Ventilator-Associated Pneumonia. Mucus Slurper. Mucucili

他说：粘液吸尘器？ 在使用气管内管(ETT)插管的患者中，常规进行吸管以清除ETT内和气管内的粘液。粘液吸尘器是一种新型的ETT，其尖端有内置的吸入口，呈放射状排列。在机械通气72小时的绵羊身上，我们评估了粘液吸入器的安全性和有效性，并与传统的气管吸引器进行了比较，以防止分泌物在ETT和气管的管腔内聚集。 2：呼吸机相关性肺炎(VAP)的气管粘液转运和呼吸机的作用 危重病患者通常以半卧位卧位，床头以30-45度的角度抬起，以防止胃食道反流和肺吸入。 我们研究了自然呼吸(无呼吸机)或机械通气绵羊，气管朝向水平上方或下方，气管插管后对气管粘液清除的影响。我们的目标也是确定气管粘液清除受损，结合水平以上的气管方向(就像在人类中处于半卧位)是否与肺部细菌定植和肺炎发作的风险增加有关。 通过对不透射线的钽盘和注入气管内的钽粉的放射跟踪测量气管粘液的速度。 我们发现，气管插管后，随着气管高于水平，气管粘液清除变得高度异常，粘液向后向肺部移动，随后肺部细菌定植。 他说：防泄漏的ETT袖口？ 市场上可买到的高容量低压袖套(HVLP)被引入以预防与压力相关的气管损伤。在这样做的过程中，袖带直径被设计得大于气管的管腔。因此，随着气管袖带在气管内充气，总是会形成褶皱。沿褶皱的定植的声门下分泌物的渗漏可导致下呼吸道的定植，以及呼吸机相关性肺炎(VAP)。 我们制作了一个原型ETT袖口，通过在标准的HVLP袖口周围覆盖第二个高度弹性的袖口，袖口由低蛋白天然乳胶橡胶制成，壁厚为40-50微米。我们在两个袖口之间的空隙中加入了少量的含水润滑剂，以均匀地分配膨胀压力。 到目前为止，我们的研究仅限于体外研究，接下来将进行体内测试和评估。 4：机械通气猪呼吸机相关性肺炎的预防 基于以前在镇静、插管和机械通气的绵羊上进行的动物研究，我们已经表明，当头/颈高于水平30-45度(如人类的半卧位)时，在24小时内开始出现均匀、广泛的气管、支气管和肺部细菌定植；随后是气体交换障碍和急性呼吸衰竭。 插管绵羊在机械通气时，使气管和气管管保持水平或略向下倾斜，然后机械通气72h，无气管、支气管或肺实质细菌定植。 然而，由于反刍动物和杂食性动物的不同解剖和生理条件(如每天产生的唾液总量、气管长度、口咽-瘤胃菌群等)，将绵羊肺部研究的病理生理学成果转移到人类病理学上是困难的。 因此，我们还研究了机械通风杂食动物(猪)，在全身麻醉和肠道喂养72-168小时。 这项研究表明，我们在绵羊身上的发现也适用于猪。 5：与医学研究中心合作： 在我们实验室发现的在两种不同动物模型中预防VAP的支持下，我们现在正在与3个医学研究中心合作(1.马萨诸塞州总医院-Zapol，Bigatello，Berra；2.米兰大学，意大利-Pesenti医生；3.NIH临床重症监护病房-Masur医生)。我们希望启动一项多中心试验，以确定我们预防VAP的方法在危重患者中是否可行、安全和有效。

1: The ?Mucus Slurper? In patients intubated with endotracheal tubes (ETT), suctioning is routinely performed to remove mucus from within the ETT, and the trachea. The Mucus Slurper is a novel ETT, with built-in suction ports arranged radially at its tip. In sheep mechanically ventilated for 72 hours, we evaluated safety and efficacy of the Mucus Slurper, compared to conventional tracheal suction, to prevent accumulation of secretions within the lumen of the ETT and trachea. 2: Tracheal mucus transport and the role of the ventilator in Ventilator Associated Pneumonia (VAP) Critically ill patients are usually positioned in the semi-recumbent position with the head of the bed elevated at an angle of 30-45 degrees, to prevent gastro-esophageal reflux, and pulmonary aspiration. We investigated the effects on tracheal mucus clearance after tracheal intubation in spontaneously breathing (without ventilator), or mechanically ventilated sheep, positioned with the trachea oriented above, or below horizontal. Our goal was also to determine whether impaired tracheal mucus clearance, combined with tracheal orientation above horizontal (as it is in semi-recumbent position in the human) was associated with increased risk for bacterial colonization of the lungs, and onset of pneumonia. Tracheal mucus velocity was measured via radiographic tracking of radiopaque tantalum disks and tantalum powder insufflated into the trachea. We found that after tracheal intubation, with the trachea elevated above horizontal, tracheal mucus clearance becomes highly abnormal, with mucus moving backward towards the lungs, followed by bacterial colonization of the lungs. 3: The ?Leak proof ETT cuff? Commercially available high-volume low-pressure cuffs (HVLP) were introduced to prevent pressure-related tracheal injury. In so doing, the cuff diameter was designed larger than the lumen of the trachea. Hence, with the tracheal cuff inflated within the trachea, folds always form. Leakage of colonized subglottic secretions along the folds can lead to colonization of the lower airways, and ventilator associated pneumonia (VAP). We manufactured a prototype ETT cuff by draping around the standard HVLP cuff a second, highly elastic cuff made of low-protein natural latex rubber, with a wall thickness of 40-50 microns. We introduced a small amount of aqueous lubricant into the space between the two cuffs to homogeneously distribute the distending pressure. Our studies until now have been confined to in vitro studies; in vivo testing and evaluation is to follow. 4: Prevention of VAP in mechanically ventilated pigs Based on previous animal studies in sheep sedated, intubated and mechanically ventilated, we have shown that when the head/neck are elevated 30-45 degrees above horizontal (as in the human in the semi-recumbent position), there was uniform, widespread tracheobronchial and lung bacterial colonization, starting within 24 h; followed by impaired gas exchange, and acute respiratory failure. When intubated sheep, on mechanical ventilation, were positioned so that the trachea and the tracheal tube were maintained horizontal, or with a slight incline downwards, and then mechanically ventilated for 72 h, there was no tracheal, bronchial, or lung parenchymal bacterial colonization. However, the transfer of pathophysiologic findings of pulmonary research in sheep, to human pathology, is difficult due to the different anatomical and physiologic conditions in ruminants and omnivores (such as the total amount of saliva produced per day, length of the trachea, oropharyngeal-rumen flora, etc.). We hence also studied mechanically ventilated omnivores (pigs), under general anesthesia and enteral feeding for 72-168 hours. This study showed that our findings in sheep, also apply to pigs. 5: Collaboration with medical research centers: Supported, by our laboratory finding to prevent VAP in 2 different animal models, we are now collaborating with 3 medical research centers (1. Massachusetts General Hospital - Drs. Zapol, Bigatello, Berra; 2. The University of Milan, Italy - Dr. Pesenti; 3. NIH Clinical Intensive Care Unit - Dr. Masur). We wish to start a multricenter trial on whether our approach to prevent VAP is feasible, safe, and effective in the critically ill human patient.