A Comparison Of Induction And Maintenance Of Anesthesia, Physiological Indicators In Beagle With Four Types Of Inhaled Anesthetics Management

Inhalation anesthesia is widely used in veterinary clinical general anesthesia,which demonstrates a high safety,reliable anesthesia effect,strong controllability,few adverse reactions,and induction and recovery rapidly and smoothly.Halothane,enflurane,isoflurane,and sevoflurane are adminstrated for inhalation maintenance anesthesia after induction of intravenous anesthetics such as propofol and thiopental in pet clinical.The commonly used thiopental sodium and propofol have inhibitory effects on the cardiovascular system.Owing to nausea and vomiting coused by etomidate and excessive respiratory secretions caused by zoletil,neither is conducive to tracheal intubation.Inhalation-induced anesthesia is recommended as a safe and reliable method for uncooperative,weak,and critical animal patients.The quality of induction and anesthesia has been often assessed by a scoring method,which is too subjective and exists error in conclusions.Through the detection and analysis of BIS and echocardiography,this study further systematically compared the effects of 4 inhaled anesthetics on mask induction and maintenance of anesthesia with beagles,in order to provid guidance for veterinary clinical anesthesia.1.The effects of induction and maintenance of anesthesia,physiological indicators in beagle with 4 types of inhaled anestheticsAccording to the Bootstrap test method,5 beagles were treated by 4 kinds of inhalation anesthetics for mask induction and maintenance,the interval between each treatment was 14 days.The experimental dogs were divided in to 4 groups,halothane treatment group（H）,enflurane treatment group（E）,isoflurane treatment group（I）and sevoflurane treatment group（S）.The number of dogs in each group was 5.The effects of induction and maintenance anesthesia,physiological indicators during the anesthesia were monitored,and the data was statisticed and analyzed.The results showed that a lot of saliva was secreted after halothane-induced anesthesia.It maybe a risk factor of suffocation if saliva enters the airway.The dogs resisted fiercely during halothane-induced anesthesia.The unsaitisfied treatment and delayed operation could be caused by fiercely resisted,extremely poor quality of induction,vocalized and sprayed feces to pollute operation room in the dogs with enflurane-induced anesthesia.Due to the quickly and smoothly anesthetized,sedation profound,and smoothly tracheal intubated,isoflurane and sevoflurane are suitable for veterinary clinical dogs as mask induction anesthetics.Maintenance anesthesia with halothane,isoflurane and sevoflurane,the period of surgical anesthesia was achieved with reliable anesthesia effect,sedation profound,no ear reflex,good analgesic effect and muscle relaxation.The anesthesia effect was unreliable and the sedative and analgesic effects were poor with limb twitching,spontaneous blinking,and tongue moving after enflurane treatment.Body temperature and the MAP had a significant decline while no significant effects were observed about Sp O₂and ETCO₂after 4 types of inhalated anesthetics treatment.Sevoflurane and enflurane had a significant effect on reducing heart rate.In addition to halothane,the other 3 inhaled anesthetics inhibited the respiratory system.The effects on these physiological indicators were all within a safe range.2.The effects of electrocardiogram and echocardiogram in beagle with 4 types of inhaled anesthetics5 beagles were treated by 4 kinds of inhalation anesthetics for mask induction and maintenance,the interval between each treatment was 14 days.ECG waveform,the changes of the reference index of the echocardiogram ultrasound during the anesthesia were monitored,and the data was statisticed and analyzed.The results showed that the effects of electrocardiogram in dogs were mainly reflected in the extension of the S-T segment time limit and Q-T interval during the anesthesia by inhaled anesthetics.The S-T segment rose out of safety in sevoflurane group,which was not observed in other 3 groups.Q-T interval is the time of ventricular depolarization to repolarization,its extend indicates myocardial hypoxia and ischemia.Intra-atrial and interatrial conduction delay,ventricular depolarization block and myocardial depression with halothane anesthesia.The conduction in the atrium was delayed with enflurane management.Isoflurane treatment had the least effect on the cardiovascular system in dogs.The end-systolic volume of the left ventricle in dogs increased with the 4 types of inhalation anesthetics.The end-diastolic volume of the left ventricle decreased with sevoflurane treatment.The average aortic blood flow pressure,the peak aortic blood flow pressure,the average aortic blood flow velocity,and the aortic peak blood flow velocity all decreased and remained stable after induction during anesthesia,which was caused by the reduced ability of the left ventricle contractility.The aortic blood flow curve integral increased to the baseline level after being reduced,but the stroke volume was still significantly different from the baseline value with sevoflurane.It was speculated that the cross-section of the left ventricular outflow tract（subaortic valve,aortic valve and upper aortic valve,etc.）was reduced by sevoflurane.In isoflurane,enflurane and halothane groups adminstration,the aortic blood flow curve integral rose to a certain extent after being reduced,but the difference was still significant compared with the baseline value.However,due to the compensatory increase of ejection time,the stroke volume had a certain rebound.In this study,there were a few cases in which the ejection fraction of the halothane and sevoflurane groups was less than 40%,indicating heart failure.Clinical usage should be combined with actual.