无创正压通气在慢性呼吸衰竭治疗中的应用

目的探讨应用无创正压机械通气（NIPPV）治疗慢性呼吸衰竭的疗效。方法回顾性分析2005年2月至2008年8月收治的368例慢性呼吸衰竭患者的临床资料,其中240例患者在治疗过程中接受了NIPPV（治疗组）,有128例患者未进行无创通气（对照组）。比较2组临床症状和动脉血气的改善情况、患者的住院时间及病死率。结果治疗组治疗后各项血气指标得到明显的改善（P〈0.05）,并且总的住院时间、病死率显著低于对照组（均P〈0.05）。结论①NIPPV适用于各种病因所致的、各种类型的以及不同严重程度的慢性呼吸衰竭的治疗。②早期上机有利于提高治疗成功率。     

Effects of Leakage in Simulations of Positive Pressure Ventilation

The fire service uses a number of tactics to reduce hazards for fire-fighters and civilians within a structure on fire. One offensive fire-fighting tactic that has potential for rapidly improving or degrading conditions within the structure is ventilating the structure. Positive pressure ventilation is a tactic in which a fan is used to push hot products of combustion out of a burning structure. While a recent body of work has been produced on the effects of positive pressure ventilation in a number of fire systems, there is still widespread uncertainty on how the tactic affects the fire environment. Computational tools will play an important role in exploring the impact of positive pressure ventilation in various fire scenarios. In many simulations of structure fires, the impact of leakage on the evolution of the fire is not addressed. We find in this study that ad hoc models of leakage have significant impact on the evolution of the fire. Several ad hoc leakage models are proposed and these are studied in terms of their impact of the fire. We show that one particular leakage geometry is able to best model leakage effects in a series of fire simulations that are compared to experiments. Simple, first-order analysis is used to understand how these leakage flows affect the predictions.     

Improvement of Positive Pressure Ventilation by optimizing stairwell door opening area

This technical note presents a strategy to increase the effectiveness of Positive Pressure Ventilation (PPV) tactics in firefighting. It is shown that deployment of a Door Open Area Reducer (DOAR) in an appropriate position, which increases the resistance to the air escaping the stairwell, can significantly improve effectiveness of PPV performance. The simulation results demonstrate that an optimal placement of the fan combined with an optimized DOAR height can increase the pressure significantly yielding higher PPV effectiveness.     

无创双水平气道正压通气治疗重症支气管哮喘的研究

目的探讨无创双水平正压通气（NIPPV）对重症支气管哮喘患者的治疗价值。方法将40例重症支气管哮喘患者按随机数字表法分成2组。对照组（n=20）予以氧疗、常规药物治疗;试验组（n=20）在氧疗、常规药物治疗的基础上予以NIPPV支持,应用美国STAR330型无创呼吸机,经面罩或鼻罩无创通气,采用S/T（自主呼吸/时间切换）,压力支持（PSV）＋呼吸末正压（PEEP）。比较2组治疗前和治疗后1、3h,第4天的血气分析指标（pH、PaCO2、PaO2、SaO2）的变化,治疗前后的最高峰流速（PEF）的改变及2组住院时间。结果治疗后,试验组血气分析指标以及PEF值的改善均较对照组明显（P〈0.05）;试验组住院时间较对照组明显缩短（P〈0.05）。结论对重症支气管哮喘患者早期应用NIPPV是有效的,但还需要大样本及更多的观察指标来监测患者的病情变化;对无创通气1～3h后病情无好转并呈进行性加重的患者应尽早改用有创机械通气,以免耽误治疗时机。     

Positive Pressure Ventilation for fighting wind-driven high-rise fires: Simulation-based analysis and optimization

