anesthetic concerns for the patient with renal and …：在肾脏和患者的麻醉问题…
Anesthetic Concerns for the Patient With Renal and Hepatic Disease,R4 ,Advanced renal or hepatic disease Systemic disease processes, affecting multiple organ systems. Fundamental defect in protein metabolism hyperammonemia or elevated BUN(markers for other circulating byproducts of protein metabolism). Defective ion transport across cell membranes, resulting in intracellular sodium and water accumulation. Imply abnormal handling of anesthetic drugs, multiorgan dysfunction, general debility, and specific problem associated with replacement therapy and transplantation. - A challenge to anesthegiologists.,Systemic Manifestations of Renal and Hepatic Disease,Chronic renal failure(1) Fluid and acid-base imbalance Dialysis : control metabolic acidosis, hyperkalemia, and CHF. In anuric patients, Only fluid loss is insensible(500ml/day) Excessive sodium intake - edema, hypertension. Excessive water intake - hyponatremia. In polyuric CRF, Urine output is normal, but concentrating ability is absent. Acute fluid loss - hypovolemia. A moderate anion gap acidosis Compensated by chronic respiratory alkalosis. Buffer base is depleted. Shock, diarrhea, or hypercatabolism(sepsis, trauma, steroid therapy). Profound metabolic acidosis.,Electrolyte imbalance Extracellular potassium Maintained in narrow range(3.5 to 5.0 mEq/l). Active intracellular transport by a sodium ATP pump at the cell membrane. Clinical and ECG manifestations of hyperkalemia(or hypokalemia) depend on potassium flux rather than the serum concentration. Catabolic stress, acidosis, potassium-sparing diuretics, erythrocyte transfusion Rapid, life-threatening hyperkalemia. Hypermagnesemia Muscle weakness, susceptibility to muscle relaxants. Hypomagnesemia Associated with hypokalemia, ventricular irritability.,Hyperphosphatemia Increased bone deposition of calcium and hypocalcemia. Decreased renal synthesis of vitamin D. Hypocalcemia Secondary hyperparathyroidism and bone resorption. The syndrome of renal osteodystrophy. Treatment : vitamin D, calcium salts, phosphate binders(aluminium hydroxide), dietary phosphate restriction. Hypophosphatemia( 2.5 mg/dl) Aggressive dialysis, aluminum hydroxide therapy, or TPN. The phosphate depletion syndrome Increased susceptibility to muscle relaxants, difficult ventilatory weaning, and CNS dysfunction.,Cardiovascular problems Systemic hypertension LVH(concentric or asymmetric) Hyperlipidemia a high prevalence of accelerated atherosclerosis. Anemia and AV shunts hyperdynamic circulation with fixed low systemic vascular resistance. circulatory reserve is impaired. Myocardial ischemia, sepsis hypotension . Uremic pericarditis, hemorrhagic pericardial effusions.,Pulmonary problems Increased minute ventilation to compensate chronic metabolic acidosis. Hypoalbuminemia, decreased serum oncotic pressure, decreased muscle strength, immunosuppression. postoperative pulmonary edema, atelectasis, pneumonia. CAPD abdominal distension compromises ventilation and forced vital capacity(FVC).,Impaired hematopoiesis Normochromic, normocytic anemia Hct. between 25 and 28%. Decreased erythrpoietin production by the kidney. Bone marrow depression(uremia, aluminum toxicity), decreased RBC survival, chronic blood loss from GI tract or laboratory studies. Uremic coagulopathy Abnormal platelet function(thrombocytopathy) occurs when BUN exceeds 60 to 80 mg/dl. Bleeding time prolonged( 15 minutes). Impaired platelet aggregation. d/t defective endothelial release of von Willebrand factor-factor VIII complex.,Impaired metabolic and immune function Hyperglycemia, hypertriglyceridemia peripheral insulin resistance and decreased lipoprotein lipase activity in uremia. protein malnutrition(kwashiorkor, hypoalbuminemic malnutrition) dietary protein restriction, chronic albuminuria. Protein loss via CAPD(10 to 20 g/dl, 30 to 40 g/dl with peritonitis). Hypoalbuminemia, lowered colloid oncotic pressure peripheral edema, pulmonary edema. Impaired leukocyte chemotaxis and immunoglobulin responses nosocomial or oppportunistic infection. Depleted lean body mass and catabolic effects of uremia. wound dehiscence, fistulas, bed sores.,Gastrointestinal dysfunction (Uremic enteropathy) Anorexia, hiccups, nausea, vomiting. Autonomic neuropathy delays gastric emptying. Regurgitation and aspiration during anesthetic induction. Peptic ulcer up to 25% in CRF patients. Hepatitis B and C high incidence in patients on chronic hemodialysis. often anicteric or in a carrier state.,Neurologic dysfunction Depend on the acuity of uremia. Personality changes, drowsiness, asterexis, myoclonus, seizures. Major surgery, gastrointestinal bleeding, infection precipitate acute encephalopathy. Lifetime hospital dependence passive-aggressive, depressed, manipulative, and churlish. Uremic distal sensorimotor neuropathy a marker for autonomic neuropathy. orthostatic hypotension, impaired circulatory response to anesthesia, delayed gastric emptying. silent myocardial ischemia(without a
