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Flashcards in Chpt. 13 - Tech Notes Deck (12):

Can the concentration of waste anesthetic gas that is hazardous to humans be determined?

It is surprisingly difficult to determine with exactness.


Long-term toxicity in anesthetic agents

It is widely accepted that anesthetic agents that are retained by the body and metabolized are likely to have greater long-term toxicity than those that are quickly eliminated through the lungs.
For this reason, isoflurane is thought to be the least toxic inhalation agent in common use, followed by sevoflurane.


Are any of the inhalant anesthetic agents considered carcinogenic?

It is now generally thought that none of the commonly used inhalant anesthetic agents (isoflurane, halothane, sevoflurane) is carcinogenic at the levels found in veterinary hospitals.


What does the American Society of Anesthesiologists Task Force on Trace Anesthetic Gases (1999) suggest?

That although adverse health effects are associated with chronic exposure to high levels of waste anesthetic gas, studies have failed to demonstrate an association between the low levels of waste anesthetic gas normally found in scavenged hospitals and adverse effects on hospital employees.


NIOSH's recommendation regarding concentration of any volatile gas anesthetic

After reviewing the available literature, NIOSH recommended that the concentration of any volatile gas anesthetic (including halothane, methoxyflurane, and isoflurane) not exceed 2 ppm when used alone and not exceed 0.5 ppm when used with nitrous oxide.
It is also suggested the nitrous oxide concentration not exceed 25 ppm.


How many air changes should all rooms in which anesthetic gases are released have?

It is advised that all rooms in which anesthetic gases are released have at least 15 air changes per hour. A rate of 20 air changes per hour is preferred.


How to keep exposure to WAG at a minimum

If proper equipment, techniques, and procedures are used, it is possible to reduce waste gas exposure to a level well below the NIOSH standards. This can be achieved through several means, including using a gas scavenging system, testing equipment for leaks, and using techniques and procedures that minimize exposure to waste gas.


A passive scavenging system is best suited for what rooms?

A passive scavenging system is best suited for rooms adjacent to the exterior of the building and is ineffective for interior rooms where the distance to the outlet is more than 20 feet (7 m).


Activated charcoal cartridge facts

- to effectively absorb anesthetic vapors, they must be replaced after 12 hours of use or after a weight gain of 50g
- unable to absorb nitrous oxide
- inefficient at flow rates greater than 2 L/min


What is a significant source of operating room pollution?

Gas leaks, as they are not reduced by a scavenging system.


Types of leak tests

- depend on the type of carrier gas used
- if both nitrous oxide and oxygen are used, both a high-pressure and a low-pressure test should be done
- if oxygen alone (w/o nitrous oxide) is used, only a low-pressure test needs to be done
- perform low-pressure tests before use of the machine each day
- high-pressure tests on nitrous oxide tanks should be performed once weekly and whenever the nitrous oxide tank is changed


Waste gas monitoring

It is advisable to periodically monitor waste anesthetic gas levels to ensure that the NIOSH-recommended levels are not exceeded, especially if a hospital employee becomes pregnant and is still working around anesthetized animals.
Waste gas monitoring is also advisable if hospital employees frequently detect the odor of anesthetic gas or if there are special concerns about waste gas levels (e.g., if the clinic is using induction chambers).