End Stage Renal Disease (ESRD)

Overview

Normal blood flow 20-25% of CO

Autoregulation usually between MAP of 80-180

Renal synthesis of vasodilating prostaglandins protects during systemic hypotension and renal ischemia

ESRD Co-morbidities: 30-40% of diabetic patients develop ESRD, up to 60% of insulin-dependent patients. Ischemic heart disease is prevalent as well.

Preop

Coexisting diseases, medications

Labs - BUN, Cr, blood count, bleeding time, electrolytes - K, last dialysis, volume status

Drugs - Benzodiazepines may be slightly prolonged

Avoid Meperidene (60% protein bound, causes seizures in high concentrations)

Uremia as Urea is a breakdown of protein metabolism formed in the liver

Normal BUN 10-20 mg/dL

BUN <8 can be a sign of overhydration or underproduction of urea

BUN 20-40 signs of dehydration or decreased GFR

Brachial blocks

Age, ASA status, and cardiovascular disease along with coagulation status. Provides maximum vascular vasodilation and no vasospasms. 40ml of 0.5% Bupivacaine. Duration may be up to 40% shorter due to increased CO and rapid clearance from the site. Reduce the dose of LA if the patient is acidotic, as it increases the risk of toxicity. Use incremental dosing and aspirate and inject continuously. Monitor pulse ox and pt continuously.

Toxicity symptoms

CNS: light-headedness, tinnitus, perioral numbness, confusion, muscle twitching, auditory and visual hallucinations, tonic-clonic seizures, unconsciousness, respiratory arrest

Cardiac: less common, can be fatal. Hypertension, tachycardia, decreased contractility and cardiac output, hypotension, sinus bradycardia, ventricular dysrhythmias, circulatory arrest

General anesthesia

Highly protein-bound drugs have higher effects due to low protein levels (more free drugs).

The acidic state increases un-ionized and unbound drugs (lipid soluble and crosses the bilipid layer), which increases availability to tissues.

Volatile agent (VA) elimination does not rely on renal excretion.

VA potentiates neuromuscular blockers, allowing for reduced doses.

Be careful not to depress cardiac function with too much anesthetic.

Neuromuscular agents - vecuronium family drugs last longer.

Creatinine clearance

GFR = (140-age) x weight/72 x Cr - for women multiply x  0.8 due to lower muscle mass.

• Normal 95-100 mL/min
• Mild dysfunction 50-80 mL/min
• Moderate dysfunction <25 mL/min
• If less than 10 mL/min, pt requires dialysis

Decrease drug doses for renal excretion and monitor fluid and electrolyte balance.

Drug clearance is dependent on glomerular filtration, active secretion, and passive reabsorption.

Cardiac

HTN and CHF are prevalent

• 90% of HTN due to volume, related to sodium and water retention
• The last 10% is due to high renin levels (decreased perfusion pressure, beta-stimulation, decreased Na delivery to Macula Densa).
• The combination of HTN, anemia, hypoalbuminemia, and volume overload due to salt and water retention contributes to the increased risk of CHF

Ischemic heart disease is prevalent due to HTN, hyperlipidemia, and abnormal carbohydrate metabolism

Fibrous pericarditis in approx 50%

For hemodynamic stability, pt should be 1-2 L above dry weight

Hematological changes

Anemia with Hct 20-30% due to a decrease in erythrocyte formation, secondary to a decrease in production by the failing kidney and a decrease in lifespan due to an abnormal chemical environment (decreased oxygen delivery)

Prolonged bleeding time treated with Desmopressin increases factor Vlll, the von Willebrand antigen in uremic patients. It can be used with uremic-induced platelet dysfunction

Gastrointestinal

High risk of bleeding.

The use of H2 blockers is recommended preoperatively

Premedicate with ZRA (Zofran, Reglan, Antacid)

Consider a full stomach

Neurological

Apathy, decreased mental activity, lethargy, fatigue and weakness

Endocrine Abnormalities

Hyperparathyroidism as the body is trying to compensate for hypocalcemia, which causes skeletal disorders/predisposed to fractures

Ensure adequate reversal of NBA prior to extubation

Respiratory

Volume overload = CHF, respiratory distress

Electrolyte abnormalities

Na wasting leads to Na retention as renal disease progresses

Hypokalemia leading to hyperkalemia with progressive renal disease

Systemic acidosis = hyperkalemia

Systemic alkalosis = hypokalemia

Treatment of Toxicities

For cardiotoxicity, give IV calcium chloride, which decreases myocardial excitability, protecting against life-threatening arrhythmias

Hyperventilation, beta-adrenergic stimulation, sodium bicarbonate, and insulin will help shift K into cells quickly