Objective To evaluate systematically the effect of ventilator circuit changes on incidence of ventilator-associated pneumonia(VAP).Methods Literatures about the effect of ventilator circuit changes on occurrence of VAP were searched from PubMed,Cochrane Library,CNKI,VIP,and Wanfang database,incidence of VAP in pa-tients who received circuit changes at different intervals was compared,odds ratio (OR)and 95%CI were as effect index of the study,RevMan 5.2 software was used for data analysis.Results A total of 12 literatures were included,including 18003 patients using ventilators.According to the interval of ventilator circuit changes,patients were divided into 1-day group (n=191),2-day group(n=8932),3-day group(n=228),and 7-day group(n=8652).Meta analysis showed that circuit changed every 7 days had a lower risk of VAP than that changed once ev-ery day (OR,3.72[95%CI,1.50,9.23]),there was no significant difference in risk of VAP between 7-day group and 2-day group (OR,1.17[95%CI,1.00,1.37])as well as 7-day group and 3-day group(OR,0.77 [95%CI, 0.49,1 .23]).Conclusion Patients who received circuit changes every 7 days have a lower risk of developing VAP than those who received circuit changes once per day,so change the ventilator circuit in patients with mechanical ventilation every 7 days is more reasonable.

Objective To investigate the effects of dexmedetomidine on the end-tidal concentration of sevoflurane during recovery from breast cancer surgery under general anaesthesia. Methods A total of 120 patients undergoing unilateral breast cancer radical operation were randomly divided into four groups:group C (infusion of saline, n=30), group D0.5 [infusion of dexmedetomidine 0.5μg/(kg·h) during operation, n=30], group D0.6 [dexmedetomidine 0.6μg/(kg·h), n=30] and group D0.7 [dexmedetomidine 0.7 μg/(kg · h), n=30]. The end-tidal concentrations of sevoflurane during surgery and postoperation were observed. The end-tidal concentration of sevoflurane on palinesthesia was recorded. The time from stopping administration of anesthetic drug to palinesthesia and the operation time were recorded. The palinesthesia of patients from general anaesthesia and the degree of emergence agitation of the patient were measured using Riker ’s sedation-agitation scale. The operation time, anesthesia time, intraoperative remifentanil dosage, intraoperative auditory evoked potential index (AAI), sevoflurane inhalation concentration and the corresponding time were recorded. Results There were no significant differences in clinical data, remifentanil dosage, operation time and AAI between four groups. The anesthesia time was longer in group D0.7 than that in the other three groups (P<0.05). Compared to group C, the end-tidal concentration of sevoflurane during surgery, postoperation and palinesthesia were lower and the time of palinesthesia was delayed in groups D0.5, D0.6 and D0.7 (P<0.05). And the time of palinesthesia was delayed in group D0.7 than that of group D0.5 and group D0.6. Compared with group C, the ratio of Riker’s sedation-agitation scale>7 was lower in groups D0.5, D0.6 and D0.7 (P<0.05). The ratio of Riker’s sedation-agitation scale>4 was significantly higher in group D0.6 and group D0.7 than that in group C and group D0.5, but the ratio of score>6 was lower (P<0.05). The ratio of score>3 was higher in group D0.7 than that of other three groups (P<0.05). Intraoperative cardiac tachycardia was found in group D0.6 and group D0.7 (4 cases, 13%and 8cases, 7%). Conclusion Sevoflurane inhalation anesthesia and intravenous infusion of dexmedetomidine 0.6μg/(kg·h) can effectively reduce intraoperative sevoflurane dosage, the end-tidal concentration of sevoflurane during recovery, and the occurrence of agitation in patients undergoing general anesthesia.