In high-rise buildings wind can greatly impact fires, creating extremely dangerous and life-threatening environments for both the firefighters and the building's occupants. Positive pressure ventilation (PPV) is found to be a successful tactic, not only to mitigate wind driven fires in high-rises, but also to significantly improve firefighters’ safety. The efficacy of PPV is strongly influenced by various parameters, mainly structural layouts, wind conditions, and fan deployment configurations. To optimize the application of PPV in high-rise fires, this paper investigates the impact of wind speed (0–10 m/s; 0–5 Beaufort wind scale) and relevant operational parameters on temperatures and smoke conditions using computational fluid dynamics model - the Fire Dynamics Simulator (FDS 5.0). The temperature results demonstrate that the effectiveness of PPV decreases with increasing wind speed necessitating the use of wind control devices (WCDs) in conjunction with deployment of PPV fans to mitigate the flow of heat and reduce the temperatures at primary vantage points (stairwell and public hallway). This tactic ultimately provides a safer environment for firefighters.     

单片机在正压气力输送系统中的应用

针对目前正压气力输送采用传统电器控制方式陈旧落后的现象,介绍了一种采用单片机程控器方便地控制输送系统的设计方法和思路,包括控制系统的硬件工作原理和软件实现方法。     

无创正压通气对产科危重症所致急性肺损伤的影响

目的探讨无创正压通气（Noninvasive Positive Pressure Ventilation,NIPPV）对产科危重症患者并发急性肺损伤（ALI）的影响。方法回顾性分析2001年1月至2008年12月收治的产科危重患者共67例。在治疗前,治疗后2、4、12、24和48 h监测并记录患者自觉症状、呼吸频率、心率、PaO2/Fi O2等动态变化。结果发生ALI的产科病例中以产后出血为最常见因素,占53.73%（36/67）。随NIPPV时间延长,患者自觉症状改善率逐步提高,但NIPPV后2、4 h呼吸困难改善率高于心悸症状改善率（P〈0.05）。使用NIPPV后2 h呼吸频率开始逐渐减慢,随着治疗时间的延长,呈现逐渐下降趋势（P〈0.05）,在治疗后12 h趋于稳定（P〉0.05）。NIPPV后4 h心率开始出现下降（P〈0.05）,直到NIPPV12 h后心率才再次继续逐渐下降（P〈0.05）。PaO2/Fi O2在NIPPV12 h后才开始改善,48 h后显著改善（P〈0.05）。94.03%（63/67）患者单纯使用NIPPV后能成功脱机,中转率5.97%（4/67）;1例发展为MODS死亡,死亡率1.49%（1/67）。结论产科危重症人群也是ALI发生的高危人群,对其应早期发现、早期诊断、早期行NIPPV,及时确定中转NIPPV时机,重视原发疾病的治疗是成功抢救的关键环节。     

The Use of Positive Pressure Ventilation Fans During Firefighting Operations in Underground Stations: An Experimental Study

Positive pressure ventilation (PPV) fans are widely used by the fire service during firefighting operations in buildings. Fans are positioned to create a flow through the enclosure. This flow can remove the smoke after the fire or affect the direction of the smoke to support firefighting operations. In subway stations, it is less common to use PPV fans. Here, 106 full-scale tests with up to four fans have been performed in a training building that represents a subway station. The fans were used as extraction fans. The generated flow through the subway station has been measured. The critical velocity for a hypothetical tunnel (W × H: 3.17 × 4.15 m) attached to the subway station has been calculated as 2.37 m/s. Reaching the critical velocity has been used as criterion for ‘success’. All combinations with four fans exceed this velocity, supporting the idea that the fans could be used to facilitate a firefighting operation. The location of the fans was varied. Combinations with three fans on the platform and one at the top of the staircase performed better than combinations with two fans on the platform, one on the landing and one at the top of the staircase. There is an optimum value for the distance between the fans on the platform and the first step of the staircase. This value depends on the angle of inclination of the fans. The fans were not capable of creating a flow that exceeded the critical velocity in the station itself (L × W × H: 60 × 7.15 × 4.53 m). However, a velocity of 2.40 m/s corresponds to a flow rate that will limit the backlayering distance in the station to 15 m. This was only achieved by tests with four fans (three on the platform and one at the top of the staircase).     

