不同密闭式吸痰方法对ARDS小猪动脉血气的影响

Effect of Closed Endotracheal Suction Performed with Hyperoxygenation and/or Recruitment Maneuvers on Arterial Blood Gas in ARDS Piglets

目的探讨密闭式吸痰时高氧法和/或肺泡复张术对急性呼吸窘迫综合征(ARDS)小猪动脉血氧分压(PaO2)、动脉血氧饱和度(SaO2)、动脉血二氧化碳分压(PaCO2)、动脉血pH值的影响。方法16只小猪给予清洁剂(detergent)(1.37±0.64)mg/kg气管注入制作ARDS模型,模型成功后随机分为呼气末正压(PEEP)0.5 kPa(5 cmH2O)和1.0 kPa(10 cmH2O)两组,每组8只。每只小猪按随机顺序分别采用单纯密闭式吸痰(简称单纯法)、高氧法密闭式吸痰即密闭式吸痰前1 min给予100%氧供并贯穿整个吸痰过程共持续2 min(简称高氧法)、复张法密闭式吸痰即吸痰后即刻调节PEEP水平到2.0 kPa(20 cmH2O),通气10 s(简称复张法)、高氧-复张法密闭式吸痰即吸痰时高氧供及肺泡复张术两种措施联合应用(简称结合法)4种方法吸痰,观察吸痰前1 min、吸痰后1 min、3 min、5 min、10 min动脉血气的变化。结果在两个PEEP水平组,单纯法吸痰后ARDS小猪动脉血氧分压(PaO2)和动脉血氧饱和度(SaO2)均下降,直到吸痰后10 min仍然低于吸痰前基线水平(P<0.05);高氧法吸痰后1min PaO2、SaO2较基线水平有所升高,其中PEEP 0.5 kPa(5 cmH2O)组P>0.05,PEEP 1.0 kPa(10 cmH2O)组P<0.05;复张法吸痰后1 min PaO2、SaO2有所下降(P>0.05),从吸痰后3 min开始恢复到基线水平;结合法吸痰后1 min PaO2、SaO2升高(P<0.05),直到吸痰后10 min仍然高于基线水平(P>0.05)。结论单纯法可引起ARDS小猪较严重的低氧血症;高氧法可暂时改善密闭式吸痰所引起的缺氧,但作用时间短暂;复张法不能避免吸痰瞬间所引起的PaO2、SaO2下降;结合法能够保持吸痰前后全过程较好氧合状态,是一种比较安全的吸痰方式。

Objective To assess the impact of closed endotracheal suction performed with hyperoxygenation and/or alveoli recruitment maneuver on PaO2, SaO2, PaCO2 and pH in ARDS piglets. Methods ARDS piglet model was introduced by injecting detergent （1.37±0.64）mg/kg into 16 piglets intratracheally, which were equally randomized into PEEP 0.5 kPa（5 cmH2O） and 1.0 kPa（10 cmH2O） groups. 4 protocols were administrated in random order：, closed endotracheal suction, closed endotracheal suction with hyperoxygenation, closed endotracheal suction with alveoli recruitment maneuver （ventilation for 10 s at 2.0 kPa PEEP）, closed endotracheal suction with hyperoxygenation and alveoli recruitment maneuver. The arterial blood gas was tested before suction, 1 min, 3 min, 5 min and 10 min after suction. Results After closed endotracheal suction alone, PaO2 and SaO2 went down and even did not restore to the normal levels right 10 min after suction （P〈0.05）. 1 min after suction with hyperoxygenation, PaO2 and SaO2 went up from the basic level（P〉0.05） in the group of PEEP 0.5 kPa（5 cmH2O） but P〈0.05 in the group of PEEP 1.0 kPa（10 cmH2O）. 1 min after suction with alveoli recruitment maneuver, PaO2 and SaO2 went down from the basic level （P〉0.05） and then restored to the basic level 3 min after suction. 1 min after suction with hyperoxygenation in combination with alveoli recruitment maneuver, PaO2 and SaO2 went up （P〈0.05） and remained at a higher level than the basic one even 10 min after suction （P〉0.05）. Conclusion Closed endotracheal suction without any assistantmaneuver may cause severe arterial blood hypoxidosis. Suction with hyperoxygenation may improve blood oxygenation, but temporarily. Suction with alveoli recruitment maneuver may lead to temporary falls of PaO2 and SaO2. Suction with hyperoxygenation in combination with alveoli recruitment maneuver may improve the oxygenation and respiratory mechanics all through the process of suction.