高呼气末正压加小潮气量治疗急性呼吸窘迫综合征

目的：评价高呼吸末正压（PEEP）加小潮气量治疗急性呼吸窘迫综合征（ARDS）的临床疗效和安全性。方法：选择2009年3月至2011年6月在中煤三建总医院重症监护病房（ICU）收治的30例ARDS患者,采用高PEEP加小潮气量（6ml／kg）及其它对症措施治疗。结果：30例患者经治疗动脉血气氧分压（PaO2）和氧合指数（PaO2／FiO2）均明显改善,治疗第2—5天动脉血氧分压（PaO2）改善最明显,第4、5天氧合指数（PaO2／FiO2）改善最为明显。患者均无气压伤发生,无心律失常发生,心率和平均动脉压无明显变化。中心静脉压随呼气末压增高而偏高,但对平均动脉压无显著影响。结论：高PEEP加小潮气量可增加肺泡气体交换,改善氧合。减少呼吸机相关性肺损伤。     

机械功率在呼吸机相关性肺损伤中的研究进展

重症加强护理病房(ICU)急性呼吸窘迫综合征具有较高的发病率和死亡率,该类患者治疗过程中通常需要机械通气来维持其呼吸功能。然而,机械通气参数设置不当可能会导致呼吸机相关性肺损伤(VILI)。为了有效防止VILI的发生,急性呼吸窘迫综合征研究联盟推荐使用小潮气量和限制气道平台压的保护性通气策略,但是从呼吸机能量传递的角度来看,VILI实际上是潮气量、气道压力和呼吸频率等呼吸参数综合作用的结果。机械功率能很好地体现了上述参数的共同作用,正日益成为临床研究的热点。主要介绍了机械能与机械功率的定义,并对不同呼吸模式下机械功率的计算方法进行系统地综述,同时总结回顾了机械功率与VILI有关的基础研究和临床研究,进一步探究机械功率的安全阈值可望为未来临床制定个性化机械通气策略,有效预防VILI的发生提供新的思路。     

重症胸外伤合并呼吸窘迫综合征的诊疗方法

目的探讨重症胸外伤并发呼吸窘迫综合征的诊疗方法。方法对19例重症胸外伤合并急性呼吸窘迫综合征患者采用机械通气治疗，比较治疗前后PaO2、PaCO2、PaO2／FiO2，并给予患者保持呼吸道通畅，检测患者生命征的变化。结果所有患者除3例死于颅内再出血和多脏器功能衰竭外，其余均治愈出院。结论呼吸窘迫综合征一经确诊，应积极进行早期有效治疗，同时改善低氧血症是治疗呼吸窘迫综合征成功的关键。     

鼻塞持续正压通气治疗早产儿呼吸窘迫综合征30例

目的 了解鼻塞持续正压通气治疗早产儿呼吸窘迫综合征(RDS)的疗效。方法 回顾性分析我院新生儿科1998～2003年收治的30例早产儿RDS。结果 30例RDS中21例治愈出院，无效放弃5例，死亡4例。结论 鼻塞持续正压通气是治疗早产儿RDS的有效方法。     

创伤性呼吸窘迫症机械通气呼吸末正压与颅内压的相关性研究

目的：研究严重脑外伤继发ARDS患者行机械通气呼吸末正压(PEEP)与颅脑内压(ICP)相关性。方法按6~8ml/kg标准体重给予潮气量，调整呼吸参数，维持二氧化碳分压40~45mmHg，氧分压90~100mmHg。在5~18cmH2O范围内滴定式调节PEEP，观察并测定mmHg，分析PEEP变化对ICP的影响。结果5~8cmH2O范围内调整PEEP，ICP基本保持(110~115) mmH2O，随压力增大变化不明显(>0.05)；在8~18cmH2O范围内调整PEEP，ICP显著增大(<0.05)，由(115±17) mmH2O增大到(198±47) mmH2O。结论创伤性呼吸窘迫症机械通气，应注意PEEP变化引起的ICP上升。     

26例胸外伤并发呼吸窘迫综合征的治疗体会

目的探讨胸外伤并发呼吸窘迫综合征的发病机制、临床特点、诊断、治疗和结果。方法回顾分析26例胸外伤并发呼吸窘迫综合征的临床资料,均采取紧急气管插管或气管切开,接呼吸机正压通气建立有效呼吸。结果23例完全恢复,3例死亡。结论胸外伤并发呼吸窘迫综合征只要及早明确诊断、治疗措施得当,大部分病人预后良好。     

老年急性呼吸窘迫综合征的临床表现及治疗

目的 分析老年急性呼吸窘迫综合征(ARDS)的临床表现及治疗方法.方法 回顾性分析我院ICU病房近两年来收治的28例老年ARDS患者的临床表现及治疗经过.结果 28例老年ARDS患者中,21例治愈,死亡7例.结论 治疗老年ARDS患者关键在于迅速、明确诊断,以肺的保护措施为主,尽早合理有效给予机械通气.     

肺保护策略与重症支气管哮喘的机械通气治疗

“肺保护策略”的目的是为了避免呼吸机所致肺损伤，主要适用于已有的急性肺损伤(如ARDS)或潜在呼吸机所致肺损伤高度危险(如严重哮喘、坏死性肺炎、大泡性肺疾病等)的病人。实施方法包括小潮气量通气即“容许性高碳酸血症通气”和加用低水平呼气末正压(PEEP)。我院自1997年至2002年对36例重症支气管哮喘合并呼吸衰竭患者采用“肺保护策略”进行机械通气治疗，均抢救成功，现报道如下。     

基于Matlab无创正压通气下呼吸道气阻与顺应性的在线测算方法研究

目的 在无创正压通气下,避免对呼吸道内部进行操作以及自主呼吸和漏气的干扰等,研究有效在线动态测算呼吸道气阻（resistance, R）和顺应性（compliance, C）的方法。方法 在呼气末气流为0时,控制呼气支持压（expiration positive airway pressure,EPAP）跃降1个幅度为Δp和时间宽度为Δt的负脉冲气压;在该负脉冲气压作用下,呼吸道出现短暂释放气流;通过获得Δt时间段的释放气流计算R和C。另外,基于Matlab建立通气模型,模拟正常成人、急性呼吸窘迫综合征（acute respiratory distress syndrome, ARDS)患者和慢性阻塞性肺疾病（chronic obstructive pulmonary disease, COPD）患者的呼吸,进行仿真实验,获取仿真数据并计算验证。结果 根据仿真数据计算得到正常成人、ARDS患者、COPD患者R和C与实践赋值的误差分别为1.6%和-1.6%、1.21%和-1.19%、-12.53%和14.32%。结论 该算法测算呼吸道R和C具有可行性和适应性。仿真研究结果有助于智能通气、比例辅助通气模式的研究与实现。     

高频振荡通气治疗新生儿呼吸衰竭的临床疗效分析

高频振荡通气（HFV）是一种高频通气辅助呼吸方法，具有高频率、小潮气量、低气道压、机械死腔小的通气特点，其通过与常频呼吸机完全不同的作用原理，改善患者的血氧分压和氧合情况，在国外应用于临床已有10余年。我科应用HFV治疗新生儿呼吸窘迫综合征及胎粪吸入综合征、重症肺炎、肺出血、气漏综合征等常频呼吸机械通气疗效差的Ⅱ型呼吸衰竭，     

小潮气量和传统潮气量机械通气治疗小儿重症肺炎的疗效对比分析

目的：对比分析小潮气量和传统潮气量机械通气治疗小儿重症肺炎的疗效。方法：对2013年6月至2015年6月在我院进行接治的100例小儿重症肺炎进行研究,将患儿随机分为对照组和观察组,各50例,对照组的患儿采用传统潮气量,潮气量为10~12 mL/kg;观察组的患儿采用小潮气量,潮气量为6~8 mL/kg,对治疗过程中两组患儿临床参数的变化进行对比分析。结果：观察组患儿的机械通气时间明显多于对照组(t=11.0770,P=0.0000),观察组患儿的病死率明显高于对照组(χ2=5.4825,P=0.0192),治疗过程中,两组患儿的平均气道压(Paw)、吸入氧浓度(fraction of inspiration O2,FiO2)、高呼吸末正压(positive end expiratory pressure,PEEP)、吸气峰压(peak inflating pressure,PIP)等临床各指标的变化无明显差异(P>0.05),观察组与对照组存活患儿的反复呼吸道感染发生率无明显差异(χ2=0.0624,P=0.8028)。结论：对重症肺炎患儿进行机械通气时,传统潮气量的治疗效果优于小潮气量。     

Is there a place for pressure-support ventilation and high positive end-expiratory pressure combined to alpha-2 agonists early in severe diffuse acute respiratory distress syndrome?

Acute respiratory distress syndrome (ARDS) is associated with a high mortality linked primarily to co-morbidities (sepsis, cardiac failure, multiple organ failure, etc.). When the lung is the single failing organ, quick resolution of ARDS should skip some complications arising from a prolonged stay in the critical care unit. In severe ARDS (PaO₂/FIO₂ = P/F < 100 with positive end-expiratory pressure (PEEP) ? 5 cm H₂O), current recommendations are to intubate the trachea of the patient and use mechanical ventilation, low tidal volume, high PEEP, prone positioning and possibly neuromuscular blockade in association with intravenous sedation.     

Assessment of mechanical ventilation parameters on respiratory mechanics

Better understanding of airway mechanics is very important in order to avoid lung injuries for patients undergoing mechanical ventilation for treatment of respiratory problems in intensive-care medicine, as well as pulmonary medicine. Mechanical ventilation depends on several parameters, all of which affect the patient outcome. As there are no systematic numerical investigations of the role of mechanical ventilation parameters on airway mechanics, the objective of this study was to investigate the role of mechanical ventilation parameters on airway mechanics using coupled fluid-solid computational analysis. For the airway geometry of 3 to 5 generations considered, the simulation results showed that airflow velocity increased with increasing airflow rate. Airway pressure increased with increasing airflow rate, tidal volume and positive end-expiratory pressure (PEEP). Airway displacement and airway strains increased with increasing airflow rate, tidal volume and PEEP form mechanical ventilation. Among various waveforms considered, sine waveform provided the highest airflow velocity and airway pressure while descending waveform provided the lowest airway pressure, airway displacement and airway strains. These results combined with optimization suggest that it is possible to obtain a set of mechanical ventilation strategies to avoid lung injuries in patients.     

Impact of mechanical ventilation and fluid load on pulmonary glycosaminoglycans

The combined effect of mechanical ventilation and fluid load on pulmonary glycasaminoglycans (GAGs) was studied in anaesthetized rats ((BW 290±21.8 (SE)g) mechanically ventilated for 4h: (a) at low (～7.5mlkg(-1)) or high (～23mlkg(-1)) tidal volume (V(T)) and zero alveolar pressure; (b) at low or high V(T) at 5cmH(2)O positive end-expiratory pressure (PEEP); (c) with or without 7mlkg(-1)h(-1) intravenous infusion of Phosphate Buffer Solution (PBS). Compared to spontaneous breathing, GAGs extractability decreased by 52.1±1.5% and 42.2±7.3% in not-infused lungs mechanically ventilated at low V(T) or at high V(T) and PEEP, respectively. In contrast, in infused lungs, GAGs extractability increased by 56.1±4.0% in spontaneous ventilation and PEEP and up to 81.1% in all mechanically ventilated lungs, except at low V(T) without PEEP. In the absence of an inflammatory process, these results suggest that PEEP was protective at low but not at high V(T) when alveolar structures experience exceedingly high stresses. When combined to mechanical ventilation, fluid load might exacerbate edema development and lung injury.     

Constant mean airway pressure with different patterns of positive pressure breathing during the adult respiratory distress syndrome

Twenty-one ARDS patients were divided into two groups of severity according to FIO2 and PEEP required to maintain an adequate gas exchange. The 10 most severe patients (group A) underwent continuous positive pressure ventilation (CPPV) (I/E 3:1) with the mean airway pressure maintained at 21 +/- 6.2 cmH2O. The PEEP values were 12.6 +/- 4.3 cmH2O during CPPV and 6.5 +/- 3.7 cmH2O during IRV (p less than 0.01). Eleven less severe ARDS patients (group B) underwent CPPV and positive pressure spontaneous breathing (CPAP) at constant mean airway pressure of 14.3 +/- 3.8 cmH2O. The PEEP was 7 +/- 2.5 cmH2O during CPPV and 14.9 +/- 4.3 cmH2O during CPAP (p less than 0.001). In five patients of each group, the SF6 shunt was measured as representative of true shunt. The results showed that gas exchange, including true shunt, and haemodynamics did not change between CPPV and IRV and between CPPV and CPAP tests. Taken with previous work on mean airway pressure, our results further support the concept that the main determinant of oxygenation and haemodynamics is the mean airway pressure, irrespective of the PEEP level and of the mode of ventilation.     

不同容量机械通气对盐酸诱导ARDS大鼠脑损伤的作用

目的研究不同容量机械通气对急性呼吸窘迫综合征（ARDS）大鼠脑损伤的作用机制。方法将30只sD大鼠随机分为对照组、盐酸＋高潮气量组（HCL＋HV组）和盐酸＋低潮气量组（HCL＋LV组）,每组10只。两个模型组麻醉后均从气管注入0．1mol盐酸。HCL＋LV组通气容量为6ml／kg体重,通气末正压为3cmH20;HCL＋Hv组通气容量为15ml／kg体重,通气末正压为0cm H2O。各组大鼠连续通气6h后处死,行肺泡灌洗并取肺及脑海马组织进行病理观察,并用ELISA法检测脑组织中的相关指标。对照组麻醉后无需特殊处理即行相关指标检测。结果模型组大鼠可见肺组织中ARDS病理改变。海马组织中间质血管轻度扩张充血。与对照组比较,HCL＋HV组和HCL＋Lv组的脑组织中还原型谷胱甘肽（GSH）含量明显降低（P均〈0．05）,而巨噬细胞炎症蛋白-2（MIP．2）、S-l008及IL．6含量明显升高（P均〈0．05）。与HCL＋HV组相比,HCL＋LV组脑组织中MIP-2、IL．6及S-100β含量明显降低（P均〈0．05）。结论HCL诱导的ARDS大鼠在机械通气情况下有远隔部位脑损伤的表现,低容量机械通气对ARDS大鼠的脑损伤有协同保护作用。     

