吸入一氧化氮联合反比通气治疗感染性急性呼吸窘迫综合征

目的 :观察吸入一氧化氮 (NO)联合反比通气 (IRV)对感染性急性呼吸窘迫综合征 (ARDS)羊血流动力学、肺气体交换和机械力学的影响。方法 :静脉注入小剂量内毒素诱导的羊感染性 ARDS模型 12只 ,随机均分为两组。 NO组吸入 4 0× 10 - 6 NO,复合组联合容量控制反比通气 (VC IRV)和吸入 4 0× 10 - 6 NO。通过肺动脉导管、动脉和混合静脉血气分析 ,测定基础、ARDS和治疗 30 m in后肺气体交换和血流动力学参数 ,记录相应时间点的气道峰压 (PIP)、平均气道压 (Pm)和内源性呼气末正压 (PEEPi)。结果 :NO组和复合组治疗期间平均肺动脉压较 ARDS时均显著降低 (P均 <0 .0 1) ,动脉血压和心排血量则无明显变化 ;治疗 30 m in后 ,两组均能明显提高 ARDS的 Pa O2 (P均 <0 .0 1) ,减少肺泡动脉氧分压差〔 P( A a) O2 〕和肺内分流 (Qs/ Qt,P均 <0 .0 1) ,复合组更为显著 (P均 <0 .0 5 ) ;NO组各监测时间点 PIP、Pm均无明显变化 ,复合组的 Pm较治疗前及NO组对应时间点高 (P均 <0 .0 5 ) ,PIP则低 (P均 <0 .0 5 )。复合组治疗时 ,PEEPi为 (2 .5± 0 .5 ) cm H2 O(1cm H2 O=0 .0 98k Pa)。结论 :吸入 NO复合 IRV可协同改善 ARDS肺氧合 ,不影响体循环。     

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     

高频震荡通气与吸入一氧化氮在严重氧合障碍患者中的应用

我们对 6例常规机械通气无效的患者 ,分别予以吸入一氧化氮 (NO)和换用高频震荡通气治疗 ,报告如下。1　病例与方法1.1　病例 :1999— 2 0 0 1年治疗的 6例患者中 ,男 5例 ,女 1例 ,均有严重的氧合功能障碍 ,并合并多器官功能不全或衰竭。 6例患者的一般情况见表 1。根据急性生理学与慢性健康状况评价系统 (APACHE )评分 ,所有患者病死率预计均达 10 0 % ,常规机械通气时所有患者均使用高档电脑呼吸机 ,模式容量控制通气 (VCV)或压力控制通气 (PCV)加呼气末正压 (PEEP) ,经 48小时以上 ,氧合指数仍 <(5 1.0± 6 .4) k Pa(1k Pa=7.5…     

醒脑静注射液联合无创正压机械通气治疗慢性阻塞性肺疾病急性发作期的临床研究

目的 :观察醒脑静注射液联合面罩无创机械通气 (NIPPV)治疗慢性阻塞性肺疾病 (COPD)急性发作期的临床疗效。方法 :对 35例 COPD急性发作期患者采用醒脑静注射液联合 NIPPV治疗 (中西医结合治疗组 ) ,并与单用 NIPPV治疗的 32例 COPD急性发作期患者 (对照组 )进行比较。结果 :中西医结合治疗组总有效率高于对照组 (91.4 %比 81.3% ,P<0 .0 5 ) ;中西医结合治疗组治疗后血气分析示动脉血氧分压 (Pa O2 )的升高幅度大于对照组〔(0 .86± 0 .0 5 ) k Pa(1k Pa=7.5 mm Hg)比 (0 .6 9± 0 .32 ) k Pa,P<0 .0 5〕,动脉血二氧化碳分压 (Pa CO2 )的下降幅度明显大于对照组〔(1.10± 0 .0 7) k Pa比 (0 .86± 0 .0 3) k Pa,P<0 .0 1〕;中西医结合治疗组治疗前后患者由意识障碍转为清醒状态所用时间要明显短于对照组〔(10 5 .0 0± 5 .5 2 )分钟比 (135 .0 0±6 .13)分钟 ,P<0 .0 1〕。结论 :醒脑静注射液联合 NIPPV治疗 COPD急性发作期患者疗效可靠 ,方便易行     

