急性呼吸窘迫综合征氧代谢变化及反比通气效应的实验研究

目的　探讨呼吸窘迫综合征的氧代谢变化和反比通气的影响及临床应用前景。方法　应用油酸型犬急性呼吸窘迫综合征模型 ,并将反比通气 (IRV)与常规通气 (VC)加PEEP比较 ,动态观察氧转运与氧消耗的变化。结果　氧转运与氧消耗在 2h和 4h后均显著降低 ,氧转运与氧消耗呈显著正相关 (r=0 73,P <0 0 1)。IRV组氧转运下降延迟 ,伤后 6h时相点氧转运和氧消耗显著高于VC组。结论　氧转运和氧消耗降低为呼吸窘迫综合征的重要特征 ,IRV对氧代谢的改善优于常规通气组 ,可能是治疗呼吸窘迫综合征的又一适当的通气模式     

反比通气与呼气末正压通气在急性肺损伤中的应用比较

采用机械通气治疗，提高动脉血氧分压（ＰａＯ２），改善机体缺氧状态，是目前治疗急性呼吸窘迫综合征（ＡＲＤＳ）的主要措施。我们采用犬盐酸吸入肺损伤模型，观察反比通气（ＩＲＶ）对血流动力学和呼吸动力学的影响，并与呼气末正压通气（ＰＥＥＰ）和间歇正压通气（Ｉ...     

反比通气与常规通气治疗犬呼吸窘迫综合征时的呼吸动力学比较

目的：探索反比通气的临床应用价值，观察反比通气对呼吸窘迫综合征时呼吸动力学的影响。方法：应用犬油酸型急性呼吸窘迫综合征（ＡＲＤＳ）模型，Ｓｉｅｍｅｎｓ９００Ｃ呼吸机和ＨＰ１１６５Ａ监护系统，观察反比通气时的气道峰压、气道阻力、平均气道压和动态胸肺顺应性变化。结果：反比通气组的气道峰压和气道阻力显著低于常规通气组（Ｐ均＜０．０１），平均气道压和动态胸肺顺应性显著高于常规通气组（Ｐ均＜０．０１～０．０５）。结论：反比通气在改善ＡＲＤＳ呼吸动力学方面明显优于常规通气，对ＡＲＤＳ的治疗有一定的临床应用价值。     

压力控制通气治疗创伤性急性呼吸窘迫综合征的应用探讨

目的：探讨压力控制通气（ＰＣＶ）用于治疗创伤性急性呼吸窘迫综合征（ＡＲＤＳ）的临床应用价值。方法：观察创伤性ＡＲＤＳ患者ＰＣＶ组和容量控制通气（ＶＣＶ）治疗后６和１２小时气道峰压（ＰＩＰ），平均气道压（ＭＰａｗ）和呼气末正压（ＰＥＥＰ）的大小，并比较ＰＣＶ治疗对血气、血压和心率的影响。结果：ＰＣＶ组治疗后６和１２小时ＰＩＰ均显著低于ＶＣＶ组（Ｐ均〈０．０１），６小时ＭＰａｗ和ＰＥＥＰ与ＶＣＶ比较无     

急性呼吸窘迫综合征患者反比通气与常规通气疗效比较

我们应用反比通气（ＩＲＶ）治疗急性呼吸窘迫综合征（ＡＲＤＳ）患者，并与常规通气作比较，探索其临床价值。报告如下。１病例与方法１．１病例：１２例患者中男７例，女５例；年龄４０岁～７８岁，平均５１岁。原发病：急性坏死性胰腺炎３例，胃癌根治术后并多脏器功能...     

治疗急性呼吸衰竭的新方法--液相通气

急性呼吸衰竭的主要治疗目标是保证动脉血和组织内足够的氧合，提供解决或改善原发病的时间。为了达到这一目的，临床上研究发展了许许多多的治疗模式，如呼气末正压通气（ＰＥＥＰ），体外生命支持系统（ＥＣＬＳ），分侧肺通气和反比通气（ＩＲＶ）等，它们在改善肺功能...     

双相气道正压通气模式对急性肺损伤动物模型心肺功能的影响

目的：研究双相气道正压通气模式（ＢｉＰＡＰ）对急性肺损伤（ＡＬＩ）动物模型心肺功能的影响。方法：１１只犬麻醉后，用油酸造成ＡＬＩ模型。采用自身对照法比较其在ＢｉＰＡＰ、压力控制反比通气（ＰＣＩＲＶ）和容量控制反比通气（ＶＣＩＲＶ）３种通气模式中的呼吸、循环参数的变化。结果：在保持相同每分通气量和平均气道压的情况下，ＢｉＰＡＰ和ＰＣＩＲＶ模式的气道峰压均分别低于相同条件下ＶＣＩＲＶ模式的气道峰压，Ｐ均＜０．０５；在平均气道压相同情况下，ＢｉＰＡＰ和ＰＣＩＲＶ模式每分通气量分别为（４．４２±０．４３）Ｌ／ｍｉｎ和（４．４３±０．３９）Ｌ／ｍｉｎ，均大于ＶＣＩＲＶ模式的（３．８４±０．２０）Ｌ／ｍｉｎ和（３．７６±０．２３）Ｌ／ｍｉｎ，Ｐ均＜０．０５；ＢｉＰＡＰ模式时，肺泡死腔和肺内分流分别为（２０．２４±２．３６）和（１５．８０±２．６２），均较ＶＣＩＲＶ模式的（２４．９６±１．８７）和（２１．３６±２．２７）低（Ｐ均＜０．０５）；但ＰＣＩＲＶ模式时，上述两个指标与ＶＣＩＲＶ模式无显著性差异。结论：ＢｉＰＡＰ将压力控制通气和自主呼吸合为一体，是一种较好的治疗ＡＬＩ的通气模式。     

犬呼吸窘迫综合征的氧代谢变化及意义

应用静脉注射油酸复制犬急性呼吸窘迫综合征模型，观察氧转运与氧消耗的变化及相关性。结果显示：氧转运与氧消耗在２小时和４小时后均显著降低，氧转运与氧消耗呈显著正相关（ｒ＝０．７３，Ｐ＜０．０１）。提示：氧转运与氧消耗降低为呼吸窘迫综合征的重要特征，监测氧转运和氧消耗对指导治疗和判断预后有一定的价值     

一种新高频通气方法对实验性急性呼吸窘迫综合征的疗效观察

在高频喷射通气（ＨＦＪＶ）治疗犬实验性急性呼吸窘迫综合征（ＡＲＤＳ）时，采用连续ＨＦＪＶ基础上间歇叠加深吸气（ＨＦＪＶ＋ＤＩ）的新通气方法，以期为ＡＲＤＳ的治疗寻找一种新途径。用油酸复制犬ＡＲＤＳ模型，并随机分为３组。ＨＦＪＶ＋ＤＩ组（ｎ＝１０）：在连续ＨＦＪＶ基础上每隔１０分钟加入１次深吸气；常规机械通气组（ＣＭＶ，ｎ＝１０），给予０．７８５ｋＰａ（１ｋＰａ＝１０．２０ｃｍＨ２Ｏ）呼气末正压（ＰＥＥＰ）治疗；对照组（ｎ＝１０），未予通气治疗。每隔１小时测定１次氧合及血流动力学指标，共观察５小时。注射油酸后，动脉氧分压（ＰａＯ２）由１２．４００ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ）降至６．５６０ｋＰａ（Ｐ＜０．０１），动脉二氧化碳分压（Ｐａ－ＣＯ２）未见明显变化。通气治疗后，ＣＭＶ和ＨＦＪＶ＋ＤＩ均使ＰａＯ２明显升高，ＰａＣＯ２无明显变化（Ｐ＞０．０５），ＨＦＪＶ＋ＤＩ的氧释放指数（ＤＯ２Ｉ）明显高于ＣＭＶ组（Ｐ＞０．０５），心脏指数（ＣＩ）在ＣＭＶ组及ＨＦＪＶ＋ＤＩ组均明显减低（Ｐ＜０．０５）。提示：ＨＦＪＶ＋ＤＩ时ＰａＯ２的提高大于ＣＩ下降所致的不利影响，在改善组织缺氧方面明显优于ＣＭＶ时加用ＰＥＥＰ     

双相气道正压通气模式对急性肺损伤动物模型心肺功能的 …

研究双相气道正压通气模式对急性肺损伤动物模型心肺功能的影响。方法：１１只犬麻醉后，用油酸造成ＡＬＩ模型，采用自身对照法比较其在ＢｉＰＡＰ，压力控制反比通气和容量控制反比通气３种通气模式中的呼吸，循环参数的变化。结果；在保持相同每分通气量和平均气道压的情况下，ＢｉＰＡＰ和ＰＣ－ＩＲＶ模式的气道峰压均分别低于相同条件下ＶＣ－ＩＲＶ模式的气道峰压，Ｐ均〈０．０５；     

