Are you studying metabolic alkalosis and need to know a mnemonic on how to remember the causes? This article will give you a clever mnemonic and simplify the signs and symptoms and nursing interventions on how to remember metabolic alkalosis for nursing lecture exams and NCLEX.
This article will cover:
- Metabolic alkalosis simplified
- Lab values expected with metabolic alkalosis
- Causes of metabolic alkalosis
- Signs and symptoms of metabolic alkalosis
- Nursing interventions for metabolic alkalosis
Lecture on Metabolic Alkalosis
Metabolic alkalosis in simple terms: a metabolic problem caused by the excessive loss of acids (H+) or increased amount of bicarb (HCO3) produced in the body that leads to an alkalotic state in the body. Disease processes and drugs can cause metabolic alkalosis.
When metabolic alkalosis happens in the body other systems try to compensate by hopefully fixing the blood’s pH and bicarb level. One system that does this is the respiratory system by stimulating the respiratory system to hypoventilate (decrease respirations) which will retain PCO2 (carbon dioxide) so it will decrease the pH back to normal, hence you will start to see bradypnea in your patient.
If a patient is experiencing metabolic alkalosis they will present with the following labs:
- HCO3: increases >26
- Blood pH: increases >7.45
- CO2: >45 or normal (may be normal but if increased this is the body’s way of trying to compensate. Remember the respiratory system tries to decrease the pH from its alkalotic state by causing hypoventilation ( bradypnea). The respiratory system hopes that if the CO2 increase enough it will cause the pH to decrease and the kidneys will start to excrete the bicarb which will hopefully decrease the overall HCO3.
Remember what normal values are:
- pH 7.35-7.45
- PaCO2 35-45
- HCO3 22-26
Causes of Metabolic Alkalosis
Remember: “Alkali” (**these are the most common causes)
**Aldosterone production excessive (hyperaldosteronism) activates renin-angiotensin-aldosterone system : the adrenal cortex is releasing too much aldosterone which causes the renal tubule in the kidneys to keep sodium which wastes hydrogen ions (ex: potassium) and this causes you to keep bicarb (HCO3)
Loop **diuretics (Lasix) or thiazide therapy: causes the kidneys to waste hydrogen ions and chloride through the urine (ALSO LOSING K+) which in turn increases the bicarb
alKali ingestion of food (baking soda, milk, antacids) increases bicarb level in the blood
Anticoagulant “citrate” (used as a storage agent in blood and during continuous forms of renal replacement therapy) Caused from a massive transfusion of whole blood (patient needs several bags of blood) and the body metabolizes the citrate used in the blood as bicarb which increases the HCO3 level in the body. Also, patients who undergo continuous forms of renal replacement therapy (CRRT) (an alternative therapy for patients who can’t undergo hemodialysis) are affected by the citrate used in the therapy.
Loss of fluids (**vomiting and **GI suctioning) hence this fluids are rich in K+ and when you lose them you are losing hydrogen ions and this causes the body to increase the bicarb level, Low potassium levels cause reabsorption of HCO3-
Increased sodium bicarb administration (trying to correct metabolic acidosis)
Signs and Symptoms of Metabolic alkalosis
- Bradypnea (hypoventilation) <12 bpm
- Many symptoms due to low potassium (dysrhythmia), tetany, tremors, muscle weakness/cramping, tired, irritable, vomiting, Depression ST, flat or inverted T wave and prominent u-wave)
Nursing Interventions for Metabolic Alkalosis
- Based on the cause: vomiting (give antiemetic ex: Zofran, Phenergan), stop diuretics
- Doctor may order Diamox (Carbonic anhydrase inhibitors): a diuretic which reduces the reabsorption of bicarb
- Watch ABGs and signs of respiratory distress
- Monitor potassium and chloride levels (wasted in this condition)