肺保护性通气对肺内外源性急性呼吸窘迫综合征外周血和肺泡灌洗液中炎性介质影响的比较

目的　观察在肺保护性通气条件下急性呼吸窘迫综合征 (ARDS)模型犬氧合指数以及外周血和肺不同部位 (肺上区、肺下区腹侧和肺下区背侧 )支气管肺泡灌洗液 (BAL F)中炎性介质的变化。方法　健康雄性杂种犬 2 4只 ,随机分为肺内源性 ARDS(ARDSp)实验组、ARDSp 对照组、肺外源性 ARDS(ARDSexp)实验组和 ARDSexp对照组 ,每组 6只。采用静脉注射油酸形成 ARDSexp模型 ,应用十六烷磺基丁二酸钠盐气管内吸入形成 ARDSp模型。实验组肺损伤后进行肺保护性通气〔潮气量 8ml/ kg,呼气末正压(PEEP) 10 cm H2 O(1cm H2 O=0 .0 98k Pa)〕;对照组则继续进行大潮气量通气。动态观察肺保护性通气条件下 ARDS模型犬外周血和肺不同部位 (如肺尖叶、肺心叶和肺膈叶 ) BAL F中的炎性介质 ,如肿瘤坏死因子α(TNFα)、白细胞介素 (IL 1β,IL 6 )的变化。结果　肺损伤后 ARDS模型犬氧合指数均显著恶化 ,外周血中炎性介质明显升高 (P均 <0 .0 5 ) ,ARDSp模型犬肺尖叶和心叶 BAL F中炎性介质水平明显高于 ARDSexp模型犬 (P均 <0 .0 5 )。应用肺保护性通气治疗后 ,实验组犬氧合指数有不同程度改善 ,炎性介质水平有不同程度下降 ;但 ARDSp实验组的治疗效果不如 ARDSexp实验组。结论　 ARDSexp和 ARDSp的肺不同部位炎性介质释放和氧合     

高频喷射通气联合气管内吹气对急性肺损伤的治疗作用

目的　探讨高频喷射通气联合气管内吹气对急性肺损伤的治疗作用。方法　杂种犬 12条 ,随机分为两组 ,用大剂量生理盐水灌洗肺造成急性肺损伤。各组分别给予高频喷射通气 ,调整呼吸机参数使第一组实验犬PaCO2 维持在 35～ 5 0mmHg,第二组实验犬PaCO2 维持在 6 0～ 80mmHg。然后进行 4L/min和 8L/min氧气流量的气管内吹气 ,每阶段进行 30min ,观察血流动力学指标和血气指标的变化。结果　①联合通气后 ,两组PaCO2 及PetCO2 均明显下降 ,且随着吹入气氧流量的增加下降更明显。②联合通气后 ,动脉血氧分压在两组中明显上升 ,但随着吹入气氧流量的增加 ,动脉血氧分压变化无明显差异 (P >0 0 5 )。③联合通气后使各组气道压明显上升。④联合通气对各组犬血流动力学无显著影响 (P >0 0 5 )。结论　高频喷射通气联合气管内吹气能有效地降低肺损伤犬PaCO2 ,促进二氧化碳的排除 ,提高肺损伤犬的氧合且不影响实验犬的血流动力学     

控制性肺膨胀对急性呼吸窘迫综合征肺静态顺应性曲线低位转折点的影响

目的 :探讨控制性肺膨胀 (SI)对急性呼吸窘迫综合征 (ARDS)肺静态顺应性曲线低位转折点压力(Pinf)的影响。方法 :30只家兔利用肺泡灌洗法建立 ARDS模型 ,并随机分为 SI组和非 SI组 ,观察 SI后 2小时动物的 Pinf、肺气体交换和肺机械力学特征改变。结果 :SI组动物 SI前 Pinf为〔(0 .90± 0 .14 ) k Pa,1k Pa=10 .2 0 cm H2 O〕,SI 2小时后 Pinf降到 (0 .6 1± 0 .14 ) k Pa(P=0 .0 2 0 ) ;非 SI组机械通气 2小时前后 Pinf无明显改变 ,P>0 .0 5。 SI组动物机械通气 2小时后动脉血氧分压 (Pa O2 )和氧饱和度 (Sa O2 )分别为 (2 4 .2 0±8.79) k Pa(1k Pa=7.5 m m Hg)和 0 .96 7± 0 .0 2 4 ,显著高于非 SI组〔分别为 (10 .80± 1.13) k Pa和 0 .76 8±0 .0 76 ,P<0 .0 5〕。 SI组动物机械通气 2小时后动态肺顺应性 (Cydn)为 (12 .2 4± 1.5 3) ml/k Pa,显著高于非 SI组〔(9.80± 0 .82 ) ml/k Pa〕。结论 :SI具有促进肺泡复张、降低 Pinf水平的效应 ,实施 SI后应重新调整呼气末正压 (PEEP)水平。     

