Ultrasound Guided Cannulation of Dialysis Fistulas

• Time to establish dialysis [ Time Frame: Within an average of 5 minutes into each of the next 12 consecutive dialysis session ] [ Designated as safety issue: No ]
  Time to commence 2 needle dialysis from first palpation or imaging of fistula
  
  

• - Patient reported pain scores Patient reported anxiety and pain [ Time Frame: enrollment, two weeks and four weeks into trial ] [ Designated as safety issue: No ]
  Patient reported pain scores and anxiety scores recorded by questionnaire
  
  
• Number of cannulation attempts( skin punctures or passes of needle) [ Time Frame: Within an average of 5 minutes into each of the next 12 consecutive dialysis session ] [ Designated as safety issue: No ]
  number of cannulation attempts required
  
  
• complications of needling [ Time Frame: Within 2 hours of completing each of the next 12 consecutive dialysis sessions ] [ Designated as safety issue: No ]
  record presence of any complications due to needle insertion
  
  
• Referral for difficult needling during trial [ Time Frame: From enrollment to 24 hours following completion of the last of 12 consecutive dialysis sessions ] [ Designated as safety issue: No ]
  Referral for difficult needling to either senior nurse or to access clinic during trial
  
  

Haemodialysis patients need to have two needles inserted into a large surgically altered vein (fistula) or surgical vascular graft/shunt for every dialysis session. Some fistulas or shunts may be more difficult to insert needles into than others. As such a system of colour coding or "traffic lighting" of patients is in place in most units. A "green light" patient is easy to "needle" with two needles and the majority of staff within the unit will be able to connect the patients to the dialysis machine. A "red light" patient is reserved for the more experienced staff within the unit who will often have to be timetabled to work specific times so that they are present to connect certain patients to the dialysis machines. "Amber light" fistulas lie between these two extremes.

Ultrasound (US) is routinely used in many hospitals and many dialysis units will have access to a machine to assess patients for problems. Indeed central venous line insertions for dialysis are now almost always performed under US guidance since two large studies in this area in 2002 provided strong evidence that US guided placement significantly reduces complications during catheter placement and a reduction in the number of attempts at insertion. In addition the National Institute of Clinical Excellence in the UK provided evidence that insertion time is quicker although this association was statistically less convincing.

Ultrasound offers the advantage of dynamic imaging without the risks of radiation exposure and can be done as an office based procedure using portable equipment.

Studies in emergency departments and particularly in paediatric care have suggested that US guidance can improve the speed and accuracy of cannulation in peripheral veins for intravenous access.

We suggest that US guided cannulation of fistulas might improve the cannulation rate of more difficult fistulas and potentially reduce the time required to commence dialysis and the number of local complications of cannulation (haematoma/aneurysm/infection).

To our knowledge US is not used in cannulation guidance in any dialysis units, although most units will have access to a machine as above. We therefore propose to perform a randomised controlled trial of US guided cannulation of fistulas versus current practice (blind cannulation) to assess the effectiveness of US controlled cannulation in a busy dialysis unit.