不同通气模式对急性呼吸窘迫综合征模型犬呼吸力学和氧代动力学的影响

目的：研究在保留自主呼吸时，双相气道正压通气和间歇正压通气对急性呼吸窘迫综合征模型犬呼吸力学和氧代动力学的影响。方法：选择健康杂种犬12只，全麻后用油酸制成急性呼吸窘迫综合征模型，采用自身对照法观察其在机械通气前、间歇正压通气和双相气道正压通气等状态下呼吸、循环指标的变化。结果：与基础值相比，双相气道正压通气和间歇正压通气时的每分钟通气量、血氧分压、氧输送均显著增加（P〈0．05）；每分钟通气量相同时，双相气道正压通气状态下气道峰压、平均气道压较间歇正压通气的相应参数值显著降低，心输出量、氧输送显著增加（P〈0．05）；平均气道压相同时，双相气道正压通气气道峰压、氧利用率较间歇正压通气显著降低；每分钟通气量、血氧分压、氧输送显著增加（P〈0．05）。结论：保留自主呼吸时，双相气道正压通气可减少急性呼吸窘迫综合征犬肺气压伤发生。     

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.     

无创正压通气治疗急性肺损伤/急性呼吸窘迫综合征的观察

目的 评价无创正压通气(NPPV)治疗急性肺损伤(ALI)／急性呼吸窘迫综合征(ARDS)患者的临床效果。方法 对18例ALI/ARDS患者实施NPPV治疗结果进行回顾性总结，分析NPPV治疗前后动脉血氧分压／吸氧浓度(PaO2／FiO2)、呼吸频率(RR)和心率(HR)的变化。结果 NPPV治疗成功率为55.6％(10／18)，8例NPPV治疗失败患者中7例改用气管插管有创通气。总死亡率为33．3％(6／18)。NPPV成功组50％(5／10)为ALI患者，治疗后1～2h PaO2／FiO2、RR和HR较治疗前有显著改善。NPPV失败组均为ARDS患者，治疗后1-2h PaO2／FiO2、RR和HR无明显变化。结论 NPPV对部分ALI／ARDS患者是有效的支持治疗手段，尤其是ARDS早期的ALI阶段可考虑选用NPPV。如NPPV治疗失败，应及时转换为气管插管有创通气。     

Controlled ventilation with best positive end-expiratory pressure (PEEP) and high level PEEP in acute respiratory failure (ARF)

We assessed hemodynamics, total lung and chest wall compliance (CT) and gas exchange using two different levels of PEEP during controlled ventilation in two different groups of patients with ARF; in the first group (Group 1, 12 patients) chest X-Rays showed a symmetrical pattern of bilateral alveolar infiltrates; in the second group (Group 2, 5 patients) chest X-Rays showed an asymmetrical pattern with unilateral lobar consolidation. A first level of PEEP (best PEEP=9±3 cm H₂O) produced an improvement in CT and in gas exchange with a slight decrease in cardiac index in both groups; but improvement in PaO₂ (from 64±33 to 122±76 torr, p<0.001 in Group 1, and from 76±39 to 91±33 torr, p<0.05 in Group 2) and decrease in QS/QT were not as well marked in Group 2 as in Group 1. A second level of PEEP (high level PEEP: 20±4 cm H₂O) produced a sharp decrease in CT and required hemodynamic support in each case (blood volume expansion with or without Dopamine infusion) to maintain cardiac index within a normal range. In Group 1 this high level PEEP produced a greater improvement in gas exchange (PaO₂ increased from 122±76 to 194±76, p<0.01) but in Group 2 it had a deleterious effect, producing a decrease in PaO₂ (from 91±33 to 76±41 torr, p<0.05), and an increase in ; with this higher PEEP we also noted an increase of alveolar dead space in Group 2.This study demonstrates the efficiency of high levels of PEEP to reduce in ARF but also shows its limitations: namely reduction in cardiac performance and in efficiency if the damage to one lung is significantly more pronounced than that to the other lung.Supported in part by a grant of the U.E.R. Paris-Ouest     

双水平压力调节通气与反比通气对健康及急性肺损伤犬心肺功能影响的比较研究

目的 :比较双水平压力调节 (BIPAP)通气和反比通气 (IRV)对心肺功能的影响。方法 :在两种通气模式 0、0 .5和 1.0 k Pa呼气末压 (EEP)时 ,分别测定健康犬及油酸诱发急性肺损伤犬的呼吸力学、血流动力学及血气分析各参数。结果 :无论有无急性肺损伤 ,BIPAP通气时平均气道压 (m Paw )均明显低于 IRV时(P均 <0 .0 5 )。给健康犬用 IRV通气时 ,上述 3种 EEP水平的 m Paw分别为 (0 .437± 0 .10 3) k Pa、(0 .811±0 .0 93) k Pa和 (1.36 0± 0 .119) k Pa;用 BIPAP通气时则分别降为 (0 .2 2 5± 0 .0 71) k Pa、(0 .6 11± 0 .10 5 ) k Pa和(1.10 7± 0 .0 89) k Pa。油酸诱发急性肺损伤后 ,m Paw分别由 IRV时 (0 .72 5± 0 .2 2 2 ) k Pa、(1.186± 0 .2 98) k Pa和 (1.6 0 0± 0 .10 0 ) k Pa降至 BIPAP时 (0 .35 0± 0 .12 9) k Pa、(0 .6 2 5± 0 .15 0 ) k Pa和 (1.12 5± 0 .0 96 ) k Pa;但两种通气模式中气道峰压、心排血量并无明显差异。另外 ,急性肺损伤时 ,BIPAP通气的动脉血氧分压 (Pa O2 )分别为 (9.10± 1.79) k Pa、(11.43± 1.80 ) k Pa和 (13.40± 3.2 0 ) k Pa,较 IRV时 Pa O2 (7.87± 2 .33) k Pa、(9.0 7±3.0 5 ) k Pa和 (9.71± 1.85 ) k Pa增高 (EEP 1.0 k Pa时 ,P <0 .0 5 )。结论 :     

影响甲型H1N1流感病毒性肺炎所致ARDS患者肺复张效果的因素探讨

目的 分析24例接受机械通气的甲型H1N1流感病毒性肺炎致ARDS患者的临床资料,探讨压力控制通气(PCV)联合间断高PEEP法肺复张的疗效及其影响因素.方法 以2009年10月至2010年2月中国医科大学附属第一医院急诊监护室(EICU)救治的24例接受机械通气的甲型H1N1流感病毒性肺炎所致ARDS患者为研究对象,均经口气管插管按照肺保护性通气策略应用PCV模式进行机械通气,当脉搏血氧饱和度(SpO2)持续低于88％超过30 min时,在原通气模式下增加PEEP至30 cmH2O(1 cmH2O =0.098 kPa)持续60 s进行肺复张,记录操作前、操作时、操作后30min内的呼吸机监测参数和患者平均动脉压、心率、SpO2等的变化,观察操作后SpO2最高值(SpO2max)、最低值(SpO2max)及其出现时间.复张操作后15 min内SpO2升高≥3％为复张有效.分析比较肺复张前后患者血流动力学和呼吸力学等指标.结果 24例患者中存活16例,死亡8例,在EICU接受机械通气时间3.5～12 d,中位数5.5d,期间肺复张操作158例次,有效76例次(48.1％),存活组复张有效的比例与死亡组比较差异有统计学意义(66.2％ vs.33.3％,x2=16.91,P＜0.01).与复张前比较,复张操作后患者心率增加(92.6±11.8)次/min vs.(73.O±12.6)次/min,t=2.12,P=0.038; MAP降低(66.1±9.3)mmHg vs.(73.9 ±11.4) mmHg(1 mmHg =0.133kPa),t=1.98,P=0.049.85.9％的患者(134例次)复张操作后SpO2较操作前下降,SpO2min出现时间在复张操作后(2.1±0.6)min,有效组复张操作后SpO2 max较操作前增加(6.9±1.6)％,SpO2max出现时间在操作后(12.7±2.6)min.有效组肺复张操作后30 min SpO2较操作前增加(90.4±4.4)％vs.(86.7±7.6)％,t=2.01,P=0.047.有效组复张操作前平均PEEP水平低于无效组(8.6±3.4) cmH2Ovs.(11.3±4.2) cmH2O,t=2.24,P=0.028;平均机械通气时间短于无效组(4.1±3.1)d vs.(5.8±2.5)d,t=2.58,P=0.011;胸廓动态顺应性较高(30.8±6.2)mL/cmH2Ovs.(26.1±5.1)mL/cmH2O,t=2.12,P=0.038.结论 30 cmH2O的PEEP持续60 s肺复张方法可引起甲型H1N1流感病毒性肺炎所致ARDS患者短暂血流动力学改变,其效果可能与复张前PEEP水平、机械通气时间和胸廓动态顺应性有关.     

