Fluids & Electrolytes

Question 1

Hyponatremia Sx?

Answer 1

• Nausea and malaise (Na < 125 to 130 meq/L)
• Headache, lethargy, obtundation & eventually seizures, coma, & resp. arrest can (Na < 115 to 120 meq/L) Noncardiogenic pulmonary edema has also been described.

Acute hyponatremic encephalopathy may be reversible, but permanent neurologic damage or death can occur, particularly in premenopausal women.
Overly rapid correction also may be deleterious, particularly in patients with chronic hyponatremia.

Question 2

Hyponatremia - effects on brain water?

Answer 2

Causes water movement into the brain (cerebral edema)

Question 3

Hypernatremia - effects on brain water?

Answer 3

Causes water movement out of the brain

Question 4

Why is acute hypernatremia dangerous?

Answer 4

The rapid decrease in brain volume can cause rupture of the cerebral veins, leading to focal intracerebral and subarachnoid hemorrhages and possibly irreversible neurologic damage.

Acute hypernatremia can also result in demyelinating brain lesions similar to those associated with overly rapid correction of chronic hyponatremia.

Question 5

Hypernatremia Sx?

Answer 5

• The clinical manifestations of acute hypernatremia begin with lethargy, weakness, and irritability, and can progress to twitching, seizures, and coma.
• Severe symptoms usually require an acute elevation in Na > 158 meq/L.
• Values above 180 meq/L are associated with a high mortality rate, particularly in adults.

Question 6

Common causes of Hyperkalemia?

Answer 6

Most often due to impaired urinary potassium excretion due to acute or chronic kidney disease and/or disorders or drugs that inhibit the renin-angiotensin-aldosterone axis.

Question 7

Hyperkalemia Sx?

Answer 7

• Muscle weakness or paralysis
• Cardiac conduction abnormalities
• Cardiac arrhythmias (Tall peaked T waves w/ shortened QT interval = 1st findings)

These manifestations usually occur when the serum [K+] is ≥7.0 meq/L with chronic hyperkalemia or possibly at lower levels with an acute rise in serum potassium

Question 8

Hypokalemia Sx?

Answer 8

• Muscle weakness, cramps, rhabdomyolysis, and myoglobinuria
• Respiratory muscle weakness
• Ileus & its ass’d sx of distension, anorexia, nausea, and vomiting
• Renal dysfunction
• Arrhythmias (ST depression & decrease in the T wave amplitude)
• Reduced insulin secretion

Question 9

____ are able to enter all body compartments.

____ are restricted to the plasma compartment.

Answer 9

Crystalloids are able to enter all body compartments.

Colloids are restricted to the plasma compartment.

Question 10

Maintenance fluids rate?

Answer 10

50ml/kg/24hr or 2ml/kg/hr

Question 11

What type of fluid should be used in resuscitation?

Answer 11

Isotonic

0.9% normal saline or Ringer’s Lactate

Question 12

When are 0.9% NS vs. Ringer’s Lactate each specifically recommended as isotonic fluid replacement?

Answer 12

RL may be preferred in hemorrhagic shock because it somewhat minimizes acidosis and will not cause hyperchloremia.

For patients with acute brain injury, 0.9% saline is preferred.

(vs. Colloid solutions are also effective for volume replacement during major hemorrhage, but albumin has been associated with poorer outcomes in patients with traumatic brain injury.)