Dialysis

Important questions to ask your patient: Where is their access, who is their Renal doctor, do they still make urine, what is their dialysis schedule, last dialysis session, any missed sessions.

Type of access:  AV Fistula vs Graft vs Catheter

AV Fistula

• Best option

• Can last up to 20 years but usually good for 5 years

• Better flow rates than other options

• Requires vein mapping and surgery by vascular, then 3 months to mature

Graft

• Synthetic material

• 2 weeks to mature

• At risk for Pseudoaneurysm

• Higher risk than AV fistula for thrombosis and infection

*M Hassan Pearl: Push on access site if you are unsure. If it is soft it is an AV fistula. If you feel something that feels like a mesh, it’s a graft

Catheter

• Emergent and temporary only

• Temporary catheters are tunneled

• Tunneled catheters at risk for SVC syndrome, thrombosis

• Indications

  • Acidosis refractory to IV bicarbonate, electrolyte abnormalities, intox/ingestions, fluid overload refractory to dialysis, uremic symptoms (e.g. delirium, asterixis, pericardial effusion).

• Dialysis Disequilibrium Syndrome

  • Rare, but potentially lethal

  • Increased intracranial pressure and rapid decrease in serum osmolality during dialysis

  • Onset within 12 hours of dialysis

  • Malaise, nausea/vomiting, muscle cramping, hypertension, headache, AMS, seizures

  • EEG: Diffuse metabolic encephalopathy

  • MRI: Osmotic demyelination of pons (and adjacent structures)

  • Tx: Anticonvulsants, mannitol, hypertonic saline

  • Prevention: Decrease initial dialysis flow rate and duration (especially if high urea concentration)

• Dialysis Hypotensive Syndrome

  • Secondary to autonomic dysfunction, rapid fluid removal, cellular fluid shifts and multiple other causes 

  • Small fluid challenges of 250 ml boluses and re-evaluation (w/ IVC u/s)

• Uremic Pericarditis > Cardiac Tamponade

  • Fluids, emergency dialysis, emergency pericardiocentesis if cardiovascular collapse

• Acute Pulmonary Edema

  • Diuretics (lasix 60-100mg IV), ACE Inhibitors, Nitroglycerin< BiPap and oxygen

  • Emergency dialysis, early Endotracheal Intubation or CPAP/BIPAP

• External Hemorrhage from AV Shunt

  • Apply direct light pressure to puncture site for 10-15 minutes (not so firm as to risk vascular obstruction and thrombosis) > Observe in Emergency Department for 1-2 hours after bleeding has stopped before discharge

  • Avoid stitching if possible (risk of damaging shunt)

  • Protamine (Not indicated if last Heparin dose was >2 hours prior to presentation), DDAVP, TXA

  • Life threatening bleeding: Emergent vascular surgery consultation, tourniquet (risk of thrombosis, limb ischemia), monofilament 3-0 figure of 8 suture

• Shunt thrombosis (or stenosis from intimal hyperplasia)

  • Bruit or thrill over access site is absent in shunt obstruction 

  • Confirm shunt thrombosis with duplex doppler ultrasound

  • Discuss with nephrology and vascular surgery (or Interventional Radiology) at an early stage

• Superior vena cava (SVC) obstruction

  • Life threatening

  • Frequent chronic complication of central vein cannulation from stenosis or occlusion of central veins 

  • Facial swelling, shortness of breath

  • Tx: endovascular intervention with angioplasty and stent placement

• High output cardiac failure

  • When a large proportion of arterial blood is shunted from the left-sided circulation to the right-sided circulation via the fistula, the increase in preload can lead to increased cardiac output > over time, the demands of an increased workload may lead to cardiac hypertrophy and eventual heart failure

  • Tachycardia, elevated pulse pressure, hyperkinetic precordium, and jugular venous distension

  • Tx: Surgical banding or ligation of the fistula

• Infection: High risk for infection. Always consider endocarditis

  • Make sure to cover MRSA

  • Pan culture

  • Don’t forget to send urine if they still urinate