吸入沙丁胺醇对呼吸衰竭患者容积标限压力控制通气时通气参数的影响

目的　探讨在容积标限压力控制 (VTPC)通气时吸入支气管扩张剂沙丁胺醇后对机械通气参数的影响。方法　 10例平均年龄为 (6 8± 5 )岁的呼吸衰竭患者均接受气管插管与机械通气支持治疗 ;采用Newport e5 0 0型呼吸机 ,并实施定容型通气 (VCV) 30 min,潮气量 (VT)为 8～ 10 ml/ kg;测定气道阻力 (Raw)和静态顺应性 (Cst)以及通气参数的变化 ,包括气道峰压 (PIP)、平台压 (Pplat)、充气时间 (Tinflate)、吸气峰流速(PIF)、呼气峰流速 (PEF)和平均吸气流速 (VT/ Tinflate)。随后转为 VTPC通气 30 m in,并同样记录上述参数。通过同轴吸入装置吸入沙丁胺醇 6 0 0 μg后重复 VCV和 VTPC通气 ,并记录上述通气参数。结果　 10例患者的 Cst为 (38.4± 2 .7) ml/ cm H2 O,Raw为 (2 0 .1± 2 .0 ) cm H2 O· L- 1 · s- 1 。VTPC时 PIP和 VT/ Tinflate较 VCV时显著降低 (P均 <0 .0 5 ) ,PIF则显著增高 ,两种通气时的 Pplat无显著性差异 ,分别为 (2 2 .1± 0 .9) cm H2 O和(2 3.0± 1.2 ) cm H2 O(P>0 .0 5 )。吸入沙丁胺醇后患者的 Raw均显著降低 ,而 Cst无明显变化 ,VCV时的 PIP有所降低 ,但 Pplat无变化 ;VTPC时的 PIP和 Pplat与吸入前比较无明显改变 ,但 PIF和 PEF出现显著增高 ,Tinflate则相应缩短 (P均 <0 .0 5     

体外膜氧合器对急性肺损伤犬血浆炎症因子的影响

目的　研究体外膜氧合器 (extracorporealmembraneoxygenation ,ECMO)对急性肺损伤犬血浆炎症因子的影响。方法　 10只健康杂种犬 ,随机分成机械通气 (MV)和体外膜氧合器联合机械通气 (ECMO+MV)两组。采用静脉注射油酸复制犬急性肺损伤模型 ,然后进行MV或ECMO治疗 2 4 0min。应用ELISA法测定血浆中细胞因子 (IL - 6、IL - 8、IL - 10和IL - 12 )。结果　应用ECMO可以改善低氧血症 (P <0 0 5 ) ,但是对于肺动脉压力没有明显改善。使用ECMO后血浆中IL - 6、IL - 8和IL - 19浓度较对照组升高(P <0 0 5 ) ,IL - 10浓度则没有明显变化。结论　体外膜氧合器可以改善急性肺损伤犬的氧供 ,但是对于肺动脉压力的高没有降低作用 ,而且使用体外膜氧合器后血浆中多种细胞因子显著升高。     

无创通气在早期急性呼吸窘迫综合征治疗中的作用

急性呼吸窘迫综合征 (ARDS)是一个弥漫性的严重肺损伤综合征 ,近年来 ,一些学者认为它不仅是多脏器功能衰竭(MODS)的肺部表现 ,更可能是其起动因子 ,因此对 ARDS的早期诊断和治疗尤为重要。随着无创正压通气技术在临床的广泛应用 ,使 ARDS的早期治疗成为可能 ,本文通过比较我院自1998- 0 8～ 2 0 0 0 - 0 8间应用双水平无创正压通气 (BIPAP)和经典有创通气治疗 ARDS,总结无创正压通气在早期 ARDS治疗中的作用。1　对象和方法资料来自我院病案室 ,共计 8例 ,其中 5例应用 BIPAP,3例应用有创通气。ARDS的诊断符合 1999年全国…     

