Objective To evaluate the effect of preloading the epidural space with normal saline (NS) on the incidence of injury to blood vessel by epidural catheter placement for cesarean section. Methods One hundred and fifty parturients with a single baby at full term in vertex presentation scheduled for cesarean section under continuous epidural anesthesia were randomly divided into 3 groups ( n = 50 each): Ⅰ group control; Ⅱ group NS needle attached to a 5 ml syringe. Loss of resistance was used to identify the epidural space. In group Ⅰ no fluid was injected into the epidural space before insertion of catheter; while in group Ⅱ and Ⅲ NS 5 ml with or without whom blood or blood tinted fluid was withdrawn from epidural catheter was recorded. Results The number of patients in whom blood or blood tinted fluid was withdrawn from epidural catheter was significantly lower in group Ⅱand Ⅲ than in group Ⅰ but was not significantly different between group Ⅱ and Ⅲ. Conclusion Preloading the epidural space with 5 ml NS can reduce the incidence of injury to blood vessel induced by insertion of epidural

Objective To evaluate the efficacy of dexmedetomidine mixed with ropivacaine for epidural anesthesia in the patients.Methods Forty-six patients, of ASA physical status Ⅰ or Ⅱ , aged 36-58 yr, weighing 48-77 kg, scheduled for elective hysterectomy under epidural anesthesia, were randomly divided into 2 groups (n =23 each) according to the random number table: normal saline + ropivacaine group (R group) and dexmedetomidine + ropivacaine group (DR group).Epidural anesthesia was performed at L2,3interspace.The catheter was inserted into the epidural space.A mixture of 0.75％ ropivacaine 15 ml and dexmedetomidine 1 μg/kg was injected epidurally in DR group.A mixture of 0.75％ ropivacaine 15 ml and normal sline 2 ml was injected epidurally in R group.The onset time of sensory block, maximum level of sensory block, and duration of sensory block were recorded.The modified Bromage scale, Ramsay sedation score and intraoperative traction reaction were assessed.The occurrence of dexmedetomidine-related cardiovascular events and respiratory depression, and epidural anesthesia-related adverse events within 2 h after operation was recorded.Results Compared with R group, the onset time of sensory block was significantly shortened, the duration of sensory block was prolonged, the maximum level of sensory block and Ramsay sedation score were increased, the degree of intraoperative traction reactions was lessened, and the incidence of shivering was decreased in DR group (P ＜ 0.05).No patients developed dexmedetomidine-related adverse events.Conclusion Epidural dexmedetomidine 1 μg/kg significantly optimize the efficacy of ropivacaine when used for epidural anesthesia in the patients.

Objective To investigate the efficacy and safety of acute normovolemic hemodilu-tion for pregnant women with total placenta pravia and accreta.Methods Fifty-two pregnant women with placenta praevia and accreta were randomly divided into three groups.Groups A and B received ANH or AHH before the operation while group C received the normal treatment.The total blood loss,transfusion of allogeneic blood and preoperative and postoperative routine blood test were recor-ded;the infants’umblical artery blood samples were taken immediately after birth,and 1 min,5 min Apgar scores and the blood gas was analyzied.Results There were no significant difference in the general condition,operation duration,blood loss among the three groups;the transfusion of allogeneic blood in groups B and C were much more than group A (P <0.05);the postoperative hemoglobin and hematocrit and the count of plateletsin in group A were better than groups B and C (P <0.05),while there were no statistically difference between groups B and C;there were not only seldom difference in the Apgar scores of 1 min and 5 min,but also barely change in the blood gas analysis of umbilical ar-tery in new borns from the three groups.Conclusion ANH could play an important role in the pre-vention of postpartum hemorrhage without doing any harm to the mother and infant.

ObjectiveTo evaluate the effect of preloading epidural space with 0.9％ sodium chloride on the incidence of the injury to blood vessel by epidural catheter insertion for cesarean section.Methods One hundred uterogestation patients with single birth,ASA class Ⅰ - Ⅱ,underwent caesarean section and requested continuous epidural analgesia were divided into group P and group C with each 50 cases by random digits table.After identification of the epidural space,group C was inserted epidural catheter directly,and 5 ml of 0.9％ sodium chloride was injected into epidural space through the epidural needle in group P,while the syringe plunger was held closed for 20 s to make sure the solution spreaded sufficiently,following insertion the epidural catheter.Between the two groups,mean arterial pressure and heart rate were recorded prior to anesthesia,2 min after turn to the supine horizontal position after succeeded puncture,the time when the fetus were born and when the surgery were over.The cases with bloody fluid in the epidural puncture needle during puncture,or in the epidural catheter during catheter placement,fresh blood in the epidural catheter,and bloody fluid in caudal end of epidural catheter during extubation were recorded.ResultsThe changes of mean arterial pressure and heart rate were all in the normal range,there was no obvious difference between the two groups.The incidence of rates with bloody fluid in the epidural puncture needle during puncture and the bloody fluid in caudal end of epidural catheter during extubation in group P were significantly lower than those in group C [ 10％ (5/50) vs.26％ (13/50),22％ (11/50) vs.48％ (24/50),P ＜ 0.05 or ＜ 0.01 ].ConclusionPreloading epidural space with 5 ml 0.9％ sodium chloride can reduce the incidence of the injury to blood vessel induced by insertion of epidural catheter.

