Remote Ischemic Preconditioning of Dynamic Cerebral Autoregulation in Healthy Adults (RIPCA)

The purpose of this study is to determine the impact of remote ischemic preconditioning on dynamic cerebral autoregulation and related hematology indexes in healthy adults.

Remote ischemic preconditioning(RIPC) is the phenomenon whereby brief cycles of ischemia and reperfusion, applied to a distant organ, provide protection to the target organ. Dynamic cerebral autoregulation(dCA), a mechanism to maintain the cerebral blood flow, has been proved to be critical for the occurrence,development and prognosis of ischemic neurovascular disease. In this study, we hypothesis that RIPC provides neuro-protection by means of improving dCA.

RIPC was induced by 4 cycles of extremities ischemia (5-minute blood-pressure cuff inflation to 200 mm Hg, followed by 5-minute cuff deflation).All subjects will take RIPC intervention, blood collection and 7 dCA measurements.

The RIPC consisted of 4 cycles of extremities ischemia (5-minute blood-pressure cuff inflation to 200 mm Hg, followed by 5-minute cuff deflation). The tourniquets were applied to one side upper arm and other side thigh. This intervention was undertaken one time in total.

Nurses will collect intravenous blood 6ml twice(at baseline and 1h after RIPC).The blood samples will be stored for laboratory test.The blood samples only use for the trial.

Serial measurements of dCA were performed at 7 time points, baseline, 1h, 3h, 6h, 9h, 12h, 24h after RIPC.The continuous ABP was measured non-invasively using a servo-controlled plethysmograph (Finometer Pro, the Netherlands) at the middle finger. Two 2 MHz transcranial Doppler probe was used to measure continuous cerebral blood flow velocity (CBFV) simultaneously in the bilateral middle cerebral arteries at a depth of 45-60 mm Endtidal CO2 was monitored using a capnograph (MultiDop X2, DWL, Sipplingen, Germany). The probes were placed over temporal windows and fixed with a customized head frame. CBFV and continuous arterial blood pressure were recorded simultaneously from each subject in the supine position for 10 minutes. All data were recorded for further assessment and analysis.

A dynamic cerebral auto-regulation parameter derived from transfer function analysis.Continuous cerebral blood flow velocities of bilateral middle cerebral artery will be assessed noninvasively using transcranial Doppler. Spontaneous arterial blood pressure will be simultaneously recorded using a servo-controlled plethysmograph on the left or right middle finger with an appropriate finger cuff size. Transfer function analysis will be used to derive the autoregulatory parameters.

Inclusion Criteria: Age from 18 to 70,both genders Willing to participate in follow-up visits Exclusion Criteria: current or having a history of chronic physical diseases or mental diseases suffering from infectious diseases in late one month pregnant and lactating women； smoking or drinking； inability to cooperate sufficiently to complete the dCA examination

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Guo ZN, Guo WT, Liu J, Chang J, Ma H, Zhang P, Zhang FL, Han K, Hu HH, Jin H, Sun X, Simpson DM, Yang Y. Changes in cerebral autoregulation and blood biomarkers after remote ischemic preconditioning. Neurology. 2019 Jul 2;93(1):e8-e19. doi: 10.1212/WNL.0000000000007732. Epub 2019 May 29. Erratum In: Neurology. 2019 Sep 24;93(13):608.