Publications Repository - Gdańsk University of Technology

Pial artery adjustments to changes in blood pressure (BP)may last only seconds in humans. Using a novelmethod called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) in humans, we aimed to assess the relationship between spontaneous oscillations in BP and cc-TQ at frequencies between 0.5 Hz and 5 Hz. We hypothesized that analysis of very short data segments would enable the estimation of changes in the cardiac contribution to the BP vs. cc-TQ relationship during very rapid pial artery adjustments to external stimuli. BP and pial artery oscillations during baseline (70 s and 10 s signals) and the response to maximal breath-hold apnea were studied in eighteen healthy subjects. The cc-TQ was measured using NIR-T/BSS; cerebral blood flow velocity, the pulsatility index and the resistive index were measured using Doppler ultrasound of the left internal carotid artery; heart rate and beat-to-beat systolic and diastolic blood pressure were recorded using a Finometer; end-tidal CO2 was measured using a medical gas analyzer. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations. The recordings lasting 10 s and representing 10 cycles with a frequency of ~1 Hz provided sufficient accuracy with respect to wavelet coherence and wavelet phase coherence values and yielded similar results to those obtained from approximately 70 cycles (70 s). A slight but significant decrease in wavelet coherence between augmented BP and cc-TQ oscillations was observed by the end of apnea. Wavelet transform analysis can be used to assess the relationship between BP and cc-TQ oscillations at cardiac frequency using signals intervals as short as 10 s. Apnea slightly decreases the contribution of cardiac activity to BP and cc-TQ oscillations.

Authors

• Paweł J. Winklewski,
• Marcin Gruszecki,
• Jacek Wolf,
• Ewa Świerblewska,
• Katarzyna Kunicka,
• Magdalena Wszędybył-Winklewska,
• dr inż. Wojciech Gumiński link open in new tab ,
• J. Zabulewicz,
• Andrzej F. Frydrychowski,
• Leszek Bieniaszewski,
• Krzysztof Narkiewicz link open in new tab ,
• Krzysztof Narkiewicz