Hypokalemia Lecture Notes

Introduction to Hypokalemia

• Hypokalemia Definition: Low levels of potassium in the blood.
• Normal Potassium Levels: 3.5 to 5.1 (varies slightly by lab).
• Dangerous Levels: Less than 2.5 requires major intervention.

Cellular Understanding

• Intracellular vs. Extracellular:
  • Potassium primarily resides inside cells.
  • Blood tests measure extracellular potassium.
• Potassium Role:
  • Nerve impulse conduction.
  • Muscle contraction (GI system, heart, etc.).

Causes of Hypokalemia

• Pneumonic: DITCH
  • Drugs: Laxatives, diuretics (e.g., Lasix), corticosteroids.
  • Inadequate intake: Anorexia, nausea, lack of intake.
  • Too much water intake: Dilutes potassium.
  • Cushing's Syndrome: Excess aldosterone secretion.
  • Heavy fluid loss: Vomiting, diarrhea, NG suction, wound drainage.
• Additional Causes:
  • Potassium shifts from extracellular to intracellular (alkalosis, hyperinsulinism).

Signs and Symptoms

• General Rule: Everything is slow and low.
• Cardiac and Respiratory:
  • Weak, irregular pulse.
  • Orthostatic hypotension.
  • Shallow respirations, diminished breath sounds.
  • EKG Changes: ST depression, flat/inverted T-wave, prominent U-wave.
• Muscle and GI:
  • Decreased deep tendon reflexes.
  • Flaccid paralysis.
  • Confusion, weakness.
  • Decreased bowel sounds.

EKG Changes

• Normal EKG: P wave, QRS complex, T wave.
• Hypokalemia Specific Changes:
  • ST segment depression.
  • Flat or inverted T-wave.
  • Prominent U-wave.

Mnemonics for Symptoms

• Seven Ls:
  1. Lethargic
  2. Low, shallow respirations
  3. Lethal cardiac changes
  4. Loss of urine
  5. Leg cramps
  6. Limp muscles
  7. Low blood pressure and heart rate

Nursing Interventions

• Monitor heart rhythm, respiratory status, GI and renal status.
• Cardiac monitoring, especially with fast potassium infusion.
• Watch for phlebitis and infiltration during IV potassium infusion.
• Be cautious with diuretics and digoxin.
• Consider potassium-sparing diuretics.

Dietary Considerations

• Potassium-rich foods (mnemonic POTASSIUM):
  • Potatoes, Pork
  • Oranges
  • Tomatoes
  • Avocados
  • Strawberries, Spinach
  • I for fIsh
  • U for mUshrooms
  • M for muskMelons, plus carrots, raisins, bananas.

Conclusion

• Review hypokalemia and hyperkalemia differences.
• Take the quiz on registernurseRN.com to assess understanding.