ESRD: irreversible loss of renal function, accumulation of toxins and loss of internal homeostasis.
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
Neurologic complications:
Subdural hematoma: 3.5% of ESRD, HTN, head trauma, bleeding dyscrasias, anticoagulants, ultrafiltration.
Uremic Encephalopathy: nonspecific centreal neurologic symptoms, responds to dialysis.
Neurologic complications:
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..

Hemodialysis
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
1. Hypotension:
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.
Intradialytic hypotension:
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
5. Hypoglycemia

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