Comparison between mainstream (Capnostat 5) and a low-flow sidestream capnometer (Capnostream) in mechanically ventilated,sevoflurane-anesthetized rabbits using a Bain coaxial delivery system     

《Veterinary anaesthesia and analgesia》2023,50(1):81-90

ObjectiveTo evaluate agreement between end-tidal carbon dioxide (Pe′CO₂) and PaCO₂ with sidestream and mainstream capnometers in mechanically ventilated anesthetized rabbits, with two ventilatory strategies.Study designProspective experimental study.AnimalsA total of 10 New Zealand White rabbits weighing 3.6 ± 0.3 kg (mean ± standard deviation).MethodsRabbits anesthetized with sevoflurane were intubated with an uncuffed endotracheal tube (3.0 mm internal diameter) and adequate seal. For Pe′CO₂, the sidestream capnometer sampling adapter or the mainstream capnometer was placed between the endotracheal tube and Bain breathing system (1.5 L minute^–1 oxygen). PaCO₂ was obtained from arterial blood collected every 5 minutes. A time-cycled ventilator delivered an inspiratory time of 1 second and 12 or 20 breaths minute^–1. Peak inspiratory pressure was initially set to achieve Pe′CO₂ normocapnia of 35–45 mmHg (4.6–6.0 kPa). A total of five paired Pe′CO₂ and PaCO₂ measurements were obtained with each ventilation mode for each capnometer. Anesthetic episodes were separated by 7 days. Agreement was assessed using Bland-Altman analysis and linear mixed models; p < 0.05.ResultsThere were 90 and 83 pairs for the mainstream and sidestream capnometers, respectively. The mainstream capnometer underestimated PaCO₂ by 12.6 ± 2.9 mmHg (proportional bias 0.44 ± 0.06 mmHg per 1 mmHg PaCO₂ increase). With the sidestream capnometer, ventilation mode had a significant effect on Pe′CO₂. At 12 breaths minute^–1, Pe′CO₂ underestimated PaCO₂ by 23.9 ± 8.2 mmHg (proportional bias: 0.81 ± 0.18 mmHg per 1 mmHg PaCO₂ increase). At 20 breaths minute^–1, Pe′CO₂ underestimated PaCO₂ by 38.8 ± 5.0 mmHg (proportional bias 1.13 ± 0.10 mmHg per 1 mmHg PaCO₂ increase).Conclusions and clinical relevanceBoth capnometers underestimated PaCO₂. The sidestream capnometer underestimated PaCO₂ more than the mainstream capnometer, and was affected by ventilation mode.  相似文献   

The effect of remifentanil infusion on sevoflurane minimum alveolar concentration–no movement (MACNM) and bispectral index in dogs     

《Veterinary anaesthesia and analgesia》2023,50(2):121-128

ObjectiveTo determine the effect of remifentanil infusion on the minimum alveolar concentration of sevoflurane preventing movement (SEVOMAC_NM) and bispectral index (BIS) in dogs.Study designProspective, unmasked study.AnimalsA total of 10 adult Beagle dogs weighing 9.0 ± 1.1 kg.MethodsDogs were anesthetized with sevoflurane and baseline SEVOMAC_NM was determined. Remifentanil was infused at 5, 10 and 20 μg kg^–1 hour^–1, in sequence, with 20 minutes washout between infusions. Variables monitored throughout anesthesia included heart rate (HR), oscillometric blood pressure, end-tidal partial pressure of carbon dioxide, end-tidal sevoflurane concentration (Fe′Sevo) and BIS. SEVOMAC_NM after remifentanil infusion (SEVOMAC_NM-REMI) determination started 20 minutes after the start of each infusion. Venous blood samples were collected for plasma remifentanil concentration determination at baseline, SEVOMAC_NM-REMI determination time points, and 20 minutes after each infusion was stopped. A mixed model analysis was used to determine the effect of remifentanil infusion on response variables. The relationships between BIS and Fe′Sevo, plasma remifentanil concentrations and the percentage decrease in baseline SEVOMAC_NM were evaluated (p < 0.05).ResultsThe overall SEVOMAC_NM at baseline was 2.47 ± 0.11%. Addition of remifentanil at all infusion rates significantly decreased SEVOMAC_NM, but the medium and high doses resulted in significantly greater decreases in SEVOMAC_NM than the lower dose. There was no difference in SEVOMAC_NM percentage change between infusions 10 and 20 μg kg^–1 hour^–1. Plasma remifentanil concentrations were significantly different in all infusion rates. Baseline BIS value was 70 ± 1 and was lower than the BIS values recorded during all remifentanil infusions. BIS values were not significantly different among infusion rates. HR was lower and mean arterial pressure was higher during remifentanil infusions than at baseline.Conclusions and clinical relevanceAll remifentanil infusions decreased SEVOMAC_NM in dogs. Remifentanil infusion at any rate studied did not reduce BIS values.  相似文献   

