kanuk]

"Janet Hoff" <Janet.Hoff.2q9e68@physicsforums.com> wrote in message
news:Janet.Hoff.2q9e68@physicsforums.com...
>
> Good day,
>
> I work in medical research with mice and rats. My work often involves
> anesthetizing rodents with isoflurane (the same type of gas anesthetic
> that is used in human medicine). The animal is placed in a small box
> and isoflurane and oxygen is introduced to the box. In a short time
> the box is filled with enough gas to put the animal to sleep. The
> animal is removed from the box and his nose placed in a cone where
> isoflurane and oxygen are delivered at a controlled rate. The problem
> lies in opening the box. Each time the box it opened, isoflurane
> escapes into the room. Typically, animals are anesthetized in groups,
> so the exposure can become dangerous.
>
> At this time, there is nothing on the market that removes the gas
> actively from the box before opening the lid. I would like to come up
> with something, for myself and others who are in this situation.
>
> The box is either 4 x 4 x 4 for mice or 8 x 4 x 4 for rats, has two one
> inch openings, one where the gas and oxygen is introduced and the other
> where the gas (passively) is removed and collected into a canister
> containing activated charcoal. I have purchased a 1 inch (computer)
> fan and placed it in line between the box and the canister to provide
> some suction, but it's not quite strong enough.
>
> I have ordered a larger, 4 inch fan, that is used in duct work.
>
> Do you think a larger fan will provide the force needed to help remove
> the gas from the box?
>
> Will it add pressure to the flow when I change the dimension of the
> line (starting at the 1 inch connection on the box, building to the 4
> inch fan, then narrowing again to the other 1 inch connection (to the
> charcold filter).
>
> Do you anticipate any fire hazards when working around oxygen this
> closely?
>
> Thanks in advance.
>
> jhLVT
>
>
> --
> Janet Hoff
> ------------------------------------------------------------------------
> Janet Hoff's Profile:
> https://www.physicsforums.com/forums/member.php?action=getinfo&userid=77661
> View this thread: https://www.physicsforums.com/showthread.php?t=169207
>[/color]
I would suggest using an aspirator water jet (vacuum)pump, available for
some few bucks. However, made of plastic (Cole-Palmer Catalog). Some problem
could be with the removal of that anesthetic, unless it is vater soluble.
Tubing for oxygen is common in welding applications (oxy-acetylene).
Cole-Palmer catalog lists several systems, which seem to be designed for
purpose similar to yours. However, they cost several hundred dolars, at
least.

 

[Janet Hoff]

Thanks for the replies.

Looking around on the internet, I found this nifty vaccum:
http://tinyurl.com/yua9zo

I was thinking of getting two of these small vacuums, and use one as a
blower to push fresh air into the box by placing it, in line, between
the fresh gas/oxygen supply and the box, then using a second Mini vac
to create a vacuum in line with the activated charcoal (waist gas
collection canister). I don't know of any alternatives to the
activated charcoal for portable waist gas collection, any ideas?

--
Janet Hoff
------------------------------------------------------------------------
Janet Hoff's Profile: https://www.physicsforums.com/forums/member.php?action=getinfo&userid=77661
View this thread: https://www.physicsforums.com/showthread.php?t=169207

 

[Tom Roberts]

If you ever expect your lab to pass a safety inspection, you must use
oxygen-certified equipment in oxygen lines. Such plastic parts in an
oxygen line are just looking to create a huge fire.

Newsgroups like this are COMPLETELY UNSUITABLE for such investigations.
You need to consult with experts on handling oxygen. Your lab OUGHT to
have a safety officer or similar person. Attempting to do this yourself,
with your obvious inexperience, is just asking for trouble.

GET SOME EXPERT HELP!Tom Roberts
Janet Hoff wrote:
> Thanks for the replies.
>
> Looking around on the internet, I found this nifty vaccum:
> http://tinyurl.com/yua9zo
>
> I was thinking of getting two of these small vacuums, and use one as a
> blower to push fresh air into the box by placing it, in line, between
> the fresh gas/oxygen supply and the box, then using a second Mini vac
> to create a vacuum in line with the activated charcoal (waist gas
> collection canister). I don't know of any alternatives to the
> activated charcoal for portable waist gas collection, any ideas?
>[/color]

 

[bz]

Janet Hoff <Janet.Hoff.2qgsu2@physicsforums.com> wrote in
news:Janet.Hoff.2qgsu2@physicsforums.com:

> Thanks for the replies.
>
> Looking around on the internet, I found this nifty vaccum:
> http://tinyurl.com/yua9zo
>
> I was thinking of getting two of these small vacuums, and use one as a
> blower to push fresh air into the box by placing it, in line, between
> the fresh gas/oxygen supply and the box, then using a second Mini vac
> to create a vacuum in line with the activated charcoal (waist gas
> collection canister). I don't know of any alternatives to the
> activated charcoal for portable waist gas collection, any ideas?[/color]

Have you considered doing things in a glove box?
Pass the animal in and out through an airlock.

There are even some inexpensive 'disposable' plastic glove boxes available
now days.
--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+spr@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap