Fluids Flashcards
What are the potential agents that increase a osmolal gap, and what is considered an elevated gap?
An elevated gap is >10.
Ethanol, methanol, isopropyl alcohol, ethylene glycol, acetone, ethyl ether, paraldehyde, lactate, or mannitol.
Hyper and Hypo electrolyte abnormalities are a result of what?
Hyper: 1) Increased retentinon 2) Extracellular shift into the serum 3) Loss of free body water.
Hypo: 1) Increased loss 2) Intracellular shift into the cells 3) Gain of free body water.
What are the causes of:
1) Hyperosmolar Hyponatremia?
2) Isotonic Hyponatremia?
3) Hyposmolar Hyponatremia?
1) Hyperglycemia, Mannitol
2) Hyperproteinemia, Hyperlipidemia
3) Hypovolemia (diuretics, salt wasting, aldosterone deficiency, volume loss), Hypervolemia (ARF, CHF, Liver failure, Nephrotic syndrome), and Euvolemia (SIADH, Hypothyroid, PPV, Drugs, glucocorticoid deficiency)
What are the diagnostic characteristics of SIADH?
- Euvolemic Hyposmolar Hyponatremia
- Urine [Na+] > 20 mEq/L
- Urine osmolality > 200mOsm/kg
- Normal adrenal, renal, cardiac, hepatic, and thyroid functions
- Correctable with water restriction
How do you calculate total body Na deficit?
How fast should chronic hyponatremia be corrected?
Total [Na+] deficit (mEq/L) = (desired Sr [Na+] – actual Sr [Na+]) × TBW
0.5 mEq/L per hour (12 mEq/L per day)
What test could you do to differentiate central from nephrogenic DI?
Vasopression 5 units
Central DI will respond with increasing urine osmolarity >800mOsm/L
Hypernatremia is caused by what factor?
Treatment should focus on what first?
Loss of free body water, or inadequate intake (increased Na intake and loss of Na excretion is much less common).
Repletion of volume with NS to restore perfusion, then switch to 1/2 NS until U/O is 0.5ml/kg/hr.
Rate of correction should be no more than 10-15mEq/L per day.
What is the relationship of serum K+ to pH?
How much will potassium change as pH is changed?
Serum K+ is inversely related to pH.
A rise in the pH of 0.10 generally causes a 0.5 mEq/L decrease in serum [K+] levels in metabolic acid-base derangements.
What ECG changes are found in Hyperkalemia?
If hyperkalemia is seen in someone who is taking Digoxin, what step should you consider not doing for treatment?
Giving calcium can potentiate the cardiac glycoside activity of digoxin.
What ECG characteristic is classic for hypocalcemia?
Prolonged QT, more specifically, a long S-T interval.
What are classic ecg characteristics for hypercalcemia?
Depressed ST segments
Widened T waves
Shortened ST segments and QT intervals.
Bradyarrhythmias may occur, with bundle branch patterns that may progress to second-degree block or complete heart block.
What are the 3 treatments for hypercalcemia?
1) Fluid resus with NS
2) Calcitonin, 4 units/kg SC
3) Zoledronic acid, 4 mg IV over 15 minutes
