Effect on Performance
The possibility that waste anesthetic gases could adversely affect
the intellectual and motor skills of anesthesiologists was also addressed during
the 1970s. In a laboratory setting using male volunteers, Bruce and Bach[14]
demonstrated
that concentrations of nitrous oxide as low as 50 ppm, either alone or in combination
with 1 ppm of halothane, result in decreased behavioral performance; however, 25
ppm of nitrous oxide combined with 0.5 ppm of halothane had no effect. It was from
these data that the NIOSH recommendations arose.[2]
Subsequently, three other groups of researchers studying volunteers in laboratories
have been unable to confirm the findings of Bruce and Bach.[14]
The lack of agreement between investigators has led some to conclude that "it is
reasonable to state that there is no convincing evidence that anesthetic agents in
concentrations equal to those found in unscavenged operating theatres have any effect
on the psychomotor performance of healthy subjects in the laboratory."[15]
A study conducted on volunteers in an operating room during normal clinical activities
in which trace concentrations of nitrous oxide and halothane ranged from 0 to 2300
and 0 to 37 ppm, respectively, also failed to detect impairment in psychomotor performance.
[16]
Despite the lack of incontestable proof that
inhaling trace concentrations of anesthetics alters higher mental functions, common
sense dictates that care should be exercised to keep levels as low as possible.
