The Feasibility Study Of Common Carotid Arterial Fentanyl And Propofol Infusion For General Anesthesia

Objective: To compare the pharmacodynamic differences of common carotid artery administration with ear vein administration of propofol and fentanyl in rabbits. Intravenous anesthesia is popular because of rapid anesthesia inducation, non-stimulation on respiratory tract, more comfortable on patients, pollution-free, faster recovery, and convenient operation, which become an important method of anesthesia in clinic. At the effective depth of anesthesia, propofol and fentanyl often inhibit significantly circulatory function, due to a large dose, which is disadvantageous particularly to the elderly and patients that have cardiovascular dysfunction and important organs function impaired, such as liver and kidney.Recent studies have shown that the drugs can directly enter the brain blood-vessels and play a role through the blood-brain barrier via internal carotid artery administration for the treatment of brain disease or study of brain nerve function, which are more advantageous for treatment, due to a small dose, the precise effect and less systemic side effects. As we all know, intravenous anesthetics and narcotic analgesics act on the central nervous system to produce anesthesia and analgesia. Drugs administrated through the internal carotid arterial or the common carotid arterial can arrive directly at the target organ the brain for anesthesia and analgesia, whether is it superior to the intravenous anesthesia?At present, the internal carotid arterial or the common carotid arterial administration of drugs to conduct clinical anesthesia is rarely reported at home and abroad. Animal studies indicate that carotid arterial administration of propofol make hemodynamic more stable without causing changes of cerebral blood flow, and the dosage is 5-10 times of intravenous administration of it for electrocerebral silence for one hour.Method60 New Zealand white rabbits were randomly divided into two groups: Group V (intravenous administration of propofol group, n=30) and group A (common carotid arterial administration of propofol group, n=30). The group V and A were divided into two subgroups: group Vv (intravenous administration of propofol and fentanyl (n=15) and Group Va (intravenous administration of propofol and common carotid arterial administration of fentanyl (n=15); group Av (common carotid arterial administration of propofol and intravenous administration of fentanyl (n=15) and group Aa (common carotid arterial administration of propofol and fentanyl (n=15). Propofol and fentanyl were administrated through the ear vein or the common carotid artery, which formed four different infusion methods.In group V and A, 0.33% propofol was administrated via the ear vein or the common carotid artery at 30mg?kg-1?h-1, and fentanyl was administrated via the ear vein or the common carotid artery at 2μg?kg-1?h-1for electrocerebral silence (the frequency of electroencephalographic waves was maintained at 0-3).Then, the speed of fentanyl infusion was regulated for maintaining electrocerebral silence for one hour. The outcomes were recorded, including The time of consciousness loss and recovery, to electrocerebral silence, dose of propofol and fentanyl during electrocerebral silence, mean arterial pressure,heart rate, respiration rate and Spo2 were continuously monitored, and the changes of hemodynamic and respiratory were observed in rabbits.Results1. By comparing within the two sub-groups of group A and between intravenous administration and common carotid artery administration of propofol or fentanyl which combined with fentanyl infusion by the same way, the differences is significant in dosage of them. By comparing within the two sub-groups of group V, the differences are yet significant in dosage of fentanyl, while the dosage of propofol is no difference.2. The time of consciousness loss and recovery, and of electrocerebral silence is shorter with propofol or fentanyl administration via common carotid artery than with propofol or fentanyl administration via ear vein, which combinated with fentanyl or propofol infusion by the same way.3. During continuous infusion of propofol and fentanyl for electrocerebral silence for one hour, blood pressure showed a downward trend in the four subgroups. Rate of declining of blood pressure is smaller with propofol administration via common carotid artery than with propofol administration via ear vein, which combinated fentanyl infusion by the same way.4. By comparing intravenous fentanyl administration with common carotid artery fentanyl administration which combined with propofol infusion by the same way, we found that rate of declining of blood pressure is yet smaller in the latter. Vv group showed the most significant declining in blood pressure,while the change in blood pressure is minor relatively in the remaining three groups. After stopping infusion, the blood pressure increased significantly, which compared with basic value in the four subgroups. Within groups, mean arterial pressure and heart rate are significant differences by comparing with baseline at four time points, namely loss of consciousness, electrocerebral silence, stopping infusion and recovery of consciousness.5. Comparing the degree of respiratory depressionNone of rabbits appeared breathing to be depressed seriously and needed to support breathing in the group Aa.While respiratory frequency and amplitude during electrocerebral silence after infusion of propofol and fentanyl were significantly depressed and needed to support breathing for maintaining Spo2 in 45 rabbits in the remaining three groups.6. Vascular endothelium is continuous, smooth and uniform color in Vv group. Vascular structure and morphology had no significant change comparing with the Vv group, without any acute injury in the remaining three groups.ConclusionThe different methods that propofol and fentanyl were administrated via the ear vien or the common carotid artery, can achieve the purpose of the maintenance of general anesthesia in rabbits. Comparing with drugs infusion via the ear vien, infusion of propofol and fentanyl via the common carotid artery is more advantageous in some aspects, such as rapid anesthesia inducation and recovery, smaller dose, no vascular injury and smaller impact on the hemodynamic and respiratory. The infusion method that both propofol and fentanyl were administrated via common carotid artery is more ideal for anesthesia, which be due to the least amount of narcotic drugs, the most rapid inducion and recovery and the most minor change of hemodynamic and respiratory.