Best Evidence Topics


Christopher H. LeMaster, MD
Infection and Natural History of Emergency Department–Placed Central Venous Catheters
Ann Emerg Med
2010 NOV; 56:492-97
  • Submitted by:Peter Himmel - Emergency Medicine Resident Physician
  • Institution:Michigan State University- Grand Rapids
  • Date submitted:23rd March 2011
Before CA, i rated this paper: 5/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes. The authors had three well defined and simple goals. First, to measure the rate of bloodstream infection associated with ED-placed central venous catheters. Second, to assess the time such catheters were left in-situ, and lastly to develop a practical way of identifying patients with ED-placed central venous catheters for use in future quality improvement efforts.
2 Design
2.1 Is the study design suitable for the objectives?
  This is a retrospective chart review. The design is appropriate for the limited objectives stated by the authors.
2.2 Who / what was studied?
  This study was designed to determine bloodstream infection and duration of catheterization rates for central venous catheters placed in the ED.
2.3 Was a control group used if appropriate?
  No control was used. Rates were compared to an historical rate 5.32 per 1,000 catheter-days found in the ICU setting.
2.4 Were outcomes defined at the start of the study?
  Yes. The outcomes designed to be studied were the rate of bloodstream infection associated with central venous catheters placed in the ED and the mean duration of catheterization.
2.5 Was this the right sample to answer the objectives?
  Charts to review were identified one of three ways. First, they reviewed charts of all hospitalized patients with bloodstream infection identified between January 1, 2007, and December 31, 2008, through prospective surveillance by the hospital’s infection control team. Next, they reviewed the charts of all ED patients admitted to any adult ICU during the study period, and lastly they reviewed the charts of all ED patients with a physician billing code for a central venous catheter during the study period.
2.6 Is the study large enough to achieve its objectives? Have sample size estimates been performed?
  Sample size estimates were carried out. They determined that to obtain a rate of infection with 95% confidence intervals that did not overlap with the known ICU infection rate they would need at least 500 catheter-days. According to pilot data, they determined that 250 central venous catheters would be required to generate this many catheter-days and that this could be found in 2 years of data.
2.7 Were all subjects accounted for?
2.8 Were all appropriate outcomes considered?
  Yes - bloodstream infection rates and mean duration of catheterization.
2.9 Has ethical approval been obtained if appropriate?
3 Measurement and observation
3.1 Is it clear what was measured, how it was measured and what the outcomes were?
  Yes. Bloodstream infection rates and mean duration of catheterization were the only outcomes reported.
3.2 Was the assessment of outcomes blinded?
3.3 Was follow up sufficiently long and complete?
  This is a retrospective review and did not involve patient follow-up. The only issue might be incomplete catchment of the population at risk or inadequate chart documentation of outcome parameters.
3.4 Are the measurements valid?
3.5 Are the measurements reliable?
  To the limits placed by chart documentation.
3.6 Are the measurements reproducible?
  Within the system and methods described.
4 Presentation of results
4.1 Are the basic data adequately described?
  The authors used a structured data abstraction form that included age; sex; date and time of ED triage, ED discharge, and hospital discharge; site of central venous catheter placement; date and time of central venous catheter placement and removal; placement of additional central venous catheters; date and time of blood culture or central venous catheter tip culture results; and discharge diagnosis.
4.2 Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
  Yes (Table)
4.3 How large are the effects within a specified time?
  They examined a total of 4,251 patient charts. There were a total of 667 central venous catheters placed in 656 patients, with 9 patients having greater than 1 concurrently placed central venous catheter. Among these 656 patients, there were 3,622 catheter-days and a total of 7 bloodstream infections, for a bloodstream infection rate of 1.93 per 1,000 catheter-days (95% CI 0.50 to 3.36).
4.4 Are the results internally consistent, i.e. do the numbers add up properly?
5 Analysis
5.1 Are the data suitable for analysis?
  The data consisted of number of catheters, total catheter days, number of blood stream infections, and duration of catheter dwell time.
5.2 Are the methods appropriate to the data?
5.3 Are any statistics correctly performed and interpreted?
  Yes. They used as the main outcome measures the rate of ED bloodstream infection expressed per 1,000 catheter-days and mean duration of catheterization expressed in days, with 95% CIs.
6 Discussion
6.1 Are the results discussed in relation to existing knowledge on the subject and study objectives?
  Yes. Rates are compared to blood stream infection rates in a historical group of ICU placed central lines. No prior studies of ED placed lines was available.
6.2 Is the discussion biased?
  Possibly. The authors used bloodstream infection as their infectious outcome, which they stated would
overestimate the actual rate of central line–related bloodstream infection. It is possible that if catheter tips were not routinely cultured on line removat that the rate might indeed be underestimated.
7 Interpretation
7.1 Are the author's conclusions justified by the data?
  Yes. To the extent that there was an adequate capture of patients at risk and that the method of determining blood stream infection was valid.
7.2 What level of evidence has this paper presented? (using CEBM levels)
7.3 Does this paper help me to answer my problem?
  Yes. The paper suggests that lines placed in the ED are at least NO MORE liable to infection than those placed in the ICU setting.
After CA, i rated this paper: 5/10
8 Implementation
8.1 Can any necessary change be implemented in practice?
  Central line placement can be considered if clinically appropriate.
8.2 What aids to implementation exist?
  The impact on infection control should be negligible as compared to ICU placed lines.
8.3 What barriers to implementation exist?
  Time and equipment constraints in the ED
8.4 Are the study patients similar to your own?
8.5 Does the paper give any conclusions that will affect what you will offer or tell your patient?
  Yes. The findings suggest that the risk of infection may be similar for central venous catheters placed in the
ED and in the ICU setting if optimal insertion practices are used. The practice of immediately removing ED central venous catheters shortly after admission to the hospital would not be supported by their findings.