气囊上滞留物引流对呼吸机相关下呼吸道感染的影响

The effect of subglottic secretion drainage on prevention of ventilator-associated lower airway infection

目的观察气囊上滞留物引流对呼吸机相关下呼吸道感染(VALAI)的影响。方法对入住呼吸重症监护病房(R ICU)预计机械通气(MV)超过48 h的患者使用可冲洗式气管插管,采用随机数字表法分为2组,即气囊上滞留物引流冲洗组为A组(53例次),非引流组为B组(55例次)。定期采用双套管保护性毛刷取下呼吸道分泌物,同步留取气囊上滞留物、咽拭子进行细菌定量培养,并记录患者的MV时间、住院时间、呼吸机相关气管-支气管感染(VAAI)和呼吸机相关肺炎(VAP)的出现时间。结果(1)MV 5日内,A组VAAI、VAP的发生率(8.3%、6.0%)显著低于B组(24.0%、20.0%,P均<0.05),A组VAAI、VAP的发生时间[(7.4±3.0)、(7.7±3.2)d]与B组[(4.9±1.4)、(4.6±2.1)d]比较差异均有统计学意义(P均<0.01)。A组患者病死率、MV时间、住院时间[10.4%、(15±14)d、(30±31)d]与B组[22.0%、(15±10)d、(32±19)d]比较差异均无统计学意义(P均>0.05)。(2)21例次(21.4%)患者下呼吸道分泌物在出现致病菌前,气囊上滞留物就发现了该致病菌。(3)A组气囊上滞留物致病菌的浓度明显低于B组气囊上滞留物致病菌的浓度(P<0.05)。(4)2组患者的下呼吸道分泌物的致病菌分布均以革兰阴性杆菌为主,主要优势菌为铜绿假单胞菌和鲍曼不动杆菌,2组主要致病菌构成比差异无统计学意义(P>0.05)。结论(1)气囊上滞留物引流和冲洗可以降低早发VALAI的发生率,可以使VAAI和VAP的发生时间延迟,对病死率、MV时间、住院时间无影响,可以使气囊上滞留物致病菌的浓度明显降低。(2)气囊上滞留物病原菌移行是VALAI的重要原因之一。(3)下呼吸道分泌物的致病菌分布以革兰阴性杆菌为主,主要优势菌为铜绿假单胞菌和鲍曼不动杆菌。

Objective To assess the influence of subglottic secretion drainage （SSD） on the morbidity of ventilator-associated pneumonia （VAP） in mechanically ventilated patients. Methods All studied patients who received mechanical ventilation（MV） estimated for more than 48 hours were intubated with a special type endotracheal tube whth a small-bore cannula in the wall for SSD. The patients were randomly divided into two groups receiving SSD（ group A） and usual care（ non-SSD,group B） respectively. Bacterial culture of samples from lower airway secretion taken regularly by Bagpipe Protected specimen brush were performed, and at the same time the subglottic secretion and scraping-pharynx specimen were collected for bacterial quantitative culture and antibiotic sensitivity test. The clinical data were recorded and the duration of MV, the length of stay in hospital and the time of occurrence of ventilator-associated airway infection（VAAI） and VAP were analyzed. Results （ 1 ） In patients with MV 〈 5 days： The incidence of VAAI and VAP in group A（ VAAI：8. 3% and VAP：6. 0% ）was lower than those in group B（ VAAI：24. 0% and VAP：20. 0% ,P 〈0. 05）. The onset of VAAI and VAP was delayed in group A [ VAAI： （7.4 ±3. 0） d and VAP： （7. 7 ±3.2） d] as compared with group B [ VAAI： （4.9 ± 1.4） d and VAP： （4. 6 ±2. 1 ） d,P 〈 0. 05 ]. There were no significantly statistic differences for hospital mortality, overall duration of mechanical ventilation,lengths of stay in the hospital between the two groups （P 〉 0. 05 ）. （2）The same organism as that previously found from subglottic secretion was isolated by PSB in 21.4% patients. （3）The concentration of bacteria in subglottic secretion from group A was decreased significantly as compared to that of group B. （4） Gram-negative bacilli were the main pathogens in the lower respitatory tract in the two groups. The dominant bacteria cultured in the lower airway secretions were Pseudomones aeruginosa and Acinetobacter baumanii. There was no singnificant diffenerce between the two groups in the spectrum of bacteria （ P 〉 0. 05 ）. Conclusions （ 1 ） SSD reduced the incidence of VAAI and VAP in patients with MV 〈 5 d. The onset of VAAI and VAP was delayed in group A as compared with group B. The concentration of bacteria in the subglottic secretion was significantly reduced by subglottic secretion drainage. （2）Migration of the dominant bacteria of the subglottic secretion was one of the important factors for VALAI. （3） The dominant cultured bacteria in the lower airway secretion were gram-negative bacilli, most commonly Pseudomones aeruginosa and Acinetobacte baumanii.