Acidosis

Definition

Acidosis is an arterial blood pH below 7.35 caused by either excess acid accumulation or loss of bicarbonate base. It is classified as respiratory (elevated PaCO2) or metabolic (decreased HCO3-), each with distinct etiologies and compensatory mechanisms.

Types and Causes

• Respiratory Acidosis (↑ CO2): COPD, opioid overdose, neuromuscular disease, hypoventilation.
• Metabolic Acidosis (↓ HCO3-): Diabetic ketoacidosis, renal failure, lactic acidosis, severe diarrhea.

Signs and Symptoms

Headache, confusion, lethargy progressing to coma; Kussmaul respirations (deep, rapid breathing) in metabolic acidosis; hyperkalemia as hydrogen ions displace potassium from cells; cardiac arrhythmias.

Nursing Considerations

Identify and treat the underlying cause, such as for respiratory acidosis, improve ventilation (bronchodilators, non-invasive ventilation, intubation). For metabolic acidosis, consider insulin/fluids for DKA, dialysis for renal failure, or sodium bicarbonate for severe pH less than 7.1, with close serum potassium monitoring. Correcting acidosis drives potassium back into cells and can precipitate hypokalemia.

NCLEX Relevance

High-yield for the Physiological Adaptation domain. Practice ROME (Respiratory Opposite, Metabolic Equal) for rapid ABG interpretation.