Routine changing of intravenous administration sets does not reduce colonization or infection in central venous catheters
This review may be edited
Posted By: rosalind elliott
Posted Date: 12/08/05
Title: Routine changing of intravenous administration sets does not reduce colonization or infection in central venous catheters
Authors: Rickard, C., Lipman, J., Courtney, M., Siversen, R., Daley, P.
Reference: Infection Control and Hospital Epidemiology 2004 Aug; 25 (8):650-655
Link: Click here for a direct link to the paper. A password may be required for access to fulltext.
Abstract: OBJECTIVE: To determine the effect of routine intravenous (IV) administration set changes on central venous catheter (CVC) colonization and catheter-related bacteremia.
DESIGN: Prospective, randomized, controlled trial.
SETTING: Eighteen-bed intensive care unit (ICU) in a large metropolitan hospital.
PARTICIPANTS: Two hundred fifty-one patients with 404 chlorhexidine gluconate and silver sulfadiazine-coated multilumen CVCs.
INTERVENTIONS: CVCs inserted in the ICU and in situ on day 4 were randomized to have their IV administration sets changed on day 4 (n = 203) or not at all (n = 201). Use of fluid containers and blood product administration sets was limited to 24 hours. CVCs were removed when not required, infection was suspected, or in place on day 7. Catheter cultures were performed on removal by blinded laboratory staff. Catheter-related bacteremia was diagnosed by a blinded intensivist using strict definitions. Data were collected regarding catheter duration, site, Acute Physiology and Chronic Health Evaluation (APACHE) II score, patient age, diagnosis, hyperglycemia, hypoalbuminemia, immune status, number of fluid containers and IV injections, and administration of propofol, blood, total parenteral nutrition, or lipid infusion.
RESULTS: There were 10 colonized CVCs in the group receiving a set change and 19 in the group not receiving one. This difference was not statistically significant on Kaplan-Meier survival analysis. There were 3 cases of catheter-related bacteremia per group. Logistic regression found that burns diagnosis and increased ICU stay significantly predicted colonization.
CONCLUSION: IV administration sets can be used for 7 days in patients with short-term, antiseptic-coated CVCs (Infect Control Hosp Epidemiol 2004;25:650-655).
Are the Results Valid?
1. Was the assignment of patients to treatments randomized? ( Was allocation concealment maintained?)
Unsure. The authors report that "a computerized random number generator randomized each CVC to either receive a routine set change or have the original administration set left intact for the duration of catheterization."
The authors do not report how allocation concealment was maintained.
N.B. - Individual patients may have had more than one catheter randomised to different groups in the trial.
2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?
2a. Was followup complete?
251 patients had 404 CVCs randomised into the trial.
  • 29 (7.1%) CVCs were not cultured (out of the whole sample)
  • Follow-up was complete for the patients
  • 2b. Were patients analyzed in the groups to which they were randomized?
    No, not really. The Unit of measurement was the CVC not the patient.
  • 157 patients had only one CVC in the study.
  • 94 patients (37%) had more than one CVC in the study at the same time. It is likely that the outcomes for the CVCs from these 94 patients are not 'independent'. In other words, the results from these catheters may be 'contaminated' because the patients were 'analyzed in both groups'.
  • 3. Were patients, health workers, and study personnel blind to treatment?
    The nurses caring for the patients were not blind to the differences in administration set change however the medical officers and the intensivist who reviewed the microbiology results were.
    4. Were the groups similar at the start of the trial?
    The patient's characteristics for the CVC groups were similiar apart from a mean six year age difference (the set change group were older) and on average more intravenous bolus injections were given in the no set change group. It is unclear how the investigators dealth with the problem of patients' subsequent CVCs being assigned to a different group.
    5. Aside from the experimental intervention, were the groups treated equally?
    What are the Results?
    1. How large was the treatment effect?
    The most reliable results from this paper would be based on the results of the 157 patients who received only one type of catheter. Unfortunately, results are not reported for these patients.
    Overall results:
    Of the 378 catheters cultured 10 in the group receiving a set change (n=189) were colonized and 19 were colonized in the group not receiving a change (n=189).
  • The overall reduction in infection rate associated with a Set Change was: -4.8% (95% CI from -10% to +1%, p=0.12)[Calc'd by Gord}
    The Authors report:
    Colonization per catheter day was 10.4 in the change group and 20.1 in the no change group. The result was not significant (change group odds ratio (OR) 0.51; 95% CI 0.24 to 1.09 p=0.34 and Kaplan-Meier log-rank test=0.87; df=1; p=0.3505).
  • 2. How precise was the estimate of the treatment effect?
    See above (and article) for 95% CI of reported outcomes.
    No change group 19/201= 0.0945
    Change group 10/203= 0.04926
    Absolute risk =-0.04526
    Relative risk =0.04926/0.0945= 0.5211
    Will the Results Help Me In Caring For My Patients?
    1. Can the results be applied to my patient care?
    The procedures, patients and type of catheters were similiar to those at RNSH. The primary outcome is a surrogate outcome (CVC colonisation). The results for secondary outcome (the study wasn't powered for this), catheter related bacteremia, were encouraging however this is a patient-level outcome and the unit of randomisation in the study was the CVC. Patient level outcomes will be unreliable because individual patients received both types of catheter care.
    2. Were all clinically important outcomes considered?
    No mortality was only considered for pts who got a catheter related bacteremia. QOL and how the patient felt were not considered.
    3. Are the likely treatment benefits worth the potential harms and costs?
    Very unclear.

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