【摘要】 目的 探讨控制性肺膨胀（SI）与肺保护性通气策略联合应用治疗急性呼吸窘迫综合征（ARDS）的疗效和维持时间。方法 利用内毒素诱导绵羊ARDS模型,观察给予一次SI（30cm H₂O,20s）后4h内绵羊氧代谢和血液动力学的变化。结果 实施SI后3h,绵羊的动脉血氧分压显著增加[SI前为（83±17）mm Hg,SI后3h为（123±2）mm Hg,P<0.05]。动脉血氧饱和度在屏气过程中轻度下降[SI前（92±3）％,SI时（91±5）％],屏气结束后逐渐增加至95％,可维持4h。实施SI后30min,混合静脉血氧分压和饱和度显著上升,并保持4h。实施SI后2h,氧输送显著增加,氧耗无改变。屏气时绵羊的平均肺动脉压、中心静脉压和肺动脉嵌顿压显著增高,屏气结束后即恢复至SI前水平。心排指数在SI后4h显著增高[SI前（5.4±1.6）L·min^-1·m^-2,SI后4h（6.5±1.8）L·min^-1·m^-2,P<0.05]。结论 SI能改善ARDS绵羊的氧合,一次SI的疗效可保持4h以上,且对血液动力学影响短暂,是有效的肺复张方法。更多还原

【Abstract】 Objective To determine the effects of sustained inflation (SI) on hemodynamics and oxygen metabolism during acute respiratory distress syndrom (ARDS) .Methods Nineteen New Zealand sheep (11 male, 8 female) weighing 32.0 ± 6.7 kg were anesthetized with intramuscular ketamine 300 mg, scopolamine 0.3 mg and fentanyl 0.2 mg. The animals were tracheotomized, intubated and mechanically ventilated. ARDS was induced by intravenous infusion of endotoxin (E. coli ) 3 μg · kg -1 over 30 min. The animals developed ARDS within 3 h. The criteria for ARDS were PaO2/FiO2 < 200 mm Hg and PAWP± 18 mm Hg. The baseline ventilatory settings were : VT = 8 ml· kg, inspiratory time = 1.0s, inspiratory flow rate = 30 L· min-1 , RR = 20 bpm. PEEP was set at 2 cm H2O above lower inflexion. Airway pressure release ventilation (APRV) mode was used for sustained inflation. The SI pressure was set at 30 cm H2 O and maintained for 20 s, followed by baseline ventilatory settings. Arterial and mixed venous blood samples were taken for determination of oxygen metabolism ( pH, PaO2 , PaCO2 , SaO2, PvO2 , SvO, , oxygen delivery (DO2), oxygen consumption (VO2) oxygen extraction (O2 ext) ) and Swan-Ganz catheter was placed for hemodynamic measurement before SI (T0) and 10 min, 30 min, 1h, 2h,3h, 4h after SI. Results PaO, was significantly increased at 3 h after SI from (83 ± 17) mm Hg (T0 ) to (123 ± 2) mm Hg ( P < 0.05). SaO2 decreased slightly during 20 s inflation but increased rapidly to 95% at 30 min after SI ( P < 0.05) PvO2 and SvO2 were significantly improved at 30 min after SI and maintained for 4 h. DO2 increased at 2 h after SI and VO2 remained unchanged. During inflation MPAP, CVP and PAWP were significantly increased. Cardiac output increased significantly from (5.4± 1.6) L·min-1·m2 before SI (T0) to (6.5± 1.8) L·min-1m2 at 4 h after SI ( P < 0.05). Conclusion A single SI can effectively improve oxygen metabolism for 4 h in sheep with ARDS. The changes in hemodynamics were transient. Sustained inflation is a safe and effective approach to alveolar recruitment.更多还原