经面罩持续气道正压治疗急性肺损伤致呼吸衰竭的临床研究

目的 评价经面罩持续气道正压通气（CPAP）治疗急性肺损伤致呼吸衰竭的疗效。方法 67例患者被随机分为CPAP治疗组和对照组，比较2组治疗1、24h后的动脉血气值，呼吸频率和脉率及1h后的主观效果。结果 1h时CPAP治疗组较对照组明显改善动脉血氧合，降低呼吸频率和脉率，改善临床症状。24h后两组结果无明显差异。结论 CPAP应用于急性肺损伤所致呼吸衰竭时，虽可改善早期生理状况，但不能改善患者预后。     

Continuous positive airway pressure (CPAP) vs. intermittent mandatory pressure release ventilation (IMPRV) in patients with acute respiratory failure

Intermittent Mandatory Pressure Release Ventilation (IMPRV) is a positive pressure spontaneous breathing ventilatory mode in which airway pressure is released intermittently and synchronously with patient's spontaneous expiration in order to provide ventilatory assistance. Eight critically ill patients free of any factor known to alter chest wall mechanics (group 1) and 8 critically ill patients whose spontaneous respiratory activity was markedly altered by a flail chest, or by a C₅ quadraplegia and/or by the administration of opioids (group 2) were studied prospectively. CPAP and IMPRV were administered to each patient in a random order during a 1 h period using a CESAR ventilator. Gas flow, tidal volume, tracheal pressure, esophageal pressure, end-expiratory lung volume and hemodynamic parameters were measured. In group 1 patients, the ventilatory assistance provided by IMPRV was associated with a significant decrease in spontaneous tidal volume whereas all other respiratory parameters remained unchanged. In group 2 patients, IMPRV increased minute ventilation from 8.0±2.61/min to 12.2±1.81/min (p<0.05), decreased PaCO₂ from 46±7.3 mmHg to 38±6.8 mmHg (p<0.05) and reduced respiratory frequency from 21±10 bpm to 14±5.7 bpm (p<0.07). These results show that IMPRV provides significant ventilatory assistance to patients with mild acute respiratory failure either by decreasing patient's contribution to minute ventilation or by increasing alveolar ventilation in presence of respiratory depression of central or peripheral origin.Presented in part at the 32th Congrès National d'Anesthésie-Réanimation, Paris, September, 24, 1990 and at the Annual Meeting of the American Society of Anesthesiologists, Las Vegas, Nevada, October 22, 1990     

Airway pressure release ventilation increases cardiac performance in patients with acute lung injury/adult respiratory distress syndrome

Background  

The purpose of the present study is to determine whether airway pressure release ventilation (APRV) can safely enhance hemodynamics in patients with acute lung injury (ALI) and/or adult respiratory distress syndrome (ARDS), relative to pressure control ventilation (PCV).     

Recruitment maneuvers and positive end-expiratory pressure/tidal ventilation titration in acute lung injury/acute respiratory distress syndrome: translating experimental results to clinical practice

Recruitment maneuvers and positive end-expiratory pressure (PEEP)/tidal ventilation titration in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) are the cornerstone of mechanical ventilatory support. The net result of these possible adjustments in ventilatory parameters is the interaction of the pressure applied in the respiratory system (airway pressure/end expiratory pressure) counterbalanced by chest wall configuration/abdominal pressure along the mechanical ventilatory support duration. Refinements in the ventilatory adjustments in ALI/ARDS are necessary for minimizing the biotrauma in this still life-threatening clinical problem.     

