双相压通气治疗急性呼吸窘迫综合征

目的：探讨双相气道正压（BIPAP）通气模式治疗急性呼吸窘迫综合征（ARDS）患者的疗效及其对血流动力学和气道力学的影响。方法;随机将20例ARDS患者分为BIPAP通气模式组（BIPAP组）和间歇正压通气模式组（IPPV组）,行机械通气治疗,每组各10例。观察两组血流动力学、血气分析、呼吸力学指标。结果：BIPAP组机械通气时间平均为13天,显著低于IPPV组的21天（P＜0．05）。BIPAP组患者安定、吗啡和万可松用量显著低于IPPV组（P＜0．05）;IPPV组吸气峰压、平台压和呼气末正压均显著高于BIPAP组（P＜0．05）。心率、平均动脉压、平均肺动脉压、体循环阻力和心脏指数两组差别无显著性意义（P＞0．05）,但IPPV组肺血管阻力显著高于BIPAP组（P＜0．05）。两组间动脉血氧分压、二氧化碳分压和pH值差别无显著性意义（P＞0．05）,BIPAP组混合静脉血氧分压显著高于IPPV组（P＜0．05）。结论：BIPAP通气模式人机关系协同性好,能够降低肺血管阻力,增加混合静脉血氧分压,缩短了ARDS治疗的机械通气时间。     

不同单肺通气模式对开胸手术患者血流动力学的影响

目的 评价不同单,肺通气模式对开胸手术患者血流动力学的影响.方法 选择拟行肺叶切除术或食道癌根治术的患者45例,年龄45～64岁,采用随机数字表法,将患者随机分为3组(n=15),间歇正压通气组(IPPV组);IPPV+呼气末正压组(IPPV+PEEP组):IPPV+5 cm H2O PEEP单肺通气30 min后,再行IPPV+10 cm H2O PEEP单肺通气30 min:IPPV+持续气道正压通气组(IPPV+CPAP组)通气侧肺采用IPPV模式,术侧肺加用5 cm H2OCPAP模式1h.于麻醉诱导前、气管插管后10 min、双肺通气30 min、单肺通气30 min、1h及术毕(T1-6)时记录MAP、HR,心排血量(CO)、心指数(CI)、每搏量(SV)和每搏指数(SVI).并于 T1,2,4-6时采集动脉血样行血气分析,记录血糖(Glu)和血乳酸(Lac)水平,计算氧供(DO2)及氧供指数(DO2I).结果 与IPPV组比较,IPPV+PEEP组T4,5时SV、SVI、CO、CI、DO2,DO2I降低(P＜0.05),Glu和Lac水平差异无统计学意义,IPPV+CPAP组上述各指标比较差异无统计学意义(P＞0.05).与IPPV+ PEEP组比较,IPPV+ CPAP组T4,5时SV、SVI、CO、CI、DO2、DO2I升高(P＜0.05),Glu和Lac水平差异无统计学意义(P＞0.05).结论 开胸手术患者通气侧肺采用IPPV模式,术侧肺加用5 cm H2O CPAP模式对患者血流动力学无明显影响,而通气侧肺IPPV+ PEEP模式虽然可导致血流动力学波动,但程度较小,可维持正常的机体氧供.     

间歇正压通气和呼气末正压通气对犬眼内压的影响

目的 探讨间歇正压通气(IPPV)和呼气末正压通气(PEEP)对犬眼内压(10P)的影响.方法 实验犬8只,麻醉后分别监测基础条件下和各种机械通气条件下的IOP、CVP、MAP.结果 实施20 ml/kg和30 ml/kg两种不同潮气量的IPPV时IOP差异无统计学意义.实施10、15、20cm H20三种不同压力值的PEEP时IOP均显著升高(P<0.01).结论 IPPV对IOP影响不大,PEEP可使IOP显著升高.     

机械通气治疗连枷胸的临床分析

目的 探讨双水平正压通气（biphasic positive airway pressure，BiPAP）在连枷胸中的治疗作用。方法 将我院1999年1月-2005年3月符合连枷胸条件的43例患者，其中14例采用无创正压通气BiPAP模式作为BiPAP组，另外29例患者采用的机械通气模式为常规的间歇正压通气（intermittent positive pressure ventilation，IPPV），作为IPPV组，比较两组的ICU住院时间、并发症、死亡率，以及24、48、72h的动脉血气中的PO2、PCO2与氧合指数。结果 BiPAP组中在ICU中治疗时间比IPPV组明显缩短，并发症、死亡率少于IPPV组。监测24、48、72h的血气分析，PO2、PCO2、PaO2／FiO2差异无显著性。结论 在连枷胸患者的治疗中，BiPAP的机械通气模式优于IPPV。     

急性呼吸窘迫综合征患者适应性支持通气的效果

目的 评价适应性支持通气（ASV）模式与间歇正压通气（IPPV）模式在急性呼吸窘迫综合征（ARDS）患者中的效果。方法 ARDS患者30例，年龄19—46岁，男18例，女12例，ASAⅢ或Ⅳ级。先应用IPPV模式，吸入氧浓度60％，PEEP为0，潮气量（VT）10ml／kg，吸呼比（I：E）1：2，维持8h后随机选择换用ASV或继续IPPV通气模式，通气时依次按0、5、10cm H2O增加PEEP，每一PEEP水平的通气时间为60min，在同样的分钟通气量的设置下，4h后更换另一种通气模式，仍按0,5、10cm H2O增加PEEP，每一PEEP水平的通气时间为60min。每个PEEP水平通气50min时，用Swan-Ganz导管、心电监测仪、呼吸机监测记录血液动力学、呼吸力学和氧代谢数据。结果 与IPPV模式比较，ASV模式下气道峰值压降低，肺动态顺应性（Cdyn）、动脉氧分压（PaO2）和氧供（DO2）增加（P〈0．05）。两种通气模式的血液动力学参数比较差异无统计学意义（P〉0．05）。结论 ASV模式比IPPV模式更有利于ARDS患者的通气治疗。     

全身麻醉中应用小潮气量联合低水平呼气末正压通气对老年患者呼吸功能的影响

目的 观察全身麻醉中应用小潮气量(VT)联合低水平呼气末正压通气(PEEP)对老年患者呼吸功能的影响.方法 20例ASAⅠ或Ⅱ级上腹部手术老年患者,随机均分为A组和B组.A组,机械通气模式为间歇正压通气(IPPV)加5cm H2O PEEP,VT=6ml/kg,f=15次/分;B组,机械通气模式为IPPV,VT=9ml/kg,f=12次/分.观察术前(T1)、麻醉插管后30min(T2)、拔管后15min(T3)的动脉氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、肺泡-动脉氧分压差(A-aDO2)、MAP、CVP及术中的气道峰(Ppeak).结果 T3时,A PaO2较B组明显升高(P<0.05),A组A-aDO2较B组明显降低(P<0.05).其他各时点A、B两组PaO2、PaCO2、A-aDO2、MAP、CVP、Ppeak组间比较差异无统计学意义.结论 小潮气量联合低水平PEEP通气能够有效改善老年患者术后低氧血症,减少肺部并发症,更有利于老年患者呼吸功能的恢复,对老年患者血流动力学无明显影响.     

肺保护性通气在开胸手术后急性呼吸窘迫综合征患者中的应用

目的 观察肺保护性通气(LPSV)对开胸手术后发生急性呼吸窘迫综合征(ARDS)患者的治疗效果.方法 37例术前无其他合并症、手术顺利而术后发生ARDS的患者在常规治疗的基础上给予机械通气[同步间歇性指令呼吸(SIMV)+压力支持模式(PSV)+呼气末正压(PEEP)或双水平气道压通气(BiPAP)],并根据通气模式的不同分为常规通气组(CMV组,20例)和肺保护性通气组(LPSV组,17例),记录两组患者机械通气后24h的动脉血气分析结果、氧合指数(PaO2/FiO2)、气道平台压(Pplat)、吸入峰值压(PIP)、PEEP及机械通气时间、气压伤等指标的差异.结果 LPSV组机械通气时间、气压伤发生率和病死率分别为7.3d、5.9%和29.4%,而CMV组为17.6d、15.0%和60.0%,两组比较差异有统计学意义 (P＜0.05);LPSV组的气道压,包括PIP和Pplat显著低于CMV组,差异有统计学意义 (P＝0.031,0.031).两组患者的动脉血氧饱和度(SaO2)、pH、动脉血二氧化碳分压(PaCO2)和PaO2/FiO2差异无统计学意义(P＞0.05).结论 LPSV可明显减少呼吸机相关性肺损伤,降低了病死率,是开胸手术后ARDS患者的一种有效通气方法.     

