Heart Biomarker Evaluation in Apnea Treatment

3.6 Peripheral Arterial Tone (PAT) Script

• This test looks at the health of the lining of the small blood vessels. One way of doing this is to test how quickly blood flow changes after a blood pressure cuff is inflated and deflated. We will make this assessment by measuring changes in the blood flow in the finger tips using a sensor worn over the finger tip. It will be important to compare the blood flow in the finger of one hand where a blood pressure cuff was used to temporarily reduce blood flow and compare that to the finger of a hand where a blood pressure cuff was not placed on the arm.
• Here are the probes. (Show participant the finger probes). We also place a blood pressure cuff on your upper arm that is going to be very tight for 5 minutes, tighter than a regular blood pressure cuff.
• If you feel that it is too uncomfortable when the cuff is inflated, please let me know. We can stop the test at any time.
• Now I will explain the entire test to you. I have placed the probes in the arm rests and I would like you to gently place your index fingers into the probes. I am now going to inflate the probes to attach them to your fingers. (Inflate the probes and start recording on standby mode.)
• Now I’d like you to rest your arms on the arm rests with your palms flat and your fingers suspended over the edge. I am now placing dividers on your fingers, which help to keep your fingers from resting on the probes. We try to keep everything away from the probes and that way we get a better signal. Are you comfortable? Would you like a blanket? (When everything is in place start recording)
• I am now recording the volume of the blood flow in your fingers. I do this for five minutes and then I inflate the cuff. When the cuff is inflated it comes up suddenly and it is very tight. We keep it like that for 5 minutes and because the blood flow is restricted, it is normal for you to feel numbness and tingling in your arm and hand, as well as pressure from the cuff. When I deflate the cuff, you will feel the blood come back into your fingers with more pressure. We continue to record the increased blood flow for 5 minutes. The test takes ten minutes and we ask that you try to keep your fingers as still as possible during the test.
• I will give you warning before I inflate the cuff and then you can let me know if it is too uncomfortable for you. If it is too uncomfortable, we can stop the test immediately. Just let me know at any time.

Just before inflation time:

• It is time to inflate the cuff. On the count of 3, I will inflate the cuff. 1 2 3. (Inflate cuff pressing timer and cuff inflation pedal simultaneously)
• How is that pressure? (If okay)
• Would you like to continue the test? (If non committal or showing signs of discomfort).
• Would you like me to stop the test? (If indicated, STOP test immediately, and thank participant for trying the test.) If you have a change of mind, we can stop the test at any time. Just let me know and I will stop the test immediately.

Just before deflation time:

• It is time to deflate the cuff now. Please continue to keep your fingers still for the last 5 minutes.

When test ends:

• The test is over now. What did you think of the test? Do you have any questions or concerns? Thank you (Remove probes and cuff)