Experimental Study On Cortical Evoked Potential And Flash Visual Evoked Potential During The Artery Blood Pressure Descended In Rabbits

Objective: To observe cortical evoked potential and flash visual evoked potential during the artery blood pressure descended in rabbits. Understand the relation between the change of evoked potential and the blood pressure descended until hemorrhagic shock. Inquiry into the pathophysiology mechanism of the change of evoked potential during hemorrhagic shock and after rectified it. Provide the experimental basis to the clinic monitor. Method: 1. Record the normal wave of evoked potential before exsanguinated. Hemorrhage maked the blood pressure descend each 10mmHg (1.33 kPa), and recorded evoked potential at each blood pressure point. Measured CEP latent period, positive wave values, negative wave values, p-p values and its timing and F-VEP P₂-N₂ values, P₂ latent period, until systolic pressure was 40 mmHg(5.32 kPa). Carry on to the each measured value to compare them. 2. Record CEP before hemorrhage, then exsanguinated, the blood pressure descended to 50-60 mmHg(6.65 - 7.98kPa) and recorded CEP. While treated (the whole blood that exsanguinated just and the same quantity physiological saline and 654-21mg/kg), wait for half an hour. The blood pressure recovered to 80 100 mmHg(10.64 13.3kPa), then recorded CEP, used statistical method to analyse. Result: (l)When the blood pressure declined by 130 mmHg to 90 mmHg (17.29- 11.97 kPa), CEP positive wave values and negativewave values were decreased with the blood pressure descended {P < 0.05). Blood pressure at the 90 - 70 mmHg (11.97 - 9.31kPa) range, the variety of positive wave values have no statistical meaning (P > 0.05). When blood pressure was 90 80 mmHg(11.97 - 10.64 kPas) and 70 60 mmHg(9.31 -7.98 kPa), the variety of negative wave values have no statistical meaning (P> 0.05). Blood pressure at 130 110 mmHg (17.29 14.63 kPa), the p-p values have no statistical meaning( P> 0.05). The p-p timing prolonged with the blood pressure descended (P < 0.05), the blood pressure from 60 mmHg to 40mmHg ( 7. 98 5. 32kPa ) , those groups were different from control group(P < 0.05). The latent period of shock group was different from the other groups (P < 0.05). (2) With the artery blood pressure descended, F-VEP P2 latent period prolonged gradually (P < 0.05). Blood pressure at 100 80 mmHg (13.30 10.64 kPa) and 70 - 50 mmHg(9.31 6.65 kPa), the variety of P2 latent period was not obvious( P > 0.05). P2-N2 values were declining with the blood pressure descended (P <0.05). But the blood pressure descended from 80 mmHg (10.64 kPa) to 60mmHg(7.98 kPa), the variety of P2-N2 value was not obvious.(P > 0.05). (3)Control group, hemorrhage group and treatment group have differences (P < 0.05). Conclusion: With artery blood pressure descended CEP positive wave values, negative wave values, the p-p values were decreasing. The latent period of the cortical evoked potential and p-p timing were prolonging with the blood pressure descended. F-VEP P2 latent period prolonged gradually, P2-N2 values decreased gradually. But when the blood pressure was low in 70mmHg (9.31 kPa), then treated it, the evoked potential could not recover as control group's. The experimental result provided methods to the treatment of the shock and valid monitor.