fluid management- lecture 25/26

euvolemia

normal amount of blood

hypervolemia signs/symptoms

edema and jvd

hyponatremia range

Na < 135

hyponatremia mild symptoms

nausea and malaise

hyponatremia moderate symptoms

headache, lethargy, restlessness, disorientation

hyponatremia severe symptoms

altered mental status

Hypovolemic hyponatremia: primary treatment?

IV 0.9% normal saline.

Severe symptomatic hypovolemic hyponatremia?

IV 0.9% NS; may consider 3% saline.

Euvolemic hyponatremia (SIADH): first-line treatment?

Treat cause + fluid restrict to <1,000 mL/day.

Severe symptomatic euvolemic hyponatremia?

Consider IV 3% saline ± loop diuretic.

Demeclocycline dose for euvolemic hyponatremia?

300 mg PO 2–4 times daily.

How does demeclocycline treat SIADH?

Inhibits ADH action in the kidneys.

Major adverse effects of demeclocycline?

Nephrotoxicity, photosensitivity, hepatotoxicity.

What do vaptans do in hyponatremia?

Increase free-water excretion and raise plasma Na⁺.

Which patients should NOT receive vaptans?

Patients with hypovolemia.

Conivaptan loading dose?

20 mg IV over 30 minutes.

Conivaptan maintenance dose?

20 mg IV over 24 hr for 2–4 days; max 4 days.

Tolvaptan starting dose?

15 mg PO once daily.

Maximum tolvaptan dose?

60 mg PO daily.

Why is tolvaptan limited to 30 days?

Risk of hepatotoxicity.

Nonemergent hypervolemic hyponatremia treatment?

Treat cause + fluid/Na restriction ± diuretic or vaptan.

Fluid restriction target in hypervolemic hyponatremia?

Sodium restriction in hypervolemic hyponatremia?

Asymptomatic hyponatremia: max correction rate?

≤0.5 mEq/L/hr; <10–12 mEq/L per 24 hr.

Symptomatic hyponatremia: initial correction rate?

Increase Na⁺ 1–2 mEq/L/hr for first few hours.

Maximum Na⁺ correction in symptomatic hyponatremia?

No more than 12 mEq/L in 24 hours.

Hypovolemic hypernatremia + unstable: initial fluid?

0.9% NaCl at 200–300 mL/hr until stable.

After stabilizing hypovolemic hypernatremia?

Use hypotonic fluid: D5W or 0.45% NaCl.

Central diabetes insipidus treatment?

ADH replacement with desmopressin (DDAVP).

Starting desmopressin dose for central DI?

10 mcg at night orally or intranasally.

Sublingual desmopressin dose listed in lecture?

60 mcg three times daily.

Does nephrogenic DI respond to ADH therapy?

No. Correct the underlying disorder.

Drug strategy for nephrogenic DI?

Thiazide diuretic + salt restriction.

Hypervolemic hypernatremia: main fluid?

D5W based on calculated water deficit.

Loop diuretic for hypervolemic hypernatremia?

Furosemide 20–40 mg IV every 6 hours.

Asymptomatic hypernatremia: max correction rate?

Decrease Na⁺ ≤0.5 mEq/L/hr; <10–12 mEq/24 hr.

Symptomatic hypernatremia: initial correction rate?

Decrease Na⁺ 1–2 mEq/L/hr for first few hours.

Mild/chronic hyperkalemia: general treatment?

Treat cause; decrease K⁺ intake/drugs; diuretic or resin; dialysis if CKD.

Severe hyperkalemia + ECG changes: first priority?

Stabilize myocardium with IV calcium.

Calcium gluconate's role in hyperkalemia?

Stabilizes myocardium; does NOT directly lower K⁺.

Calcium gluconate dose for severe hyperkalemia?

10% calcium gluconate 10 mL IV over 2–3 min.

How quickly does calcium gluconate work?

Within minutes; lasts about 30–60 minutes.

Calcium chloride vs calcium gluconate potency?

Calcium chloride is about 3× more potent.

Hyperkalemia: insulin dose to shift K⁺ into cells?

Regular insulin 10 units IV ×1.

Dextrose dose given with insulin for hyperkalemia?

D50 50 mL IV ×1.

When can dextrose be omitted with hyperkalemia insulin?

If significantly hyperglycemic (>250 mg/dL).

How much can insulin lower K⁺?

About 0.6–1 mEq/L.

Insulin onset for hyperkalemia?

About 10–20 minutes.

How does albuterol lower potassium?

β2 stimulation activates Na⁺/K⁺ ATPase → K⁺ shifts into cells.

Albuterol dose listed for severe hyperkalemia?

Nebulized 10–20 mg/mL per dose.

How much can albuterol lower K⁺?

About 0.5–1 mEq/L.

When should sodium bicarbonate be used in hyperkalemia?

Only when otherwise indicated; it is not very effective.

What does calcium do vs insulin in hyperkalemia?

Calcium protects heart; insulin shifts K⁺ into cells.

What treatments actually REMOVE K⁺ from the body?

Cation-exchange resins and dialysis.

Kayexalate dose listed for hyperkalemia?

Sodium polystyrene sulfonate 15 g PO ×1.

Lokelma dose listed for hyperkalemia?

Sodium zirconium cyclosilicate 10 g PO ×1.

Veltassa dose listed for hyperkalemia?

Patiromer 8.4 g PO ×1.

Most effective way to remove K⁺ from the body?

Dialysis.

Hypokalemia treatment: what must also be checked/corrected?

Magnesium deficiency.

Severe Mg deficiency with hypokalemia: IV dose?

Magnesium 2 g IV over 1 hour.

Non-severe Mg deficiency: IV dose listed?

Magnesium 4 g IV over 12 hours.

Mild/chronic hypokalemia: treatment options?

Dietary K⁺, K⁺-raising drugs, and oral supplementation.

Best oral K⁺ salt for diuretic/diarrhea hypokalemia?

Potassium chloride (KCl).

Best K⁺ salt if phosphorus is also low?

Potassium phosphate.

Best K⁺ salt when metabolic acidosis is present?

Potassium bicarbonate.

When is IV potassium preferred?

Severe/symptomatic hypokalemia or unable to tolerate PO.

Typical initial IV KCl dose in severe hypokalemia?

KCl 40 mEq IV ×1, then reassess.

Should IV KCl be mixed in NaCl or D5W?

NaCl preferred; avoid D5W if possible.

Maximum peripheral IV K⁺ rate?

10 mEq/hr.

Maximum central-line IV K⁺ rate?

40 mEq/hr with telemetry.

Why avoid excessive IV potassium rates?

Phlebitis, hyperkalemia, arrhythmia, and death.