What is the actual potassium of a patient with pH of 7.8 and serum potassium of2.2?
The change in potassium associated with alkalosis can be calculated by the following formula:
Potassium decreases by 0.3 mEq/L for every 0.1 increase in pH above normal
The free water deficit of a 70 kg man with serum sodium of 154 is:
This is the formula used to estimate the amount of water required to correct hypernatremia
Water deficit L = (serum sodium -140 / 140) X TBW
Estimate TBW (total body water) as 50% of lean body mass in men and 40% in women.
A patient with serum calcium of 6.8 and albumin of 1 .2 has a corrected calcium of
When measuring total serum calcium levels, the albumin concentration must be taken into consideration.
Adjust total serum calcium down by 0.8 mg/dL for every 1 g/dL decrease in albumin.
All the following treatments for hyperkalemia reduce serum potassium EXCEPT
When ECG changes are present, calcium chloride or calcium gluconate (5- 10 mL of 10% solution) should be administered immediately to counteract the myocardial effects of hyperkalemia. Calcium infusion should be used cautiously in patients receiving digitalis, because digitalis toxicity may be precipitated. Glucose and bicarbonate shift potassium intracellularly. Kayexalate is a cation exchange resin that binds potassium, either given enterally or as an enema
An alcoholic patient with serum albumin of 3.9, K of 3.1, Mg of 2.4, Ca of 7.8, and P04 of 3.2 receives three boluses of IV potassium and has serum potassium of 3.3. You should:
Magnesium depletion is a common problem in hospitalized patients, particularly in the I CU. The kidney is primarily responsible for magnesium homeostasis through regulation by calcium/magnesium receptors on renal tubular cells that sense serum magnesium levels. Hypomagnesemia results from a variety of etiologies ranging from poor intake (starvation, alcoholism, prolonged use of IV fluids, and total parenteral nutrition with inadequate supplementation of magnesium), increased renal excretion (alcohol, most diuretics, and amphotericin B), GI losses (diarrhea), malabsorption, acute pancreatitis, diabetic ketoacidosis, and primary aldosteronism. Hypomagnesemia is important not only for its direct effects on the nervous system but also because it can produce hypocalcemia and lead to persistent hypokalemia. When hypokalemia or hypocalcemia coexist with hypomagnesemia, magnesium should be aggressively replaced to assist in restoring potassium or calcium homeostasis.
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