Optimum cardiopulmonary resuscitation for basic and advanced life support: a simulation study

Optimum cardiopulmonary resuscitation (CPR) for both basic and advanced cardiac life support depends on a compromise between the number of chest compressions delivered and the amount of ventilation provided. This study used theoretical models of blood flow and both arterial and venous blood gas values to investigate the influence of different compression to ventilation ratios on CPR efficiency, as well as the effects of different inspired oxygen concentrations. With mouth-to-mouth ventilation, greater numbers of compressions between each ventilation provided progressively greater blood flow. However, a greater the number of compressions, reduced the arterial oxygen levels and carbon dioxide clearance. There was an optimum ratio, in terms of both oxygen delivery and carbon dioxide clearance, of around 20:1 compressions to ventilation. Optimum oxygen delivery was 0.19 L/min at 20:1, which was better than the oxygen delivery for standard CPR based on a ratio of 15:2 (0.13 L/min). When patients were ventilated with supplemental oxygen (either 50 or 85%) the lungs rapidly became saturated with oxygen, and oxygen delivery depended more on blood flow. Higher numbers of compressions provided greater oxygen delivery, but at the cost of increasing hypercarbia, which is thought to affect resuscitation success rates adversely. The simulation results suggested ratios around 20:1 would be the best compromise between blood flow, oxygen delivery (0.25 L/min) and avoidance of hypercarbia. The best results were provided by continuous chest compressions and simultaneous, asynchronous ventilation in an intubated patient. Arterial and venous oxygen and carbon dioxide levels were well maintained, with very good oxygen delivery (0.32 L/min). Intubation with continuous chest compressions and asynchronous ventilation can therefore significantly improve the quality of CPR as a whole, and not just ventilation.     

不同频率控制通气对脓毒性休克患者血流动力学影响的研究

目的 观察脓毒性休克患者在进行机械通气时,不同频率控制通气对血流动力学、呼吸力学、氧代谢各项指标的影响.方法 筛选ICU收治的脓毒性休克患者中符合入选标准的患者共20例纳入研究.在持续药物镇静状态下给予基础通气条件：双水平正压通气（BiPAP ）模式,吸气压力（positive end-expiratory pressure high,PEEPh）=25cmH2O,呼气末正压（positive end-expiratory pressure high,PEEP）=5cmH2O,控制通气频率（frequency,F）=20次/min,压力支持（pressure support,PS）=0cmH2O,氧浓度（FiO2）根据氧合情况调整,脉氧饱和度维持在95%～100%.调整PEEPh,从25cmH2O 开始,以2cmH2O递增或递减,至转变为完全控制通气时为止,此时的PEEPh为所需设定值.将每位患者的F按随机顺序设置为20次/min（F20组）、15次/min（F15组）、10次/min（F10组）、5次/min（F5组）.通气20min后测定并记录血流动力学、氧代谢和呼吸力学指标.结果 ①不同频率控制通气对血流动力学的影响：随着控制通气频率的减少,自主呼吸比例增加,心排指数（cardiac output index,CI）、胸腔内血容积指数（intrathoratic blood volume index,ITBVI）、平均动脉压（mean arterial pressure,MAP）增加,体循环阻力指数（systemic vascular resistance index,SVRI）、中心静脉压（central venous pressure,CVP）降低,具有显著的相关性（P＜0.01）.控制通气频率与心率（heart rate,HR）、血管外肺水（extravascular lung water index,EVLWI ）之间均无相关性（P＞0.05）.组间比较：F5组与F20组相比,CI、ITBVI、MAP增加,SVRI、CVP降低,有统计学差异（P＜0.05）;F10组与F20组相比,CI、ITBVI增加,CVP降低,有统计学差异（P＜0.05）;F15组与F20组相比,仅CVP降低,有统计学差异（P＜0.05）.EVLWI 、HR各组间两两比较均无统计学差异（P ＞0.05）.②不同频率控制通气对呼吸力学的影响：随着控制通气频率的减少,气道峰压（peak air-way pressure,Ppeak）和平均气道压（mean air-way pressure,Pmean）降低,具有相关性（P＜0.05）.F5组与F20组相比Ppeak和Pmean均降低,具有统计学差异（P＜0.05）;其余各组之间比较无统计学差异（P＞0.05）.③不同频率控制通气对氧代谢的影响：随着控制通气频率的减少,氧输送（oxygen delivery,DO2）增加（P＜0.01）,氧合指数下降（P＜0.05）,均具有相关性.氧合指数组间两两比较均无统计学差异（P均＞0.05）.F5组DO2值最大,与其他各组相比均具有统计学差异（P＜0.05）;F10组与F20、F15组相比也具有统计学差异（P＜0.05）.结论 对于机械通气的脓毒性休克患者,随着控制通气比例的降低,自主呼吸比率增加,使心脏前负荷和心输出量增加,提高了氧输送,可能与气道压降低有关.     

