Deck One Flashcards
Theory, Function and Procedure
What is the definition of the Intox EC/IR II?
An approved instrument which analyzes a sample of deep lung air and reports the results in milligrams of alcohol in 100 milliliters of blood.
What is Henry’s Law in relation to breath analysis?
At 34 degrees Celsius the concentration of alcohol in deep lung air is proportional to the concentration of alcohol in blood.
What is the breath:blood ratio?
At 34 degrees Celsius, 2100 parts deep lung air contains the same amount of alcohol as 1 part blood.
What factors will affect a breath test result?
Breath temperature (fever or hyperventilation), mouth alcohol or shallow blow.
What is the margin of acceptability for the alcohol standard test? Or, what does it mean when the instrument is found to be in proper working order?
The alcohol standard test results are within 10% of the target value.
What are the preset target values for the wet bath and dry gas alcohol standards?
100 mg% and 82% respectively.
Where does gas exchange occur within the lungs?
In the alveolar airspace (tiny air sacs deep within the lungs).
What 2 analytical techniques does the Intox EC/IR II use to achieve a blood alcohol concentration?
Infrared (IR) analysis and an electrochemical sensor (fuel cell).
What is the purpose the purge fan?
Draw air into the IR sample chamber and clear the system of any residual alcohol.
What are the 2 functions of the pressure sensor?
Monitor flow rate and volume of the breath sample and monitor ambient atmospheric pressure.
What is RFI and what are 2 safeguards used to protect against RFI?
Radio frequency interference. Faraday cage and the metal instrument case protect against RFI.
What is the purpose of the IR system?
To monitor the quality of the breath sample and detect mouth alcohol.
How does IR detector function?
Since there is a direct relationship between amount of alcohol in chamber and amount of energy absorbed, it monitors the amount of energy at specific wavelengths (3), 1 for CO2 and 2 for ethanol, and measures the amount of energy that passes through then determines the amount of energy absorbed by the alcohol.
How is mouth alcohol detected?
The IR system detects high breath alcohol concentration due to large decrease in ethyl alcohol wavelength energy which is quickly replaced by breath with a much lower alcohol concentration.
What are the 3 sample acceptance criteria?
Minimum flow rate of 12L/min, minimum volume of 1.5L and a 5% drop in flow rate after minimum volume is reached.
What are the 3 criteria of a proper breath test (PBT)?
2 suitable breath samples which agree within 20 mg% of each other, 2 diagnostic tests that passed and 2 alcohol standard tests within 10% of the target value.
What are the 5 phases of the breath test procedure?
Observation period, information gathering, data entry, breath test analysis and final check.
What is the simulator temperature range?
33.8-34.2 degrees Celsius.
How many times during a subject test will the QT be prompted to check the simulator temperature?
3 times.
How many subject tests and tests per subject be taken at the same time using the Intox EC/IR II?
4 test subjects and 4 tests per subject.
When would a QT perform a quick test?
When there is an equivocal refusal.
At what temperature is the breath tube maintained?
40 degrees Celsius +/- 1.
What are the primary and secondary functions of the fuel cell?
Primary purpose is to determine blood alcohol concentration; secondary function is to determine if interfering substances are present.
What is the breath sample sequence?
Subject provides breath sample, fuel cell is trigerred to open, the sample is drawn in and there is a fuel cell reaction (higher alcohol means higher voltage which results in higher BAC).