Objective To observe the minimum effective local anesthetic dose of intra-articular ropivacaine with dexmedetomidine for analgesia after knee arthroscopy in patients.Methods Seventy-two patients (35 males,37 females,aged 60-75 years,ASA grade Ⅰ or Ⅱ)undergoing knee arthro-scopy under total intravenous anesthesia were randomly divided into two groups (n =36 each):ropiv-acaine group (group R)and ropivacaine with dexmedetomidine group (group DR);Ropivacaine was injected intra-articularly in group C,and dexmedetomidine 1 μg/kg with ropivacaine was injected intra-articularly in group DR.ED50 of ropivacaine was determined by the sequence method.VAS score3 two hours after operation was rated as effective.The initial dose was 3 mg and according to the effective or ineffective results in previous patient,a dose of ropivacaine was decreased or increased 1.1 times to the previous patient.BP,HR,VAS Score,and OAA/S score were recorded five minutes preoperatively(T0 ),1 h (T1 ),2 h (T2 ),3 h (T3 ),6 h (T4 ),12 h (T5 ),24 h (T6 ),and 48 h (T7 ) after operation in two groups.Results There was no significant difference between the two groups with regard to the BP,HR,VAS Score,and OAA/S score.ED50 of ropivacaine for analgesia after knee arthroscopy was 0.31% (95%CI 0.30%-0.32%),and ED50 of ropivacaine with dexmedetomi-dine for analgesia after knee arthroscopy was 0.14% (95% CI 0.14%-0.1 5%). Conclusion Intra-articular administration of ropivacaine with dexmedetomidine could provide superior postoperative analgesia.The dose of ropivacaine for analgesia after knee arthroscopy should be reduced when combined with dexmedetomidine in patients.

Objective In order to lay the foundation for establishment of a clean grade Meriones meridianus popu-lation, and provide reference for the formulation of Meriones meridianus parasite detection standard.Methods A survey of parasite infection in Meriones meridianus was carried out, and three kinds of antiparasitic drugs, tetramethrin/per-methrin, praziquantel, and tinidazole were used in high-, medium-and low-doses for eradication of the target parasites. Results Three types of parasites were detected among the animals.The infection rate of surface parasite Myobia musculi was 82.1%(23/28), that of intestinal parasite Hymenolepis nana was 78.1% (25/32) and Tritrichomonas muris was 90.6%(29/32).Significant results of parasite eradication were achieved with the antiparasitic drugs.Medicated bath u-sing 1%tetramethrin/permethrin for 30 s every 4 days for 5 times and 1.5%tetramethrin/permethrin for 30 s every 4 days for 3 times completely eradicated the surface Myobia musculi infection.Praziquantel in a dose of 31 mg/kg by daily gastric gavage for consecutive 7 days was the optimal dosage to completely eradicate the intestinal Hymenolepis nana.Tinidazole in a dose of 42 mg/kg administered by gastric gavage daily for consecutive 7 days was the optimal dosage for eradication of in-testinal Tritrichomonas muris infection.Conclusions Three types of parasites are detected in Meriones meridianus in our laboratory, i.e.surface infection with Myobia musculi, and intestinal infection with Tritrichomonas muris and Hymenolepis nana.Tetramethrin/permethrin, praziquantel and tinidazole can be used to effectively eradicate these three types of para-sites, respectively.

Objective:To evaluate the effect of melatonin on prefrontal cortex ischemia-induced cognitive impairment in rats and to investigate the receptor mechanism.Methods:Clean-grade adult male Sprague-Dawley rats, weighing 300 g, were selected, and a catheter was implanted into the prefrontal cortex.The experiment was performed in two parts.Experiment Ⅰ Twenty-four rats, in which catheters were successfully inserted into the prefrontal cortex, were assigned into 3 groups ( n=8 each) using a random number table method: control group (group C), model group (group M) and melatonin group (group ME). Normal saline 0.5 μl was injected into the prefrontal cortex in group C, 1 μmol/L endothelin 0.5 μl was microinjected into the prefrontal cortex in group M, and 1 μmol/L endothelin and 1 μmol/L melatonin 0.5 μl were injected into the prefrontal cortex in group ME.Experiment Ⅱ Forty-four rats, in which catheters were successfully inserted into the prefrontal cortex, were assigned into 4 groups ( n=11 each) using a random number table method: model group (group M), melatonin group (group ME), MT 1/2R antagonist luzindole + melatonin group (group L + ME) and MT 2R antagonist 4p-pdot + melatonin group (group P + ME). In group M, 1 μmol/l endothelin 0.5 μl was microinjected into the prefrontal cortex.In group ME, 1 μmol/L endothelin + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.In group L + ME, 1 μmol/L endothelin + 1 μmol/L MT 1/2R antagonist + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.In group P + ME, 1 μmol/L endothelin + 1 μmol/L MT 2R antagonist + 1 μmol/L melatonin 0.5 μl was injected into the prefrontal cortex.T-maze and the open field tests were performed at 1 week after administration. Results:Experiment Ⅰ There was no significant difference in the locomotor speed in open field test among C, M and ME groups ( P>0.05). The rate of correct selection in T-maze test was significantly lower in M and ME groups than in group C and higher in group ME than in group M( P<0.05). Experiment Ⅱ There was no significant difference in the locomotor speed in open field test among the four groups( P>0.05). Compared with group M, the rate of correct selection in open field test was significantly increased in ME and P+ ME groups ( P<0.05), and no significant change was found in group L+ ME ( P>0.05). Compared with group ME, the rate of correct selection in open field test was significantly decreased in group L+ ME ( P<0.05), and no significant change was found in group P+ ME( P>0.05). Conclusion:Melatonin can attenuate prefrontal cortex ischemia-induced cognitive impairment in the rats, and the mechanism is related to activation of MT 1R.

Objective To investigate the capability for distinguishing between the morphology of Oncomelania hupensis and Tricula snails and its influencing factors among schistosomiasis control professionals in Yunnan Province, so as to evaluate the interference of Tricula snails with O. hupensis surveys. Methods O. hupensis and Tricula snails were sampled from 9 schistosomiasis-endemic counties (districts) in Yunnan Province. The capability for distinguishing between O. hupensis and Tricula snails was evaluated using online questionnaire surveys and field blind tests among schistosomiasis control professionals, and the proportions of correct judgment, misjudgment and missed judgment were calculated. Univariate and multivariate logistic regression models were created using the software SPSS 25.0, and factors affecting the proportion of correct judgments of O. hupensis snails were identified among schistosomiasis control professionals. Results Questionnaire surveys and field blind tests showed that the overall proportions of correct judgments of O. hupensis snails were 56.77% (2 305/4 060) and 68.28% (1 556/2 279) among schistosomiasis control professionals in Yunnan Province, respectively. Univariate logistic regression analysis of online questionnaire surveys identified gender [odds ratio (OR) = 1.244, 95% confidential interval (CI): (1.073, 1.441), P < 0.05], professional title [OR = 0.628, 1.741, 95% CI: (0.453, 0.871), (1.109, 2.734), both P < 0.05], working duration [OR = 0.979, 95% CI: (0.971, 0.987), P < 0.05] and classification of schistosomiasis epidemics in endemic foci [OR = 1.410, 0.293, 0.523, 95% CI: (1.103, 1.804), (0.237, 0.361), (0.416, 0.657), all P < 0.05] as factors affecting the proportion of correct judgments of O. hupensis snails among schistosomiasis control professionals in Yunnan Province, and multivariate logistic regression analysis after adjustments showed that the proportion of O. hupensis snail misjudgments was 1.179 times higher among male schistosomiasis control professionals than among females [OR = 1.179, 95% CI: (1.006, 1.382), P < 0.05], and 1.474 times higher among schistosomiasis control professionals in schistosomiasis-elimination areas with snails than in areas without snails [OR = 1.474, 95% CI: (1.145, 1.898), P < 0.05], and the proportions of missed judgments of O. hupensis snails were 0.284 [OR = 0.284, 95% CI: (0.225, 0.359), P < 0.05] and 0.523 times [OR = 0.523, 95% CI: (0.412, 0.664), P < 0.05] higher among schistosomiasis control professionals in transmission-interruption areas with snails and schistosomiasis-elimination areas with snails than in schistosomiasis-elimination areas without snails. Univariate logistic regression analysis of field blind tests showed age [OR = 2.381, 95% CI: (1.677, 3.381), P < 0.05], professional title [OR = 1.688, 95% CI: (1.103, 2.582), P < 0.05］, working duration [OR = 0.970, 95% CI: (0.956, 0.984), P < 0.05] and classification of schistosomiasis epidemics in endemic foci [OR = 0.262, 0.593, 95% CI: (0.188, 0.364), (0.420, 0.837), both P < 0.05] as factors affecting the proportion of correct judgments of O. hupensis snails among schistosomiasis control professionals in Yunnan Province, and multivariate logistic regression analysis after adjustments showed the proportions of missed judgments of O. hupensis snails were 0.263 [OR = 0.263, 95% CI: (0.176, 0.394), P < 0.05] and 0.604 times [OR = 0.604, 95% CI: (0.416, 0.875), P < 0.05] higher among schistosomiasis control professionals in transmission-interruption areas with snails and schistosomiasis-elimination areas with snails than in schistosomiasis-elimination areas without snails. Conclusions Schistosomiasis control professionals in Yunnan Province have a low accuracy rate for distinguishing between the morphology of O. hupensis and Tricula snails, and gender and classification of schistosomiasis epidemics in endemic foci are factors that affect their ability to distinguish. The presence of Tricula snails causes a high degree of interference with O. hupensis surveys in O. hupensis snail-infested areas of Yunnan Province. Reinforced training for distinguishing between O. hupensis and Tricula snails is required among schistosomiasis control professionals in Yunnan Province.