Experimental Study on the Use of Positive Pressure Ventilation for Fire Service Interventions in Buildings with Staircases

During fire service interventions, positive pressure ventilation (PPV) systems with mobile fans are often used to try and make (or keep) a staircase smoke free and to remove smoke from the fire rooms. The positioning (distance from the door opening) and inclination angle of the fan determine the effect of the PPV fans in the staircase. In the present paper results are discussed of an experimental study, performed at full-scale. Based on different sets of cold experiments, the impact is quantified of: the distance between the fan and the door; the inclination angle of a single fan; and the use of multiple fans. The closer the single fan is put to the door opening, the more effective the PPV becomes. Obviously, there is a trade-off with effectiveness of the fire service intervention, since the fan must not block the door opening. With respect to inclination, it is best to apply an inclination angle of 75° (i.e., an upward tilting of the fan axis by 15°, which is the maximum value tested) for ventilation at ground level with the fan tested. This ensures safety in the case of fire at ground level due to full coverage of the entry door opening, while only a relatively limited loss in PPV effectiveness is observed compared to a horizontal fan (in some cases, the PPV effectiveness is even higher with inclined fan). When the fire room is at a higher floor, an inclination angle of 90° (i.e. horizontal fan axis) can generate a higher average flow velocity, depending on the staircase configuration inside the building. If two fans are used, V-shape positioning is shown to be more effective than a set-up in series or in parallel. A V-shape with inner angle of 60° between the fan axes is more effective than an angle of 90°. If three fans are available, still higher average flow velocities are measured. Positioning two fans outside in V-shape and one fan inside at the bottom of the staircase is more effective than putting the three fans outside, On the other hand, the latter set-up may be required for firefighting tactics.     

无创机械通气联合枸橼酸咖啡因治疗早产儿呼吸暂停的效果观察

目的:探究早产儿呼吸暂停采取无创机械通气(NIPPV)联合枸橼酸咖啡因的临床疗效。方法:选取2016年2月-2019年2月在本院治疗的早产儿呼吸暂停患儿共75例,其中2018年1月-2019年2月50例。按治疗方法分成对照组A(n=25)、对照组B(n=25)与观察组(n=25)。对照组A行持续气道正压(CPAP)联合枸橼酸咖啡因治疗,对照组B行NIPPV治疗,观察组行NIPPV联合枸橼酸咖啡因治疗,比较三组监测指标、临床疗效及并发症。结果:观察组呼吸暂停次数,呼吸暂停持续天数、用氧时间、住院时间及无创呼吸时间均低于对照组A、B,且治疗总有效率高于对照组A、B(P<0.05)。观察组慢性肺病、颅内出血与视网膜病变发生率均低于对照组A、B(P<0.05)。观察组脑白质软化发生率略低于对照组A、B,但差异均无统计学意义(P>0.05)。观察组鼻黏膜损伤发生率略高于对照组A,而略低于对照组B,差异均无统计学意义(P>0.05)。结论:NIPPV联合枸橼酸咖啡因治疗早产儿呼吸暂停可减少每日呼吸暂停次数,缩短无创呼吸时间、用氧时间与住院时间,改善血气指标,提高临床疗效,减少并发症发生率。     