七氟醚安氟醚对犬单肺通气期间肺分流与氧供及氧耗的影响

目的 观察犬单肺通气时,不同浓度七氟醚,安氟醚对Ｑｓ／Ｑｔ和氧供及氧耗等氧合指标的影响。方法 １４只健康杂种犬,诱导后插入双腔气管内导管,股动静脉分别置管监测血气和各自压力。随机分为两组,Ａ组吸入０．５ＭＡＣ、１．０ＭＡＣ安氟醚,待完全排除后再顺序吸入七氟醚;Ｂ组反之,各时相均分为双肺通气（ＴＬＶ）和单肺通气（ＯＬＶ）阶段,分别于ＴＬＶ、ＯＬＶ１５分钟后测量ＱＱｔ及氧供（ＤＯ２）、氧耗（ＶＯ２）等     

Optimum compression to ventilation ratios in CPR under realistic,practical conditions: a physiological and mathematical analysis

OBJECTIVE: To develop and evaluate a practical formula for the optimum ratio of compressions to ventilations in cardiopulmonary resuscitation (CPR). The optimum value of a variable is that for which a desired result is maximized. Here the desired result is assumed to be either oxygen delivery to peripheral tissues or a combination of oxygen delivery and waste product removal. METHOD: Equations describing oxygen delivery and blood flow during CPR as functions of the number of compressions and the number of ventilations delivered over time were developed from principles of classical physiology. These equations were solved explicitly in terms of the compression/ventilation ratio and evaluated for a wide range of conditions using Monte Carlo simulations. RESULTS: As the compression to ventilation ratio was increased from 0 to 50 or more, both oxygen delivery and the combination of oxygen delivery with blood flow increased to maximum values and then gradually declined. For variables typical of standard CPR as taught and specified in international guidelines, maximum values occurred at compression/ventilation ratios near 30:2. For variables typical of actual lay rescuer performance in the field, maximal values occurred at compression/ventilation ratios near 60:2. CONCLUSION: Current guidelines overestimate the need for ventilation during standard CPR by two to four-fold. Blood flow and oxygen delivery to the periphery can be improved by eliminating interruptions of chest compression for these unnecessary ventilations.     

Helium-oxygen and conventional mechanical ventilation in the treatment of large airway obstruction and respiratory failure in an infant

The application of 70% helium-30% oxygen mixtures by tight-fitting face mask in the emergency management of large airway obstruction is well known. We present the case of an infant with severe large airway obstruction and respiratory failure that was unresponsive to the more traditional approaches of airway management, including the delivery of He-O2 by face mask, endotracheal intubation, and conventional mechanical ventilation with oxygen alone. This case was successfully managed with He-O2, when concentrations of O2 were lower than those previously reported in association with conventional mechanical ventilation, until the obstruction could be surgically corrected. We suggest using a new combination of the low-density helium-oxygen gas mixtures and conventional mechanical ventilation, both of which are readily available in most intensive care units.     

限制性与开放性液体复苏对脓毒性休克患者呼吸力学及氧代谢的影响

目的 比较两种液体复苏方案对脓毒性休克(SS)患者呼吸力学与氧代谢功能的影响。方法 选取我院收治的SS患者98例,其中接受限制性液体复苏治疗的患者(观察组)45例,接受开放性液体复苏治疗的患者(对照组)53例,对比两组复苏治疗前、治疗后72 h呼吸力学、氧代谢、血流动力学指标以及药物使用情况。结果 治疗后,观察组静态肺顺应性(Cst)、氧输送(DO₂)、氧合指数(PaO₂/FiO₂)高于对照组,血乳酸(Lac)低于对照组(均P<0.01)。观察组24 h复苏液体量小于对照组,血管活性药物剂量大于对照组,使用时间长于对照组(均P<0.05);相关分析显示,24 h复苏液体量与Cst及DO₂、PaO₂/FiO₂均存在负相关(均P<0.01);观察组机械通气时间、住院时间短于对照组(均P<0.01),两组28 d病死率差异无统计学意义(P=0.350)。结论 治疗SS采用限制性液体复苏方案能够改善患者肺顺应性与氧代谢功能,且对血流动力学无不良风险。     