高频双向喷射通气和常规机械通气对蒸气吸入性损伤犬治疗效果的比较

目的：观察高频双向喷射通气（ＨＦＴＪＶ）和常规机械通气（ＣＭＶ）对蒸气吸入性损伤犬的呼吸循环动力学参数、肺容量及血气的影响。方法：通过蒸气吸入致伤，复制了犬重度蒸气吸入性损伤模型。结果：①两种通气方式下呼吸系统总阻力（Ｒｒｓ）、肺阻力（ＲＬ）均显著高于对照值（Ｐ均＜０．０１），呼吸系统总顺应性（Ｃｒｓ）、肺顺应性（ＣＬ）均显著低于对照值（Ｐ均＜０．０５），但两者之间比较，Ｒｒｓ、ＲＬ和Ｃｒｓ、ＣＬ的变化均无显著性差异（Ｐ均＞０．０５）。②ＣＭＶ能引起ＣＯ２潴留；ＨＦＴＪＶ比ＣＭＶ显著增加ＣＯ２排出量（ＶＣＯ２，Ｐ＜０．０５），降低过高的ＰａＣＯ２（Ｐ＜０．０１）。③两种通气方式下功能残气量（ＦＲＣ）、心输出量（ＣＯ）、平均动脉压（ＭＡＰ）和ＰａＯ２均无显著变化（Ｐ均＞０．０５）。结论：两种通气方式均能克服气道阻力辅助呼吸，但不能使伤后高气道阻力和低肺顺应性恢复正常。ＣＭＶ的通气效率较低，可引起ＣＯ２潴留；ＨＦＴＪＶ的通气效率则明显优于ＣＭＶ，且能维持吸入性损伤犬的血气至正常水平。     

Airway pressure release ventilation

Airway pressure release ventilation (APRV) delivers continuous positive airway pressure (CPAP) and may support ventilation simultaneously. This investigation tested whether, after acute lung injury (ALI), APRV promotes alveolar ventilation and arterial oxygenation without increasing airway pressure (Paw) above the CPAP level and without depressing cardiac function. Ten anesthetized dogs randomly received either intermittent positive-pressure ventilation (IPPV) or APRV. APRV was delivered with a continuous-flow CPAP system. Expiration occurred when a switch in the expiratory limb opened and Paw decreased to near-ambient, which decreased lung volume. After baseline data collection, ALI was induced by infusing oleic acid iv. Two hours later, IPPV and APRV were administered randomly, and data were collected. With normal lungs, APRV and IPPV achieved similar gas exchange and hemodynamic function. During ALI, arterial oxygenation was improved, and peak Paw which did not exceed the CPAP level, was lower during APRV. Similar minute ventilations were delivered by both modes but resulted in lower PaCO2 with APRV. Thus, APRV decreased physiologic deadspace ventilation. Hemodynamic status was similar during both modes. Therefore, APRV is an improved method of oxygenation and ventilatory support for patients with ALI that will allow unrestricted spontaneous ventilation and may decrease the incidence of barotrauma.     

Regional lung aeration and ventilation during pressure support and biphasic positive airway pressure ventilation in experimental lung injury

Introduction  

There is an increasing interest in biphasic positive airway pressure with spontaneous breathing (BIPAP+SB_mean), which is a combination of time-cycled controlled breaths at two levels of continuous positive airway pressure (BIPAP+SB_controlled) and non-assisted spontaneous breathing (BIPAP+SB_spont), in the early phase of acute lung injury (ALI). However, pressure support ventilation (PSV) remains the most commonly used mode of assisted ventilation. To date, the effects of BIPAP+SB_mean and PSV on regional lung aeration and ventilation during ALI are only poorly defined.     

