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  • Anesthesia and renal disease

  • Physiology

    Regulation

    Volume & composition of body fluids

    Elimination of toxins

  • Physiology

    Endocrine function

    Renin-Angiotensin-Aldosterone

    Erythropoietin

    Vitamin D and Ca++ homeostasis

    Insulin metabolism

  • Physiology

    Glomerular Filtration Rate (GFR)

    125ml/min

    90% reabsorbed

    GFR = Kf where

    Kf = (PGC-PBC) (GC- BC) P = Hidrostatic pressure, = Oncotic pressure GC = glomerular capillary, BC = Bowman capsule

  • Physiology

    Renal bloodflow (RBF)

    25% of cardiac output

    Cortex = 66%

    Medulla 33%

    Autoregulated between 60 160mmHg

    RBF = Cl-

    Stimulate JXA R-A-A Stimulate sympathetic system

  • Evaluation of renal function

    Urea

    Creatinine

    Creatinine clearance

    Fractional excretion of Na+

    Other

    Proteinuria, hematuria, MCS, ultrasound, CT MRI,

  • Effects of anesthesia on renal

    function

    GFR as CO Induction agents, volatiles

    Autoregulation remains intact

    Stress response = ADH = concentrated urine

    IPPV = atrial pressure = ANP = Na+

    excretion

  • Direct nefrotoxic effects

    Enflurane

    Long exposure (9.6 MAC hours)

    Free fluoride inhibits tubular function

    Cl- transport in ascending loop

    concentation defect

    high output renal failure resistant to vasopressin

  • Direct nefrotoxic effects

    Sevoflurane

    2-5% liver metabolism = free F-

    Potentially nefrotoxic

  • Direct nefrotoxic effects

    Sevoflurane

    Low flow in Baralime

    Degradation = Compound A

    lyase

    Nefrotoxic metabolite

    Rare in humans

    10% lyase activity

  • Perioperative renal failure

    Co-existing renal disease

    Hypovolemia

    Liver cirrhosis

    Sepsis

    Multi organ trauma

    Congestive cardiac failure

    Abdominal aneurism resection

    Cardio pulmonary bypass

    Advanced age

  • Chronic renal failure

    Anemia

    Pruritis

    Coagulopathies

    Altered hydration and e- balance

    Metabolic acidosis

    Systemic hypertension

    Increased susceptibility to infections

  • Chronic renal failure:

    Anemia

    Decreased erythropoietin production

    Increased cardiac output

    Hyperdynamic circulation

    OHEC shifts to right

    Tolerate Hb > 6 for surgery

    Transfusion fluid overload

    Erythropoietin worsen hypertension

  • Chronic renal failure:

    Pruritis

    Sign of end stage disease

    circulating levels of histamine

    Erythropoietin may [histamine]

  • Chronic renal failure:

    Coagulopathies

    Defective platelet function

    Defective vWF

    Systemic heparinisation for dialysis

  • Chronic renal failure:

    Altered hydration

    Unpredictable volume status

    Overload

    Hypovolemic after dialysis

    Disequilibrium syndrome

    CNS symptoms post dialysis due to more rapid

    lowering of extracellular osmolarity tha

    intracellular

  • Chronic renal failure:

    Hyperkalemia K+> 5.5

    ECG changes neccesitates Rx

    Peaked T waves

    Prologation PR time, ORS complex

    Heart block

    Rx

    Hyperventilation

    Insulin and glucose

    CaCl2 (physiological antagonist)

  • Chronic renal failure:

    Hypocalcemia

    GFR = PO4 = Ca++

    Hypocalcemia = PTH = bone resorption

    Renal osteodystrophy

    1,25 DHCC production intestinal absorbsion of Ca++

  • Chronic renal failure:

    Hypermagnesemia

    Oral Mg++ containing antacids

    CNS depression

    Potentiation of muscle relaxants

  • Chronic renal failure:

    Metabolic acidosis

    GFR = decreased H+ excretion

    pH < 7.35

    Hyperventilation (compensatory)

    neuromuscular responsiveness

  • Chronic renal failure:

