To begin, ask the participant to lie in a supine position on an examination plinth or bed. Place a cuff around the thigh, proximal to the knee, ensuring that the tubes do not come into contact with the calf. Elevate the leg with the foot and ankle on foam support, leaving the lower leg stable and accessible For measurements.
Turn on the rapid cuff inflator module. Activate the cuff inflator air source. Verify air passage through the hose and connect the hose to the thigh cuff.
Fix the near infrared spectroscopy or NIRS transmitter receiver probe on the skin overlying the measurement sites. Cover the probe with black kinesiology tape to block ambient light, preserving NIRS signal integrity. Instruct the participant to maintain a relaxed posture, avoid talking, and keep their legs still throughout the data collection period.
Using the computer interface, start the NIRS device and acquire the data for a minimum of two minutes before starting the measurement. Monitor the computer screen to ensure data signal integrity and physiologically plausible values. If no fluctuations in the NIRS signal are noted, push the corresponding button on the software to set the NIRS data baseline.
Collect at least one minute of baseline data ensuring no signal fluctuations or movement artifacts in recording. Set the cuff pressure to 200 millimeters of mercury on the rapid cuff inflator. before selecting the cuff mode.
Inform the participant about potential sensations during the cuff's inflation to 200 millimeters of mercury for five minutes and subsequent total cuff deflation. When ready to initiate cuff inflation, mark the end of the baseline period in the recording. Inflate the thigh cuff to a supra systolic pressure of 200 millimeters of mercury.
Monitor the computer or screen to ensure data integrity during the occlusion period. Just before the end of the five minute occlusion, remind the participant to keep their legs still, and refrain from talking for approximately three minutes after cuff deflation. After five minutes, rapidly deflate the thigh cuff to zero millimeters of mercury, and simultaneously mark the end of the occlusive period in the recording.
After a three minute post-occlusion or after the NIRS data has returned to baseline, mark the end of the recovery period and stop the measurement. Finally, export the NIRS results and save the data treatment and analysis. NIRS distinguishes microvascular responsiveness between healthy individuals and those with peripheral arterial disease during reactive hyperemia testing.
