ARDS的机械通气

8th Respiratory Support UpdateOctober 23, 2008,ARDS的机械通气北京协和医院杜斌,病例摘要,男性, 70岁, 2001年1月9日入院咳嗽, 咳痰12天, 发热4天, 呼吸困难1天12天前: 咳嗽, 咳黄粘痰, 伴全身乏力4天前寒战高热, 体温39.5CCXR: 肺部感染, 右上肺膨胀不全头孢呋肟治疗无效1天前: 呼吸困难, 紫绀, 伴血压下降(50/20 mmHg),病例摘要,入ICU时BT 37.2CHR 130 bpmBP 84/40 mmHg (DA 10 g/kg/min)SpO2 78%双肺散在湿罗音,病例摘要,呼吸功能支持(SIMV + PSV)FiO2 100%PEEP 10 cmH2OSpO2 92%循环支持羟基淀粉500 ml扩容无效DA 13 g/kg/min NE 1.2 g/kg/minBP 110/70 mmHg,病例摘要,ARDS的机械通气,保护性通气策略小潮气量适当的PEEP,Girard TD, Bernard GR. Mechanical Ventilation in ARDS: A State-of-the-Art Review. Chest 2007; 131: 921-929,ARDS肺的形态学,FRC and EELV reduction in ARDS ptsFrom L. Puybasset, et al. Regional distribution of gas and tissue in acute respiratory distress syndrome. I. Consequences for lung morphology. Intensive Care Med 2000; 26: 857-69.,ARDS肺的形态学,“婴儿肺”的概念保持通气的肺仅相当于正常肺的20 - 30%ARDS患者肺容积的减少并不意味着胸腔内容积的减少, 仅是气体被组织所替代,Gattinoni L, et al. Relationships between lung computed tomographic density, gas exchange and PEEP in acute respiratory failure. Anesthesiology 1988; 69: 824-32.,ARDS: 机械通气的设置,主要目标维持血气水平正常氧气二氧化碳通过给予超过生理水平的潮气量, 且不限制气道压力,呼吸机设置PEEP10.9 4.2 cmH2OVt11.5 2.2 ml/kgRR16.8 9 bpmPIP39.4 8.6 cmH2O,机械通气相关性肺损伤(VALI),Tobin MJ. Advances in mechanical ventilation. N Engl J Med 2001; 344: 1986-1996,VALI: 动物试验证据,Dreyfuss DP. AJRCCM 1988; 137:1159,VALI: 临床试验证据,ARDS潮气量的选择: 临床试验, measured body weight; ideal body weight = 25 x (height in meters)2; Dry weight measured weight minus estimated weight gain from salt and water retention; Predicted body weight 50 (for males) or 45.5 (for females) + 2.3 (height in inches) - 60,ARDS Network Low VT Trial,满足ALI/ARDS诊断标准 10%47%体重误差 20%19%身高误差 10%0%(PBW/Measured body weight = 0.83),Bloomfield R, Steel E, MacLennan G, et al. Accuracy of weight and height estimation in an intensive care unit: Implications for clinical practice and research. Crit Care Med 2006; 34: 2153-2157,小潮气量通气: 理想体重,男性 = 50 + 0.91 x (Ht - 152.4)女性 = 45.5 + 0.91 x (Ht - 152.4),The Acute Respiratory Distress Syndrome Network: Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med 2000; 342:1301-1308,如果PaCO2 ,若Pplat不高, 可适当增加潮气量维持Pplat 30 cmH2O,Vt 6 ml/kg时, 可逐渐降低潮气量但PaCO2 允许性高碳酸血症(PHC),允许性高碳酸血症,Kregenow DA, Rubenfeld GD, Hudson LD, et al. Hypercapnic acidosis and mortality in acute lung injury. Crit Care Med 2006; 34: 1-7,允许性高碳酸血症,Kregenow DA, Rubenfeld GD, Hudson LD, et al. Hypercapnic acidosis and mortality in acute lung injury. Crit Care Med 2006; 34: 1-7,如果Pplat 6 ml/kg时往往因胸腔负压过高跨肺压并不低无需调整呼吸机参数降低潮气量需要镇静和(或)肌松镇静和(或)肌松后气道压力升高自主呼吸消失, 胸腔负压降低,低氧血症,改善氧合的方法FiO2PEEP,氧中毒,临床诊断极为困难尽量避免FiO2 