不同镇静药物对机械通气患者血流动力学及氧代谢的影响

目的探讨丙泊酚、咪达唑仑及右美托咪定对机械通气患者血流动力学及氧代谢的影响。方法将60例机械通气患者分为丙泊酚组（P组）、咪达唑仑组（M组）及右美托咪定组（D组）,每组各20例。对每组镇静前后及不同组间镇静后血流动力学及氧代谢指标变化进行比较。结果三组患者镇静后心率、平均动脉压、心排量、心指数及氧供均有不同程度下降,中心静脉血氧饱和度（ScvO2）均有不同程度上升,而全身血管阻力指数（SVRD、全心舒张末期容积指数（GEDVI）仅在D组镇静后有所下降（P均〈0．05）。镇静后三组患者的心率、平均动脉压、SVRI、GEDVI、心排量、心指数、氧供及ScvO2比较,差异均有统计学意义（P均〈0．05）。进一步两两比较,心率、平均动脉压及ScvO2在M组与D组比较时有统计学意义（P=0．003、0．006、0．000）,SVRI水平在D组与P组及M组比较时均有统计学意义（P=0．001、0．015）,而GEDVI、心排量、心指数仅在D组与P组比较时有统计学意义（P=0．015、0．011、0．002）。结论三种药物均能达到减少氧耗作用且镇静效果确切,但使用右美托咪定镇静时需注意药物所致心动过缓及低血压的风险,而使用丙泊酚镇静时需注意药物对心功能的抑制。     

Quality of CPR with three different ventilation:compression ratios

Current adult basic cardiopulmonary resuscitation (CPR) guidelines recommend a 2:15 ventilation:compression ratio, while the optimal ratio is unknown. This study was designed to compare arterial and mixed venous blood gas changes and cerebral circulation and oxygen delivery with ventilation:compression ratios of 2:15, 2:50 and 5:50 in a model of basic CPR. Ventricular fibrillation (VF) was induced in 12 anaesthetised pigs, and satisfactory recordings were obtained from 9 of them. A non-intervention interval of 3 min was followed by CPR with pauses in compressions for ventilation with 17% oxygen and 4% carbon dioxide in a randomised, cross-over design with each method being used for 5 min. Pulmonary gas exchange was clearly superior with a ventilation:compression ratio of 2:15. While the arterial oxygen saturation stayed above 80% throughout CPR for 2:15, it dropped below 40% during part of the ventilation:compression cycle for both the other two ratios. On the other hand, the ratio 2:50 produced 30% more chest compressions per minute than either of the two other methods. This resulted in a mean carotid flow that was significantly higher with the ratio of 2:50 than with 5:50 while 2:15 was not significantly different from either. The mean cerebrocortical microcirculation was approximately 37% of pre-VF levels during compression cycles alone with no significant differences between the methods. The oxygen delivery to the brain was higher for the ratio of 2:15 than for either 5:50 or 2:50. In parallel the central venous oxygenation, which gives some indication of tissue oxygenation, was higher for the ratio of 2:15 than for both 5:50 and 2:50. As the compressions were done with a mechanical device with only 2-3 s pauses per ventilation, the data cannot be extrapolated to laypersons who have great variations in quality of CPR. However, it might seem reasonable to suggest that basic CPR by professionals should continue with ratio of 2:15 at present if it can be shown that similar brief pauses for ventilation can be achieved in clinical practice.     

The ventilatory cost of exercise compared in chronic heart failure and chronic renal anaemia.

The cardiorespiratory responses to maximal treadmill exercise were compared in matched groups of patients with chronic renal anaemia or treated chronic heart failure, and in normal controls. Exercise capacity was similarly reduced in both patient groups compared to normal controls, the raised respiratory exchange ratio at peak exercise implying anaerobic metabolism due to limited oxygen delivery in heart failure and limited oxygen carrying capacity in anaemia. Minute ventilation (VE) was related linearly to minute CO2 production (VCO2) in all subjects (each r > 0.92) from all three groups. The slope of the VE/VCO2 relationship was normal in anaemia but steeper in heart failure, reflecting ventilation/perfusion mismatching in chronic heart failure.