支气管堵塞器行单肺通气的临床研究

目的比较双腔支气管导管与纤支镜引导下插入支气管堵塞器2种单肺通气方式的麻醉操作、血流动力学、呼吸功能监测的变化。方法胸外科手术行单肺通气患者40例,用抽签法随机分为2组,每组20例,对照组（A组）行双腔支气管导管下行单肺通气,观察组（B组）行纤支镜引导下插入支气管堵塞器行单肺通气。分别行麻醉操作监测,包括插管次数、插管时间、纤支镜定位时间、手术野暴露满意及术后咽喉疼痛及肺部感染;在T0（术前30min）、T1（单肺通气30min）、T2（单肺通气60min）、T3（术后6h）时间点进行血流动力学监测和呼吸功能监测,并记录HR、MAP、CVP、CO、SVV数据和SPO2、PetCO2、Paw、CLdyn、PO2、PCO2数据。结果 1）插管时间、纤支镜定位时间,B组明显优于A组（P〈0.05）;术野暴露满意度和术后肺部感染发生率,A组与B组比较差异无统计学意义（P〉0.05）;术后声嘶咽喉疼痛发生率,A组明显高于B组（P〈0.05）。2）T1、T2时,A组较B组HR变化明显,A组或B组MAP、CVP、CO、SV、SVV明显优于T0。3）T1、T2时,Paw、CLdyn B组明显优于A组。T1、T2时,A组或B组PetCO2、Paw、CLdyn、PO2、PCO2明显优于T0。结论在胸外科手术中使用纤支镜定位简单准确、手术视野清晰、术后并发症少,使用支气管堵塞器在肺顺应性、气道阻力及对心脏负荷的影响方面都明显优于双腔支气管导管。     

慢性阻塞性肺病急性加重期早期使用无创正压通气的临床观察

目的:探讨无创正压通气治疗慢性阻塞性肺病急性加重期早期的临床疗效。方法:选择180例慢性阻塞性肺病急性加重期早期患者,随机分为研究组与对照组,对照组给予止咳、平喘、化痰、吸氧、抗感染等一系列常规治疗,研究组在此基础之上给予无创正压通气治疗。结果:治疗1周后,两组患者的呼吸频率、心率、平均动脉压等基本情况均有所改善,而研究组的改善情况明显好于对照组(P<0.01);两组患者的PaO2水平均有所上升,PaCO2水平均所有下降,而研究组患者两种指标水平的变化明显大于对照组(P<0.01)。结论:采用无创正压通气方法治疗慢性阻塞性肺病急性加重期早期的临床疗效较为显著,适合临床推广应用。     

热压引射通风设计的应用技术

热压自然通风设计是一种有效的被动式节能技术手段。分析了常规热压通风设计的应用模式和存在的问题,在此基础上,提出了一种全新的热压引射通风设计模式,并初步探讨了该通风设计的工作原理、应用技术,说明了其节能及理论设计上的可行性。结论指出了这种新的设计模式可广泛适用在夏季温热地区,特别是多层内廊式建筑的竖向集中排气系统中,也为深入研究和应用热压自然通风新技术提供一定的思路。     

肠内营养在慢性阻塞性肺疾病并呼吸衰竭使用无创通气治疗患者中的应用

目的探讨肠内营养在治疗慢性阻塞性肺疾病（chronic obstructive pulmonary disease,COPD）并呼吸衰竭使用无创通气治疗患者中的应用价值。方法将52例COPD并呼吸衰竭已使用无创通气治疗患者按随机数字表法分为治疗组26例和对照组26例,2组患者均给予抗感染、相关对症治疗,治疗组采取留置鼻胃管方式鼻饲肠内营养液能全力,行肠内营养支持治疗15d。记录2组患者肠内营养治疗前后血液生化指标（包括血红蛋白、血浆总蛋白、白蛋白）、体质量测量指标（包括体质量、肱三头肌皮皱厚度、上臂肌围）、无创通气时间及使用有创机械通气的病例数、ICU住院时间。结果治疗组肠内营养支持治疗15d后,血液生化指标较治疗前显著升高（均P〈0．05）,体质量测量指标较治疗前显著增加（P〈0．05）;与对照组比较,治疗组肠内营养支持治疗后血液生化指标和体质量测量指标均明显增加（P〈0．05）、无创通气时间及ICU住院时间明显缩短（P〈0．05）,使用有创机械通气的比率明显下降（P〈0．05）。结论对COPD并呼吸衰竭患者,合理的肠内营养支持治疗可以改善机体的营养状态,缩短无创通气及ICU住院时间,降低有创机械通气的比率。     

