M. Abel et Jb. Eisenkraft, ERRONEOUS MASS-SPECTROMETER READINGS CAUSED BY DESFLURANE AND SEVOFLURANE, Journal of clinical monitoring, 11(3), 1995, pp. 152-158
Objective. Medical mass spectrometers are configured to detect and mea
sure specific respiratory and anesthetic gases. Unrecognized gases ent
ering these systems may cause erroneous readings. We determined how th
e Advantage 1100 (Perkin-Elmer, now Marquette Gas Systems, Milwaukee,
WI) and PPG-SARA (PPG Biomedical Systems, Lenexa, KS) systems that wer
e not configured to measure desflurane or sevoflurane respond to incre
asing concentrations of these new potent volatile anesthetic agents. M
ethods. Desflurane 0% to 18% in 3% increments or sevoflurane 0% to 7%
in 1% increments in 5-L/min oxygen was delivered to the Advantage and
PPG-SARA mass spectrometry systems. For each concentration of each age
nt, the displayed gas analysis readings and uncompensated collector pl
ate voltages were recorded. Results. The Advantage 1100 system read bo
th desflurane and sevoflurane mainly as enflurane and, to a lesser ext
ent, as carbon dioxide and isoflurane. For enflurane(E) readings <9.9%
, the approximate relationships are: %Desflurane = 1.6E; %Sevoflurane
= 0.3E. These formulas do not apply if E >9.9% because of saturation o
f the summation bus. PPG-SARA read desflurane mainly as isoflurane(I)
and, to a lesser extent, as nitrous oxide. PPG-SARA read sevoflurane m
ainly as enflurane(E) and, to a lesser extent, as nitrous oxide and ha
lothane. The approximate relationships are: %Desflurane = 1.1I (for I
<9%); %Sevoflurane = 2.1E. Conclusions. Advantage 1100 and PPG-SARA sy
stems not configured for desflurane or sevoflurane display erroneous a
nesthetic agent readings when these new agents are sampled. Advantage
1100 also displays falsely elevated carbon dioxide readings when desfl
urane is sampled.