60%,重力依赖区域的肺不张,重力依赖区域的肺不张,重力依赖区域的肺不张,Control:VT 7; PEEP 3MVHP:VT 15; PEEP 10MVZP:VT 15; PEEP 0HVZP:VT 40; PEEP 0,Tremblay L. J Clin Invest 1997; 99:944,PEEP: 动物试验证据,PEEP: 细菌移位,目的: 检验PIP和PEEP对菌血症发生的影响方法: 80只大鼠, 气道内植入肺炎克氏菌植入细菌22小时后进行机械通气3小时4种通气策略(13/3; 13/0;30/10;30/0)血培养,Verbrugge, Lachmann Intens Care Med 1998;24:172-7,Amato M, et al. N Engl J Med. 1998.,PEEP: ARDS患者预后,Amato M, et al. N Engl J Med. 1998.,PEEP: ARDS患者预后,与通气疗效有关的预后指标:APACHE II评分最初36小时内平均PEEP (保护作用)最初36小时内驱动压力 (Pplat - PEEP),PEEP: ARDS患者预后,Barbas V, Carmen Silvia C. Lung recruitment maneuvers in acute respiratory distress syndrome and facilitating resolution. Crit Care Med 2003; 31(4) Supplement: S265-S271,PEEP Story: 1936 2005,最小PEEP,在可接受的FiO2下维持充分氧合(PaO2)所需的PEEP水平如何定义最小PEEP?充分氧合SpO2 88%1可接受FiO2FiO2 0.602,Brower RG, Lanken PN, MacIntyre N, et al. Higher versus lower positive endexpiratory pressures in patients with the acute respiratory distress syndrome. N Engl J Med 2004; 351:327336.Amato MBP, Barbas CSV, Medeiros DM, Magaldi RB, Schettino G, Lorenzi-Fihlo G, Kairalla RA, Deheinzelin D, Munoz C, Oliveira R, Takagaki TY, Carvalho CRR. Effect of protective-ventilation strategy on mortality in the acute respiratory distress syndrome. N Engl J Med 1998; 338: 347-354,ALVEOLI: 试验设计,NHLBI ARDS Clinical Trial Network. Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome. N Engl J Med 2004; 351: 327-36.,0.0,0.5,1.0,Probability,0 10 20 30 40 50 60Days after Randomization,Lower PEEP, overall survival,Higher PEEP, overall survival,Higher PEEP, discharge,Lower PEEP, discharge,ALVEOLI: 临床预后,NHLBI ARDS Clinical Trial Network. Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome. N Engl J Med 2004; 351: 327-36.,ALVEOLI: 临床预后,NHLBI ARDS Clinical Trial Network. Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome. N Engl J Med 2004; 351: 327-36.,ALVEOLI: 总结,对于ALI/ARDS患者, 高PEEP:随机分组后最初7天内PaO2/FiO2较高随机分组后最初3天内Pplat较高随机分组后最初3天内VT较低RR, PaCO2, 或pH无差异病死率无差异器官功能衰竭或气压伤无差异IL-6, ICAM-1, SP-D无差异,NHLBI ARDS Clinical Trial Network. Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome. N Engl J Med 2004; 351: 327-36.,为何高PEEP不能改善预后,高PEEP的有益作用被副作用抵消?需要肺复张?“低PEEP”足以保护肺不出现剪切力损伤?,NHLBI ARDS Clinical Trial Network. Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome. N Engl J Med 2004; 351: 327-36.,ARDS: 如何设置PEEP,NHLBI ARDS Clinical Trial Network. Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome. N Engl J Med 2004; 351: 327-36.,ARDS的机械通气,反比通气(IRV)俯卧位通气吸入NO (iNO)高频振荡通气(HFOV)肺复张(RM),ARDS: 反比通气(IRV),IRV*I:E 1:1对传