Ch.32 Anesthesia for Patients with Renal Disease

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Ch.32 Anesthesia for Patients with Renal Disease

• R1 ???

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• Diseases affecting the kidneys
• Nephrotic syndrome
• Acute renal failure
• Chronic renal failure
• Nephritis
• Nephrolithiasis
• Urinary tract obstruction
• Infection
• ????? ???? syndrome ??? preoperative renal
  function? ?? ????? ?

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EVALUATING RENAL FUNCTION
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BLOOD UREA NITROGEN(BUN)

• Primary source of urea liver
• Protein catabolism ???? ammonia ??
• Hepatic conversion? ?? ammnia? urea? ??? toxic
  ammonia level? ??
• BUN? protein catabolism? ???? ????? GFR? reliable
  indicator ?? ??
• ???? 40-50? renal tubule?? passively reabsorbed
  ? (hypovolemia? ??)
• NL BUN concentration 10-20mg/dL
• Lower values starvation, liver disease
• Elevations decreases in GFR, increases in
  protein catabolism (high catabolic state trauma
  or sepsis)
• 50mg/dL ??? ?? ?? renal impairment ??

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SERUM CREATININE

• Creatine product of muscle metabolism
• Nonenzymatically converted to CREATININE
• Creatinine production? ??? ???? muscle mass? ???
• ?? 20-25mg/kg in men, 15-20mg/kg in women
• Not reabsorbed in kidneys
• NL serum creatinine concentration
• 0.8-1.3mg/dL in men, 0.6-1mg/dL in women
• Large meat meals, cimetidine therapy, increases
  in acetoacetate (ketoacidosis)?? GFR? ?? ???
  serum creatinine ??
• GFR? ??? ?? ?? (5 per decade after age 20)
• Muscle mass ?? ????? serum creatinine? ??? ?? ??
• Acute changes in GFR ? 48-72? ??? ??? level? ?? ??

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BUN CREATININE RATIO

• Low renal tubular flow rates? urea reabsorption?
  ????? creatinine handling?? ??? ??
• BUN to serum creatinine ratio? 101 ???? ??
• BUN creatinine ratio gt 15 1
• Volume depletion, edematous disorders (heart
  failure, cirrhosis, nephrotic syndrome),
  obstructive uropathies

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CREATININE CLEARANCE

• Creatinine clearance measurements
• ? most accurate method available for clinically
  assessing overall renal function
• 40-60mL/min Mild renal impairment
• 25-40mL/min moderate renal dysfunction
• Nearly always cause symptoms
• Less than 25mL/min renal failure
• Progressive renal disease ??? proximal tubule???
  creatinine secretion? ???
• ?? GFR? overestimation ?? ?

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URINALYSIS

• Routine urinalysis
• pH
• Systemic acidosis with urinary pH gt 7.0 renal
  tubular acidosis
• Specific gravity
• 1.010 corresponds to urinary osmolality 290
  mOsm/kg
• Overnight fast ? 1.018 ?? indication of
  adequate renal concentrating ability
• Glucose, protein, bilirubin? detection
  quantification
• Proteinuria 24-h urine collection ??
• Urinary protein gt 150mg/d ? significant
• Elevated levels of bilirubin biliary
  obstruction
• Urinary sediment? ?? microscopic examination
• Red cells, white cells, bacteria
• Tubular casts disease processes at the level of
  the nephron

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ALTERED RENAL FUNCTION THE EFFECTS OF
ANESTHETIC AGENTS
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INTRAVENOUS AGENTS

• Propofol etomidate
• Not significantly affected by impaired renal
  function
• Hypoalbuminemia ? etomidate? protein binding ????
  effects ??
• Barbiturates
• Induction? sensitivity ??
• Protein binding? ???? free circulating agent ??
• Acidosis? nonionized fraction? ???? brain?? ??
  ??? ???
• Ketamine
• ?? active hepatic metabolites? renal excretion
• Potentially accumulate in renal failure
• Secondary hypertensive effect ?? ??
• Benzodiazepines
• Hypoalbuminemia? sensitivity ??
• Opioids
• Morphine meperidine significant accumulation
  of active metabolites
• Prolong respiratory depression
• Normeperidine (meperidine metabolite) ???
  seizures? ??

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INTRAVENOUS AGENTS (2)

• Anticholinergic agents
• Atropine glycopyrrolate? predemication dose?
  ???? ?? ??
• ??? ??? 50??? active metabolites? urine?? ?? ?
  repeated dose? potential for accumulation
• Scopolamine renal excretion? ? ???
• Azotemia? CNS effect ???
• Phenothiazines, H2 blockers, related agents
• Phenothiazines
• azotemia? potentiation of central depressant
  effects can occur
• Antiemetic action? ?? ? ?? ??
• Droperidol partly dependent on kidneys for
  excretion
• H2 blockers very dependent on renal excretion
• Metoclopramide partly excreted unchanged in
  urine

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INHALATION AGENTS

• Volatile agents
• Enflurane and sevoflurane (with lt 2L/min gas
  flows) undergoing long procedures
• ? potential for fluoride accumulation
• Nitrous oxide
• Renal failure? 50? ??
• Anemia? arterial oxygen content ????? ??
  (hemoglobin lt 7g/dL)