Objective To predict the potential geographic distribution of Oncomelania hupensis in Yunnan Province using random forest (RF) and maximum entropy (MaxEnt) models, so as to provide insights into O. hupensis surveillance and control in Yunnan Province. Methods The O. hupensis snail survey data in Yunnan Province from 2015 to 2016 were collected and converted into O. hupensis snail distribution site data. Data of 22 environmental variables in Yunnan Province were collected, including twelve climate variables (annual potential evapotranspiration, annual mean ground surface temperature, annual precipitation, annual mean air pressure, annual mean relative humidity, annual sunshine duration, annual mean air temperature, annual mean wind speed, ≥ 0 ℃ annual accumulated temperature, ≥ 10 ℃ annual accumulated temperature, aridity and index of moisture), eight geographical variables (normalized difference vegetation index, landform type, land use type, altitude, soil type, soil textureclay content, soil texture-sand content and soil texture-silt content) and two population and economic variables (gross domestic product and population). Variables were screened with Pearson correlation test and variance inflation factor (VIF) test. The RF and MaxEnt models and the ensemble model were created using the biomod2 package of the software R 4.2.1, and the potential distribution of O. hupensis snails after 2016 was predicted in Yunnan Province. The predictive effects of models were evaluated through cross-validation and independent tests, and the area under the receiver operating characteristic curve (AUC), true skill statistics (TSS) and Kappa statistics were used for model evaluation. In addition, the importance of environmental variables was analyzed, the contribution of environmental variables output by the models with AUC values of > 0.950 and TSS values of > 0.850 were selected for normalization processing, and the importance percentage of environmental variables was obtained to analyze the importance of environmental variables. Results Data of 148 O. hupensis snail distribution sites and 15 environmental variables were included in training sets of RF and MaxEnt models, and both RF and MaxEnt models had high predictive performance, with both mean AUC values of > 0.900 and all mean TSS values and Kappa values of > 0.800, and significant differences in the AUC (t = 19.862, P < 0.05), TSS (t = 10.140, P < 0.05) and Kappa values (t = 10.237, P < 0.05) between two models. The AUC, TSS and Kappa values of the ensemble model were 0.996, 0.954 and 0.920, respectively. Independent data verification showed that the AUC, TSS and Kappa values of the RF model and the ensemble model were all 1, which still showed high performance in unknown data modeling, and the MaxEnt model showed poor performance, with TSS and Kappa values of 0 for 24%(24/100) of the modeling results. The modeling results of 79 RF models, 38 MaxEnt models and their ensemble models with AUC values of > 0.950 and TSS values of > 0.850 were included in the evaluation of importance of environmental variables. The importance of annual sunshine duration (SSD) was 32.989%, 37.847% and 46.315% in the RF model, the MaxEnt model and their ensemble model, while the importance of annual mean relative humidity (RHU) was 30.947%, 15.921% and 28.121%, respectively. Important environment variables were concentrated in modeling results of the RF model, dispersed in modeling results of the MaxEnt model, and most concentrated in modeling results of the ensemble model. The potential distribution of O. hupensis snails after 2016 was predicted to be relatively concentrated in Yunnan Province by the RF model and relatively large by the MaxEnt model, and the distribution of O. hupensis snails predicted by the ensemble model was mostly the joint distribution of O. hupensis snails predicted by RF and MaxEnt models. Conclusions Both RF and MaxEnt models are effective to predict the potential distribution of O. hupensis snails in Yunnan Province, which facilitates targeted O. hupensis snail control.