无创正压通气治疗对COPD稳定期患者CRP、血气分析及生活质量影响的临床研究

目的:观察无创正压通气治疗对COPD稳定期患者生活质量、血气分析及CRP的影响。方法:将32例确诊为慢性阻塞性肺疾病稳定期患者按照随机数字表法分为治疗组与对照组,对照组给予常规治疗,治疗组在对照组基础上予无创呼吸机辅助通气,分别于治疗前、治疗后1个月、治疗后3个月,观察患者血气分析及CRP的变化,并通过CAT评分、6 min步行试验评价患者的生活质量。结果:无创正压通气治疗对COPD稳定期患者的血气分析无显著影响,但治疗组患者的生活质量与CRP较对照组均改善,差异均有统计学意义(P<0.05)。结论:无创正压通气治疗能较好改善COPD稳定期患者的生活质量,可降低其CRP值,值得临床推广。     

动态超压控制在正压送风系统中的运用

在大多数高层建筑中,正压送风系统均采用纯机械送风,易影响消防逃生效果.以上海海南路10号工程为例,介绍了正压送风系统中进行动态超压控制的理由及基本原理,以及在工程中利用VAV控制器对疏散楼梯间与消防合用前室的正压送风进行动态超压控制的方案和选用方案时的思考,对类似项目具有一定借鉴意义.     

急诊无创正压通气联合小剂量肾上腺素治疗重症支气管哮喘合并呼吸衰竭的临床效果研究

目的:研究急诊无创正压通气方法联合小剂量肾上腺素对重症支气管哮喘合并呼吸衰竭的临床实际疗效。方法:选择2012年6月-2016年5月本院收治的70例重症支气管哮喘合并呼吸衰竭患者,两组均给予基础治疗,吸氧、平喘、激素抗炎、解痉以及祛痰等常规急救处理,对照组实施无创正压通气治疗,观察组在此基础上加用小剂量肾上腺素治疗。结果:两组RR与HR治疗72 h变化均显著(P<0.05),两组RR与HR治疗72 h比较差异均有统计学意义(P<0.05)。两组治疗72 h后PaO_2含量显著上升,PaCO_2含量显著下降,pH值显著上升,IL-17含量显著降低,ECP含量显著降低,MPO含量显著降低,MDC含量显著降低(P<0.05)。治疗72 h后观察组PaO_2含量显著高于对照组,PaCO_2含量显著低于对照组(P<0.05)。两组治疗有效率、转有创通气率比较,差异均有统计学意义(P<0.05)。结论:急诊无创正压通气联合小剂量肾上腺素治疗可以显著改善重症支气管哮喘合并呼吸衰竭的血气以及炎症因子指标,有效提高临床疗效。     

住宅新风系统风量分配装置压力平衡研究

为确保住宅建筑新风系统风量的合理分配,本文提出了一种新风系统设计方法,并通过计算流体力学模拟了一体积较小且带有六个出口的风量分配装置,以在不同位置设置不同长度的导流板的方式,得出在两侧设置长度为43 mm的导流板,在中心设置长度为44 mm导流板时,可以实现在一定风量范围内达到风量平衡且出口压力相等。     

热源面积对室内热压自然通风的影响

针对具有内热源的民用建筑,采用计算流体力学(CFD)方法,通过改变热源面积对热压自然通风流场进行数值模拟分析,得出了不同热源面积下的通风量、排风温度及其变化规律,分析了不同工况下的温度场和速度场,得出了中和面高度和有效热量系数随热源面积的变化规律。结果表明:热源面积的变化主要影响房间下部的温度场,对通风量和排风温度的影响不大,对中和面高度和有效热量系数均有一定的影响。该结论为民用建筑自然通风系统的设计提供了理论依据。     

关于通风除尘管道压力平衡公式的修正

对风道水力计算中调整管径的压力平衡公式进行了分析,指出了该公式存在的问题及其原因,并用最小二乘法对公式进行了修正,通过模拟计算得到修正公式,验证表明用该公式计算能够较好地符合设计规范要求。