    Hypertension

    Activation of R-A-A

    Vasoconstriction (to increase renal blood flow)

    Retention of fluid (due to aldosterone)

    Fluid overload

    Rx

    ACE inhibitors / ARB

    Ca++ channel antagonists

  • Chronic renal failure:

    Hypertension

    >80% of all renal patients

    Most significant risk factor for

    Congestive cardiac failure

    Myocardial infarction

    Stroke

  • Chronic renal failure:

    Pericardial disease

    Pericardial effusion +/- tamponade

    Due to uremia

    Acute tamponade

    Life threatening

    Rx= pericardiocentesis, dialysis.

  • Chronic renal failure:

    Central cervous system

    Encephalopathy

    Depression

    Sedation

    Coma

    Seizures

    Acute hypertension, brain edema

  • Chronic renal failure:

    Peripheral nervous system

    Distal symmetric mixed polyneuropathy

    Median, Peroneal

  • Chronic renal failure:

    Autonomic nervous system

    Cardiac

    Resting tachycardia

    Attenuated response to hypovolemia, IPPV

    Orthostatic hypotension

    GIT

    Delayed gastric emptying

  • Chronic renal failure:

    Infection

    Most common cause of death

    High risk

    Decreased phagocyte activity Immunosuppressant

    drugs.

    Frequent transfusions Hep B & C, HIV

    Strict aseptic placement of IV lines

  • Preoperative evaluation

    Etiology of renal failure

    Estimate daily urine production

    Dialysis

    Type

    Frequency

    Side effects

    Time of last dialysis

  • Preoperative evaluation

    Note any systemic manifestations of uremia

    Cardiovascular, pulmonary

    Bleeding diathesis

    Sepsis

    Neuropathy, encephalopathy

    Hydration status

    Note presence of A-V fistulas

  • Preoperative dialysis

    Fluid overload

    Hyperkalemia

    Metabolic acidosis.

    Pericarditis

    Coagulopathy

    Drug toxicity

    Refractory GIT symptoms

  • Preoperative preparation

    Transfuse

    only if Hb < 6

    Extensive surgery with blood loss

  • Preoperative preparation

    Correct platelet dysfunction

    DDAVP 0.3mg/kg IV

    Hypertension

    Multidrug therapy

    170/100 mmHg acceptable

  • Preoperative preparation

    Hyperkalemia

    Glucose-insulin infusion

    CaCl2

    Kayexilate

    Emergency dialysis

    Premedication

    Midazolam if necessary

  • Preoperative preparation

    Wear gloves, masks

    Prevent hypothermia

    A-V fistulas

    No IV lines

    No blood pressure cuffs

  • Induction of anesthesia

    Pre-oxygenate

    Careful fluid load

    Especially after dialysis

    Lower dose induction agent

    free fraction = albumin, acidosis

    Ketamine useful

  • Induction of anesthesia

    Rapid sequence induction

    Suxamethonium safe if K+ < 5.5 mmol

    Modified RSI with atracurium, cis-atracurium

    Avoid steroid relaxants

    dependant on renal excretion

    vecuronium has active metabolite (10%)

    recurarisization

  • Maintenance of anesthesia

    Safe vapours

    Isoflurane, desflurane

    Avoid

    Enflurane = inorganic fluoride production

    Sevoflurane = Compound A

    Halothane = dysrhythmias

    N2O = decreased O2 delivery in severe anemia

  • Maintenance of anesthesia

    Narcotics

    Short acting, lower doses

    Accumulation

    Morphine-6-glucuronate prolonged effect

    Nor-pethidine = seizures

  • Intra operative problems

    Hypertension

    Direct vasodilators, B blockade to decrease BP

    Exaggerated hypotension

    Relatively small fluid losses

    Deep anesthesia

    Dysrhythmias

    Excessive bleeding

  • Post operative problems

    Delayed awakening

    Nausea and vomiting

    Hypertension

    Respiratory depression

    Pulmonary edema

  • Conclusion

    Multi system disease

    Increased risk of peri-operative morbidity and

    mortality

    Handle with care!