Dialysis complications

Hypotension

Background

• Most frequent complication of hemodialysis (20%-30% of tx)
• Timing of intradialytic hypotension is helpful in formulating DDX:
  • Hypotension early in session usually due to preexisting hypovolemia
  • Hypotension during the session is often due to blood loss (from tubing or filter leak)
  • Hypotension near the end usually result of excessive ultrafiltration
    • Underestimation of pt's ideal blood volume (dry weight)
    • Also consider pericardial or cardiac disease

Clinical Features

• N/V
• Anxiety
• Dizziness
• Orthostatic hypotension
• Syncope

Diagnosis

1. Assess:
   1. Volume status (US)
   2. Cardiac function
   3. Pericardial disease
   4. Infection
   5. GI bleeding

DDX

1. Excessive ultrafiltration
2. Predialytic volume loss
   1. GI losses
   2. Decreased oral intake
3. Intradialytic volume loss
   1. Tube and hemodialyzer blood losses
4. Postdialytic volume loss
   1. Vascular access blood loss
5. Medication effects
   1. Antihypertensives
   2. Opiates
6. Decreased vascular tone (sepsis)
7. Cardiac dysfunction
   1. LVH, ischemia, hypoxia, arrhythmia, pericardial tamponade
8. Pericardial disease
   1. Effusion
   2. Tamponade

Dialysis Disequilibrium Syndrome

• Diagnosis of exclusion (r/o SDH, CVA)
• Clinical syndrome occurring at end of dialysis
  • Large solute clearances -> cerebral edema
• Characterized by N/V, HTN
  • Can progress to seizure, coma, death)
• Occurs most commonly during initial dialysis or during hypercatabolic states
• Treat w/ mannitol

Air Embolism

• Acute dyspnea, chest tightness, LOC, cardiac arrest
• Treat w/ 100% NRB

Vascular Access Complications

Thrombosis and Stenosis

• Most common causes of inadequate dialysis flow
  • Loss of bruit and thrill over access
• Stenosis and even thrombosis are not emergencies
  • Can be treated w/in 24hr by angiographic clot removal or angioplasty
  • Thrombosis of vascular access can be treated w/ direct injection of alteplase 2.2mg ***This therapy should be discussed with the vascular surgeon first

Vascular Access Infection

• Pts often p/w signs of systemic sepsis (fever, hypotension, leukocytosis)
  • Classic signs of pain, erythema, swelling, d/c from infected access are often missing
• Dialysis catheter–related bacteremia is common and potentially life-threatening
  • Give vancomycin 1gm IV +/- genamicin 100mg IV (if gram neg suspected)
  • Do not remove dialysis patient's access
• Draw peripheral and catheter blood cultures simultaneously
  • 4x higher colony count in catheter blood cx suggests catheter is source of bacteremia
    • Even so catheter is only removed if fever persists for 2-3d after abx are started

Hemorrhage

• Potentially life-threatening
• Can result from aneurysms, anastomosis rupture, or over-anticoagulation
• Control bleeding w/ pressure applied to puncture site for 5-10min; observee for 1-2hr
• Types
  • Aneursym (true)
    • Most are asymptomatic; rarely rupture
  • Pseudoaneurysm
    • Results from subcutaneous extravasation of blood from puncture sites
    • Bleeding from puncture site is usually controlled by digital pressure or subq suture
    • Consider vascular surgery consultation for continued bleeding or infection
    • Arterial Doppler US studies can identify the aneurysm or pseudoaneurysm

Vascular insufficiency

• Distal extremity becomes ischemic due shunting of arterial blood to venous side
  • Exercise pain, nonhealing ulcers, cool, pulseless digits
  • Diagnosed by Doppler US or angiography, repaired surgically

High-output heart failure

• Occurs when >20% of cardiac output is diverted through the access
  • Branham sign (drop in HR after temporary access occlusion) is diagnostic
  • Doppler US can accurately measure access flow rate and establish the diagnosis **Surgical banding of the access is treatment of choice

Source

Tintinalli