Effects Of Replacement Time Of The Tip Of Closed Suction Catheter On The Catheter Bacterial Colonization And Ventilator-associated Pneumonia Incidence

ObjectivesHospital-acquired pneumonia (HAP), with a mortality rate up to 30% currently, is the primary cause of death among kinds of hospital-acquired infection. Ventilator-associated pneumonia (VAP) is the most common factors of hospital-acquired pneumonia. Because the current gold standard for diagnosis of VAP is difficult to implement in the clinical, through prevention, although they can prevent, or reduce the incidence of VAP, but the prevention technique involves many aspects of clinical work. A patient with mechanical ventilation in Intensive Care Unit (ICU) is recently with a very high risk of VAP, The reported incidence of foreign up to 9%-40%, National report is 10%-65%, and the mortality rates of VAP are also high. Hence, how to prevent VAP is an urgent topic to the ICU medical staff, even to the whole critical medical profession nowadays.Since the occurrence of VAP requires two important aspects:respiratory tract bacterial colonization and contaminated airway secretions, treatment liquid or aerosol going into the lower respiratory tract, thus preventing the occurrence of VAP mainly concentrated in the fight against bacterial respiratory tract colonization and reduction of aspiration. While focusing on the nursing scare, the preventive measures includes the timely clearing the oropharyngeal respiratory secretions, as well as environmental management, wash hands, raise the bedside, attach importance to oral care, to prevent regurgitation and aspiration, attention to air bag pressure, use of humidification devices, replacement breathing circuit, dumping wetting liquid in time, and so on.Airway suction through the endotracheal intubations has become one of the measures to prevent VAP. However, the early suction system we adopted is open suctioning system (OSS). But the use of OSS has lots of disadvantage, such as breaking the mechanical ventilation, cross-contamination and polluting the environment and other problems. The Closed suction systems (CSS) emerged in the atmosphere, and began used in the clinical area 1980s. The use of CSS solves the problems of OSS which we mention above. But so far, domestic and foreign researchs has no significant difference was seen either in the incidence of VAP or mortality between CSS and OSS suction. But the use of CSS did not increase the incidence of VAP. So some studies started to pay attention to economic cost comparison between the application of CSS and the OSS. So the first problem of CSS we need to solve is to certainty the best replacement time of CSS which do not increase the incidence of VAP. However, the optimal replacement time on the CSS is uncertain as well as no precise guidance from clinical findings. So a large-scale randomized, controlled clinical trials and a more rigorous analytical methods for analysis is needed to obtain more accurate information to guide clinical care of CSS. In the course of VAP, the impact of bacterial colonization in the tip of closed suction catheter (CSC) is not yet clear now. CSC currently study abroad, the replacement time most set in 24h,48h,72h. But in domestic Study, we can only see one controlled study between 24h and 48h, the replacement time extended to 72 hours has not yet reported. In order to solve these problems and provide reference to clinical CSC use,, the study is a randomized controlled clinical study, it is a compare of the replacement time on the CSS between 24h and 72h with the mechanical ventilation of patients in our hospital, and investigate whether different time of CSC effects the colonization in the tip of CSC and VAP incidence, in addition, to explore closed suction catheter colonization-related factors and VAP-related risk factors.Objects and Methods Objects:70 patients undergoing mechanical ventilation who were in either respiratory intensive care unit, or nerve ICU, or surgical ICU during April 2009-February 2010 were enrolled. Inclusive criteria:age more than 18 yrs; patients start mechanical ventilation; without hyperimmunologic function diseases, the time of mechanical ventilation more than 72 hours. Exclusive criteria:age less than 18 yrs; has been Mechanical ventilation before enrolled to the trial; with hyperimmunologic function diseases(includes acquired immune deficiency syndrome, agranulocytosis, underwent solid organ transplantation, systemic or pulmonary use of steroid or immunosuppressive drugs, and etc.); the time of undergoing mechanical ventilation was less than 72h. Group:Use software SPSS13.0,70 patients undergoing mechanical ventilation were randomized into 24 h group (replace the closed suction catheter per 24 h) or 72 h group (replace the closed suction catheter per 72 h),35 patients each group. In the 24h group,2 patients were eliminated as undergoing mechanical ventilation less than 72h.In the 72h group,4 patients were eliminated as undergoing mechanical ventilation less than 72h,2 patients were eliminated, as the time of replace the closed suction catheter was changed by operators. the actual complete examples were 62 (33 patients in 24h,29 patients in 72h).Methods:1.The selected patients' basic information were recorded in detail, the factors include age, sex, acute physiology and chronic health-Ⅱ(APACHE-Ⅱ) score, intubation's method, underlying diseases (including COPD, lung infection, lung cancer, brain diseases), smoking history, the application of stomach tube, the application of sedatives, antacids and application frequency of fiberoptic bronchoscope.2. Two groups be obtained at the start of mechanical ventilation etiology sputum examination (including sputum culture and colony count).3. Two groups at the time of mechanical ventilation for 72 hours, the front 5cm line of suction tube was took for pathogenic examination(including culture and colony count) immediately after replacement.4.Dynamic observation of the groups with sputum color, sputum volume, body temperature, pulmonary signs, white blood cell count and chest radiograph changes, when the clinical signs of suspected VAP (including fever, increased sputum volume, sputum color, grows white blood cell count＞10.0×109/L or＜4.0×109/L, with or without a left shift, pulmonary infiltrates or a chest appear on the original basis of new infiltrates) were found, the sputum samples were sent for pathologic examination.5.Observation set date for 