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 dimention 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
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Uncle Al
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
> 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.
<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
kanuk
"Janet Hoff" <Janet.Ho...@physicsforums.com> wrote in message
news:Janet.Ho...@physicsforums.com...
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
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?
Tom Roberts
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
bz
> 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?
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+...@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap