Study On Cerebrovascular Reactivity Of Normal People Acclimatized To Plateau At Different Times

Objective: To explore the changes of cerebrovascular reactivity in normal people acclimatized to plateau at different times.Methods: Selected 30 young Han people who entered Xining?2260m?from the plain for 2-3 days as the acute exposure group;selected 30 young Han people who entered the plateau from the plain for 7-12 days as the preliminary acclimatization group;selected 30 young Han people who had lived in Xining for at least 10 years as the complete acclimatization group.Collect general information,blood pressure?BP?and blood oxygen saturation?SpO₂?.Through Multi-Dop X transcranial Doppler ultrasound monitor produced by DWL company in Germany and in normal mode measure bilateral middle cerebral arteries,bilateral vertebral arteries,basal arteries,the systolic velocity?Vs?,diastolic velocity?Vd?,mean velocity?Vm?,pulsatility index?PI?,resistent index?RI?of each vessel were recorded.QL software system to measure the before and after inhaled CO₂ bilateral middle cerebral artery of cerebral blood flow velocity and inhaled CO₂ partial pressure,at the end of the calculation of cerebrovasular reactivity?CVR?and cerebrovascular reserve index?CVRI?.Statistical methods were used to analyze whether there were differences in blood pressure?BP?,blood oxygen saturation?SpO₂?,cerebral vascular parameters?Vs,Vd,Vm,PI,RI?,CVR and CVRI among the three groups.Results:?1?Blood pressure in the acute exposure group were significantly higher than those in the preliminary acclimatization group and in the complete acclimatization group,and the differences were statistically significant?P<0.05?.There was no significant difference in blood oxygen saturation among the three groups?P>0.05?.?2?Partial middle cerebral artery vascular parameters?Vs,Vd,Vm,?and basal arterial vascular parameters?Vs,Vd,Vm?in the acute exposure group were significantly higher than those in the preliminary acclimatization group and in the complete acclimatization group,and the differences were statistically significant?P<0.05?.Partial middle cerebral artery vascular parameters?PI,RI?in the acute exposure group were significantly lower than those in the complete acclimatization group,the differences were statistically significant?P<0.05?.?3?The CVR?2.86± 0.66 cm/s?mm Hg?in the acute exposure group was higher than the CVR in the preliminary acclimatization group?2.41.±0.45 cm/s?mm Hg?and the CVR?2.21±0.42 cm/s?mm Hg?in the complete acclimatization group,the difference was significant?P<0.05?;there was no significant difference in CVR between the preliminary acclimatization group and the complete acclimatization group?P>0.05?.?4?The CVRI?4.32±1.00%/mm Hg?of the acute exposure group was significantly higher than the CVRI?3.74±0.79%/mm Hg?of the preliminary acclimatization group and the CVRI?3.66±0.97%/mm Hg?of the complete acclimatization group,the difference was significant?P<0.05?;there was no significant difference in CVRI between the preliminary acclimatization group and the complete acclimatization group?P>0.05?.Conclusion:?1?Acute hypoxia can increase cerebral blood flow velocity and cerebral blood flow?CBF?.?2?The effect of different acclimatization time on cerebrovascular reactivity is different.The cerebrovascular reactivity of the acute exposure people is higher than those complete acclimatization people.With the prolongation of body acclimatization time,it is basically close to the complete acclimatization people.