Revisiting the use of hydroxyethyl starch solutions in equine fluid therapy

The last decade has led to major shifts in opinions on the use of hydroxyethyl starch (HES) solutions in fluid therapy, specifically in human patients with sepsis. The majority of evidence documenting adverse effects of HES solutions on coagulation and renal health come from studies in people. However, these findings have led to investigation into the safety of HES solutions in veterinary species. While there are now studies investigating the effects of HES solutions on coagulation and renal health in dogs, cats and horses, information regarding long-term follow-up, clinical significance of these changes and use of these solutions in critically ill animals is still lacking. The information presented here serves to review the physiology of oncotic pressure and the rationale behind colloid use, specifically HES solutions. Additionally, the foundation of arguments against the use of HES and the available literature regarding HES use in animals will be summarised.     

青藏高原典型高寒荒漠生长季蒸散及水分消耗特征研究

为探究青藏高原典型高寒荒漠下垫面水分消耗规律,以2019年青藏高原典型高寒荒漠地区沱沱河站监测的涡动数据和微气象数据为基础,分析不同时间尺度蒸散值的变化特征和下垫面水分消耗特征,研究结果表明：小时平均蒸散发量最大值出现在14—15时,达0.46 mm·h^-1;日蒸散值最大值出现在7月7日,为8.58 mm·d^-1,最小值出现在4月2日,为0.30 mm·d^-1;整个生长季蒸散值呈先增加后减小趋势,其中7月份最大,为120.68 mm,4月份最小,为64.80 mm;生长季总蒸散发量为581.15 mm,平均每天蒸散4.01 mm。整个生长季累计降水量为235.70 mm,蒸散发量与降水量（Precipitation,Pr）的差值（The difference between ET and Precipitation,IETP）显示,2019年青藏高原典型高寒荒漠植被生长季（4—8月）水汽交换以下垫面水分消耗为主。     

Quantification of reservoir bags as airway pressure-limiting devices in a nonrebreathing system

ObjectiveTo evaluate the influence of reservoir bag types, volumes and previous use on the peak pressures (Pmax) and the times to develop 30 cmH₂O pressure (P30) within a nonrebreathing system with a closed adjustable pressure-limiting (APL) valve.Study designIn vitro study using three-way factorial design with repeated measure on one factor.SubjectsA total of 75 new anesthesia reservoir bags (five types, three volumes, five bags from each type × volume). The bag types were reusable latex (RL), disposable latex (DL) and three disposable neoprene (DN-1, DN-2 and DN-3).MethodsEach bag was tested three times (treatments): new, after prestretching and 1 week later. The bags were attached to a Bain system and anesthesia machine with closed APL valve and patient port with O₂ flow 2 L minute^–1 until Pmax was reached. The Pmax and time to reach P30 values were determined from recorded pressure traces. General linear mixed model analysis was used to examine the effects of bag type, volume and treatment. One-sided 95% upper prediction limits of Pmax were calculated to test the null hypothesis that predicted Pmax of new bags would be ≥ 50 cmH₂O for each factor combination.ResultsRL bags were the least and DN-3 bags were the most compliant. Prestretching increased compliance in all bag types. Smaller bags of RL, DL and DN-1 were less compliant than larger ones. The predicted Pmax values were < 50 cmH₂O only for DN-3 bags after prestretching. The time to reach P30 was critically low when using 0.5 L bags (median 17 seconds).Conclusions and clinical relevanceTo minimize the risk of barotrauma, highly compliant reservoir bags (e.g. DN-3) are recommended and reusable bags should be avoided. Bags should be prestretched before first use, 0.5 L bags should be avoided and fresh gas flow minimized.     

Evaluation of the agreement of two oscillometric blood pressure devices with invasive blood pressure in anaesthetized chimpanzees (Pan troglodytes)

ObjectiveTo evaluate the agreement of two noninvasive blood pressure devices: a human device with the cuff placed on the wrist (Omron R1) and a veterinary device with the cuff placed on the upper brachium (Surgivet Advisor Vital Signs Monitor) with invasive blood pressure (IBP) measurement in anaesthetized chimpanzees.Study designProspective clinical study.AnimalsA convenience sample of 11 adult chimpanzees undergoing anaesthesia for translocation and routine health checks.MethodsSystolic (SAP) and diastolic arterial pressures (DAP) were continuously recorded via a transducer connected to a femoral artery cannula, and at 5 minute intervals from the two oscillometric devices. Agreement was explored using Bland-Altman analysis and bias defined as the mean difference between the two measurement methods. Spearman correlation coefficients were calculated. Significance was set at p < 0.05.ResultsBias and standard deviation for the Surgivet compared with IBP were 8.6 ± 18 for SAP and 8.4 ± 9.9 for DAP, showing a significant underestimation of both variables. Limits of agreement (LOA) were from –27 to 44 for SAP and from –11 to 28 for DAP. Correlation coefficients between the Surgivet and IBP values were 0.86 for SAP and 0.85 for DAP (p < 0.0001). Bias and standard deviation for the Omron compared with the IBP were –21 ± 25 for SAP and –18 ± 15 for DAP, showing a significant overestimation of both variables. LOA were from –70 to –28 for SAP and from –47 to 11 for DAP. Spearman correlation coefficients between the Omron and IBP values were 0.64 for SAP and 0.72 for DAP (p < 0.0001).Conclusions and clinical relevanceAlthough neither device met all the criteria for device validation, the Surgivet presented better agreement with IBP values than the Omron in adult anaesthetized chimpanzees.     

