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呼吸机治疗的肺保护策略,.,呼吸机相关性肺损伤acute parenchymal lung injury and an acute inflammatory response in the lung. cytokines alveoli and the systemic circulation multiple organ dysfunction mortality,.,呼吸机相关性肺损伤ventilator-induced lung injury,容量性损伤 Volutrauma(large gas volumes )压力性损伤 Barotrauma(high airway pressure )不张性损伤 Atelectotrauma(alveolar collapse and re-expansion)生物性损伤 Biotrauma(increased inflammation ),.,肺 损 伤 病 理,alveolar structural damagepulmonary edema、 inflammation、 fibrosis surfactant dysfunctionother organ dysfunctionexacerbate the disturbance of lung development Semin Neonatol. 2002 Oct;7(5):353-60.,.,Approaches in the management of acute respiratory failure in childrenprotective ventilatory and potential protectiveventilatory modes lower tidal volume and PEEP permissive hypercapnia high-frequency oscillatory ventilation airway pressure release ventilation partial liquid ventilationimprove oxygenation recruitment maneuvers prone positioning kinetic therapy reduce FiO2 and facilitate gas exchange inhaled nitric oxide and surfactant Curr Opin Pediatr. 2004 Jun;16(3):293-8.,.,Can mechanical ventilation strategies reduce chronic lung disease?continuous positive airway pressurepermissive hypercapnia patient-triggered ventilation volume-targeted ventilation proportional assist ventilation high-frequency ventilation Semin Neonatol. 2003 Dec;8(6):441-8,.,小潮气量和呼气末正压 lower tidal volume and PEEP,.,Ventilation with lower tidal volumes versus traditional tidal volumes in adults for ALI and ARDS1202 patientslower tidal volume (7ml/kg) low plateau pressure 30 cm H2O versus tidal volume 10 to 15 ml/kgMortality at day 28 long-term mortality was uncertainlow and conventional tidal volume with plateau pressure 31 cm H2O was not significantly different Cochrane Database Syst Rev. 2004;(2):CD003844,.,Higher versus lower positive end-expiratory pressures in patients with the acute respiratory distress syndrome,549 patients acute lung injury and ARDSlower-PEEP group 8.33.2cmH2O higher-PEEP group 13.23.5cmH2O (P0.001). tidal-volume 6ml/kg end-inspiratory plateau-pressure30cmH2OThe rates of death 24.9 % 27.5 % (p=0.48) From day 1 to day 28, breathing was unassisted 14.510.4 days 13.810.6 days (p=0.5)clinical outcomes are similar whether lower or higher PEEP levels are used. N Engl J Med. 2004 Jul 22;351(4):327-36.,.,Increasing inspiratory time exacerbates ventilator-induced lung injury during high-pressure/high-volume mechanical ventilationSprague-Dawley rats negative control group low pressures (PIP = 12 cm H2O), rate = 30, iT = 0.5, 1.0, 1.5secs experimental groups high pressures (PIP = 45 cm H2O), rate = 10, iT = 0.5 , 1.0 , 1.5 secslung compliance, PaO2 /FiO2 ratio, wet/dry lung weight, and dry lung/body weightas inspiratory time increased ,static lung compliance (p =.0002) and Pao2/Fio2 (p =.001) decreased. Wet/dry lung weights (p .0001) and dry lung/body weights (p .0001) increasedLight microscopy revealed evidence of intra-alveolar edema and hemorrhage in the iT = 1.0 and iT = 1.5 animals but not the LoP and iT = 0.5 animals. Crit Care Med. 2002 Oct;30(10):2295-9.,.,新生儿呼吸窘迫综合征呼吸机治疗的肺保护性策略研究,施丽萍 孙眉月 杜立中 中华儿科杂志2003,.,本项目研究的目的通过肺力学参数的监测(PM)指导呼吸机参数的调节来降低呼吸机相关性肺损伤的发生探讨新生儿RDS最合适的呼吸机参数允许性高碳酸血症对新生儿的影响,.,非肺力学监测组(NPM):19941997年, RDS 50例,作为对照组 肺力学监测组(PM): 19982001年,RDS 60例,作为观察组 肺力学监测仪(Bicore CP100),.,两组胎龄、体重、病情严重程度比较,.,对照组(NPM): 应用人工呼吸机限压定时持续气流型,通气模式为IMV,持续脉搏血氧饱和度监测使其维持在8595%,每8h监测动脉血气一次,要求血气维持在正常范围内,PaO2 40-70mmHg, PaCO2 35-45mmHg,.,观察组(PM组): 1、肺力学监测仪(Bicore CP100)每812h 监测一次机械通气时肺力学参数 2、监测时要求患儿与呼吸机完全同步或无自主呼吸状态(必要时通过药物抑制呼吸) 3、肺力学监测仪的传感器置于近端接口 4、气管插管气漏率小于20% 5、每监测一次持续0.51h至数据稳定后记录监测的数据,.,NPM 组和PM组的评估指标 1. 疾病极期,即生后2448h时呼吸机要求最高值,包括FiO2、 PIP、PEEP、Ti、MAP、VR 2. VE、C20/C、TC(限于PM组), 3. 记录血pH、PaO2、PaCO2、氧合指数(OI )(OI=FiO2MAP/PaO2)和心率、血压 4. 呼吸机应用时间,用氧时间,住院天数,病死率,PDA,IVH和呼吸机相关性肺损伤的发生率。,.,两组呼吸机参数比较,.,.,两组血气监测结果比较,.,.,两组呼吸机相关性肺损伤、PDA、IVH、呼吸机应用时间、用氧时间、住院天数、病死率比较,.,结论,肺力学监测能指导正确应用呼吸机,降低呼吸机相关性肺损伤 从本研究结果推荐RDS呼吸机应用的参数为:PIP 25cmH2O左右,短Ti 0.30.5秒,应用适当的PEEP 5-7cmH2O治疗RDS,不影响氧合。 PaCO2的轻度增高(PaCO2 45-60),IVH的发生未见增加。