Management Of Anesthesia In Chronic Renal Failure Patients

(brief practical review)

Reza Aminnejad; M.D.Anesthesiologist.

In The Name of God

Chronic Renal Failure

CRF CRF is the progressive, irreversible

deterioration of renal function that results from a wide variety of diseases.

Diabetes mellitus is the leading cause of end-stage renal disease (ESRD) followed closely by systemic hypertension.

TABLE 14-5   -- Causes of Chronic Renal Failure

Glomerulopathies   Primary glomerular disease  Focal glomerulosclerosis  Membranous nephropathy  Ig A nephropathy   MPGN (Mmmbranoproliferative Glomerulonephritis)  Glomerulopathies associated with systemic disease  (DM, Amyloidosis, Postinfectious glomerulonephritis, SLE, Wegener's granulomatosis 

Tubulointerstitial disease Analgesic nephropathy

Reflux nephropathy with pyelonephritisMyeloma kidneySarcoidosis  

Heredity disease   Polycystic kidney disease  Alport syndrome  Medullary cystic disease  

Systemic hypertension  Renal vascular disease  Obstructive uropathy  Human immunodeficiency virus

In renal failure Only 10% of nephrons are functioning. GFR is less than 12 ml/min Uremia is present. Increased BUN & Cr, anemia, hyperkalemia &

increased BT can be seen. Other symptoms associated with CRF include

cognitive impairment, peripheral neuropathy, infertility, and increased susceptibility to infection

Comorbidities CRF and cardiac disease are intimately

linked, and as CRF progresses, coronary artery disease and congestive heart failure contribute to symptomatology.

Classification of Chronic Renal Disease

Stage 1: Kidney damage with normal or ↑ GFR (≥90 ml/min)

Stage 2: Kidney damage with mild ↓ GFR (60–89 ml/min)

Stage 3; Moderate ↓ GFR (30–59 ml/min)

Stage 4: Severe ↓ GFR (15–29 ml/min) Stage 5: Kidney failure with GFR<15 or

need to dialysis

Definition of Chronic Kidney Disease

CKD is defined as either kidney damage or a GFR less than 60 mL/min/1.73 m2 for 3 months or more. Kidney damage is defined as a pathologic abnormality or markers of damage including abnormalities of the blood or on urine or imaging studies.

Manifestations of CRFElectrolyte imbalance    Hyperkalemia   Hypermagnesemia   Hypocalcemia

Metabolic acidosis  Unpredictable intravascular fluid volume status  Anemia   

Increased cardiac output  Oxyhemoglobin dissociation curve shifted to the right  

Uremic coagulopathies   Platelet dysfunction  

Neurologic changes   Encephalopathy  

Cardiovascular changes   Systemic hypertension  Congestive heart failure Attenuated sympathetic nervous system activity due to treatment with

antihypertensive drugs  Renal osteodystrophy  Pruritus

Diagnosis of Chronic Renal Insufficiency

Oliguria does not set in until late in the disease and is an unreliable marker of disease progression.

diagnosis is made from signs and symptoms of f luid overload and concomitant cardiac disease and confirmed by laboratory testing.

Proteinuria & urinary sediment are also helpful in diagnosis.

Anesthetic Management An important assessment is whether the renal

disease is stable, progressing, or diminishing. Drugs that their action is terminated by renal

excretion are: Gallamine, Metocurine, Digoxin, Inotropes, Aminoglycosides, vancomycin, Cephalosporin & penicillin.

Drugs that their action is partially terminated by renal excretion are: Barbiturates, Pancuronium, Vecuronium, Neostigmine, Edrophonium, Atropine, Glycopyrrolate, Milrione, Hydralazine, Sulfonamides.

Preoperative Evaluation Means of blood volume status assesment:

Comparing body weight before and after hemodialysis, Monitoring vital signs & Measuring atrial filling pressures.

Glucose management in diabetic patients is of concern.

