Complications of Vascular Access for Hemodialysis- more frequent with autologous vein, polytetrafluorethylene, or bovine carotid artery graft (as opposed to native artery or vein) - account for more inpatient hospital days than any other complication of hemodialysis
Thrombosis and Stenosis - most common causes of inadequate dialysis flow (<300 mL/min) - grafts have higher rate of stenosis than fistulas - signs: loss of bruit or thrill over access - treatment: angiographic clot removal or angioplasty within 24 hours; direct injection of alteplase can be considered for thrombosis
Vascular Access Infections - 2 - 5% of AV fistulas, 10% of grafts - etiology: Staphylococcus aureus (most common), Gram-negative bacteria - signs/symptoms: hypotension, fever, leukocytosis - may not have pain, erythema, swelling, or discharge from access site - after 6 months, approximately 1/2 of patients with dialysis catheter develop bacteremia - diagnosis: peripheral and catheter blood cultures drawn simultaneously -> catheter is confirmed source if colony count is 4 times higher in catheter culture than peripheral culture - treatment: vancomycin IV (drug of choice) +/- gentamicin (if Gram-negative organisms suspected); consider access removal if fever for > 2 - 3 days
Hemorrhage - rare - causes: aneurysms, anastosmosis rupture, overanticoagulation
Management of Hemorrhage 1. manual pressure to puncture sites for 5 - 10 min and observe for 1 - 2 hours if ceased 2. apply pressure for 10 min using absorbable gelatin sponges soaked in reconstituted thrombin or chemical thrombotic (e.g., transexamic acid) 3. protamine 0.01 mg per unit of heparin dispensed during dialysis - if dose is unknown, protamine 10 - 20 mg is sufficient to reverse typical dose of heparin (usually 1000 to 2000 U) 4. desmopressin acetate 0.3 mcg/kg IV can be used as adjunct in consultation with nephrologist or vascular surgeon 5. consider placing figure-8 suture 6. tourniquet proximal to vascular access while awaiting urgent vascular surgery consultation
Vascular Access Aneurysms - caused by repeated punctures - usually asymptomatic, possibly occasional pain or impingement neuropathy - rarely rupture
Vascular Access Pseudoaneurysms - from subcutaneous extravasation of blood from puncture sites - signs: bleeding, infection at access site - diagnosis: arterial Dopper ultrasound studies - treatment: surgery
Vascular Insufficiency - usually occurs in extremity distal to vascular access - due to shunting of arterial blood to venous side of access - "steal syndrome" - signs/symptoms: exercise pain, nonhealing ulcers, cool/pulseless digits - diagnosis: Doppler ultrasound or angiography - treatment: surgery
High-output Heart Failure - occurs when >20% of cardiac output is diverted through access - signs/symptoms: Branham sign (drop in heart rate after temporary access occlusion) - diagnosis: Doppler ultrasound to measure flow rate - treatment: surgical banding of access
Resources Tintinalli's Emergency Medicine, 8th Edition