The Feasibility Study Of Intracarotid Propofol Infusion For General Anesthesia

The feasibility study of intracarotid propofol infusion for general anesthesiaIntroductionThe direct injection of drugs into one of the main arteries supplying the encephalon has been largely utilized in experimental neurophysiology in recent years. Compared with intravenous infusion drugs, there are four main superiority of intracarotid infusing drugs: (1) the rapid effect of infusing drugs; (2) the strong therapy purpose; (3) the good therapy effects and (4) the minor general side effect, et al.The drugs used via intracarotid were multiformities such as radiopaque materials of ^99mrc and ¹³³Xe, calcium ion channel blockers of verapamil, thrombolytic drugs of rokinase, hormone of prednisolone, anesthetic drugs of amobarbital, cardiazol, megimide and chems drugs of cisplatinum and so on. It has been widespread used of intracarotid infusing drugs in the therapy territory of cerebral infarction, functional localization of cerebral region, brain protection and the therapy of brain tumor, et al.As we know that the brain is intravenous anesthetics' target organ. Therefore, can we anesthetize patients via intracarotid infusing anesthetics, then? Whether the benefits of intracarotid infusing drugs are better than intravenous infusion or not? To our knowledge, there is no intracarotid infusing anesthetics for general anesthesia purpose in clinical work.First, to compare the effects of intracarotid and common carotid artery and femoral vein administration of propofol for electrocerebral silence (ES) on circulatory and respiratory function and the dosage of propofol required during ES in dogs, we plan to discuss the benefits of intracarotid infusing anesthetics. Secondly, to observe the possibility injuries of vascular and nervous tissues in the propofol filling encephalic regions and to investigate the safety of propofol direct infusion via intracarotid at the levels of cell, molecule and gene for general anesthesia purpose in clinical operation, we plan to establish the intracarotid infusion model in Wistar rat. Thirdly, we plan to use this anesthesia method in clinical operation patients and to observe whether intracarotid anesthesia effect is better than intravenous anesthesia or not. If the result is coincidence with our hypothesis, therefore, it can be a new anesthesia method for the patient who is poorer in circulatory and/or respiratory fuction and/or liver-renal fuction.The research consists of the following three aspects: first, comparison of the pharmacodynamics difference between intracarotid, common carotid artery and intravenous propofol in dogs; second, the influence on the rat's brain when continuely infusion propofol via intracarotid; third, general anesthesia effect of propofol continuous infusion via common carotid artery in clinical anesthesia.Materials and Methods Materials1. AnimalsEight adult dogs weighting 9～17kg, were used in this study.100 healthy Wistar rats weighting 280～320g, 4～6 month, were used in this study. The animals provided by Shengjing hospital laboratory animal center of China Medical University.Clinical cases: Thirty-five patients of operation on abdominal region without neurosystem disease.2. Kits and drugsPropofol, RNA-out extract, RNA lysate, kit of RNA extract, Takara kit, DNA marker, bcl-2 and bax andβ-actin primer.3. EquipmentsHitachi H-600 transmission electron microscope, 8800 type ultrathin slicer, Olympus microscopic camera, Alphainnotech Chemi Imager 500 gel imaging analytical system, UV-visible Spectrometer UV300, Biometra PCR amplication device, Bio-rad powerpac 200 electrophoresis device.MethodsPart 1: animal study (dogs)1. Animal modelThe animals were anesthetized with intramuscular ketamine and common carotid artery, intracarotid, femoral artery and femoral vein were isolated. Then, Y-type vein needles were implanted in every dog's common carotid artery, intracarotid, femoral artery and femoral vein respectively and were heparinized. The dog without any abnormalities was choosed to be experimented via different route infusing propofol after twenty-four hours' carefully observation. Random sequence to administrate propofol via intracarotid or common carotid artery or femoral vein in each dog (own control experiment) and the pharmacodynamics differences of different route' propofol were observed carefully.2. Experimental designsOwn control experiment design. According to the different route drugs infusion, intracarotid group and intravenous group.3. Parameters and methodsThe flowing indexes were observerd at the same depth of anesthesia (CSI=0～3).(1) The hemodynamic changes during the period of infusing drugs;(2) The respiratory changes during the period of infusing drugs;(3) The speed of anesthesia induction and recover of consciousness;(4) The dosage of propofol consumption at different depth of anesthesia.Part 2: animal study (rats)1. Animal model After intraperitoneal injection propofol (100mg·kg^-1), rat's common carotid artery was isolated, extra carotid artery was ligated and propofol or 0.9% NS was administration via common carotid artery or femoral vein for one hour.2. Experimental designsOne hundred rats were randomly allocated into two groups.Control group, 0.9%NS was administrated via intracarotid at 3ml·kg^-1·h^-1 while propofol was infused via femoral vein at 30mg·kg^-1·h^-1 for 1 hour in ten rats. Animals were executed after 4 hours when drugs infusion stopped and the brain tissues of the side of infusing drugs were obtained immediately detected by light microscope, electron microscope and RT-PCR method.Experiment group, propofol was administrated via intracarotid at 30mg·kg^-1·h^-1 while 0.9%NS was infused via femoral vein at 3ml·kg^-1·h^-1 for 1 hour in ninety rats. nimals were executed after 4 hours when drugs infusing stopped and the brain tissues of the side of infusing drugs were obtained immediately detected by light microscope, electron microscope