Preoperative medication must be individualized. Patients on hemodialysis should undergo dialysis

during the 24 hours preceding elective surgery (serum potassium concentration should not exceed 5.5 mEq/L on the day of surgery)

Anemia is evaluated preoperatively. The preoperative presence of a coagulopathy may be

treated with DDAVP.

Induction of Anesthesia Intravenous anesthetic drugs (propofol, etomidate, thiopental)

are safe. These patients may exhibit uremia-induced slowing of gastric

emptying. Slow injection of induction drugs is preferred to minimize the

likelihood of drug-induced decreases in systemic blood pressure (regardless of blood volume status, these patients often respond to induction of anesthesia as if they were hypovolemic)

Small decreases in blood volume, institution of PPV of the patient's lungs, abrupt changes in body position, or drug-induced myocardial depression can result in an exaggerated decrease in systemic blood pressure.

Maximum drug-induced potassium release is 0.5–1.0 mEq/L Small doses of nondepolarizing muscle relaxants

administered before the injection of succinylcholine do not reliably attenuate the succinylcholine-induced release of potassium.

Maintenance of Anesthesia Nitrous oxide combined with isoflurane, desflurane, or short-

acting opioids is a preferred combination for dialysis dependent patients.

Sevoflurane may be avoided because of concerns related to fluoride nephrotoxicity or production of compound A.

TIVA with remifentanil, propofol, and cisatracurium has been recommended for patients with end-stage renal failure.

Opioids decrease the likelihood of cardiovascular depression and avoid the concern of hepatotoxicity or nephrotoxicity. opioids do not reliably control intraoperative SBP elevations. Furthermore, prolonged sedation and depression of ventilation from small doses of opioids have been described in anephric patients. Conceivably, pharmacologically active metabolites of opioids accumulate in the circulation and cerebrospinal fluid when renal function is absent.

Muscle Relaxants Clearance of mivacurium, atracurium, and

cisatracurium from plasma is independent of renal function.

It seems prudent to decrease the initial dose of the drug and administer subsequent doses based on the responses observed using a peripheral nerve stimulator.

Other explanations except residual neuromuscular blockade (antibiotics, acidosis, electrolyte imbalance, diuretics) should be considered when neuromuscular blockade persists or reappears in patients with renal dysfunction because renal excretion accounts for approximately 50% of the clearance of neostigmine and approximately 75% of the elimination of edrophonium and pyridostigmine.

Fluid Management and Urine Output in Hemodialysis Dependent Patients Noninvasive operations require replacement of

only insensible water losses with 5% glucose in water (5–10 mL/kg IV).

The small amount of urine output can be replaced with 0.45% sodium chloride.

Third space loss is often replaced with balanced salt solutions or 5% albumin solutions.

Measuring the central venous pressure may be useful for guiding fluid replacement.

Monitoring For invasive monitoring radial, ulnar, brachial &

axillary arteries should be avoided (they are needed for AVF in the future).

Catheterization of femoral artery carries the risk of line infection.

( 1 ) the catheter must be accessed aseptically, just as it is at the time of dialysis, ( 2 ) the catheter is left heparinized and must be aspirated before connecting to an intravenous line or pressure transducer, ( 3 ) if it is to be disconnected at the end of the procedure, it must be reheparinized and sealed aseptically again.

Associated Concerns premedication may or may not be necessary. Intramuscular injection of any premedication

should be avoided in consideration of low muscle mass and uremic platelet dysfunction.

Attention to patient positioning on the operating room table is important.

Guidelines recommend that arm veins of the nondominant hand not be used for intravenous cannulas and to even advise patients to wear Medic Alert bracelets to this effect

Regional Anesthesia Adequacy of coagulation should be

considered and the presence of uremic neuropathies excluded before regional anesthesia is performed in these patients.

Co-existing metabolic acidosis may decrease the seizure threshold for local anesthetics.

Postoperative Management Consideration of inadequate reversal of

muscle relaxant in anephric patients who show signs of skeletal muscle weakness

Caution in the use of parenteral opioids Continuous monitoring of the ECG is helpful

for detecting cardiac dysrhythmias (Hyperkalemia)

Continuation of supplemental O2 into the postoperative period (anemia)