Airway pressure release ventilation in a neonatal lamb model of acute lung injury

OBJECTIVE: To determine if airway pressure release ventilation (APRV) is feasible in a neonatal animal model with acute lung injury. DESIGN: Nonrandomized, repeated, bracketed measures. SETTING: University research laboratory. SUBJECTS: Seven neonatal sheep (5.6 +/- 0.6 kg), less than 10 days of age. INTERVENTIONS: Acute lung injury was induced by oleic acid infusion and cardiorespiratory profiles were compared during spontaneous ventilation at ambient airway pressure, continuous positive airway pressure (CPAP), APRV, and conventional positive-pressure ventilation (PPV). MEASUREMENTS AND RESULTS: Oleic acid resulted in acute lung injury with stable cardiorespiratory status during the 3-hr study period. Mean airway pressure (Paw) was comparable for all three positive-pressure modes (CPAP 13.4 +/- 1.5, APRV 13.5 +/- 1.4, PPV 13.9 +/- 1.4 cm H2O, NS). After acute lung injury, CPAP increased arterial oxygenation compared with spontaneous ventilation (77.3 +/- 6.9 vs. 57.7 +/- 4.2 torr [10.3 +/- 0.9 vs. 7.7 +/- 0.6 kPa], p less than .05), and this increase was maintained during APRV (73.3 +/- 5.6 vs. 77.3 +/- 6.9 torr [9.8 +/- 0.7 vs. 10.3 +/- 0.9 kPa], NS). Alveolar ventilation was increased by APRV compared with CPAP (PaCO2 29 +/- 1 vs. 41 +/- 2 torr [3.9 +/- 0.1 vs. 5.4 +/- 0.3 kPa], p less than .05) without impairment of cardiovascular performance (cardiac output 1.18 +/- 0.16 vs. 1.20 +/- 0.17 L/min, NS). To achieve ventilation equivalent to APRV during PPV, peak Paw was greater (36.4 +/- 3.2 vs. 19.7 +/- 1.7 cm H2O, p less than .05) and cardiac output (0.94 +/- 0.11 vs. 1.18 +/- 0.16 L/min, p less than .05) and mean arterial pressure (91 +/- 7 vs. 96 +/- 6 mm Hg, p less than .05) were decreased during PPV compared with APRV. CONCLUSIONS: In this neonatal laboratory model of acute lung injury, APRV maintained oxygenation and augmented alveolar ventilation compared with CPAP. Compared with PPV, APRV provided similar ventilation and oxygenation, but at lower peak Paw than PPV, without compromising cardiovascular performance.     

The effect of positive end-expiratory pressure during partial liquid ventilation in acute lung injury in piglets.

OBJECTIVES: To investigate the effects of positive end-expiratory pressure (PEEP) application during partial liquid ventilation (PLV) on gas exchange, lung mechanics, and hemodynamics in acute lung injury. DESIGN: Prospective, randomized, experimental study. SETTING: University research laboratory. SUBJECTS: Six piglets weighing 7 to 12 kg. INTERVENTIONS: After induction of anesthesia, tracheostomy, and controlled mechanical ventilation, animals were instrumented with two central venous catheters, a pulmonary artery catheter and two arterial catheters, and an ultrasonic flow probe around the pulmonary artery. Acute lung injury was induced by the infusion of oleic acid (0.08 mL/kg) and repeated lung lavage procedures with 0.9% sodium chloride (20 mL/kg). The protocol consisted of four different PEEP levels (0, 5, 10, and 15 cm H2O) randomly applied during PLV. The oxygenated and warmed perfluorocarbon liquid (30 mL/kg) was instilled into the trachea over 5 mins without changing the ventilator settings. MEASUREMENTS AND MAIN RESULTS: Airway pressures, tidal volumes, dynamic and static pulmonary compliance, mean and expiratory airway resistances, and arterial blood gases were measured. In addition, dynamic pressure/volume loops were recorded. Hemodynamic monitoring included right atrial, mean pulmonary artery, pulmonary capillary wedge, and mean systemic arterial pressures and continuous flow recording at the pulmonary artery. The infusion of oleic acid combined with two to five lung lavage procedures induced a significant reduction in PaO2/FI(O2) from 485 +/- 28 torr (64 +/- 3.6 kPa) to 68 +/- 3.2 torr (9.0 +/- 0.4 kPa) (p < .01) and in static pulmonary compliance from 1.3 +/- 0.06 to 0.67 +/- 0.04 mL/cm H2O/kg (p < .01). During PLV, PaO2/FI(O2) increased significantly from 68 +/- 3.2 torr (8.9 +/- 0.4 kPa) to >200 torr (>26 kPa) (p < .01). The highest PaO2 values were observed during PLV with PEEP of 15 cm H2O. Deadspace ventilation was lower during PLV when PEEP levels of 10 to 15 cm H2O were applied. There were no differences in hemodynamic data during PLV with PEEP levels up to 10 cm H2O. However, PEEP levels of 15 cm H2O resulted in a significant decrease in cardiac output. Dynamic pressure/volume loops showed early inspiratory pressure spikes during PLV with PEEP levels of 0 and 5 cm H2O. CONCLUSIONS: Partial liquid ventilation is a useful technique to improve oxygenation in severe acute lung injury. The application of PEEP during PLV further improves oxygenation and lung mechanics. PEEP levels of 10 cm H2O seem to be optimal to improve oxygenation and lung mechanics.     

