Friday, November 19, 2010
• Is a set of symptoms caused by hypoxia (lack of oxygen to the tissues).
• 'Patients feel pain that can range from minor to severe.
• In most patients, steal syndrome pain lessens over time because extra blood vessels grow and supply blood to the area (collateral circulation)
• Some of the symptoms to watch for or ask your patients about include:
• Pain in the access limb
• Tingling in the access limb
• Cold feeling in the access limb
• A change in motor skills in the hand.
• Nail beds that are blue in color
• Necrotic (dead / slacked) spots on the ...
• Decreased feeling in the access limb
• Try to keep the patient's hand warm during dialysis, perhaps with a mitten, blanket, or tube sock.
• Changing the position of the patient's arm may help increase blood flow in the hand
• Can be treated by reducing blood flow through the fistula, making the vessels larger, or tying off some blood vessels surgically.
• Putting needles in the access in the same general area time after time can cause an aneurysm.
• This pattern of cannulation weakens the vessel wall and causes a bulge or "gumdrop" to"ballooning" to form the access.
• Aneurysms are more likely to occur upstream
(retrogradeO from a venous stenosis, especially at sites of repeat needle insertion.
The sites are easy to see.
• Rotate needle puncture sites or use the buttonhole technique to prevent aneurysms.
• Do not insert needles into areas of aneurysms.
• Aneurysms leave less surface area for cannulation.
• Is a narrowing of the blood vessel that shows the flow of blood through the access.
• There are three major sites where stenosis is likely to form:
• The most common type of inflow stenosis is called juxta-anastomotic stenosis (JAS).
• It is found in the vein right next to the anastomosis.
• It will keep a fistula from maturing because it does not allow enough blood flow to enter the fistula.
• It may be due to stretching, twisting, or other trauma during the fistula surgery.
• Can occur anywhere along the outflow vein.
• May occur in an area where the patient has had an IV placed in the past.
• The area past the stenosis may appear smaller, making needle insertion more difficult for fear of infiltration.
3. Central vein
• Central venous stenosis occurs in the large draining vein of the arm, often in the shoulder area.
• If a stenosis is suspected, the venous system should be checked from the fistula to the heart, so a central stenosis can be found.
•These stenosis are most likely caused by catheter placement in the past.
• High-pitched or louder-pitched bruit
• Harsh or water-hammer pulse
• Discontinuous bruit (each sound separate - whoosh . whoosh... whoosh) Decreased thrill
• Trouble inserting or threading the dialysis needles.
• Swelling of the patient's access limb Increased venous pressure during treatment,
• Forcing you to turn the blood pump down
• Extracorporeal system clotting off during treatment Increased bleeding after needles are removed postdialysis
• "Black blood syndrome"
• Decrease kt/v and URR
• Inability to obtain prescribed blood flow rate
• Is caused by injury of the blood vessel lining that scars the blood vessel and creates flow turbulence.
• This leads to overgrowth of smooth muscle cells or aneurysm formation.
• Stenosis may recur after treatment.
• To find venous or arterial stenosis, dye is injected into the vessel. With the dye, any narrowing will show up on an x-ray (fistulogram, venogram)
• It can also be found by color Doppler ultrasound.
• Ultrasound is a non-invasive way to look at blood vessels and blood flow.
• Some cases can be treated with angioplasty, which is an outpatient procedure.
• The doctor threads a catheter with an inflatable balloon tip into the vessel
• Once the balloon is in place, he/she inflates it to expand the vessel lumen
• Formation of a thrombus, or blood clot
• Occurs in all types of a vascular access, but less than 1/6 as often in AVFs than in grafts
• Blood has a number of components ..o stop a wound from bleeding by forming a clot.
• These include clotting proteins called plasma coagulants and platelets - tiny blood cells that sticr. together to seal off damaged blood vessels.
• Platelets clump when they are "activated" by contact with damaged blood vessel walls or by turbulence inside a blood vessel.
• Activated platelets and damaged tissues signal blood clotting proteins to form a strong net of fibers (fibrin).
• This net traps more platelets and RBCs, so the clot gets more solid as it grows bigger
• A clot may start to form any time there is low blood flow due to low blood pressure, dehydration, or too much pressure on access,
• These conditions let blood pool at a damaged surface, like a needle site.