Objective To determine the optimum dose of normal saline (NS) for preloading epidural space required to prevent the injury to blood vessel by epidural catheter placement for caesarean section.Methods Two hundred ASA Ⅰ or Ⅱ parturients with a single baby at full term in vertex presentation,aged 24-35 yr,weighing 63-78 kg,scheduled for caesarean section under continuous epidural anesthesia,were randomly divided into4 groups (n-50 each):control group (group Ⅰ),NS2 ml group (group Ⅱ),NS5 ml group (group Ⅲ)and NS 10 ml group (group Ⅳ).The epidural puncture was performed at L2-3 interspace with a Tuohy needle attached to a 5 ml syringe.Loss of resistance was used to identify the epidural space.In group C no fluid was injected into the epidural space before insertion of the catheter,while in groups Ⅱ,Ⅲ and Ⅳ NS 2,5 and 10 ml were injected into the epidural space before the catheter insertion respectively.After a test dose of 3 ml 1.5％ lidocaine,0.75％ ropivacaine 10-20 ml was administered through the epidural catheter.MAP and HR were recorded before epidural puncture (T0),at 10 and 20 min after the end of epidural administration (T1.2),and at the end of surgery (T3).The number of patients in whom blood or blood tinted fluid was withdrawn from the epidural catheter was recorded.The amount of ropivacaine consumed was recorded.The upper level of anesthesia was measured by pin-prick and the degree of motor block was assessed using modified Bromagc scale at T2.Results The hemodynamic parameters were in the normal range in the four groups.MAP was significantly lower at T2,the upper level of anesthesia was significantly higher,and the degree of motor block was significantly smaller in group Ⅳ than in groups Ⅰ,Ⅱ and Ⅲ (P ＜ 0.05).There was no significant difference in MAP among groups Ⅰ,Ⅱ and Ⅲ (P ＞ 0.05).There was no significant difference in HR and the amount of ropivacaine consumed among the four groups (P ＞ 0.05).The number of patients in whom blood or blood tinted fluid was withdrawn fiom epidural catheter was significantly smaller in groups Ⅲ and Ⅳ compared with groups Ⅰ and Ⅱ (P ＜ 0.05).Conclusion Preloading the epidural space with NS 5 ml can prevent the occurrence of injury to blood vessel induced by insertion of epidural catheter with no influence on the efficacy of anesthesia and NS 5 ml is the optimum dose.

Objective To evaluate the clinical value and safety of prelocalization with ultrasound during internal jugular vein cannulation. Methods One hundred patients scheduled for internal jugular vein cannulation from February 2009 to April 2010 were divided into two groups by random digits table with 50 cases in each group. Group U patients were performed by ultrasound-prelocalization method and group T patients were performed by traditional technique. The first successful punctures and the first successful catheterization,puncture times,operation time and complications were recorded. Results Compared with group T, puncture times,operation time and complications were lower in group U [(1.0±0.5) times vs.(2.1±1.4) times;(4.5±1.2) min vs.(6.8±1.6) min;0 vs. 12.0%(6/50)](P＜ 0.01 ). The first successful punctures and the first successful catheterization [96.0% (48/50) and 95.8% (46/48)] in group U were obviously higher than those in group T [ 72.0%(36/50) and 77.8% (28/36)] (P ＜ 0.01 ). Two cases were failed in group T. Conclusion Ultrasound-prelocalization technique is simply and practically method for internal jugular vein cannulation under the stable body position.

ObjectiveThe human angiotensin converting enzyme2 （hACE2） transgenic mouse model was used to clarify the antiviral efficacy of BD-77 against a novel coronavirus SARS-CoV-2 and explore the action mechanism of BD-77 against SARS-CoV-2. MethodSARS-CoV-2 Omicron and Delta variant strains-infected VeroE6 cell models were established and administered with BD-77 to observe the antiviral effect of BD-77 in vitro. A kit was used to detect the effect of BD-77 in vitro on the binding of spike S protein of SARS-CoV-2 virus （Delta/Omicron） to angiotensin converting enzyme2 （ACE2）. Chromatography was adopted to detect the binding of BD-77 to the S protein and N protein of the novel coronavirus. hACE2 transgenic C57BL/6 mice were divided into a blank control group， SARS-CoV-2 infection group， BD-77 administration groups of 37.5 mg·kg^-1 and 75 mg·kg^-1， with eight mice in each group. The pneumonia model of SARS-CoV-2-infected hACE2 transgenic mice was built to observe the survival of the mice， detect the virus titer of the lung tissue of the mice， and observe the lesions in the lung tissue. ResultBD-77 had a certain inhibitory effect on Omicron and Delta variant strains in vitro， with median inhibitory concentration （IC₅₀） of 526.3 mg·L^-1 and 653.0 mg·L^-1， respectively. BD-77 had no significant inhibitory effect on the binding of the S protein of WT， Omicron， and Delta variant strains of SARS-CoV-2 to ACE2 and had no binding effect with the S protein and N protein of the novel coronavirus. No mice in the blank group died， while the mortality rate of SARS-CoV-2-infected mice was 75%. There was a large amount of virus replication in the lung tissue of the mice and large areas of inflammatory infiltration in the lung tissue and interstitium. Compared with the model group， BD-77 administration groups of 37.5 mg·kg^-1 and 75 mg·kg^-1 could reduce the mortality of mice， significantly lower the virus titer in the lung tissue of mice （P<0.05）， and improve lung lesions. ConclusionBD-77 demonstrated significant inhibitory effects against SARS-CoV-2 virus in vitro and in vivo. However， its mechanism of action did not involve direct inhibition of the virus itself or intervention in the virus-host binding process. This finding suggests that the mechanism of action of BD-77 needs to be thoroughly investigated and elucidated by further experiments.