10 days.6. All the cases of VAP were diagnosed by specialist respiratory physician who did not know the randomized group of patients. Outcome measures:1.The replacement time on the CSC of two groups, the rate of bacterial colonized, the density of colonized bacterial and kinds of colonized bacteria on the tip of CSC were compared.2.The incidences of VAP were affected by the different replacement time on the CSC of two groups, the affects were compared, and analyze the pathogenic characteristics of patients with VAP.3.Analyzing related factors of colonization group and non-colonization group, look for CSC in this study may be relevant factors tip bacteria colonization.4.Analyzing associated factors of VAP group and non-VAP group, in order to explore the possible risk factors of VAP in the current study.Statistical treatmentThe results were analyzed by SPSS13.0. Normality test of measurement data were carried out. If the data accord with normal distribution, they would be present as mean±SD; the skewed distributive data are present as median (Interquartile Range). t test was used to compare the normal distribution data accord with homogeneity of variance, non-parametric tests (Mann-Whitney U test) were used in the comparison of other data. Categorical data are presented as numbers (percent), andχ2 test or Exact probability test was conducted for comparison between groups. Ambi-nonparameter test was used for the significance different factors in uni-factor analysis in part two for the correlation. P values＜0.05 were considered significant.ResultsPart oneThe rate of bacterial colonized on the tip of catheter in total patients, in 24 h group and 72 h group was 66.1%,60.6%and 72.4%respectively. And there was no significantly difference between 24 h group and 72 h group (P＞0.05). The density of colonized bacterial in 24h group and 72h group was 50 (1000) cfu/ml,1000 (4000) cfu/ml respectively, though the density of colonized bacterial was higher in 72 h group than that in 24 h group, no significantly difference was found between two groups (P＞0.05). The density of colonized bacterial in 24h group and 72h group in colonized positive patients was 1000 (2400) cfu/ml,1800 (54500) cfu/ml respectively, also no significantly difference was found between two groups (P＞0.05).Bacteria strains of catheter tip culture are as follows:Acinetobacter baumannii (12 cases), Pseudomonas maltophilia (6 cases), Pseudomonas aeruginosa (4 cases), Escherichia coli (2 cases), Klebsiella pneumoniae (4 cases), Onion Holder bacteria (4 cases), Sticky Chryseobacterium (1 case), Aerobacter sp film clip (1 case), Candida albicans (7 cases), Candida tropicalis (1 case), Streptococcus viridans (2 cases). Enterobacter, Acinetobacter, Pseudomonas and Candida accounted for 15.9% (7/44),27.4 (12/44),31.8%(14/44) and 18.2%(8/44) of total bacteria respectively, and no significantly difference was found between the 24h group and 72h group (P＞0.05). The number of bacteria of Catheter colonization which consistent with the bacteria of sputum culture was 20 (45.5%,20/44),8 in 24 group (40.0%) and12 in 72h group (50.0%), No significantly difference was found between the 24h group and 72h group (P＞0.05). No significantly difference was found between CSC colonization group and non CSC colonization group in all the possible CSC colonization-related factors (included age, sex, acute physiology and chronic health-Ⅱ(APACHE-Ⅱ) score, intubation's method, underlying diseases (including COPD, lung infection, lung cancer, brain diseases), smoking history, the application of stomach tube, the application of sedatives, the application of antacids and frequency of fiberoptic bronchoscope (all P＞0.05).Part twoVAP occurred in 14 patients,10 cases of early-onset and 4 cases of late onset. The incident rate of VAP in total patients, in 24 h group and 72 h group was 22.6% (14/62),15.2%(5/33)and 31.0%(9/29)respectively. And there was no significantly difference between 24 h group and 72 h group (P＞0.05).14 cases sputum culture was positive, among 14 patients, the positive rate of culture was 100%(14/14) Bacteria strains of sputum of VAP patients are as follows:Acinetobacter baumannii (7 cases), Pseudomonas maltophilia (3 cases),coli (1cases), Small moving Sphingomonas sp (1 case), Streptococcus viridans (1 case), Candida tropicalis (1 cases) and Candida albicans (1 case).12 patients out of 14 VAP patients (85.71%) were with a positive CSC colonization; 10 patients out of 14 VAP patients (71.4%) with the characteristics that its bacteria of sputum culture was accord to the CSC colonized bacteria; The density of CSC colonization bacteria in 24h group and 72h group among VAP patients were 1000 (3350.00) cfu/ml,1000 (504700) cfu/ml respectively, and no statistically significant difference was found between the two groups(P＞0.05).The single factor group analysis between VAP group and non VAP group indicated:the VAP-related factor with significantly difference is relevant to the application of antacids, P=0.012(between the two groups,P＞0.05). The ambi-nonparameter test was used for the the VAP-incidence rate and the application of antacids. Kendall coefficient correlation is 0.305,P=0.016. It cues significantly positive correlation between the VAP-incidence rate and the application of antacids. But the correlation isn't closeness(coefficient correlation＜0.05).ConclusionsPart one The different replace time of CSC impacted on the bacterial colonization on the tip of suction tube was no significant difference. The bacteria colonized in the tip of CSC were mostly gastrointestinal derived opportunist pathogen. With the prolong time of the CSC replacement, the lung-derived pathogens colonize in the tip of CSC is higher, but there were no significantly difference between the kinds and density of the colonized bacteria. The current study can not temporarily consider the frequency of replacement of the closed suction catheters has impact on the CSC bacterial colonization.Part two The different replace tme of CSC impacted on the incidence of VAP was no significant difference. The pathogens of VAP were mainly gastrointestinal derived opportunist pathogen. The pathogens of VAP are highly accord to the bacteria colonized in the tip of CSC. The current study can not temporarily confirm the frequency of replacement of the CSC has impact on the incidence of VAP. The application of fiberoptic bronchoscope in patients with mechanical ventilation is a risk factor of VAP incident.