Ventilation with biphasic positive airway pressure in experimental lung injury

Objective We investigated whether improvement in ventilation perfusion (_A/) distribution during mechanical ventilation using biphasic positive airway pressure (BIPAP) with spontaneous breathing may be attributed to an effectively increased transpulmonary pressure (P_TP) and can also be achieved by increasing P_TP during controlled ventilation.Design In 12 pigs with saline lavage-induced lung injury we compared the effects of BIPAP to pressure-controlled ventilation with equal airway pressure (PCV_AW) or equal transpulmonary pressure (PCV_TP) on _A/ distribution assessed by the multiple inert gas elimination technique (MIGET).Setting Animal laboratory study.Measurements and results Intrapulmonary shunt was 33±11% during BIPAP, 36±10% during PCV_AW and 33±15% during PCV_TP (p= n.s.). BIPAP resulted in higher PaO₂ than PCV_AW (188±83 versus 147±82 mmHg, p<0.05), but not than PCV_TP (187±139 mmHg). Oxygen delivery was significantly higher during BIPAP (530±109 ml/min) versus 374±113 ml/min during PCV_AW and 353±93 ml/min during PCV_TP (p<0.005). Tidal volume with PCV_TP increased to 11.9±2.3 ml/kg, compared to 8.5±0.8 with BIPAP and 7.6±1.4 with PCV_AW (p<0.001) and cardiac output decreased to 3.5±0.6 l/min (BIPAP 4.9±0.8 and PCV_AW 3.9±0.8, p<0.006).Conclusions In experimental lung injury, BIPAP with preserved spontaneous breathing was effective in increasing regional P_TP, since pressure-controlled ventilation with the same P_TP resulted in similar gas exchange effects. However, PCV_TP caused increased airway pressures and tidal volumes, whereby, with BIPAP, less depression of oxygen delivery and cardiac output were observed. BIPAP could be useful in maintaining pulmonary gas exchange and slightly improving oxygenation without interfering with circulation as strongly as PCV does.An editorial regarding this article can be found in the same issue ()     

高频部分液体通气治疗吸入性肺损伤的实验研究

目的：观察高频部分液体通气治疗吸入性肺损伤的效果,并与单纯高频喷射通气的疗效比较。方法：将16只犬经蒸气吸入造成吸入性肺损伤模型,并随机分为对照组和治疗组。2组动物致伤后均行高频喷射通气,治疗组动物同时经气管导管将氟碳液体（3ml/kg)缓慢注入肺内,实行高频部分液体通气治疗,于30、60及90分钟测定动脉血气、肺顺应性和气道阻力。结果：治疗组动脉血氧分压（PaO2)进行性上升,各时间点与致伤后比较均有显著性差异（P均＜0．05）,动脉血二氧化碳分压（PaCO2)也逐渐增高,于60和90分钟显著高于致伤后水平（P均＜0．05）;与对照组比较,治疗组各时间点的PaO2稍有升高,而PaCO2于90分钟显著增高（P＜0．05）。在各时间点的动、静态气道阻力和动、静态肺顺应性,2组比较均无明显差异。结论：高频部分液体通气与单纯高频喷射通气相比,更有利于动脉血氧合,但也有轻度CO2潴留现象。     

