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Predicting CVCrBSI

Citation/s: McKinley S, et al. Incidence and Predictors of Central Venous Catheter related Infection in Intensive Care Patients. Anaes Intensive Care 1999;27:164-169
Lead author's name and fax: Prof. S. McKinley, Royal North shore Hospital, Sydney, Australia.

Three-part Clinical Question: In critically ill patients, does the choice of CVC site, affect the incidence of CVC colonization or CVCrBSI.
Search Terms: see summary

The Study: Prospective, observational, Cohort Study.

The Study Patients: 12-bedded general ICU and 8-bedded neurosurgical ICU patients. Only CVC lines inserted in ICU and expected to be in situ for more that 72 hours. Protocolized care. Catheter replacement (at a new site) on day 7.
 

Exposure of Interest: CVC insertion and the effects on rates of catheter related infections of: age, primary diagnosis, gender, duration of catheterization, insertion site, TPN, repeated catheterization, season. For the purposes of this CAT we shall only consider the estimation of the effect of site of catheter.
 

The Outcome: CVC colonization or CVCrBSI.
Can't tell if the subjects were defined and similar in other important ways. The exposures and outcomes were either objective or measured blind. Follow-up was long enough; follow-up was complete enough.

The Evidence:

There were only five cases of CVCrBSI. There were only 4 femoral CVCs inserted.

EBM questions:

1.      Do the methods allow accurate testing of the hypothesis? No. there were inadequate numbers of femoral catheters in the study to assess their risk of infection. There was no comparison of patient demographics between insertion sites. This could lead to factors other that site affecting the rate of CVCrBSI. For example neurosurgical patients displayed very low rates of infection – if a large proportion of them have subclavian rather than internal jugular lines, that could affect the results. After controlling for primary diagnosis and duration of catheterization the authors found that the use of the IJ site had an OR of 3.39 (95% CI 1.2-11.4) for colonization when compared with the SCL site.

2.      Do the statistical tests correctly test the results to allow differentiation of statistically significant results? Yes.

3.      Are conclusions valid in light of the results? Yes. IJ placement is associated with a higher colonization rate.

4.      Did results get omitted, and why? Yes. Of the 181 CVCs inserted in 75 patients, complete data was only available on 119 catheters.

5.      Did they suggest areas of further research? Yes. To determine the magnitude of aseptic technique as a risk factor for CVCrBSI.

6.      Did they make any recommendations based on the results and were they appropriate? The internal jugular site should be avoided. This study only demonstrated a significant difference in catheter colonization rates between IJ and SCL sites, not in CVCrBSI. This may not represent a clinically significant difference. The small size of the study (96 IJ or Scl) and the lack of patient demographic data reduce to validity of the results.

7.      Is the study relevant to my clinical practice? Yes

8.      What level of evidence does this study represent? 2^-

9.      What grade of recommendation can I make on this result alone? none

10.  What grade of recommendation can I make when this study is considered along with other available evidence? N/A

11.  Should I change my practice because of these results? no

12.  Should I audit my current practice because of these results? no

Appraised by: Dr Chris Cairns, Consultant, ICU, Stirling Royal Infirmary, UK; 01 June 2005
Email: Chris.Cairns@fvah.scot.nhs.uk
Kill or update By: June 2010

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