CO2-O2混合喷吹对铁液中C、V元素氧化的影响     

文钢  王雨  堵伟桐 《保鲜与加工》2015,(5):66-72

为了验证用CO2替代部分O2进行转炉氧化提钒的可行性,在实验室进行了CO2-O2混合喷吹提钒模拟实验。结果显示C的氧化量与C的氧化速率随CO2含量的增加而升高;V的氧化量随CO2含量的增加而降低,其中CO2含量为20%与纯O2对C、V的氧化量接近;纯O2喷吹时C的氧化量为34.56%,V的氧化量为96.85%;CO2含量为20%混合气体喷吹时C的氧化量为36.83%,V的氧化量为93.29%;以V的相对氧化量与C的相对氧化量的比值(ΔV/ΔC)来衡量提钒保碳能力,CO2含量为20%的最终ΔV/ΔC为5.96,CO2含量,40%、60%、80%的最终ΔV/ΔC均小于3.8;反应前期,V的氧化速率随CO2含量的增加而升高,反应后期V的氧化速率随CO2含量的增加而降低。  相似文献   

THE INDUSTRIAL ORGANIZATIONS AND THE L-S-BUSINESS STRATEGIES     

He Zonglu 《保鲜与加工》1992,(4):111-117

This papar presents an evolution model in business behaviors-the L-S Business Strategies,gives some examples and predictions which support these strategies,and analyzes the relationship between the industrial organizations in China and the L-S Business strategies.  相似文献   

高氨氮厌氧消化液后处理技术研究   总被引：2，自引：0，他引：2  

宋国梁  邓良伟 《中国沼气》2007,25(2):7-10

采用SBR-絮凝沉淀-Fenton氧化-活性炭吸附组合工艺对高氨氮厌氧消化液的后处理进行实验研究.结果表明,当进水COD浓度为4516 mg·L^-1时,SBR出水COD可降为1752 mg·L^-1,去除率达到61.2%;絮凝沉淀出水COD浓度为1189 mg·L^-1,去除率为32.1%;Fenton氧化和活性炭吸附出水COD浓度分别为452和216 mg·L^-1,去除率分别为61.7%和52.7%.当进水NH3-N浓度2162 mg·L^-1时,SBR出水NH3-N浓度降至13.8 mg·L^-1,去除率为99.4%,NH3-N主要在该段去除.整个组合工艺对COD和NH3-N的去除率分别达到95.2%和99.9%,达到了很好的有机物和氨氮去除效果,在技术上是可行的.  相似文献   

柴油机燃用菜籽油的耐久性试验研究     

叶丽华  施爱平  张春丰 《农机化研究》2007,(11):205-207

柴油机燃用菜籽油植物油的短期耐久试验证明了植物油可作为一种代用燃料,但同时也暴露出了一系列的问题.试验后观察试验柴油机的主要零部件可看到:燃烧室的表面有大量的积碳、喷油器结焦、气门黏滞、缸套轻微刮伤等现象.这导致了柴油机性能的下降、油耗的升高和经济性的下降.其中,喷油器结焦和气门黏滞是性能下降的主要原因.  相似文献   

