Biomedical Engineering Reference
In-Depth Information
areas where the duplicating machines were located exceeded the 15
minutes NIOSH recommended short-term ceiling of 800 ppm. Improve-
ment in ventilation reduced the airborne level of methanol and the
incidence of symptoms (Frederick et al., 1984).
In two Russian studies (Chao, 1959; Ubaydullayev, 1963), slight
CNS and ocular effects were reported at very low levels (12mg/m
3
).
There are many details lacking in these earlier papers and the results are
questionable in light of lack of any methanol-related effects reported in
later more detailed papers, including controlled human chamber studies
at levels of 200 ppm methanol.
It appears that if workplace exposure to methanol is kept below the
workplace standard (TLV) of 200 ppm no adverse effects would be
expected from repeat inhalation exposure.
3.8 MANAGEMENT OF METHANOL POISONING
Treatment of methanol poisoning is based on many factors and some
general guidance is given below. Figure 3.1 gives excellent guidance in
the treatment of methanol poisoning but each case should be handled by
the treating physician based on the individual laboratory values, the time
elapsed following ingestion, clinical symptoms, and so on. The reader is
directed to the American Academy of Clinical Toxicology Practice
Guidelines on the Treatment of Methanol Poisoning published in
2002 for more detail discussion of dosing regimens and other factors
thatmay be significant in the treatment ofmethanol poisoning (Barceloux
et al., 2002). Included is an excellent comparison of the issues involved in
the use of ethanol versus Fomepizole to inhibit or slow down methanol
initial metabolism to formaldehyde. Hemodialysis is recommended, if
blood methanol levels exceed 50mg/dl (Kavet and Nauss, 1990).
For patients with blood pH below 7.3 and an indication of methanol
ingestion, IV sodium bicarbonate is recommended. Metabolism of
methanol should be reduced by treatment with ethanol (oral or IV)
or Fomepizole.
Ethanol has approximately 10 times greater affinity for ADH than
does methanol and therefore ethanol competitively inhibits or slows
