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Metabolic complications from TPN

* EFA deficiency:
* Hyper Vitamin A & D;
* Fluid Over Load: (See CHF)
* Hypercholemic Metabolic Acidosis: from excessive Cl from IV or from amino acid solutions (as HCL salts - more common in children or patients w/ decrease renal f(x) );
* Hypercalcemia / Hypo Ca
* Hypoglycemia:
    May occassionally occur when weaning from TPN; give D5W;
* Hyperglycemia:
    - uncontrolled hyperglycemia during TPN is probably the most common cause of serious hypernatremia;
    - if not correct for several days - Non Ketotic Coma may ensue;
* Hyerphosphatemia / Hypo P;
* Hypermagnesemia / Hypo Mg
    Like hyperkalemia, seen patients with renal failure;
    When potassium must be reduced, magnesium must also be reduced;
* HyperKalemia
    - most TPN formulations contain 40-50 mEq potassium/Lit and are intended for pts w/ normal renal function;
    - excess potassium over and above that required for maintenance and urine losses (usually 3-5 mEq/gm nitrogen given) are included;
    - potassium must be closely followed in elderly and those with impaired renal function;
* Hypernatremia
    - uncontrolled hyperglycemia during TPN is probably the most common cause of serious hypernatremia;
    - associated glycosuria cause osmotic diuresis of large volumes of salt poor fluid, resulting in hypernatremia and a extracellular fluid volume deficit;
* Hyponatremia:
* HyperOsmolar Nonketotic Coma:
    - uusally found in patients w/ impaired insulin response in improperly monitored patient;
    - caused by excessive glucose levels, usually corrected by insulin and re-hydration:
    - if this complication occurrs, stop TPN infusion and begin infusion of normal Saline until there is adequate volume repletion/urine output;
    - following volume repletion, hypotonic solutions are infused to decrease tonicity;
    - may give modest Insulin infusion of 10-25 units IV along w/ constant infusion of 5-10 units per hour until blood sugar drops below 500 mg/ml;
* Azotemia
    - administration of excessive amino acids can result in azotemia, as evidenced by high BUN, and must be differentiated from increases caused by dehydration;
* Elevated Liver function tests:
    - usual cause is excessive glucose infusion;
    - when primary metabolic pathway for glucose becomes saturated, excess glucose is converted to intracellular triglycerides in the liver;
    - this is especially seen when 25% dextrose solution is given at rates > 125 ml per hour;
    - to reverse this process, reduce the glucose load and if necessary, substitute fat calories;
* Metabolic alkalosis:
    - to treat, increase the Cl level in the solution and reduce acetate content (may reduce further by giving less total amino acids