Blutalkohol 2005 - BADS (Bund gegen Alkohol und Drogen im ...

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Breitmeier/Besch/Gebel/Panning,
Measuring of end-expired breath ethanol concentration following percutaneous ethanol injections
(PEI) carried out on patients suffering from hepatocellular Carcinoma
cess to blood vessels can be obtained. The use in ambulances or physician-staffed cars is
also possible.
When using the devices plus the supplied additional material a falsification of data is not
to be expected. One should not use different materials in anesthesia as they may influence
or falsify the results. Further any measurings of breath alcohol concentration with mobile
devices should always be taken before the airway filter (heat and humidity store) normally
used in anesthesia. BrAC data taken immediately behind the airway filter were strikingly
lower than those taken before. BrAC devices should also not be connected directly to
the port of the filter, this can also lead to false results. Personnel which does not know the
effects of the airway filter on breath alcohol analysis and therefore connects the gas-sample
tube directly to the filter or behind the filter will get incorrect data. Breath alcohol concentration
can be used to estimate blood alcohol concentration by multiplying it by the
conversion factor Q (blood-breath-ratio). In this study we used the mean BAC/BrAC conversion
factor of 2,1 (2,098 ± 0,110) ‰/mg/l derived from SCHOKNECHT [12]. However,
the conversion factor Q is not a constant value [3, 4, 7, 10]. A major influence on the measured
breath alcohol concentration is the period of alcohol metabolism (resorption, distribution,
and elimination period), during which measuring takes placed [6, 13, 15]. In addition
the relevant BAC/BrAC-quotient can also be influenced by the temperature of the
environment [14]. In most countries police routinely use a conversion rate of between 2,0
and 2, 3 [8], however, most widely accepted is a value of about 2,1 [9], which was also used
for conversion in this study. By using this factor sufficiently precise correlation factors between
BrAC and BAC could be determined. Statistical analysis of the results obtained
shows also that in the Dräger group BAC which was estimated after measuring BrAC
seems to correlate better with blood alcohol concentration determined in the laboratory
than measurings taken in the Envitec group. However, the additional analysis according to
BLAND and ALTMANN [2, 3] could prove that despite excellent correlation in the Dräger
group (BrAC/arterial BAC) a higher bias than in other comparative examinations could be
found.
Alcohol concentrations above 1,0 ‰ lead in the Envitec group to a stronger spread of results
compared to concentrations below l ,0 ‰. These observations correlate well with the
manufacturer’s Information, which mentions maximum misreadings below 1,0 ‰ with
0,05 % and above 1,0 ‰ with 5 %. Identical misreadings are provided by the manufacturer
for the Dräger device, in good agreement with the calibration fault limits [11], yet that a
similar spreading could not be observed seems to be based on the fact that the Envitec device
was used in the mainflow and the Dräger device in secondary flow.
The simple execution of the measurings is a point in favour of the Envitec device. Automatic
ventilation does not have to be interrupted. As a result of its use in secondary flow
greater deviations between BrAC and BAC were recorded when the device was used
wrongly.
In automatic mode the Dräger device excludes taking a faulty measuring. Due to the
measuring in mainflow whereby for each measuring the device needs to be connected
again to the airway system via the bronchoscopy adapter, taking a measuring turned out to
be far more cumbersome.
This study corresponds not in all aspects to the demands of a classical assessment of the
evidence (evaluation study). For that one would have to inject determined amounts of
ethanol into intubated patients. Then measurings of BrAC would have to take place at pre-
BLUTALKOHOL VOL. 42/2005