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MUSCLE RELAXANTS

• Succinylcholine
• Induction? serum potassium ??? 5mEg/L ??? ??
  renal failure??? ???? ?? ??
• Cisatracurium, atracurium, mivacurium
• Cisatracurium atracurium
• Enzymatic ester hydrolysis nonenzymatic Hofmann
  elimination
• Renal failure? drugs of choice
• Vecuronium rocuronium
• Vecuronium 20? eliminated in urine
• Rocuronium hepatic elimination
• Severe renal disease? prolongation ? ? ??
• Curare 40-60? urine?? excretion
• Pancuronium, pipecuronium, alcuronium,
  doxacurium
• Primarily dependent on renal excretion (60-90)
• Metocurine, gallamine, decamethonium
• Entirely dependent on renal excretion
• Should be avoided in impaired renal function
• Reversal agents
• Edrophonium, neostigmine, pyridostigmine renal
  excretion is the principal route

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ANESTHESIA FOR PATIENTS WITH RENAL FAILURE
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PREOPERATIVE CONSIDERATIONS

• Acute renal failure
• Rapid deterioarion in renal function
• ? retention of nitrogenous waste products
  (azotemia)
• Prerenal acute decrease in renal perfusion
• Renal intrinsic renal dis., renal ischemia,
  nephrotoxins
• Postrenal urinary tract obx. Or disruption
• ? prerenal postrenal reversible in initial
  stages
• ???? oliguria ??
• Nonoliguric Pts. (urinary outputs gt 400mL/d)
• Tend to have greater preservation of GFR
• Course
• Oliguria lasts for 2 wks, followed by a diuretic
  phase

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PREOPERATIVE CONSIDERATIONS (2)

• Chronic renal failure
• ??? 3-6 ??? ?? progressive irreversible decline
  in renal function
• m/c cause hypertensive nephrosclerosis,
  diabetic nephropathy, chronic glomerulonephritis,
  polycystic renal disease
• Uremia GFR decreases below 25mL/min
• Clearnaces below 10mL/min (ESRD) dependent on
  dialysis
• On daily dialysis generally feel entirely normal
• ??? 1?? 3? ??
• Cx
• hypotension, neutropenia, hypoxemia,
  disequilibrium syndrome
• ? generally transient
• Disequilibrium syndrome transient neurological
  Sx? ???
• ? rapid lowering of extracellular osmolality than
  intracellular osmolality

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PREOPERATIVE CONSIDERATIONS (3)Manifestations of
renal failure

• Metabolic
• Hyperkalemia, hyperphosphatemia, hypocalcemia,
  hypermagnesemia, hyperuricemia, hypoalbuminemia ?
• Water sodium retention
• High anion gap metabolic acidosis
• Hyperkalemia most lethal
• ?? creatinine clearances lt 5mL/min? ? ??
• Large potassium load ???? ?? ??
• Trauma, hemolysis, infections, potassium
  administration
• Hematological
• Anemia creatinine clearance lt 30mL/min? ?
• Hb 6-8g/dL
• Edcreased erythropoietin production, decreased
  red cell production, decreased cell survival
• 2,3-diphosphoglycerate (2,3-DPG)
• Hb??? oxygen ???? ?? ??
• Metabolic acidosis ?? Hb-O2 dissociation curve?
  right shift ??
• Symptomatic heart dis. ?? ?? ?? well tolerate the
  anemia
• PLT, WBC function are impaired
• Prolonged bleeding time, increased susceptibility
  to infections
• ??? hemodialysis ?? ??? ?? residual anticoagulant
  effects from heparin ??

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PREOPERATIVE CONSIDERATIONS (4)Manifestations of
renal failure

• Cardiovascular
• Renal failure ? oxygen delivery ?? ?? cardiac
  output ????? ?
• LVH common finding
• Congestive heart failure, pulm. Edema? ??
• Sodium retention? ?? extracellular fluid overload
• Arrhythmias, uremic pericarditis
• ARF? diuretic phase??? intravascular volume
  depletion ????? ?
• Pulmonary
• Metabolic acidosis? compensation?? minute
  ventilation ???
• Alveolar-capillary memb.? permeability ??? ??
  pulm. edema ?? ? ??
• butterfly wings on chest film

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PREOPERATIVE CONSIDERATIONS (5)Manifestations of
renal failure

• Endocrine
• Abnormal glucose tolerance
• Pph. Resistance to insulin ??
• Secondary hyperparathyroidism
• Metabolic bone disease ?? ? ??
• Hypertriglyceridemia
• Gastrointestinal
• Anorexia, nausea, vomiting, adynamic ileus
• Peptic ulceration G-I hemorrhage
• Delayed gastric emptying predispose to
  aspiration
• High incidence of viral hepatitis (B C)
• Neurological
• Uremic encephalopathy? menifestations
• Asterixis, lethargy, confusion, seizures, coma
• Sx? ?? azotemia ??? ??
• Autonomic peripheral neuropathies
• Pph. Neuropathies typically sensory, involve
  distal lower extremities

