Comparative Study On Hemodynamic Effects Of Two Groups Of Premedication Combined With Emulsified Sevoflurane Intravenous Anesthesia On Ponies

The diagnosis and treatment of animals with low domestication degree in large wild animals and zoos should be based on the principle of minimizing animal stress and preventing accidents,In order to protect their lives,reliable and effective anesthesia is the first prerequisite.Pony is a common animal in zoos.However,in some zoos,pony is not well domesticated,wild and hard to approach.At present,there are few studies on the anesthesia methods of ponies.Therefore,this study investigated the effects of intravenous injection of emulsified sevoflurane on hemodynamics and cardiac function of zoo ponies after sedation with different pre anesthetic drugs,and objective to monitor the safety and operability of two different anesthesia schemes for ponies,so as to provide reliable theoretical basis for clinical anesthesia of ponies.In this study,10 ponies were randomly divided into Ketamine（5mg/kg）+Xylazole（0.5mg/kg）+Fentanyl（0.3μg/kg）+6%Emulsified Sevoflurane（Infusion rate:2.1m L/kg/h）group（KF group）and Dexmedetomidine（10.08μg/kg）+Ketamine（6.05mg/kg）+Butorphanol（27.01μg/kg）+Fentanyl（0.2μg/kg）+Emulsified Sevoflurane（Infusion rate:2.1m L/kg/h）group（KB group）.The patient was sedated by pre anesthetic administration.And the ponies were anesthetized by continuous intravenous infusion of Emulsified Sevoflurane.By adjusting the infusion rate of emulsified sevoflurane,the anesthesia can be controlled to moderate or deep anesthesia.At 0,30,60,90,120 min after intravenous infusion of Emulsified Sevoflurane anesthesia in the KF and KB experimental groups,noninvasive blood pressure monitoring,electrocardiogram,multi-functional integrated monitor,blood gas,thermometer,ELISA were used as monitoring and detection methods,Systolic blood pressure（SBP）,diastolic blood pressure（DBP）,mean arterial pressure（MAP）,harmful stimulus reflex,heart rate（HR）,blood oxygen saturation（Sp O₂）,respiratory rate（RR）and body temperature（T）were monitored.Plasma renin（PRA）,angiotensin II（Ang II）,aldosterone（ALD）,troponin（TN）,endothelin（ET）,neurotensin（NT）,atrial natriuretic peptide（ANP）and brain natriuretic peptide（BNP）were measured,and the contents of Ca²⁺,Mg²⁺,Pi in serum and K⁺,Na⁺,Cl^-,HCO₃^-in whole blood were detected,And the above test results were compared and analyzed.The experimental results show that,（1）In this experiment,after intravenous injection of emulsified sevoflurane,the eyelid and anal reflex disappeared,and T and RR showed a downward trend;HR decreased to the lowest in 30 minutes,compared with 0 min,KF group and KB group decreased by about 35%;the pain of trunk and limbs disappeared;at the end of the experiment,the blood pressure of KF group decreased significantly.Compared with 0 min,SBP decreased by 16%,DBP decreased by 21%,map decreased by 18%,although the blood pressure of ponies in KB group decreased,there was no significant change.（2）During anesthesia,both the KF group and KB group were inhibited by RAAS,During 0～90 min of anesthesia,the inhibition of RAAS system was similar between the two groups.After 90 min,the inhibition of RAAS system in KB group was stronger than that in KF group;（3）After anesthesia,the changes of blood gas analysis and ion content in the two experimental groups were increased in the normal physiological range,and the changes of each index were within the physiological range of the ponies;（4）During anesthesia,there was no significant difference in plasma ET Content between the two experimental groups,but the change trend was different;the plasma NT content of the two experimental groups was significantly increased,but after 90 minutes,the plasma NT content of the KB group decreased,while that of the KF group did not;the plasma ANP content of the KB group changed more significantly than that of the KF group;（5）The phenomenon of S-T segment shift was found in both KF group and KB group during the experiment,which was significant at 30 min,and the plasma Tn and BNP of the two experimental groups showed an increasing trend,and the Tn content increased.However,after 30 min,the plasma Tn and BNP of KF group recovered to nearly0 min,while the plasma Tn content of KF group was significantly higher than that of 0 min.The above results show that KF and KB groups can produce rapid and stable sedative effect on ponies.After intravenous infusion of emulsified sevoflurane for general anesthesia on ponies,they can produce rapid,stable and controllable anesthetic effect,which has good muscle relaxation analgesic effect;The respiration of ponies was significantly inhibited in both groups,but the inhibition of body temperature in KB group was lower than that in KF group.The hemodynamic effect of the two groups was stable,but KF group had more significant effect on the cardiac function of dwarf horse than in KB group.Therefore,the pre anesthesia drug group of KB group is more suitable for the long-term general anesthesia of dwarf horses.