Uremia: clinical syndrome resulting from ESRD.
Pathophysiology of Uremia
Excretory Failure: causes >70 chemicals to elevate. Urea= major breakdown of proteins. Limit protein intake
Biosynthetic Failure: loss of hormones 1,25(OH)3 vit D3 and erythropoietin.
85% of erythropoietin produced by kidney.
Vit. D3 deficiency= secondary hyperparathyroidism, renal bone disease.
Regulatory Failure: over secretion of hormones , disruption of normal feedback mechanisms
Clinical Features of Uremia
Subdural hematoma: 3.5% of ESRD, HTN, head trauma, bleeding dyscrasias, anticoagulants, ultrafiltration.
Uremic Encephalopathy: nonspecific centreal neurologic symptoms, responds to dialysis.
Dialysis Dementia: like uremic encephalopathy but progressive and fatal, seen after 2 years on dialysis
Peripheral neuropathy: >50% of HD patients. “glove and stocking pattern”, improves after transplant
Autonomic dysfunction: common; dizzy, impotence, bowel dysfunction.
Cardiovascular complications: prevalence is greater in ESRD
d/t pre-existing conditions, uremia, toxins, high lipids, homocystine, hyperparathyroidism, dialysis related conditions..
Uses ultrafiltration and clearance to replace nephron.
Solute removal depends on filter pore size and concentration gradient
Heparin 1000-2000 units typically used
Sessions take @ 3-4 hrs.
Vascular Access Complications
Types of Access:
1. A-V fistula
2. Vascular graft: higher complication rates, shorter functional lifes.
3. Tunnel-cuffed catheters; Hickman, Quinton
Complications During Hemodialysis
Most frequent, 10-20% of treatments
Dialysis can remove up to 2 L/hr.
Cardiac compensation limited d/t ↓ diastolic function common in ESRD
Abnormalities in vascular tone; sepsis, anit HTN meds, ↑ nitric oxide
Early hypotension: pre-existing hypovolemia
Peridialysis losses; starts HD below dry weight; d/t sepsis, GI bleed, vomiting, diarrhea, decreased salt/water intake
Intradialytic blood loss from tubing/dialyzer leads
Hypotension at end of dialysis: excessive removal, cardiac or pericardial disease.
N/V/anxiety, ortho hypotension, tachycardia, dizzy, syncope.
Tx.; stop HD, Trendelenburg. Salt, broth by mouth, NS 100-200 cc. IV.
If these fail look for other causes than excessive fluid removal
2. Dialysis disequilibrium:
End of dialysis
N/V, HTN...progress to coma, seizure and death
d/t cerebral edema after large solute clearance in HD
Tx. Stop HD, administer Mannitol IV.
3. Air Embolism:
s/s: dyspnea, chest tightness, unconscious, full cardiac arrest. Cyanosis, churning sound in heart from bubbles
Clamp venous blood line, place supine
Other Tx’s: percutaneous aspiration from R ventricle, IV steroids, full heparinization, hyperbaric O2 treatment
4. Electrolyte abnormalities