Subclavian vs. Femoral Central Line Placement
Benefits in NNT
None were helped by a subclavian central line over a femoral central line
100% saw no consistent or reliable patient-oriented benefit
Harms in NNT
None were harmed by a subclavian central line over a femoral central line
0% saw no consistent or reliable patient-oriented harm
SourceHamilton HC, Foxcroft DR. Central venous access sites for the prevention of venous thrombosis, stenosis and infection in patients requiring long-term intravenous therapy. Cochrane Database Syst Rev. 2007 Jul 18;(3):CD004084
Merrer J et al. Complications of femoral and subclavian venous catheterizaiton in critically ill patients: a randomized controlled trial. JAMA. 2001 Aug 8;286(6):700-7
Efficacy EndpointsCatheter-related infectious complications (colonization with or without sepsis), Catheter-related thromboses (fibrin sleeves, major and complete vessel thrombosis)
Harm EndpointsCatheter-related mechanical complications (arterial puncture, minor bleeding, hematoma, misplaced catheter)
NarrativeCentral venous access is often felt to be essential during management of the critically ill patient. Ideally, clinicians choosing anatomic sites for central venous access would be aware of the disadvantages and advantages associated with the most commonly used sites. These sites include the internal jugular vein, the subclavian vein and the femoral vein.
The Cochrane Review identified one randomized control trial that examined the difference between subclavian and femoral vein sites, concluding that the subclavian site is associated with a significantly decreased rate of both infectious and thrombotic complications. This conclusion however was based on disease-oriented (rather than patient-oriented) outcomes such as 'line colonization', and ultrasound detected femoral vein thrombosis. There was no difference between the two sites in terms of actual clinical infections. There was also no significant increase in mechanical complications during or secondary to line insertion.
CaveatsThere is currently only one high quality randomized control trial that examines the differences among these sites. The study included a total of only 293 patients and was underpowered (too small) to be able to reliably detect differences in clinical infection rates. When combining clinical infection with 'line colonization', a surrogate marker measuring bacteria detected on the tip of a catheter that had been removed, the investigators were able to report a difference with statistical significance. There was no difference in clinical infection rates (a patient-oriented benefit) between groups, however. During the study, there were also four pneumothoraces that occurred in association with subclavian line placement, an important complication that is not associated with the femoral access site. Furthermore, the study only examined the difference between subclavian and femoral access sites. While there are multiple prospective and retrospective studies that include analysis of internal jugular central venous access, neither the Cochrane Review nor this author were able to find a randomized trial that examined complication rates among subclavian, internal jugular and femoral access sites.
Finally, the study from which the Cochrane review reports its data was performed nearly a decade ago, a time when the 'checklist' approach that includes new and diligent measures to prevent infection were not in widespread use. This has the potential to render these data irrelevant to the current routine practice of central line placement. There is therefore a lack of high quality, applicable evidence pertaining to the preferred site of central venous access.