Chapter 5: Fluids & Electrolytes

Hydrogen Ion Concentration (Cellular Function)

H+ concentration determines pH. Proper pH is essential for enzyme activity, protein structure, membrane integrity, electrolyte imbalance and neuromuscular function

What is the pH range indicating acidosis?

Too few, A pH less than 7.35

What are the effects of acidosis on the central nervous system?

Depressed CNS leading to confusion, lethargy, and coma.

What is hyperkalemia and how is it related to acidosis?

In acidosis, H+ shifts into cells, causing K+ to shift out, leading to elevated potassium levels.

What pH level indicates alkalosis?

Too many, A pH greater than 7.45.

What symptoms are associated with alkalosis?

Overexcitation of nerves, tingling, tetany, and seizures.

How does alkalosis affect potassium levels?

Causes hypokalemia as K+ shifts into cells while H+ shifts out.

What is the role of buffers in pH regulation?

Buffers bind excess H+ when acidity increases and release H+ when pH is too alkaline.

What is the primary extracellular buffer system?

The Bicarbonate-Carbonic Acid System (HCO3-/H2CO3).

How do protein buffers function?

Albumin and hemoglobin carry negative charges and can bind or release H+ as needed.

What is the significance of the phosphate buffer system?

It is important in the intracellular space and kidneys.

How do the lungs regulate acid-base balance?

By adjusting CO2 levels, which forms carbonic acid in the blood.

What happens to pH during increased CO2 levels?

Decreased pH, leading to acidosis.

What happens to pH during decreased CO2 levels?

Increased pH, leading to alkalosis

Acidosis pH low

Lungs increase ventilation blowing off CO2 raising pH

Alkalosis pH high

Lungs decrease ventilation retaining CO2 lowering pH

Kidneys

Metabolic Regulation, the only organ that removes acids from the body

What is the kidney's role in acid-base balance?

The kidneys excrete H+ into urine and reabsorb bicarbonate (HCO3-).

Acidosis Causes

Increased potassium levels where hydrogen ions move into the cells pushing potassium into vessels, hypoventilation.

Alkalosis Causes

High pH, low CO2, hyperventilation

What causes respiratory acidosis?

CO2 retention due to hypoventilation.

What are common causes of respiratory acidosis?

COPD, pneumonia, overdose, and airway obstruction.

What symptoms are associated with respiratory acidosis?

Shallow breathing, hypoxia, headaches, and hyperkalemia.

What is the treatment for respiratory acidosis?

Improving ventilation, oxygen therapy, bronchodilators, suctioning, possible BiAP, and treating underlying causes.

Respiratory Acidosis Compensation

Increasing H+ excretion, reabsorbing more HCO3-, takes hours to days

What causes respiratory alkalosis?

Blowing off too much CO2 due to hyperventilation.

What are the common causes of Respiratory Alkalosis?

Anxiety, Pain, Fever, Pregnancy, Early PE

What are symptoms of respiratory alkalosis?

Lightheadedness, tingling, and tachycardia.

What is the treatment for Respiratory Alkalosis?

Slow breathing, treating anxiety/pain/fever, Correct Hypoxia, Adjusting ventilator settings

What is metabolic acidosis?

A condition characterized by too much acid (H+) or too little base (HCO3-).

What are major causes of metabolic acidosis?

DKA, renal failure, diarrhea, shock, and toxins.

What symptoms are associated with metabolic acidosis?

Kussmaul respirations, warm flushed skin, and hyperkalemia.

What is the treatment for Metabolic Acidosis?

Fluids, Insulin (DKA), Dialysis (Renal Failure), Bicarb if severe, Treating cause (diarrhea, toxins, sepsis

Metabolic Acidosis Compensation

Rapid deep breathing (Kussmauls) and blowing off CO2

What is metabolic alkalosis?

A condition characterized by loss of acid (H+) or too much base (HCO3-).

What are major causes of metabolic alkalosis?

Vomiting, NG suction, diuretics, and antacids.

What are the symptoms of Metabolic Alkalosis?

Hypoventilation, Hypokalemia, Arrythmias

What is the treatment for Metabolic Alkalosis?

IV Fluids (NS), Antiemetics, stop suction & diuretics, Replace K+/Cl-, Acetazolamide in severe cases

Metabolic Alkalosis Compensation

Slow shallow breathing to retain CO2 and Increase H2CO3 which lowers pH

Clinical Approach to ABGs

1 - Check pH

2 - Check PCO2 (checking for either metabolic or respiratory)

3 - Check HCO3 or CO2 for compensation

ABG Ranges

• pH = 7.35-7.45

• PO2 > 80 mmHg

• PCO2 = 35-45 mmHg

• HCO3- = 22-26 mEq/L

• O2 Saturation = 95-100%