双相气道正压通气对急性呼吸窘迫综合征模型犬心肺功能的影响

目的：研究在消除自主呼吸前、后,双相气道正压通气（BIPAP）对急性呼吸窘迫综合征（ARDS）模型犬心肺功能的不同影响。方法：选择健康杂种犬12只,全麻后用油酸制成ARDS模型,采用自身对照法观察其在机械通气前、BIPAP（包括用肌松药消除自主呼吸前、后）等3种状态下呼吸、循环及血气的变化。结果：在保留自主呼吸时,BIPAP通气状态下犬的PaO2、CO、DO2、CL均显著高于消除自主呼吸后相应参数值,VO2／DO2、Qs/Qt、VD／VT、RL则显著降低（P＜0．05）;和基础值相比,BIPAP通气时的PaQ2、DO2、RL均显著增加（P＜0．05）,而保留自主呼吸时,BIPAP的CL、CO显著增加;Qs/Qt、VD／VT VO2／DO2显著降低;消除自主呼吸后,其Qs/Qt、VD／VT、RL、PVR显著增加,CD显著降低（P＜0．05）。结论：与消除自主呼吸后相比,保留自主呼吸时,BIPAP能明显改善ARDS模型犬氧合状态和通气血流分布,对循环亦无明显的抑制作用,是较为理想的通气方式。     

小潮气量联合PEEP对单肺通气时胸外科手术患者血管外肺水的影响

目的 探讨小潮气量联合呼气末正压(PEEP)对单肺通气时胸外科手术患者血管外肺水的影响.方法 食道癌手术患者40例,年龄45～80岁,体重48～83kg,性别不限,ASA分级Ⅰ或Ⅱ级,随机分为2组(n=20):传统模式单肺通气组(Ⅰ组)机械通气模式为间歇正压通气(IPPV),VT9 ml/kg,通气频率12次/min;小潮气量联合PEEP单肺通气组(Ⅱ组)机械通气模式为IPPV联合PEEP5 cm H2O,VT6 ml/kg,通气频率15次/min.于麻醉诱导前(T0)、双肺通气30 min(T1)、单肺通气30 min(T2)、单肺通气1 h(T3)、恢复双肺通气拔管前(T4)和术后18 h(T5)时,记录血管外肺水(EVLW)、血管外肺水指数(EVLWI)、肺血管通透性指数(PVPI)和心输出量(CO),于T1～4时记录气道峰压(Ppeak);取股动脉血样,进行血气分析,并计算氧合指数(OI).结果 与Ⅰ组比较,Ⅱ组单肺通气期间EVLWI和.PVPI升高(P＜0.05),其余指标比较差异无统计学意义(P＞0.05);两组各时点OI、CO和Poeak比较差异无统计学意义(P＞0.05);与T0时比较,Ⅰ组T1时PVPI升高(P＜0.05),其余时点PVPI、EVLW和EVLWI差异无统计学意义(P＞0.05),Ⅱ组T2时EVLW、T1～4时EVLWI和T1.2时PVPI升高(P＜0.05);与T1时比较,Ⅰ组T2～5时EVLW、EVLWI和PVPI差异无统计学意义,Ⅱ组T5时PVPI降低(P＜0.05).结论 采用VT6 ml/kg、PEEP 5 cm H2O的单肺通气可增加患者血管外肺水,未对肺功能产生有利作用.     

