Acid-base imbalances

Flashcards covering acid-base concepts, buffers, ABG interpretation, common disturbances, symptoms, and management based on lecture notes.

What is an acid?

A substance that releases a hydrogen ion (H+).

What is a base (alkali)?

A substance that binds to a hydrogen ion (H+).

What is acid-base balance?

The homeostasis of pH in body fluids maintained by buffers, lungs, and kidneys.

What is a cellular buffer?

A substance that reacts with acid or base to prevent a large change in pH.

What is the normal pH range for blood?

7.35 to 7.45.

What is the common acid in the body?

Hydrochloric acid (gastric acid).

What is the common base in the body?

Bicarbonate (HCO3-).

What are the primary acid-base controls in the body?

Lungs and kidneys.

Name examples of cellular buffers.

Proteins, hemoglobin, bicarbonate, and phosphates.

How do the lungs respond to acidosis?

Blow off extra CO2 through rapid, deep breathing.

How do the lungs respond to alkalosis?

Conserve CO2 with shallow respirations.

How do the kidneys help regulate acid-base balance?

Slow to respond; regulate bicarbonate by reabsorbing it and forming acids and ammonium.

What are the four primary acid-base disturbances?

Respiratory acidosis, respiratory alkalosis, metabolic acidosis, metabolic alkalosis.

What pH indicates acidosis? What pH indicates alkalosis?

Acidosis: pH < 7.35; Alkalosis: pH > 7.45.

What does the ABG mnemonic ROM(E) stand for (ROME)?

Respiratory disturbances show pH and PCO2 move in opposite directions; Metabolic disturbances show pH and HCO3- move in the same direction.

Where are most body fluids found?

Intracellular (intercellular) space.

Common causes of respiratory acidosis

Hypoventilation due to drug overdose, anesthesia, COPD, pneumonia, or atelectasis.

Common causes of metabolic acidosis

Diabetic ketoacidosis, severe diarrhea, renal failure, shock.

Signs and symptoms of metabolic acidosis

Headache, decreased BP, hyperkalemia, muscle twitching, warm flushed skin, N/V, diarrhea, changes in LOC, Kussmaul respirations.

ABG changes for metabolic acidosis (pH, HCO3-)

pH < 7.35 and HCO3- < 22 mEq/L.

How is metabolic acidosis treated?

Sodium bicarbonate; insulin for DKA; monitor ABGs and potassium; treat underlying cause.

What indicates compensatory respiration in metabolic acidosis?

Kussmaul respirations (compensatory hyperventilation).

Signs of respiratory acidosis

Hypoventilation, rapid/shallow respirations, headache, dyspnea, hyperkalemia, dysrhythmias, confusion.

ABG findings in respiratory acidosis

pH decreases; PaCO2 increases.

Management of respiratory acidosis

Maintain airway patency; treat underlying cause; bronchodilators; antidotes if overdose.

Causes of respiratory alkalosis

Hyperventilation (anxiety, pain, fever, PE, fear).

Causes of metabolic alkalosis

Vomiting, excessive gastric suctioning, diuretics, excessive NaHCO3, antacid overuse, potassium wasting (hypokalemia).

Signs of metabolic alkalosis

Restlessness, lethargy, dysrhythmias, compensatory hypoventilation, confusion, numbness/tingling, N/V, tremors, cramps, hypokalemia.

Assessment and treatment of metabolic alkalosis

pH > 7.45 and HCO3- > 26 mEq/L; restore fluid volume; monitor ABGs.

Signs of respiratory alkalosis

Hyperventilation; tachycardia; numbness/tingling around mouth; hyperreflexia; seizures.

ABG changes in respiratory alkalosis

pH increased; PaCO2 decreased; HCO3- decreased or near normal.

How is respiratory alkalosis managed?

Breathe into a paper bag to rebreathe CO2; provide oxygen if hypoxic; monitor ABGs.

How to assess ABGs: Step 1

Check pH to determine acidosis, normal, or alkalosis.

How to assess ABGs: Step 2

Determine primary cause: if acidosis with CO2 > 40 mmHg = respiratory; if acidosis with HCO3- < 24 = metabolic; if alkalosis with CO2 < 40 = respiratory; if alkalosis with HCO3- > 24 = metabolic.

Which electrolyte is most critical to healthy cardiac rhythm?

Potassium (K+).