The Attorney General of Canada recently amended the Approved Screening Devices Order to recognize a new Approved Screening Device (for the purposes of section 254(2)). The new device is the Drager Alcotest 6810.
On its webiste Drager notes the following as one of the 6810's benefits:
The electrochemical sensor (fuel cell) of the Dräger Alcotest® 6810 reacts specifically to alcohol and excels with very short response times. Even with a very high alcohol content, the devices ensures quick measurements.
Another important feature of the 6810 is noted on another website (electrogasmonitors) to be its ability to obtain readings with "low" respiratory volume:
Even with high alcohol concentration, the Dräger Alcotest 6810 reacts within a short period. Blowing resistance is low, therefore the test can also be used if the test person has a low respiratory volume. The automatic adjustment measures the respiratory flow and adapts the minimum volume in such a way that air is taken from deep inside the lungs. Manually triggered collection can even be used for people who are not consciously in a position to provide a breath sample. The device displays the test results on a backlit graphics display with LEDs in different colors and, with acoustic signals.
This feature will be helpful in rebutting the argument - to the extent it has any validity - that a person has a reasonable excuse for not providing a sample due to some medical issue.