Clin Microbiol Infect 2011; 17: 870–872
Guidelines for the prevention of catheter-related bloodstream infection (CRBSI) recommend subclavian rather than femoral venous access to minimize the risk of CRBSI. However, they do not address the issue of CRBSI with subclavian venous access in the presence of tracheostomy, where the incidence of CRBSI has been found to be higher than without tracheostomy. In this study, we found lower CRBSI in subclavian venous access in the presence of tracheostomy than in femoral venous access (3.9 vs. 10.1 CRBSI per 1000 catheter-days; odds ratio = 0.39; 95% confidence interval ≤0.001–0.91; p 0.03).
A higher incidence of catheter-related bloodstream infection (CRBSI) in femoral than in subclavian catheter sites has been found [1,2]. Different guidelines for the prevention of CRBSI recommend avoiding femoral venous access sites [3,4].
However, the incidence of CRBSI in subclavian sites in the presence of tracheostomy is higher than without tracheostomy [5,6]. In addition, the incidence of CRBSI in jugular sites with tracheostomy is higher than in femoral sites . Currently, there are no comparative data on the incidence of CRBSI between the femoral venous and the subclavian venous catheter site in the presence of tracheostomy and there are no recommendations in the guidelines relating to this circumstance; this was the objective of this study.
A prospective observational 6-year study was carried out in the Intensive Care Unit of the University Hospital of the Canary Islands (Tenerife, Spain). We included all patients undergoing insertion of subclavian venous catheter in the presence of tracheostomy (subclavian-CVC+tracheo) or femoral venous catheter (femoral-CVC). The study was approved by the institutional review board, which waived the need for informed consent. Catheter tips were cultured using the method described by Maki et al. . Microbiological surveillance during the ICU stay included twice weekly cultures of urine, tracheal aspirate and wounds.
CRBSI was defined according to the following criteria: positive blood culture obtained from a peripheral vein, and signs of systemic infection (fever, chills and/or hypotension), with no apparent source of bacteraemia except the central venous catheter, and catheter-tip colonization (growth of a microorganism >15 colony-forming units from the central venous catheter tip) with the same organism as in the blood culture (the same species with identical antimicrobial susceptibility).
The diagnosis of pneumonia was established when all of the following criteria were met: (i) new onset of bronchial purulent sputum, (ii) body temperature of >38°C or <35.5°C, (iii) white blood cell count >10000/mm3 or <4000/mm3, (iv) chest radiograph showing new or progressive infiltrates, and (v) significant quantitative culture of respiratory secretions by tracheal aspirate (>106 CFU/mL). The criteria for diagnosis of tracheobronchitis are the same as those for pneumonia without radiograph change. Tracheal colonization was defined as the isolation of a microorganism in the tracheal aspirate without signs of respiratory infection.
Bacteraemia with the same microorganism in tracheal aspirate, catheter tip and blood culture was considered as secondary to the respiratory origin in the presence of tracheobronchitis or pneumonia, and related to the catheter in the presence of tracheal colonization.
Statistical analyses were performed with SPSS 12.0.1 (SPSS Inc., Chicago, IL, USA), LogXact 4.1 (Cytel Co., Cambridge, MA, USA) and StatXact 5.0.3 (Cytel Co.). Continuous variables are reported as median (25th–75th percentiles) and categorical variables as frequencies and percentages. We compared continuous variables between groups using the Wilcoxon–Mann–Whitney test and categorical variables using the Kruskall–Wallis test for singly ordered RxC tables. We used Poisson regression logistic analysis for the comparison of CRBSI incidence per 1000 catheter-days between groups, and the log-rank test to compare distributions of CRBSI-free time between groups. The magnitude of the effect is expressed as odds ratio (OR) and its 95% confidence interval (95% CI). A p-value <0.05 was considered statistically significant.
Subclavian-CVC+tracheo showed a lower incidence of CRBSI than femoral-CVC (3.9 vs. 10.1 CRBSI episodes/1000 catheter-days; OR = 0.39; 95% CI ≤ 0.001–0.91; p 0.03) (Table 1). The microorganisms responsible for CRBSI are described in Table 2.