连续性静脉-静脉血液滤过联合机械通气治疗ARDS的临床观察

目的　观察连续性静脉 -静脉血液滤过 (CVVH)联合机械通气治疗ARDS患者的临床疗效。方法　选择入住ICU符合ARDS诊断标准的患者 4 0例 ,随机分为 2组 :A组 2 1例 ,采用常规治疗 +机械通气 ;B组 1 9例 ,采用常规治疗 +机械通气 +CVVH。分别观察 2组患者在使用呼吸机时间、氧合指数、吸入氧浓度、动脉血氧分压、PEEP水平、心率、血压及病死率等方面的差别。结果　A、B两组患者在病因、年龄、性别、APACHEⅡ评分及平均脏器功能障碍数等方面相似 ,B组患者加用CVVH后 ,各项指标经统计学处理显示 :病死率 ,B组与A组比较 ,差异有显著性意义 (P <0 0 5 ) :其他指标与A组比较 ,差异均有高度显著性意义 (P <0 0 1 )。结论　CVVH疗法可有效清除ARDS患者血管外肺水和各种应激激素、致炎介质 ,明显改善了ARDS患者肺部氧合功能及血流动力学指标 ,提高了抢救成功率     

Effects of recruitment maneuvers in patients with acute lung injury and acute respiratory distress syndrome ventilated with high positive end-expiratory pressure

Objective: Positive end-expiratory pressure (PEEP) and recruitment maneuvers (RMs) may partially reverse atelectasis and reduce ventilation-associated lung injury. The purposes of this study were to assess a) magnitude and duration of RM effects on arterial oxygenation and on requirements for oxygenation support (Fio2/PEEP) in patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS) receiving ventilation with low tidal volumes and high levels of PEEP; and b) frequency of adverse respiratory and circulatory events attributable to RMs. Design: Prospective, randomized, crossover study. Setting: Thirty-four intensive care units at 19 hospitals. Patients: Seventy-two patients with early ALI/ARDS. Baseline PEEP and Fio2 were 13.8 +/- 3.0 cm H2O and 0.39 +/- 0.10, respectively (mean +/- sd). Interventions: We conducted RMs by applying continuous positive airway pressure of 35-40 cm H2O for 30 secs. We conducted sham RMs on alternate days. We monitored oxyhemoglobin saturation by pulse oximetry (SpO2), Fio2/PEEP, blood pressure, and heart rate for 8 hrs after RMs and sham RMs. We examined chest radiographs for barotrauma. Measurements and Main Results: Responses to RMs were variable. Greatest increments from baseline SpO2 within 10 mins after RMs were larger than after sham RMs (1.7 +/- 0.2 vs. 0.6 +/- 0.3 %, mean +/- SEM, p < .01). Systolic blood pressure decreased more +/- 1.1 mm Hg, p < .01). Changes in Fio2/PEEP requirements were not significantly different at any time after RMs vs. sham RMs. Barotrauma was apparent on first radiographs after one RM and one sham RM.Conclusions: In ALI/ARDS patients receiving mechanical ventilation with low tidal volumes and high PEEP, short-term effects of RMs as conducted in this study are variable. Beneficial effects on gas exchange in responders appear to be of brief duration. More information is needed to determine the role of recruitment maneuvers in the management of ALI/ARDS.     

急性左心衰患者应用呼气末正压通气的治疗效果分析

目的探讨调节呼吸末正压通气(PEEP)水平对急性左心衰疗效及预后的影响。方法将49例急性左心衰患者随机分为2组,对照组(n=22)在常规药物治疗基础上加用低水平PEEP(<5 cmH2O),治疗组(n=27)在常规药物治疗基础上加用较高水平PEEP(5~10cmH2O),记录2组治疗前、治疗后2 h及治疗后8 h的血压、心率、氧合指数(PaO2/FiO2)、二氧化碳分压(PaCO2),观察疗效。结果 2组治疗后1 d及2 h血压、心率、PaO2/FiO2、PaCO2均较治疗前显著改善(P<0.01),治疗组各指标改善情况优于对照组(P<0.05或P<0.01)。结论较高水平的PEEP有利于急性左心衰的治疗。     

CT定量分析急性呼吸窘迫综合征模型兔肺复张呼气末正压通气最佳压力

目的 以CT定量评估不同肺复张呼气末正压(PEEP)通气治疗急性呼吸窘迫综合征(ARDS)模型兔,并确定最佳PEEP.方法 纳入10只成年大耳兔,建立ARDS兔模型.采用压力控制通气进行肺复张,分别于4、8、12、16、20、24及28 cmH2O PEEP下行肺部CT扫描,并按CT值将肺分为不通气区(-100～100...