,.,允许性高碳酸血症Permissive hypercapnia,.,Permissive hypercapnia-role in protective lung ventilatory strategies First, we consider the evidence that protective lung ventilatory strategies improve survival and we explore current paradigms regarding the mechanisms underlying these effects Second, we examine whether hypercapnic acidosis may have effects that are additive to the effects of protective ventilation Third, we consider whether direct elevation of CO2, in the absence of protective ventilation, is beneficial or deleteriousFourth, we address the current evidence regarding the buffering of hypercapnic acidosis,.,Lung-protective ventilation in acute respiratory distress syndrome: protection by reduced lung stress or by therapeutic hypercapnia? hypercapnic acidosis lung-protective ventilation respiratory acidosis protected the lung The protective effect of respiratory acidosis inhibition of xanthine oxidase prevented by buffering the acidosis . the protection resulted from the acidosis rather than hypercapnia Am J Respir Crit Care Med. 2000 Dec;162(6):2021-2.,.,Permissive hypercapnia in ARDS and its effect on tissue oxygenationThe right-shift of the haemoglobin-oxygen dissociation curvereduce intrapulmonary shunt (Qs/Qt) by potentiating hypoxic pulmonary vasoconstrictionaffect the distribution of systemic blood flow both within organs and between organs Acta Anaesthesiol Scand Suppl. 1995;107:201-8,.,Hypercapnic acidosis attenuates endotoxin induced acute lung injuryattenuated the decrement in oxygenation improved lung compliancereduced alveolar neutrophil infiltration and histologic indices of lung injury Am J Respir Crit Care Med. 2004 Jan 1;169(1):46-56,.,Hypercapnic acidosis is protective in an in vivo model of ventilator-induced lung injury12 rabbits ventilator-induced lung injury (VILI)PaCO2 40 mm Hg n = 6 PaCO2 80-100 mm Hg n = 6respiratory mechanics (plateau pressures) 27.0 2.5 20.9 3.0 p = 0.016gas exchange (PaO2 ) 165.2 19.4 77.3 87.9 p = 0.02wet:dry weight 9.7 2.3 6.6 1.8 p = 0.04bronchoalveolar lavage fluid protein concentration 1350 228 656 511 p = 0.03 cell count 6.86 x 105 2.84 x 105 p = 0.021 injury score 7.0 3.3 0.7 0.9 p 60% and MAP20 cm H2O or PEEP15 cm H2O Crit Care Med. 2003 Apr;31(4 Suppl):S317-23,.,Elective high frequency oscillatory ventilation versus conventional ventilation for acute pulmonary dysfunction in preterm infants updated in May 2003 3275 Randomized controlled trials comparing HFOV and CV in preterm or low birth weight infants with pulmonary dysfunctionno evidence of effect on CLD and mortality at 28-30 days Pre-specified subgroup analyses Short term neurological morbidity Grade 3 or 4 IVH and PVL (no using high volume strategy) Cochrane Database Syst Rev. 2003(4):CD000104,.,Open lung ventilation improves gas exchange and attenuates secondary lung injury in a piglet model of meconium aspirationProspective, randomized animal study36 newborn piglets (6 saline controls) PPV(OLC), HFOV(OLC), PPV(CON) ventilated for 5 hrsbronchoalveolar lavage fluid myeloperoxidase activity lung injury score Alveolar protein influx no differentsuperior oxygenation and less ventilator-induced lung injury Crit Care Med. 2004 Feb;32(2):443-9,.,Changes in mean airway pressure during HFOV influences cardiac output in neonates and infants14 patients 1 year weight 10 kg HFOVstudy group (n = 9) MAP +5 and -3 cmH2Ocontrol group (n = 5) Cardiac output echocardiography Doppler techniqueCardiac output the study group (P = 0.02)the greatest change at the highest Paw at -11% (range: -19 to -9) compared with baseline. Acta Anaesthesiol Scand. 2004 Feb;48(2):218-23,.,Randomized trial of high-frequency oscillatory ventilation versus conventional ventilation:effect on systemic blood flow in very preterm infants43 infants 29w 8 kg Vital signs, airway pressures, minute ventilation, Spo(2), and E(T)CO(2) were recordedAPRV provided similar ventilation, oxygenation, mean airway pressure, hemodynamics, and patient comfort as SIMVAPRV significantly lower inspiratory peak and plateau pressures Pediatr Crit Care Med. 2001 Jul;2(3):243-6,.,Airway pressure release ventilation as a primary ventilatory mode in acute respiratory distress syndrome 58 patients randomized APRV or SIMV PIP at APRV-group (25.9 0.6 vs. 28.6 0.7 cmH2O) (P = 0.007). no different PEEP and physiological variables (PaO2/FiO2, PaCO2, pH, minute ventilation, mean arterial pressure, cardiac output)At day 28, the number of ventilator-free days was similar (13.4 1.7 , 12.2 1.5), the mortality (17% and 18%) APRV did not differ from SIMV with PS in clinically relevant outcome Acta Anaesthesiol Scand. 2004 Jul;48(6):722-31,.,APRV,No evidence to indicate that APRV is better than conventional ventilation,.,谢 谢!,.,
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