|Characteristics||Femoral-CVC (n = 313) (2565 days)||Suclavian-CVC +tracheo (n = 147) (1268 days)||p|
|Age (years), median (25th–75th percentiles)||62 (48–69)||62 (51–70)||0.83|
|Male sex, n (%)||176 (56.2)||80 (54.4)||0.76|
|APACHE-II score, median (25th–75th percentiles)||14 (10–80)||15 (11–19)||0.31|
|Admission diagnostic, n (%)|
|Cardiology||74 (23.6)||46 (31.3)||0.57|
|Respiratory||49 (15.7)||17 (11.6)|
|Digestive||24 (7.7)||10 (6.8)|
|Neurological||79 (25.2)||33 (22.4)|
|Traumatology||77 (24.6)||36 (24.5)|
|Intoxication||10 (3.2)||5 (3.4)|
|Use of mechanical ventilation after CVC insertion, n (%)||242 (77.3)||118 (80.3)||0.54|
|Use of antimicrobials after CVC insertion, n (%)||253 (80.8)||116 (78.9)||0.62|
|Use of total parenteral nutrition after CVC insertion, n (%)||38 (12.1)||16 (10.9)||0.76|
|Reason for catheter removal, n (%)|
|Death||47 (15.0)||23 (15.6)||0.86|
|Suspicion of catheter-related infection||71 (22.7)||27 (18.4)|
|Change with guidewire due to longer need||31 (9.9)||17 (11.6)|
|No longer needed||157 (50.2)||76 (51.7)|
|Accidental removal||7 (2.2)||4 (2.7)|
|Catheter days, median (25th–75th percentiles)||8 (6–10)||8 (6–11)||0.17|
|CRBSI, n (%)||26 (8.3)||5 (3.4)||0.03|
|CRBSI incidence, number CRBSI/1000 catheter-days||10.1||3.9||0.03|
|Femoral-CVC (n = 26)||Subclavian-CVC +tracheo (n = 5)|
|Total gram-positive bacteria, no. (%)||11 (42.31)||4 (100.0)|
|Coagulase-negative staphylococci||5 (19.23)||4 (80.0)|
|Methicillin-resistant Staphylococcus aureus||1 (3.85)||0|
|Methicillin-sensitive Staphylococcus aureus||2 (7.69)||1 (20.0)|
|Enterococcus faecalis||3 (11.54)||0|
|Total gram-negative bacteria, –no. (%)||11 (42.31)|
|Escherichia coli||7 (26.92)|
|Klebsiella spp.||1 (3.85)|
|Enterobacter spp.||1 (3.85)|
|Serratia marcescens||1 (3.85)|
|Pseudomonas aeruginosa||1 (3.85)|
|Total yeasts, no. (%)||4 (15.38)||0|
|Candida albicans||4 (15.38)|
Survival analysis showed that subclavian-CVC+tracheo had greater CRBSI-free time than femoral-CVC (χ2 = 4.69; p 0.03).
One patient in the subclavian-CVC+tracheo group and another in the femoral-CVC group showed bacteraemia with the same microorganism in the catheter tip and tracheal aspirate, and colonization of tracheal aspirate without respiratory infection; both cases of bacteraemia were considered as CRBSI.
In the femoral-CVC group, one patient with pneumonia showed bacteraemia with the same microorganism in the catheter tip and tracheal aspirate, and this bacteraemia was considered as secondary to pneumonia and not CRBSI.
We diagnosed 23 CRBSIs in 279 femoral-CVC without the presence of tracheostomy during 2297 days (10.0 CRBSI episodes/1000 catheter-days) and three CRBSIs in 34 femoral-CVC with tracheostomy during 268 days (11.2 CRBSI episodes/1000 catheter-days). Subclavian-CVC+tracheo showed a lower incidence of CRBSI than femoral-CVC without tracheostomy (3.9 vs. 10.0 CRBSI episodes/1000 catheter-days; OR = 0.39; 95% CI ≤ 0.001–0.93; p 0.04). There was a tendency to a lower incidence of CRBSI in subclavian-CVC+tracheo than in femoral-CVC with presence of tracheostomy (3.9 vs. 11.2 CRBSI episodes/1000 catheter-days; OR = 0.35; 95% CI ≤ 0.001–1.69; p 0.20).
The novel finding of our study was a lower incidence of CRBSI in subclavian access with tracheostomy than in femoral access. This could help in decision making regarding certain patients, given the absence of published data about this comparison and the fact that current guidelines on the prevention of CRBSI contain no recommendations for this circumstance [3,4].
A significant finding of our study was that there were no cases of CRBSI caused by gram-negative bacteria or Candida spp. in the subclavian group. This is important because it could help decision making regarding the type of empirical antibiotics to be used for suspected CRBSI.
Our study has several limitations. Data in relation to the specific experience of each operator in central venous catheter insertion and the training of nursing staff performing catheter and tracheostomy care were not recorded. The choice of the insertion site was not randomized. We did not use molecular techniques to genetically relate the microorganism isolated from the catheter, the peripheral vein blood culture and the tracheal aspirate. The very broad confidence interval is probably due to the small numbers, but nevertheless the results were statistically significant. The main comparison was between subclavian-CVC+tracheo vs. femoral-CVC, and we found a tendency to a lower incidence of CRBSI in subclavian-CVC+tracheo than in femoral-CVC with tracheostomy (the difference was not significant, probably because of the low number of cases). Finally, approximately 80% of both groups of patients received antibiotics and it is possible that in some patients the respiratory cultures were negative due to the suppressive effect of concurrent antibiotic therapy.
In conclusion, subclavian-CVC+tracheo could be considered a safer venous access site than femoral-CVC in order to minimize the risk of CRBSI.
There are no conflicts of interest.