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PREOPERATIVE CONSIDERATIONS (6)

• Preoperative evaluation
• ????? ???? complete evaluation ??
• All reversible menifestation of uremia should be
  controlled
• Preoperative dialysis ?? ?? or ??
• Evaluation
• Signs of fluid overload or hypovolemia
• Pts current weight
• Hemodynamic data, chest film
• Arterial blood gas analysis dyspnea ??? ????
• Detecting hypoxemia, evaluating acid-base status
• ECG signs of hyperkalemia, hypocalcemia
• Echocardiography
• Preop RBC transfusion
• Only to severely anemic Pts. (Hb lt 6-7g/dL)
• Significant intraop. Blood loss is expected

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PREOPERATIVE CONSIDERATIONS (7)

• Premedication
• Reduced doses of opioid or benzodiazepine
• Promethazine, 12.5-25mg IM
• Additional sedation, antiemetic properties
• Aspiration prophylaxis
• H2 blocker
• Metoclopramide, 10mg orally or slowly IV

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INTRAOPERATIVE CONSIDERATION

• Monitoring
• A-V fistula ?? ??? cuff? ?? ?? ??
• Intraarterial, central venous, pulm. A.
  monitoring
• Major surgery ??? advanced renal dis. ?? DM ??
• ? aggressive invasive monitoring
• Induction
• Rapid-sequence induction with cricoid pressure
• Nausea, vomiting, G-I bleeding ?? ?
• Thiopental, 2-3mg/kg, or propofol, 1-2mg/kg
• Etomidate, 0.2-0.4mg/kg hemodynamically
  unstable Pts.
• Opioid, ß-blocker (esmolol), lidocaine
• To blunt hypertensive response to intubation
• Succinyulcholine, 1.5mg/kg
• Serum potassium lt 5mEq/L ??? ??
• Laryngeal mask airway
• ? avoids excessive sympathetic (hypertensive)
  response

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INTRAOPERATIVE CONSIDERATION (2)

• Maintenance
• Ideally control HTN with minimal effects on
  cardiac output
• Volatile agents isoflurane, desflurane
• Nitrous oxide
• Very low Hb (lt7g/dL)? 100 oxygen ?? ?? nitrous
  oxide ?? ??
• Controlled ventilation
• Inadequate spontaneous ventilation
• ? respiratory acidosis
• Preexisting acidemia ??
• Potentially severe circulatory depression
• Dangerously increase serum potassium concentraion
• Fluid therapy
• Supf. Op. only insensible fluid losses with 5
  dextrose in water
• Major fluid losses or shifts isotonic
  crystalloids, colloids
• Lactated Ringers injection hyperkalemic Pt??
  ??
• Glucose-free solutions

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ANESTHESIA FOR PATIENTS WITHMILD TO MODERATE
RENAL IMPAIRMENT
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PREOPERATIVE CONSIDERATIONS

• Large reserve in function
• GFR, creatinine clearance? 120?? 60mL/min?? ????
  ??? clinically perceptible change ?? ? ??
• ?? maintaining normovolemia
• Creatinine clearance? 25-40 mL/min? ??? renal
  impairment? moderate ? renal insufficiency
• Significant azotemia? ?? ??? HTN, anemia ??
• Relatively high incidence of postop. Renal
  failure
• Cardiac and aortic reconstructive surgery
• Intravascular volume depletion, sepsis, obx.
  jaundice, crush injuries, recent contrast dye
  injections
• Aminoglycoside, ACEi, NSAIDs
• Prophylaxis against renal failure
• Generous hydration together with solute diuresis
• In high-risk pts., cardiac, major aortic
  reconstructive surgery
• Mannitol (0.5g/kg) should be started prior to
  or at the time of induction
• intravascular volume depletion ???? iv fluid? ???
  ??
• Fenoldopam or low-dose dopamine increase renal
  blood flow
• Small dose of loop diuretics
• Acetylcysteine prior to radiocontrast dyes

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INTRAOPERATIVE CONSIDERATIONS

• Monitoring
• Hourly urinary output, intravascular volume
• Urine gt 0.5mL/kg/h
• Intraarterial pressure monitoring
• Induction
• Induction ?? adequate intravascular volume ??? ?
  preop. hydration
• ?? ?? ? hypotension? ?? intubation?? surgical
  stimulation?? ???

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INTRAOPERATIVE CONSIDERATIONS (2)

• Maintenance
• Exception of sevoflurane with low gas
  flows(lt2L/min)
• Deterioration in renal function ??
• Surgery hemorrhage
• Anesthesia cardiac depression or hypotension
• Indirect hormonal effects sympathoadrenal
  activation or antidiuretic hormone secretion
• Positive pressure ventilation impeded venous
  return
• ? ??? ??? ??? Iv fluid ??? completely reversible
• Large doses of predominantly a-adrenergic
  vasopressors (phenylephrine, norepinephrine) ?? ?
• Renal blood flow ????? small intermittent doses
  or brief infusio? ???
• Fluid therapy
• Judicious fluid administration
• ?? excessive fluid overload (pulm. Congestion or
  edema)? ARF?? ???? ??