• In a fistula, blood flow through an area of stenosis may cause enough turbulence to activate platelets, so they stick to the vessel wall.
• Repeated cannulalions also damage vessel walls, causing rough surfaces that activate platelets.
• Early thrombosis is most often caused by surgical problems with the anastomosis or twisting of the blood vessel.
• It can also be caused by stenosis, reduced blood flow due lo hypotension at dialysis, a cardiac arrest, or compression of the vessel.
• The vessel can be compressed after surgery if blood leaks into the tissues causing swelling and
• Hematomas may also form at the site of an infiltration, or if an access is used too soon after surgery.
• Applying too much pressure for too long to the puncture site after treatment may also lead to thrombosis.
• Pressure should not be placed on a puncture site for more than 20 minutes.
• If bleeding lasts longer than 20 minutes, the nurse should look at the heparin dose and check for an access problem, like stenosis.
• Late thrombosis may develop in a fistula that was working. It can be caused by increased turbulence from stenosis.
• Untreated thrombosis can destroy an access
• Thrombosis is most often caused by stenosis and low blood flow.
• Signs of pending access thrombosis:
• Reduced thrill and bruit
• Poor blood flow through the access
• Inability to obtain prescribed blood flow rate
• Sudden swelling of the hand on the access arm in a patient with a history of stenosis and blood flow problems
• Abnormally high venous pressure readings during dialysis
• A high recirculation rate; always check if the needle placement may have had an effect before calling the nephrologist Increased TMP.
• Suspect thrombosis if you feel no pulse or thrill and hear no bruit along the outflow vein.
• Thrombosis in a previously working access often follows stenosis. Early detection and repair of stenosis may help save the access.
• The KDQI Clinical Practice Guidelines for Vascular Access recommend that centers have an access monitoring program. - it helps to improve patient's vascular access outcomes by identifying problems early.
• AVF can be monitored through measurement of dynamic and static venous pressure, access flow measurement, and duplex ultrasound.
• Thrombosis can be treated b surgical, mechanical, or . chemical (use of drug to dissolve the clot) thrombectomy.
• 90% of cases ~ stenosis is the cause of the clot
• This maybe corrected by surgery to revise the access, or angioplasty after the clot is removed.
Patient Actions to Prevent Thrombosis
To avoid thrombosis, patient should:
• Prevent medical staff from using the access or access limb for routine blood draws, IVs, or blood pressure checks
• Feel for the thrill and listen to the bruit daily to ensure patency
• Think about learning how to self-cannulale to reduce the risk of mispuncture
Patient should not:.
• Sleep on the access arm
• Put too much treasured on the puncture site after removing the dialysis needle
Wear tight-fifing clothing or jewelry that squeeze the access arm
• Carry object objects across the arms that compress the access, such as a purse
• Use the access for IV drugs
• Wear a watch on the hand that has a radiocephalic or lower arm fistula
High Output Cardiac Failure
• An AVF can be one cause of high output cardiac failure.
This is a complex condition in which:
• The fistula brings more blood to the heart
• The heart works harder, reducing resistance in the arteries
• Arterial blood pressure falls
• The drop in arterial blood pressure triggers the renin-angiotensin system
• Patients with high output cardiac failure may have rapid pulses as their hearts try to make up for the extra blood flow (20% or greater) caused by the access.
• They may be short of breath if the blood does not contain enough oxygen.
• Swelling may occur In the hands and fee because return circulation to the hearts poor.
• If untreated, it can cause chest pain, fluid in the lungs, abnormal heart rhythms, and death.
• High cardiac output may also be caused by anemia or heart disease the patient had before the vaacular access
• Prevention is best aimed at treating anemia and creating an access that will not tax the patient's hcart.
• If high output cardiac failure occurs, limiting fluid gain between treatments will reduce the strain on the heart.
• Longer and/or more frequent treatments may help will fluid gains, reducing the strain.
• Medication may also be given to help the heart beat strongly.
• Surgery may be needed to reduce blood flow through the access.
• Surgery is either done either to band the arterial anastomosis or to tie off the fistula.