压力支持通气和双相气道正压通气通过肺血流重新分布从而提高氧合

背景机械通气时保留自主呼吸（spontaneousbreathing,SB）可改善气体交换,主要是因为这种通气方式可使萎陷的肺复张。在保留SB的机械通气中,常选择压力支持通气（pressuresupportventilation,PSV）和双相气道正压通气（biphasicpositiveairwaypressure,BIPAP）。但医师对这些辅助性机械通气方式改善肺功能的机制却不甚了解。我们评价了采用PSV和BIPAP改善氧合的机制。方法5头猪（25-29．3kg）于仰卧位行机械通气,并通过清除肺表面活性物质诱发其发生急性肺损伤（acutelung砸jury,Au）。状态稳定后,给予BIPAP通气,初期较低持续气道正压设置为5cmH2O,随后逐渐增加持续气道正压至维持潮气量在6-8ml／kg。减浅麻醉深度,当SB≥每分通气量的20％时,随机进行1小时的PSV或BIPAP＋SB通气。于呼气末行全胸螺旋式计算机体层扫描,并记录肺功能参数。静脉给予荧光微球体来记录肺血流（pulmonarybloodflow,PBF）,并利用空间聚类分析来评估每种通气方式对PBF重新分布的影响。结果Au损伤肺功能并加大了下肺萎陷或不张组织的面积（P〈0．05）。和对照组比较,PSV和BIPAP＋SB的通气模式提高了氧合并减少了静脉血掺杂（P〈0．05）。尽管如此,我们观察到自主呼吸时下肺的不张肺组织或通气不良组织明显增加,而可正常通气的肺组织减少。观察到6例中有5例行PSV或sB＋BIPAP通气时PBF由下至上重新分布,肺通气也较好。结论在ALI模型中采用PSV或BIPAP＋SB行机械通气可改善氧合,减少静脉血掺杂的原因为PBF由下至上的重新分布,而不是因为下肺复张。     

无创正压通气治疗全麻拔管后呼吸衰竭

目的 评价无创正压通气(NIPPV)治疗全身麻醉手术拔管后呼吸衰竭的疗效及影响因素.方法 全麻手术拔管后48 h内发生呼吸衰竭的患者34例,应用BiPAP Vision呼吸机实施无创正压通气治疗,比较治疗后避免再插管(成功组)和需要再插管(失败组)患者的基础状态、通气疗效及临床结果,并分析可能的影响因素.结果 无创正压通气使70.6%的术后呼吸衰竭患者避免插管.与失败组相比,成功组心肺并发症所致呼吸衰竭的比例和需要人工辅助吸痰的比例明显低(P<0.05),麻醉药残留呼吸抑制的比例高(P<0.01).结论 无创正压通气治疗全身麻醉手术后呼吸衰竭能够减少再插管率,但可能不适用于存在心肺并发症和排痰障碍的患者.     

In what respect does high frequency positive pressure ventilation differ from conventional ventilation?

The original rationale for HFPPV was that under certain conditions adequate alveolar ventilation could be achieved with high ventilatory frequencies and small tidal volumes. It was theorized further that increased ventilatory frequencies and low tidal volumes would decrease the airway pressures, barotrauma, and cardiovascular and other systemic consequences seen with conventional mechanical ventilation. The first clinical applications of HFPPV were in bronchoscopy and laryngoscopy for diagnostic and/or therapeutic purposes. Apart from these endoscopic applications, volume-controlled HFPPV has been compared with conventional ventilation in upper abdominal surgery and coronary artery bypass grafting. The possible advantages of HFPPV over conventional volume-controlled ventilation in the intensive care setting are still unclear. Provided that the mean lung volumes are similar, oxygenation in acute respiratory failure is similar with both ventilation methods. Although the role of HFPPV in the management of pulmonary diseases still remains to be clarified, it does provide effective ventilation in selected types of patients needing ventilatory support. New modes of pressure-controlled ventilation have not resolved all clinical problems in severe ARDS and/or acute respiratory failure. The search for means of optimal ventilatory support with minimal complications must continue, as conventional ventilation does not always offer the best treatment.     

Development and Evaluation of a Flow-Dividing Unit for Differential Ventilation and Selective PEEP

Differential ventilation with selective positive end-expiratory pressure (PEEP) was studied in a two-compartment lung model, using one ventilator and a flow-dividing unit consisting of inspiratory flow resistors and an inspiratory threshold valve. The compliance of each lung compartment was varied between 0.15 and 0.23 1 X kPa-1 and the resistance was varied from 0 to 3.5 kPa X 1(-1) X s. The minute volume was 12 1 and the respiratory frequency 12/min, with an inspiratory:expiratory ratio of 1:2. An even distribution of ventilation to the two lung compartments was obtained with the inspiratory flow resistors or the threshold valve under all conditions studied. However, a stepwise increase in the inspiratory resistance of one lung compartment from 1.0 to 2.5 or from 2.5 to 3.5 kPa X 1(-1) X s required readjustment of the inspiratory flow resistor to achieve an even distribution of ventilation, whereas the inspiratory threshold valve needed no readjustment. Large differences in the inspiratory impedance of the two lung compartments caused asynchronous gas delivery when the ventilation distribution was adjusted by means of the flow resistors. Use of the threshold valve resulted in synchronous gas delivery. The flow-dividing unit consists of non-active elements and can thus be connected to any ventilator.     

