简介:摘 要:饱和蒸汽在管道内长距离输送过程中,蒸汽压力、温度不断降低,且不断有凝结水产生,造成终点蒸汽品质降低和蒸汽量的损失。结合相关设计经验,给出了饱和蒸汽管道水力和热力计算的主要内容和方法,包括蒸汽压降、保温、疏水量计算等。
简介:摘要目的探讨肾氧饱和度(RrSO2)和腹部局部氧饱和度(A-rSO2)在婴幼儿心脏手术中的变化规律和临床应用价值。方法随机连续选取2019年4-8月河南省人民医院儿童心脏中心体外循环(CPB)下行房间隔缺损和/或室间隔缺损修补的患儿30例,男15例,女15例,年龄2~13个月,体质量4.5~10.0 kg,美国麻醉医师协会(ASA)分级Ⅰ~Ⅲ级。应用近红外线分光仪的探头分别固定于患儿右肾体表定位处和肚脐下方1 cm,术中持续监测患儿RrSO2和A-rSO2。分别记录麻醉诱导后(T0),体外循环开始即刻(T1),阻断升主动脉后5 min(T2),体温最低时(T3),开放升主动脉后5 min(T4),停机后5 min(T5)的RrSO2、A-rSO2、平均动脉压(MAP)、鼻咽温等参数的变化。记录术中CPB时间、升主动脉阻断时间、手术时间等相关情况。记录围术期(术后)急性肾损伤(AKI)、胃肠道功能障碍等并发症发生情况。记录术后首次开始进食时间等相关情况。结果本研究共纳入30例患儿,患儿RrSO2和A-rSO2基础值分别为(70.00±7.50)%、(70.70±11.29)%。与T0比较,患儿RrSO2和A-rSO2在T1时下降,在T2、T3、T4时逐渐升高,在T5时恢复至T0水平。患儿RrSO2和A-rSO2在T0、T1、T2、T3、T4差异无统计学意义。Pearson相关分析显示患儿A-rSO2与RrSO2呈正相关(r=0.806,P<0.01),RrSO2和A-rSO2均与MAP呈正相关(r=0.565、0.605,均P<0.05),与鼻咽温均呈负相关(r=-0.365、-0.331,均P<0.05)。其中,术后发生AKI患儿3例,AKI总体发生率10%(3/30例)。与T0比较,患儿RrSO2值在T1、T2、T3、T4时明显降低(P<0.05)。术后发生胃肠功能滞后患儿6例,胃肠功能滞后总体发生率20%(6/30例)。胃肠功能滞后患儿A-rSO2值在T0~T5明显低于未发生胃功能滞后患儿(P<0.05)。结论作为一种新型无创监测手段,近红外线光谱技术在婴幼儿简单先天性心脏病修补术围术期肾功能和肠道功能的监测方面具有一定的临床指导价值。
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简介:AbstractBackground:Texture analysis (TA) can quantify intra-tumor heterogeneity using standard medical images. The present study aimed to assess the application of positron emission tomography (PET) TA in the differential diagnosis of gastric cancer and gastric lymphoma.Methods:The pre-treatment PET images of 79 patients (45 gastric cancer, 34 gastric lymphoma) between January 2013 and February 2018 were retrospectively reviewed. Standard uptake values (SUVs), first-order texture features, and second-order texture features of the grey-level co-occurrence matrix (GLCM) were analyzed. The differences in features among different groups were analyzed by the two-way Mann-Whitney test, and receiver operating characteristic (ROC) analysis was used to estimate the diagnostic efficacy.Results:InertiaGLCM was significantly lower in gastric cancer than that in gastric lymphoma (4975.61 vs. 11,425.30, z = -3.238, P = 0.001), and it was found to be the most discriminating texture feature in differentiating gastric lymphoma and gastric cancer. The area under the curve (AUC) of inertiaGLCM was higher than the AUCs of SUVmax and SUVmean (0.714 vs. 0.649 and 0.666, respectively). SUVmax and SUVmean were significantly lower in low-grade gastric lymphoma than those in high grade gastric lymphoma (3.30 vs. 11.80, 2.40 vs. 7.50, z = -2.792 and -3.007, P = 0.005 and 0.003, respectively). SUVs and first-order greylevel intensity features were not significantly different between low-grade gastric lymphoma and gastric cancer. EntropyGLCM12 was significantly lower in low-grade gastric lymphoma than that in gastric cancer (6.95 vs. 9.14, z = -2.542, P = 0.011) and had an AUC of 0.770 in the ROC analysis of differentiating low-grade gastric lymphoma and gastric cancer.Conclusions:InertiaGLCM and entropyGLCM were the most discriminating features in differentiating gastric lymphoma from gastric cancer and low-grade gastric lymphoma from gastric cancer, respectively. PET TA can improve the differential diagnosis of gastric neoplasms, especially in tumors with similar degrees of fluorodeoxyglucose uptake.