非充分灌溉条件下水稻生长发育及生理机制研究

本文以水稻非充分灌溉试验的大量实测资料为基础，分析了水分胁迫对水稻主要形态指标、生理机制及产量的影响，对非充分灌溉条件下水稻所持有的生理机制进行了较细致的研究。研究结果对于指导有效、省水的稻田灌溉具有重要意义。     

离心泵叶轮出口宽度对泵腔内压力脉动分布的影响

在试验和数值模拟相互验证的基础上,开展叶轮出口宽度对离心泵泵腔内压力脉动分布影响的研究．通过试验和数值计算获得离心泵的外特性、泵腔内静压分布、泵腔内压力脉动分布及泵体表面的压力脉动幅值分布,并进行对比分析,结果表明：前泵腔内静压和压力脉动幅值随出口宽度的增大而增大,随半径的减小而增大;后泵腔内静压和压力脉动随出口宽度和半径的变化不十分明显．综合考虑外特性和压力脉动,在比转数 ns ＝97时叶轮出口宽度与叶轮出口直径之比应小于0.06;为了使压力脉动在泵腔内有效地衰减,出口宽度与前腔间隙的比值在1.81附近时最佳．研究结果可用于指导离心泵叶轮的优化设计．     

宽幅高效离心式双圆盘撒肥机设计与试验

为解决现有水旱田撒肥机械作业效率低、撒肥量调节技术落后、施肥均匀性稳定性差等实际问题,设计了一种同轴驱动的离心式双圆盘撒肥机。介绍了整机结构与工作参数,研究设计了撒肥传动系统、撒肥盘结构、排肥量液压调节装置等,并确定了关键结构和参数,同时进行了试验研究。试验结果显示,推肥板推肥角度-20°~30°可调,撒肥幅宽达到50m,总排肥量稳定性变异系数低于6%,施肥均匀性变异系数低于16%。研究结果表明,撒肥机工作性能稳定、撒肥量可控、抛撒均匀,整机设计满足水旱田宽幅高效撒肥作业要求。     

用水户协会管理模式比较与改进对策

发展农民用水户协会,激励农民参与灌溉管理,明确小型水利产权和管护主体。以奥斯特洛姆的多中心治理理论为基础,分析用水户协会管理模式与多中心治理理论原则的耦合性,从自主治理的视角对典型用水户协会管理模式进行比较,分析各种管理模式存在的问题,从多中心治理角度提出完善用水协会多元决策机制和多中心治理结构等改进对策。     

自来水电子压力表的设计

文章阐述了一种自来水电子压力表的设计装置,具有压力系数大小实时现实、存储、查询、报警等功能。该系统采用高精度的传感器来检测压力,低温漂的仪表放大器AD620对数据进行放大,通过8位AD转换器件ADC0808进行AD采集和数据变换处理,并可将数值通过串口发送到电脑,实现压力系数的数字化测量。     

CORRELATIONS AMONG ULTRASONOGRAPHIC MEASUREMENTS OF OPTIC NERVE SHEATH DIAMETER,AGE, AND BODY WEIGHT IN CLINICALLY NORMAL HORSES

Early diagnosis of high intracranial pressure (ICP) is critical for minimizing progressive brain injury due to reduced cerebral perfusion. In people, detecting enlargement of the optic nerve sheath diameter (ONSD) by transpalpebral ultrasonography has been found to be an accurate test for high ICP. Aims of this prospective, observational, cross‐sectional study were to test hypotheses that (1) ultrasonographic measurement of ONSD would be repeatable in horses, (2) have acceptable interobserver agreement, and (3) would be correlated with age and body weight. The sample population included 48 horses without clinical signs of high ICP and with varying ages and body weights. Two observers independently performed ONSD measurements in both eyes. All measurements ranged from 2.6 to 6.5 mm. The mean difference of repeated measures within observers was ≤0.1 mm and the coefficients of variation ranged from 5.0% to 8.8%. The mean difference of measures between observers was ≤0.2 mm. After correcting for performing multiple tests, no significant rank correlation (all r < 0.4 [absolute value]) was detected between ONSD and age or body weight. However, we observed smaller ONSD in foals versus adults (all P ≤ 0.002). In the foals, all observed measures of rostrocaudal and dorsoventral ONSD were <5 mm. In the adults, all observed measures of rostrocaudal and dorsoventral ONSD were ≤6.5 mm. Findings indicated that ultrasonographic ONSD measurement is a feasible test for use in horses of varying ages and sizes. Further investigation of this ultrasonographic measure as a clinical test for horse with suspected high ICP is warranted.