Friday, January 21, 2011

ICU Rounds Report - Jan 21st 2011

Subclavians, PICCs and need for Dialysis. We're often told by renal to stay the hell away from subclavian and PICC lines in patients with a current, potential or future need for hemodialysis. Why? What truly is the rate of subclavian stenosis (SCS) after subclavian lines? PICCs? What impact does SCS have on long-term AV fistula patency?  

The access goal for hemodialysis patients is always an AV fistula or graft. Among the choices, they have by far fewer complications, lower cost and significantly lower mortality rates. We know SCS rates after placement of large-diameter subclavian dialysis lines can be quite high - up to 50%, which is why you never see renal do it. Stenosis in subclavian lines is so detrimental to long term function (problems include lympaedema, graft thombosis, failure), that surgeons screen for it routinely prior to placement of AV fistulas/grafts. In one series looking for SCS in patients presenting for fistula creation, screening found occult moderate to severe stenosis in 40% of patients - in every case thought due to prior lines.

The data for the smaller catheters we commonly use are less clear, as no study has screened for SCS specifially. One meta-analysis looking at some very heterogenous papers found no difference in symptomatic stenosis rates between IJ and SC sites, although no screening was done. Remember, total subclavian stenosis is frequently asymptomatic.  So what do we know about PICC lines? Radiologists at Thomas Jefferson in Philly followed 150 patients pre and post PICC placement with venography studies and found rates of SCS from PICCs of around 7%, with a mean followup of 20 months (range 3 days - 54 months). Longer indwelling times, left side, line infections, thrombus development and malpositioned lines are all risk factors for development of SCS.

So does it matter? Yes. Graft development and maintenance in ESRD patients is a huge problem. Among patients who develop AV fistula or graft dysfunction, 25% are found to have SCS, almost universally due to prior central venous access passing through the subclavian vein. By contrast, rates of stenosis found with screening following IJ cannulation for HD lines are much lower - 0-10%.
Cimochowski GE, Worley E, Rutherford WE, et al. Superiority of the intemal jugular over the subclavian access for temporary dialysis. Nephron 1990;54: 154-160
Ruesch, SM. Complications of central venous catheters: Internal jugular versus subclavian access-A systematic review
Crit Care Med 2002(30)2:454-460

Gonsalves CF, Eschelman DJ, Sullivan KL, DuBois N, Bonn J: Incidence of central vein stenosis and occlusion following upper extremity PICC and port placement. Cardiovasc Intervent Radiol 26:123–127, 2003

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