Remote Ischemic Preconditioning of Dynamic Cerebral Autoregulation in Healthy Adults

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.