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Objective To investigate the effect of magnesium sulfate on epidural labor analgesia with ropivacaine in the patients with preeclampsia. Methods Seventy nulliparous parturients with pre?eclampsia, aged 23-34 yr, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, weighing 63-81 kg, with a singleton fetus in vertex presentation, without contradications to neuraxial anesthesia, waiting for vaginal delivery, received epidural analgesia for labor. The patients were divided into magnesi?um sulfate group and control group using a random number table, with 35 patients in each group. In magne?sium sulfate group, magnesium sulfate 50 mg∕kg ( 30 ml) was infused intravenously over 15 min when their cervical dilation was 3 cm, while the equal volume of normal saline was given in control group. Epi?dural labor analgesia was performed with ropivacaine. The up?and?down sequential allocation was used to determine the median effective concentration of epidural ropivacaine ( EC50 ) . The severity of pain was as?sessed with visual analogue scale score. Effective analgesia was defined as visual analogue scale score of≤1. The initial concentration of ropivacaine was 0.15%. Each time the concentration was increased∕decreased according to whether or not analgesia was effective, and the ratio between the two successive concentrations was 0.9. The EC50 and 95% confidence interval ( CI) of ropivacaine for epidural labor analgesia was calcu?lated. Results The EC50 (95% CI) of ropivacaine for epidural labor analgesia was 0.066% (0.062%-0.071%) in magnesium sulfate group. The EC50 (95% CI) of ropivacaine for epidural labor analgesia was 0.078% (0.072%-0.085%) in control group. The EC50 of ropivacaine was significantly lower in magnesi?um sulfate group than in control group ( P<0.05) . Conclusion Magnesium sulfate can enhance the effica?cy of ropivacaine for epidural labor analgesia in the patients with preeclampsia.
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Objective To evaluate the effect of dexmedetomidine administered locally on the median effective concentration ( EC50 ) of ropivacaine for paravertebral nerve block ( PVNB) . Methods Forty?eight ASA physical status Ⅰ or Ⅱ female patients, aged 20-64 yr, with body mass index<24 kg∕m2 , scheduled for elective unilateral segmental mastectomy under PVNB, were randomly divided into 2 groups ( n=24 each) using a random number table: ropivacaine group ( group R) and ropivacaine mixed with dexmedetomidine group ( group RD) . PVNB was performed at T4 on the operated side guided by ultrasound and nerve stimulator. Ropivacaine 20 ml and a mixture of ropivacaine and 20 μg dexmedetomidine 20 ml were injected locally in group R and group RD, respectively. The concentration of ropivacaine was determined by up?and?down sequential allocation. The initial ropivacaine concentration was set at 0. 35%, and the ratio between the two successive concentrations was 1. 2. The EC50 and 95%confidence interval of ropivacaine were calculated using Dixon?Massey method. Results The EC50 ( 95%confidence interval) of ropivacaine was 0.27% (0.23%-0.30%) and 0.22% (0.18%-0.25%) in group R and group RD, respectively. Compared with group R, the EC50 of ropivacaine was significantly decreased by 19% in group RD. Conclusion Small dose of dexmedetomidine administered locally can significantly enhance the efficacy of PVNB with ropivacaine.
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Objective To evaluate the feasibility of using corrected body weight to set the tide volume (VT) for mechanical ventilation during general anesthesia in obese patients.Methods Sixty ASA physical status Ⅰ or Ⅱ obese patients,with a body mass index of 28-44 kg/m2,scheduled for elective extremity surgery under general anesthesia,were randomly divided into 3 groups (n =20 each):VT based on actual body weight group (group A),VT based on ideal body weight group (group Ⅰ),and VT based on corrected body weight group (group C).The pulmonary function of all patients was normal.The patients were endotracheally intubated and mechanically ventilated after induction of anesthesia.According to the corresponding body weight,the initial VT was set based on 8 ml/kg in each group (RR 15 bpm,I ∶ E =1 ∶ 2,FiO2 =100％).At 10 min after start of mechanical ventilation,peak airway pressure (Ppeak),airway plateau pressure (Pplat),airwayresistance (Raw) were recorded.Arterial blood samples were collected at 30 min of mechanical ventilation for blood gas analysis and PaO2,PaCO2 and the patients requiring readjustment of VT (PaCO2 ＞ 45 mm Hg or ＜ 35 mm Hg) were also recorded.Results Compared with group A,PaCO2 was significantly increased and Ppeak,Pplat and Raw were decreased in I and C groups (P ＜ 0.01).PaCO2 was significantly lower and Ppeak,Pplat and Raw were higher in group C than in group Ⅰ(P ＜ 0.01 or 0.05).There were no patients requiring readjustment of VT in group C,however,95％ patients required readjustment of V+ in group A and 80％ in group B.The percentage of patients requiring readjustment of VT was significantly higher in A and B groups than in group C (P ＜ 0.01).Conclusion Corrected body weight based on 8 ml/kg can be used to set the Vr for mechanical ventilation during general anesthesia in obese patients with normal pulmonary function.
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Human errors are errors found in planning or implementation, and those found in medical practice are often major causes of mishaps.To name a few, wrong-site surgery, medication error, wrong treatment, and inadvertent equipment operation.Errors of this category can be prevented by learning from experiences and achievement worldwide.Preventive measures include those taken in human aspect and system aspect, reinforced education and training, process optimization, and hardware redesign.These measures can be aided by multiple safety steps in risky technical operations, in an effort to break the accident chain.For example, pre-operative surgical site marking, multi-department co-operated patient identification, bar-coded medication delivery, read-back during verbal communication, and observation of clinical pathway.Continuous quality improvement may be achieved when both the management and staff see medical errors in the correct sense, and frontline staff are willing to report their errors.
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By inhibiting 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, statins up-regulate the expression and activation of endothelial nitric oxide synthase (eNOS) in brain tissues, increase the levels of serum catalase and plasma nitric oxide, enhance antioxidant capacity, decrease oxygen free radical release, improve immunoreactivities of tight junction (zonula occludens), transmembrane proteins and glial fibrillary acidic protein of astrocyte. Stains may also exert the effects that is completely unrelated with inhibiting HMG-CoA reductase, e.g. binding to leucocyte function-associated antigen-1(LFA-1) L-site, restraining its interactions between LFA-1 and intercellular adhesion molecule-1 (ICAM-1), and playing anti-inflammation and immunoloregulation roles. The above mechanisms contribute to remain the integrity of blood-brain barrier and the activity of astrocyte under the pathological conditions.