ABSTRACT
Objective To observe the effects of propofol or thiopental on the changes of blood brain barrier (BBB) permeability in focal cerebral ischemia Methods Focal cerebral ischemia model was induced with occluding the middle cerebral artery (MCA) Sixty adult male SD rats were divided randomly into 5 groups: control group(group MC): without any anesthetics; propofol pretreated group (group MP1) or thiopental pretreated group (group MT1): intravenous bolus of propofol 20mg/kg or thiopental 40mg/kg, followed by intravenous infusion of propofol or thiopental at rate of 50 60 mg?kg 1 ?h 1 or 100 120 mg?kg 1 ?h 1 ,respectively ,to achieve and maintain the EEG burst suppression 30 min before MCA occlusion until the beginning of reperfusion; propofol therapy group (group MP2) or thiopental therapy group (group MT2): from the beginning to the end of the reperfusion , propofol or thiopental was administered at the same dose as group MP1 or group MT1; Blood pressure, P ET CO 2, ECG and EEG were monitored throughout the experiment Rectal temperature was maintained between 37 5℃ and 38 5℃ At the end of the experiment, after intravenous bolus of 2% evans blue dye(EB) 3ml/kg, the brain was taken out to check out the extends and areas of EB staining on the surface and standardized serial coronal sections of the brain ,under the optical microscope and electromicroscope Results 1 Both propofol groups did not alleviate BBB permeability changes and cerebral damage 2 Cerebral injury was most slightly in group MT1 3 BBB permeability and brain injury in group MT2 were slighter than those in group MC and MP1, MP2 Conclusions Thiopental at the dose maintaining EEG burst suppressioncan can reduce the brain injury induced with ischemia and reperfusion, with the better protective effects following the prophylactic administration Propofol at that dose can not improve the cerebral ischemic reperfusion injury
ABSTRACT
This study was performed for the output of nitrous oxide (N_2O) after N_2O cessation. The breathing bag with the volume of 3000 ml served as the simulator lung,and 5 patients, ASA grade Ⅰ,aged 18-48 years scheduled for elective surgery,acted as the clinical subiects. After the equilibration of end-expiratory N_2O concentration of 50% was developed,the N_2O administration was cut off,then was expelled with oxygen flow rate at 3L/min or 6L/min. The inspiration-expiration N_2O concentration difference of simulator or patient lung (SC_(I-E) N_2O or PC_(I-E) N_2O)was recorded with an infra-red gas analyser. The N_2O dilution induced by the anesthesia circuit volume and the functional residual capacity, was similar to that by simulator lung,so the clinical output of N_2O in one minute was calculated as followed: N_2O output=(PC_(I-E) N_2O-SC_(I-E) N_2O)?minute volume of ventilation. The results showed that in the first minute after N_2O termination,there was no N_2O output,but from the second to the tenth minute the N_2O output increased gradually and was kept at the high level,additionally,the levels of N_2O output at the oxygen flow rate of 6L/min were higher than those at 3L/min in the corresponding times, respectively. It is suggested that following the withdrawal of 1:1 N_2O-O_2 anesthesia ,the N_2O output is related to the oxygen flow rate,and there is not the occurance of diffusion hypoxia.
ABSTRACT
Objective To evaluate the influence of propofol on the permeability of the blood brain barrier(BBB) in adult and aged rats.Methods Aged or adult rats were given two doses propofol in 1 hour,respectively.BBB permeability was examined by optical microscopy,electromicroscopy and Evans blue(EB) staining.Results (1)Brain EB staining was not seen in aged or adult groups that at either dose of propofol.(2)In all groups of aged and adult rats,the structure of the blood vessels was normal and lanthanum was not seen outside the blood vessels.(3)There were no significant changes in the central nervous system under microscope or electromicroscope in any groups.Conclusions Propofol at the two doses has no significant effect on BBB permeability or on the central nervous system morphology in aged and adult rats.
ABSTRACT
To observe the influence of different concentrations of sevoflurane on blood brain barrier permeability in rats, thirty adult male SD rats were randomly divided into three groups: control group (without general anesthetics), 1 MAC sevoflurane and 1.5 MAC sevoflurane groups (maintaining end expiratory concentration to 2.2% and 3.3% respectively for 1 hour). Before the end of the experiment, 2% Evans′ blue dye (EB, 3ml/kg) was intravenously injected. The range and areas of EB staining on the surface and standardized serial coronal section of the brain were assessed. The brain was also observed under the light microscope and electron microscope. The results indicated that sevoflurane at both concentrations did not increase the permeability of BBB to EB and lanthanum, and there were no significant changes in morphological features of central nervous system after inhalation of sevoflurane.