持续声门下吸引预防呼吸机相关性肺炎的前瞻性随机对照临床研究

Effect of continuous aspiration of subgiottic secretions on the prevention of ventilator-associated pneumonia in mechanically ventilated patients：a prospective, randomized, controlled clinical trial

目的评价持续声门下吸引预防呼吸机相关性肺炎（VAP）的意义。方法选2004年10月-2006年4月收住东南大学附属中大医院急诊与危重病医学科需要建立人工气道实施机械通气的18岁以上成年患者，随机分为持续声门下吸引组（CASS组）与不行声门下吸引组（NASS组）。用VAP临床诊断标准和简化临床肺部感染评分（CPIS）进行VAP评估。记录声门下引流量、VAP发生情况、28d病死率等。结果共有101例患者人选，机械通气48h以上CASS组48例，NASS组43例，2组患者平均APACHEⅡ为（20．8±6．1）分，诊断VAP时CPIS为（5．6±1．0）分。CASS组患者第一个24h声门下引流量平均为（27．2±21．2）ml。CASS组、NASS组VAP发生率分别为25．0％、46．5％（P=0．032），发生时间分别为（7．3±4．2）d、（5．1-t-3．0）d（P=0．100）。NASS组发生VAP的患者下呼吸道标本革兰阳性球菌比例明显高于CASS组（P=0．004）。发生VAP的患者第一个24h声门下引流量明显少于未发生者（P=0．006）。发生VAP患者机械通气时间明显延长、住院病死率和28d病死率显著增加（P值分别为0，000、0．009、0．035）。结论有效的声门下吸引可显著降低早发性VAP的发生率。

Objective To evaluate the effect of continuous aspiration of subglottic secretions （CASS） on the prevention of ventilator-associated pneumonia （VAP） in mechanically ventilated patients. Methods Patients ventilated mechanically at the ICU from October, 2004 to April,2006 were randomly divided into 2 groups： one group received CASS and the other did not （NASS group）. CASS was performed immediately after admission for patients in the CASS group. The diagnosis of VAP was made based on clinical presentations, and the evaluation of VAP was done using simplified version of the clinical pulmonary infection score （CPIS）. The general status of the patients, days of ventilated treatment, the volume of daily aspirated aubglottic secretions, the morbidity and timing of VAP, days of stay in ICU and mortality within 28 days of hospitalization were recorded. Results One hundred and one patients were included in the study. There were 48 patients in the CASS group who were treated with mechanical ventilation more than 48 hours, and 43 patients in the NASS group. There was no significant difference in the general status of the patients and days of ventilation between 2 groups with the averaged score of APACHE Ⅱ being 20. 8±6. 1. The average of CPIS was of 5.6± 1.0 when VAP was diagnosed. The mean volume of aspirated subglottic secretions within the first 24 hours in the CASS group （ n = 48 ） was （27.2 ± 21.2 ） ml. The morbidity of VAP in the CASS and the NASS groups was 25.0% and 46. 5% respectively （P =0. 032）, and the length of time before the onset of VAP in these 2 groups was （7.3 ±4. 2） days and （5.1±3.0） days respectively （P = 0. 100 ）. There was a significant increase in the percentage of gram-positive cocci from the lower respiratory tracts in the NASS group compared with that in the CASS group （P = 0. 004）. In the CASS group, the volume of the first daily aspirated subglottic secretions in patients with VAP was significantly less than that in patients without VAP（ P =0. 006）. The morbidity of VAP in patients with failed early aspiration （the volume of first daily aspirated secretions ≤20 ml） was significantly higher than that in patients in whom the aspiration was effective （ P 〈 0. 01 ）. The length of mechanical ventilation in patients with VAP was significantly longer than that in patients without VAP（P = 0. 000）. The in-hospital mortality in patients with VAP was significantly higher than that in patients without VAP （ P = 0. 009 ）, and the mortality in 28 days after admission in patients with VAP was significantly higher than that in patients without VAP（P=0. 035 ）. Conclusion Effective continuous aspiration of subglottic secretions could significantly reduce the morbidity of early-onset VAP.