The aim of the study was to study changes of hyperoxic brain arterial reactivity (BAR) and frequency of occurrence in the investigation in patients with hypertension.Design and method:
All participants of research have given the informed agreement. We used ultasonography of transcranial Doppler‘s method in the middle cerebral arteries (MCA) from temporal window. We studied the changes of flow Velocity mean (Vm) starting, during hyperoxia (inhalation 2 min with 100% oxygen) and FmV in period of recovery (rec) (air-inhalation 2 min) of 264 patients with essentially hypertension (BP > 140/90 mmHg without antihypertensive drugs), age 52.7 ± 11.2years. High - resolution annular array scanners was determined - a nominal axial resolution of 0.2 mm, and 30 frames per second's acquisition rate with a 2.5–4 MHz sectored array transducer in the quiet dark room at the temperature 26 degrees on Celsius. We used Indexes of FVm; IFVm = (Vm0-Vm)/ Vm0*100, Speed Modification of FVm: SM = (Vm-Vm0)/120, Index of Recovery of FVm: IR = Vm0/Vmrec: Vm0, BP0 are starting and Vm, BP are the parameters at period of inhalation, Vmrec is Vm after 120 sec. - time of inhalation.Results:
Patients with hypertension had the different types of hyperoxic BAR/ and frequency of occurrence in the investigation: the intensity of the response to hyperoxia: 1-th type normal (IFVm −26.6 ± 2.8)/2.4%, 2-nd type - abnormal reduced (IFVm −10.2 ± 1.9/22.4%) p = 0.011; the third - abnormal opposite (IFVm 10.2 ± 2.5/76.2%); 2 types of speed-reactions: normal (SM −0.26 ± 0.01/2.0%) abnormal slow (SM 0.04 ± 0.0/98%1) p = 0.001; 2 types of recovery-reactions: normal recovery (Vmrec 1.2 ± 0.3)/53%, abnormal slow recovery (Vmrec 0.6 ± 0.2)/47% p = 0.002Conclusions:
Patients with hypertension had the different types of hyperoxic BAR: 3 different types of reactions by reaction force, 2 types its speed of development and 2 types rate of recovery and different their of frequency occurrence.