or RT-PCR method. According to the different detection method, ninety rats were divided into three subgroups with thirty animals in each subgroup.3. Parameters and methods(1) The hemodynamic changes during the period of infusing drugs;(2) The brain tissues histopathologic examination by light microscope;(3) The brain tissues ultrastructural pathology examination by Electron Microscope;(4) The changes of bcl-2 and bax mRNA in brain tissues detected by the method of RT-PCR.Part 3: clinical observation1. Case collectionThirty-five adult patients of operation on abdominal region were randomly assigned to receive propopol via common carotid artry (IA group, n=24) or median cubital vein (â…£group, n=11).2. Parameters and methodsThe HR, MAP, the propofol dosage used, the time of respiration and consciousness recovered were recorded when drugs infusion stopped. The patients were carefully observed after the sugery operations in order that to make sure of whether this kind of infusion propofol is harmful to human's health or not.Results1. Comparison of the pharmacodynamics difference between intracarotid and common carotid artery and intravenous propofol in dogsThe mean dose of intracarotid, common carotid arterial propofol was significantly less than that of intravenous propofol at the point of consciousness loss, 10s, 30min and 60min of CSI=0～3, about 25.4%～30.1% and half that of intravenous propofol dose required (37.3±8.4mg, 76.1±24.3mg and 146.9±48.3mg; 108.3±35.1mg, 221.3±47.4mg and 353.3±89.2mg; 254.3±60.1mg, 474.9±122.5mg and 845.8±206.8mg; 395.4±108.9 mg, 721.3±204.0mg and 1401.4±410.4mg, respectively, P＜0.01). Compared with baseline values, the mean arterial pressure and respiration rate remained unchanged or decreased transiently during ES with intracarotid or carotid artery propofol. in contrast, intravenous propofol resulted in systemic hypotension and severe respiratory depression. The effect of intracarotid propofol is minor than carotid artrery'. As for recovery of spontaneously breathing and consciousness, intracarotid or carotid artery propofol were more quickly than intravenous infusion and intracarotid infusion is more quickly than that of intravenous.2. The influence on the rat's brain when continuely infusion propofol via intracarotid(1) The changes of hemodynamics and respiratory parameters during propofol infusing period The MAP, HR, R were steady during drugs infusing period in control group. However, the MAP, HR and R were slower and lower in experiment group (P＜0.05).(2) The changes of cortical neuron and endangium of rat observed by light microscopeThe nucleoli and nuclear membrane were clear and integrity of cortical neuron in control group while the endangium was smooth and glossy and the coloration was uniform. So does the experiment group. There is no any acute injury to be found by light microscope.(3) The ultrastructural changes of cortical neuron and endangium of rat observed by transmission electron microscopeNEURON: the cellular nucleus appearance was normal, the nuclear membrane was smooth and glossy and the distribution of chromoplasm was uniform. The cellular organ was abundant, the distribution of rough endoplasmic reticulum was normal, the network and cavitas was uniform with plenty of ribosomal particles on its surface and the cytochondriome was prosperous whose double membrane of superficies externa and internal cristae were distinct and clear. The polarity of Golgi's complex was obvious and the capsular space was normal. So does the experiment group.BLOOD CAPILLARY: The structure of Blood capillary was normal in control group. so does the experiment group. There was no any acute injury to be found by transmission electron microscope.(4) The genetic expression changes of bcl-2 mRNA and box mRNA of cerebral cortex of ratSemi-quantitation method of RT-PCR was adopted. The needed amplification fragment of cDNA was obtained in every specimen. The expressed quantity of bcl-2 mRNA and bax mRNA in control group were the same as that of in experiment group. No any acute injury has been found at molecular level in the infusing side of cerebral cortical when long time and large dose propofol was infusion via intracarotid in rat.3. General anesthesia effect of propofol continuous infusion via common carotid arteryThe dose of propofol used in group IC and IV were 2.57±0.67 and 5.72±1.37 mg·kg^-1·h^-1 respectively during the surgery of CSI=40±5 (P＜0.01). At this depth of anesthesia, about one-third patients' blood pressure were higher than their baseline, some even more than one third of their basline and need to be controlled by hypotensive drugs in group IC. Whereas, the blood pressure was steady and decreaseing 15% of basic values in group IV only. As for recovery of spontaneously breathing and consciousness, patients in the group IA were more quickly than that in the group IV. The results were 6.70±4.9, 12.1±6.34min (P＜0.01) and 18.45±10.39, 26.10±8.32min (P＜0.05) respectively.Conclusions1. Intracarotid or carotid artery propofol resulted in electrocerebral silence at a fraction of the intravenous dose that was not associated with systemic hypotension or respiratory depression. The induction and recovery time were significantly shorter after intracarotid or carotid artery propofol than after intravenous injection. The anesthesia effect of intracarotid propofol is better than carotid artery propofol but not convenient than carotid artery infusion of propopol.2. The brain received long time and large dose of intracarotid infusion of propofol showed no evidence of any acute neuronal injury.3. Consciousness and nervous reflex disappeared can be achieved when anesthesia via common carotid artery infusing propofol; the dose of propofol used in group IA was one half that of group IV at the same depth of anesthesia; the recovery of spontaneously breath and consciousness were more quicker in group IA than in group IV when propofol infusing stopped at the end of the operation.