Evaluation of continuous aspiration of subglottic secretion in an in vivo study
Evaluation of continuous aspiration of subglottic secretion in an in vivo study
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DOI：
10.1097/01.ccm.0000142575.86468.9b
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发表时间：
2004-10-01
影响因子：
8.8
通讯作者：
Kolobow, T
中科院分区：
文献类型：
--
作者：
Berra, L;De Marchi, L;Kolobow, T
目的：持续抽吸声门下分泌物（CASS）被认为可以降低呼吸机相关性肺炎的发生率。尚未进行动物研究来确定 CASS 的安全性和有效性。设计：前瞻性随机动物研究。地点：美国国立卫生研究院动物研究机构。受试者：22 只羊。干预措施：羊被随机分为三组。 C组（对照组），8只羊保持俯卧位，用标准气管导管（ETT）插管，机械通气72小时，头和ETT抬高30度角。在 CASS-HU 组（CASS，头朝上）中，七只羊作为 G 组进行管理，并使用 Hi-Lo Evac、Mallinckrodt ETT 进行插管（CASS 吸力保持在小于或等于 20 mm Hg）。在 CASS-HD 组（CASS，头朝下）中，7 只羊保持 CASS 俯卧，ETT 和气管水平，以促进粘液从 ETT 自发排出。测量和结果：CASS-HU 组的下呼吸道在所有 7 只羊中都有严重定植（中位数 4.6 x 10(9)，范围：1.5 x 10(8) 至 7.9 x 10(9) 菌落形成单位/克），与 C 组相比，肺部细菌定植减少（p = .05）。在 CASS-HD 组中，七只羊中有六只的下呼吸道没有定植。一只羊的细菌生长水平较低（中位数为 0；范围为 0-2.2 x 10(5)）。尸检时，所有14只患有CASS的羊，在ETT吸口水平均发现气管粘膜有不同程度的严重损伤。结论：在CASS-HU组中，尽管发现下呼吸道细菌定植略有减少，但气管-支气管-肺部细菌定植普遍存在。其次，当 CASS ETT 的方向处于水平或略低于水平时，细菌定植很少或不存在。第三，使用 CASS 会造成气管粘膜/粘膜下层广泛损伤。请注意，由于解剖和功能差异，在动物模型中进行的研究结果始终难以外推到临床实践。
Objective: Continuous aspiration of subglottic secretions (CASS) is believed to lower the incidence of ventilator-associated pneumonia. Animal studies to establish safety and efficacy of CASS have not been conducted.Design: Prospective randomized animal study.Setting: Animal-research facility at the U.S. National Institutes of Health.Subjects: Twenty-two sheep.Interventions: Sheep were randomized into three groups. In group C (control), eight sheep were kept prone, intubated with a standard endotracheal tube (ETT), and mechanically ventilated for 72 hrs with head and ETT elevated at an angle of 30degrees. In group CASS-HU (CASS, head up), seven sheep were managed as group G and intubated with a Hi-Lo Evac, Mallinckrodt ETT (CASS suction kept at less than or equal to20 mm Hg). In group CASS-HD (CASS, head down), seven sheep were kept prone with CASS, and the ETT and trachea were horizontal to promote spontaneous drainage of mucus from the ETT.Measurements and results: The lower respiratory tract in the CASS-HU group was heavily colonized in all seven sheep (median 4.6 x 10(9), range, 1.5 x 10(8) to 7.9 x 10(9) colony-forming units/g), with a reduction of lung bacterial colonization compared with the C group (p = .05). In group CASS-HD, the lower respiratory tract was not colonized in six of seven sheep. One sheep showed low levels of bacterial growth (median, 0; range, 0-2.2 x 10(5)). At autopsy, in all 14 sheep with CASS, we found tracheal mucosal injury of different degrees of severity at the level of the suction port of the ETT.Conclusions: In group CASS-HU, regardless of finding a marginal decrease of the bacterial colonization of the lower airways, there was pervasive trachea-bronchial-lung bacterial colonization. Second, there was minimal, or absent, bacterial colonization when the orientation of the CASS ETT was at, or just below, horizontal. Third, there was widespread injury to tracheal mucosa/submucosa from the use of CASS.Note that results of studies conducted in an animal model are always difficult to extrapolate to the clinical practice due to anatomical and functional differences.