Can carbon sequestration markets benefit low-income producers in semi-arid Africa? Potentials and challenges   总被引：1，自引：0，他引：1  

Carlos Perez  Carla Roncoli  Constance Neely  Jean L. Steiner 《Agricultural Systems》2007

The Clean Development Mechanism (CDM) of the Kyoto Protocol of the United Nations Framework Convention on Climate Change allows a country that emits C above agreed-upon limits to purchase C offsets from an entity that uses biological means to absorb or reduce greenhouse emissions. The CDM is currently offered for afforestation and reforestation projects, but may apply subsequently to sequestration in agricultural soils. Additionally, markets outside of the Protocol are developing for soil C sequestration.  相似文献   

高浓度城市污水处理正交试验研究     

刘畅  程晓如  郑旭荣  龚兵  曾勇 《中国农村水利水电》2004,(6):34-36

针对新疆石河子市城市污水CODcr高于1000mg／L的特点，采用SBR工艺进行处理试验，并用正交试验的方法对最佳工艺条件进行了探讨。试验表明，该工艺对高浓度城市污水有较好的处理效果。通过控制运行条件，可使出水各项指标分别满足污水综合排放标准和农业灌溉的要求。  相似文献   

基于计算机视觉系统的溶液浓度快速检测方法     

赵海燕  贾贵儒  侯彩云 《农机化研究》2006,(12):136-138

基于计算机视觉系统的RGB色度学理论,提出一种测定有色溶液浓度的数字色度法,并开发了与之配套的软件检测系统。该方法与分光光度计相比,大大提高了检测效率,理论上每分钟可完成上百个样品浓度的同时测定。通过软件系统分析样品色度信息,实现自动显示被测溶液浓度的良好效果,为一次性成批检测溶液浓度提供了一种简捷快速的新思路。  相似文献   

宁夏荒漠草原不同土地利用方式对土壤活性有机碳的影响     

李学斌  李月飞  陈林  苏莹  祝忠有 《北方园艺》2021,(1):91-99

以宁夏荒漠草原不同土地利用方式(耕地、弃耕地、草地和柠条地)的土壤为研究对象,测定了不同土层土壤有机碳和活性有机碳含量,分析了土壤活性有机碳占有机碳的比例,以期探寻不同土地利用方式对土壤活性有机碳的影响。结果表明:不同土地利用方式土壤总有机碳含量范围在1.78~6.17 g·kg^-1,具体表现为弃耕地>柠条地>草地>耕地。表层(0~5 cm)土壤有机碳含量显著高于深层(10~60 cm),说明荒漠草原土壤有机碳主要富集在表层;4种土地利用方式土壤易氧化有机碳含量为0.57~1.38 mg·g^-1,变化趋势具体表现为柠条地>草地>耕地>弃耕地,且柠条地在每个土层都高于其它3种土地利用方式;土壤可溶性有机碳含量范围为6.8~11.1 mg·kg^-1,变化趋势表现为草地>耕地>柠条地>弃耕地。土壤易氧化有机碳含量占有机碳的比例范围为13.7%~43.1%,大小排序为柠条地>耕地>草地>弃耕地;土壤可溶性有机碳含量占有机碳的比例范围为0.11%~0.48%,比例大小为耕地>草地>柠条地>弃耕地,耕地和草地中土壤可溶性有机碳含量占有机碳比例随着土壤深度的增加而减小,这与有机碳在耕地和草地中变化趋势一致。土地利用变化可以显著影响土壤活性有机碳的含量与分布,能够敏感的反映土壤碳库的变化,可以作为评价宁夏荒漠草原土壤质量和肥力的指标之一。  相似文献