Ventilator strategies for posttraumatic acute respiratory distress syndrome: airway pressure release ventilation and the role of spontaneous breathing in critically ill patients

PURPOSE OF REVIEW: Patients who experience severe trauma are at increased risk for the development of acute lung injury and acute respiratory distress syndrome. The management strategies used to treat respiratory failure in this patient population should be comprehensive. Current trends in the management of acute lung injury and acute respiratory distress syndrome consist of maintaining acceptable gas exchange while limiting ventilator-associated lung injury. RECENT FINDINGS: Currently, two distinct forms of ventilator-associated lung injury are recognized to produce alveolar stress failure and have been termed low-volume lung injury (intratidal alveolar recruitment and derecruitment) and high-volume lung injury (alveolar stretch and overdistension). Pathologically, alveolar stress failure from low- and high-volume ventilation can produce lung injury in animal models and is termed ventilator-induced lung injury. The management goal in acute lung injury and acute respiratory distress syndrome challenges clinicians to achieve the optimal balance that both limits the forms of alveolar stress failure and maintains effective gas exchange. The integration of new ventilator modes that include the augmentation of spontaneous breathing during mechanical ventilation may be beneficial and may improve the ability to attain these goals. SUMMARY: Airway pressure release ventilation is a mode of mechanical ventilation that maintains lung volume to limit intra tidal recruitment /derecruitment and improves gas exchange while limiting over distension. Clinical and experimental data demonstrate improvements in arterial oxygenation, ventilation-perfusion matching (less shunt and dead space ventilation), cardiac output, oxygen delivery, and lower airway pressures during airway pressure release ventilation. Mechanical ventilation with airway pressure release ventilation permits spontaneous breathing throughout the entire respiratory cycle, improves patient comfort, reduces the use of sedation, and may reduce ventilator days.     

急性心源性肺水肿机械通气患者呼气末正压设定的临床研究

目的探讨急性心源性肺水肿(ACPE)时不同呼气末正压(PEEP)水平对血流动力学与肺参数的影响。方法39例呼吸衰竭机械通气患者根据心排血指数(CI)分为两组。观察心功能正常组(n=18,CI≥2.0L·min-1·m-2)与心功能低下组(n=21,CI<2.0L·min-1·m-2)在双水平气道正压通气(BIPAP)模式下不同PEEP水平对血流动力学〔心排血量(CO)、CI、肺毛细血管血流(PCBF)、中心静脉压(CVP)、外周血管阻力(SVR)〕、肺参数〔内源性呼气末正压(PEEPi)、气道峰压(Ppeak)、平均气道压(Pmean)、每分通气量(MV)、肺泡通气量(Vtalv)〕及经皮血氧饱和度(SpO2)、血压(BP)、心率(HR)等的变化。结果心功能正常组PEEP在0～13cmH2O(1cmH2O=0.098kPa)对血流动力学无明显影响,肺参数中Ppeak、PEEPi随着PEEP增高而相应增高,气道阻力(R)下降;心功能低下组随着PEEP变化SVR、CO、CI呈曲线性变化,以PEEP0～7cmH2O时CO、CI值较高而SVR较低,10～13cmH2OCO、CI值较低而SVR较高,对肺参数影响以PEEP5～7cmH2O时PEEPi较小。结论ACPE患者机械通气调节应结合血流动力学变化并兼顾肺机械参数变化,PEEP使用具有明显个体化倾向,以PEEP5～7cmH2O(一般<10cmH2O)为宜。     

The technique of inverse ratio ventilation. Steps to improve oxygenation and decrease dead space ventilation

Inverse ratio ventilation (IRV) differs from other ventilatory techniques in that it employs a prolonged inspiratory time. In theory, pressure-control IRV allows you to maintain ventilation and oxygenation with lower peak airway and end-expiratory pressures; this may reduce the potential for lung damage secondary to shearing forces. Consider pressure-control IRV for patients with acute lung disease characterized by low lung compliance, diffuse microatelectasis, and increased intrapulmonary shunting. Currently, the chief limitation of this technique is that the patient cannot breathe spontaneously during its use. The best inspiratory to expiratory ratio is the shortest inspiratory time that improves oxygenation with minimal hemodynamic compromise; depression of cardiac output will negate any potential improvement in arterial oxygenation.