石河子大学医学院第一附属医院

目的：探讨胸科开胸手术单肺通气定容通气模式下和定压通气模式下PetCO2（呼气末二氧化碳分压）与PaCO2（动脉二氧化 碳分压）的相关性。方法：选择40 例择期左侧开胸手术单肺通气成年患者,ASAⅠ～Ⅱ级,随机分为A组（n=20）采用VCV（容量 控制通气）模式通气、B组（n=20）采用PCV（压力控制通气）模式通气。比较两组各时段的PaCO2和PetCO2的差异及相关性。结 果：经统计学分析,除第一时间点,两组同一时间点的PetCO2比较及PaCO2比较差异均有统计学意义(P＜0.05),A 组PetCO2四个 时间点比较及PaCO2四个时间点比较差异均有有统计学意义(P＜0.001),B组除PetCO2第三与第四个时间点比较差异无统计学 意义外,余PetCO2各时间点相比较及PaCO2各时间点相比较差异均有统计学意义(P<0.05)。单肺通气定压通气模式下PetCO2与 PaCO2在各个时间点的相关系数均大于定容通气模式时。无论是定容还是定压通气模式,单肺通气时间越长,其PetCO2与PaCO2 的相关系数也越小。结论：1.同双肺通气相比,单肺通气时定压通气模式下PaCO2及PetCO2的改变小于定容通气模式时。2.单肺 通气时,定压通气模式下PetCO2与PaCO2的相关性好于定容通气模式时。3.在这两种通气模式下PetCO2与PaCO2的相关性与单 肺通气的时间成反比。     

单肺通气时两种通气模式对PetCO2与PaCO2相关性的影响

目的：探讨胸科开胸手术单肺通气定容通气模式下和定压通气模式下PetC02（呼气末二氧化碳分压）与PaCO2（动脉二氧化碳分压）的相关性。方法：选择40例择期左侧开胸手术单肺通气成年患者,ASAI～II级,随机分为A组（n=20）采用VCV（容量控制通气）模式通气、B组（n=20）采用PCV（压力控制通气）模式通气。比较两组各时段的PaCO2和PetCO2的差异及相关性。结果：经统计学分析,除第一时间点,两组同一时间点的PetC02比较及PaCO2比较差异均有统计学意义（P〈O．05）,A组PetC02四个时间点比较及PaCO2四个时间点比较差异均有有统计学意义（P〈0．001）,B组除PetCO2第三与第四个时间点比较差异无统计学意义外,余PetCO2各时间点相比较及PaCO2各时间点相比较差异均有统计学意义（P〈0．05）。单肺通气定压通气模式下PetCO2与PaCO2在各个时间点的相关系数均大于定容通气模式时。无论是定容还是定压通气模式,单肺通气时间越长,其PetCO2与PaCOz的相关系数也越小。结论：1．同双肺通气相比,单肺通气时定压通气模式下PaCO2及PetCO2的改变小于定容通气模式时。2．单肺通气时,定压通气模式下PetCO2与PaCO2的相关性好于定容通气模式时。3．在这两种通气模式下PetCO2与PaCO2的相关性与单肺通气的时间成反比。     

A novel approach for using dielectric spectroscopy to predict viable cell volume (VCV) in early process development

Online monitoring of viable cell volume (VCV) is essential to the development, monitoring, and control of bioprocesses. The commercial availability of steam‐sterilizable dielectric‐spectroscopy probes has enabled successful adoption of this technology as a key noninvasive method to measure VCV for cell‐culture processes. Technological challenges still exist, however. For some cell lines, the technique's accuracy in predicting the VCV from probe‐permittivity measurements declines as the viability of the cell culture decreases. To investigate the cause of this decrease in accuracy, divergences in predicted vs. actual VCV measurements were directly related to the shape of dielectric frequency scans collected during a cell culture. The changes in the shape of the beta dispersion, which are associated with changes in cell state, are quantified by applying a novel “area ratio” (AR) metric to frequency‐scanning data from the dielectric‐spectroscopy probes. The AR metric is then used to relate the shape of the beta dispersion to single‐frequency permittivity measurements to accurately predict the offline VCV throughout an entire fed‐batch run, regardless of cell state. This work demonstrates the possible feasibility of quantifying the shape of the beta dispersion, determined from frequency‐scanning data, for enhanced measurement of VCV in mammalian cell cultures by applying a novel shape‐characterization technique. In addition, this work demonstrates the utility of using changes in the shape of the beta dispersion to quantify cell health. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 30:479–487, 2014