SHORT TERM CONTROL OF BLOOD PRESSURE: COHERENCE BETWEEN BLOOD PRESSURE AND SYSTEMIC PERIPHERAL RESISTANCE FLUCTUATIONS AROUND 0.1 HZ

Background: Task Force Monitor enables the beat-to-beat blood pressure (BP) and total  peripheral resistance (TPR) monitoring. Those data can be used for evaluation of the baroreceptors elicited TPR response if the coherence between BP and TPR fluctuations around 0.1 Hz is relatively high (>0.5).
Aim: The measurement of coherence (COH) between systolic BP and TPR (COH SBP-TPR) fluctuations around 0.1 Hz was the aim of the present study.
Methods. Blood pressure, cardiac impedance and ECG were monitored during 5-minute metronome-controlled breathing (0.33 Hz) in 10 volunteers (age between 30 and 60 years). Spectral analysis was performed and baroreflex heart rate sensitivity (BRS, ms/mmHg) was calculated. In the range of frequencies 0.05 – 0.15 Hz the maximal COH between SBP and inter-beat interval (COH SBP-IBI), between SBP and cardiac output (COH SBP-CO) and between SBP and TPR (COH SBP-TPR) were determined (mean ± SD).
Results: The following values were obtained: BRS: 9.59±7.14 ms/mmHg, COH SBP-IBI: 0.69±0.18, (COH SBP-CO):0.68±0.17, COH SBP-SPR: 0.67±0.24.
Conclusion: Results indicate that COH SBP-TPR is similar to COH SBP-IBI and COH SBP-CO and therefore the spectral method of calculation of baroreflex response of TPR can be elaborated. However, because of the difference between stroke volume and volume of blood flow from the aorta during the corresponding cardiac interval, the method will not be as simple as the spectral method for determination of BRS and further development will be necessary.

Support: MSM0021622402