敷料预防无创正压通气鼻面部压疮效果的网状Meta分析

目的采用网状Meta分析方法评价7种常用敷料预防无创正压通气(NIPPV)患者鼻面部压疮的效果。方法以压疮、正压通气、positive pressure pespiration、pressure ulcer等检索词检索PubMed、EMbase、Cochrane Library、Web of Science、CINAHL、中国生物医学文献数据库(CBM)、中国知网(CNKI)及万方数据库等中外文数据库,检索时间截止2015年7月,纳入对比敷料预防NIPPV患者鼻面部压疮的随机对照试验(RCT)。由2名研究者独立进行数据提取和质量评价,采用WinBugs、Stata软件分析数据。结果最终纳入27个RCT,共2 797例患者。网状Meta分析结果显示,7种敷料预防NIPPV患者鼻面部压疮效果均优于常规护理措施(均P0.05)。根据累积排序概率曲线下面积(SUCRA)排序结果,凝胶敷料、泡沫敷料是预防NIPPV患者鼻面部压疮的较优方案。结论基于网状Meta分析结果和SUCRA排序结果,凝胶敷料和泡沫敷料预防NIPPV患者鼻面部压疮效果优于其他敷料。未来研究应关注不同种类敷料间效果的直接比较及成本效果评价。     

Pressure-controlled ventilation is superior to volume-controlled ventilation with a laryngeal mask airway in children

Background:  This prospective, randomized, crossover study had two purposes: first, to determine whether pressure-controlled ventilation (PCV) is safer than volume-controlled ventilation (VCV) by preventing gastric insufflation in children ventilated through an laryngeal mask airway (LMA); second, to assess whether the measurement of LMA leak pressure (P_leak) is useful for preventing leakage during positive pressure ventilation (PPV).
Methods:  Forty-one, 2 to 15-year-old children underwent general anesthesia with an LMA. The expiratory valve was set at 30 cmH₂O and P_leak was measured using constant gas flow. Children were randomly ventilated using PCV or VCV for 5 min in order to reach a P_ETCO₂ not exceeding 45 mm Hg, and then they were ventilated with the alternative mode. If the target P_ETCO₂ could not be obtained in one mode, we switched to the other. If both modes failed, children were intubated. Tidal volumes, P_ETCO₂ and airway pressures were noted and compared between modes. Gastric insufflation was checked by epigastric auscultation.
Results:  PCV provided more efficient ventilation than VCV, as targeted P_ETCO₂ was obtained without gastric insufflation using PCV in all cases except one, whereas VCV failed in three cases. No gastric insufflation occurred when ventilating below peak.
Conclusions:  These findings suggest that in the age group studied, PCV is more efficient than VCV for controlled ventilation with a laryngeal mask. Gastric insufflation did not occur with this mode.     

Pressure versus volume-controlled ventilation with a laryngeal mask airway™ in paediatric patients

BACKGROUND: The utility of positive pressure ventilation with the laryngeal mask airway (LMA) in children was described previously, but the possibility of gastric insufflation, related to high peak airway pressure, continues to be a disadvantage. In this prospective study, inspiratory pressures, air leak and signs of gastric insufflation were compared between volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) using an LMA. METHODS: Thirty-two ASA I patients, aged 4.5 +/- 4 years, who were scheduled for elective procedures under combined general anaesthesia and caudal analgesia, were enrolled. After inhalation induction and LMA insertion, each patient was randomly assigned to receive successively PCV and VCV. Peak pressures (PCV) and tidal volumes (VCV) were changed in order to achieve adequate ventilation [endtidal CO2 5-5.4 kPa (38-42 mmHg)]. RESULTS: Peak airway pressures were significantly lower with PCV than VCV (14.1 +/- 1.6 cmH2O versus 16.7 +/- 2.3 cmH2O, P < 0.001). No patient ventilated with PCV required peak pressure higher than 20 cmH2O compared with six patients ventilated with VCV (P < 0.05). Haemodynamic parameters, expiratory tidal volume and percent of leak were similar in both ventilatory modes and no signs of gastric insufflation were detected. CONCLUSIONS: During general anaesthesia in children using an LMA, PCV offers lower peak inspiratory airway pressures while maintaining equal ventilation compared with VCV. Although no signs of gastric insufflation were detected in both groups, the lower pressures might be significant in patients with reduced chest wall or lung compliance.