Pulmonary clearance of inhaled [99Tcm]DTPA: effects of ventilation pattern

While a rise in lung volume is known to increase the pulmonary clearance of technetium-99m-labelled dietylene triamine pentaacetate ([99Tcm]DTPA), little interest has been focused on the effects of changes in ventilation frequency, tidal volume and airway pressure. We studied adult, anaesthetized and intubated rabbits during three ventilation patterns (VP) using pressure controlled ventilation (ServoVentilator 900C). VP was either deep slow (f = 20 min-1, tidal volume (VT) = 30 +/- 4 ml kg-1 and positive end-expiratory pressure (PEEP) = 0.2 kPa [VP 20/0.2, n = 8]) or rapid shallow (f = 80 min-1, VT = 11 +/- 2 ml kg-1 and PEEP = 0.2 or 0.4 kPa [VP 80/0.2, n = 6 and VP 80/0.4, n = 6]). The mean airway pressure was similar at VP 20/0.2 and VP 80/0.4. During administration of [99Tcm]DTPA aerosol all animals were ventilated under the same conditions (f = 40 min-1 and PEEP = 0.2 kPa). The pulmonary clearance rate expressed as the half-life time (T1/2) of [99Tcm]DTPA was at VP 80/0.2 = 113 +/- 31 min, at VP 80/0.4 = 70 +/- 24 min (P less than 0.01 compared to VP 80/0.2) and at VP 20/0.2 = 36 +/- 18 min (P less than 0.001 compared to VP 80/0.2 and P less than 0.01 compared to VP 80/0.4). We conclude that the pulmonary clearance of [99Tcm]DTPA increases (1) during rapid shallow ventilation when PEEP is increased from 0.2 to 0.4 kPa; (2) during deep slow ventilation relative to rapid shallow ventilation even when the mean airway pressure is similar.     

High tidal volume ventilation in infant mice

Infant mice were ventilated with either high tidal volume (V(T)) with zero end-expiratory pressure (HVZ), high V(T) with positive end-expiratory pressure (PEEP) (HVP), or low V(T) with PEEP. Thoracic gas volume (TGV) was determined plethysmographically and low-frequency forced oscillations were used to measure the input impedance of the respiratory system. Inflammatory cells, total protein, and cytokines in bronchoalveolar lavage fluid (BALF) and interleukin-6 (IL-6) in serum were measured as markers of pulmonary and systemic inflammatory response, respectively. Coefficients of tissue damping and tissue elastance increased in all ventilated mice, with the largest rise seen in the HVZ group where TGV rapidly decreased. BALF protein levels increased in the HVP group, whereas serum IL-6 rose in the HVZ group. PEEP keeps the lungs open, but provides high volumes to the entire lungs and induces lung injury. Compared to studies in adult and non-neonatal rodents, infant mice demonstrate a different response to similar ventilation strategies underscoring the need for age-specific animal models.     

肺复张策略对急性呼吸窘迫综合征模型犬压力-容积曲线和肺组织病理的影响

 目的：探讨肺复张策略（LRM）对急性呼吸窘迫综合征（ARDS）模型犬静态P-V曲线和肺组织病理的影响。方法：健康犬24只,随机分为肺外源性ARDS（ARDSexp）组和肺内源性ARDS（ARDSp）组,每组12只,经股静脉注射油酸复制ARDSexp模型,盐酸灌肺复制ARDSp模型,再随机各分为2组,每组6只,分别采用肺保护通气策略（LPVS）和LPVS联合以压力-容积曲线为导向的LRM（LPVS+LRM）进行机械通气。LRM采用压力控制通气（PCV）,压力上限为高位转折点（UIP）, 呼气末正压(PEEP)为低位转折点（LIP）+2 cmH₂O,维持时间60 s。观察LRM后P-V曲线LIP、UIP以及肺复张容积变化。4 h后取肺组织行病理学评分。结果：应用LRM后,ARDSp组和ARDSexp组LIP均明显降低,与ARDSp组相比,ARDSexp组LIP下降更为显著;ARDSexp组4例犬P-V曲线出现UIP消失,2例无改变,ARDSp组犬UIP无明显变化;肺复张容积增加,肺病理损伤评分明显下降,ARDSp组的改善程度不如ARDSexp组。结论：LRM可降低LIP,导致P-V曲线发生改变,LRM后应重新根据P-V曲线调整呼吸机通气参数;对于不同原因ARDS,LRM具有增加肺复张容积、减轻肺损伤的作用,ARDSexp组的治疗效果明显优于ARDSp组。