This article will help you better understand the sequence of breathing normally, the pathophysiology of respiratory acidosis, the causes of respiratory acidosis, the signs and symptoms we need to watch out for, and of course the interventions we need to do as nurses.
Let’s start with what happens during normal breathing. Oxygen enters the mouth or nose then it goes to the pharynx down to the larynx or throat, going to the trachea, to the bronchi (bronchi have left and right bronchioles that have alveolar sacs attached to each).
What Are Alveolar Sacs?
Alveolar sacs are small sacs where the exchange of gases happens—where carbon dioxide and oxygen diffuse across the membrane. Oxygen then gets absorbed and is released into your bloodstream and carbon dioxide (co2) is exhaled and released through your mouth or nose.
Normal Values
| Acidic | Normal | Base | |
| pH | 6 – 7.35 | 7.35 – 7.45 | 7.8 – 9 |
| PCO2 | >45 | 35 – 45 | <35 |
| HCO3 | <22 | 22 -26 | >26 |
Note:
- Discrepancies with CO2 ALWAYS indicates a RESPIRATORY issue
- Discrepancies with HCO3 ALWAYS indicates a METABOLIC issue
Causes of Respiratory Acidosis
Respiratory acidosis occurs when the lungs are unable to expel all of the CO2 the body produces. As a result, the blood and other body fluids become acidic.
In respiratory acidosis, there is only one cause and that is bradypnea which is slow breathing. The patient would be experiencing breathing less than 12 breaths per minute, where the normal breathing is 18 to 20 breaths per minute.
Contributing factors to a patient experiencing bradypnea can be summarized with the Mnemonic DEPRESS. Why did we use depression? Remember that depressed breathing can cause bradypnea because of a blockage in the airway, or anything that causes the diaphragm not to work properly as normal—then it will cause respiratory acidosis.
- D – Drugs, for example, opioids
- E – Edema, pulmonary edema which means there is extra fluid in the lungs
- P – Pneumonia which is excessive mucus
- R – Respiratory center is damaged—this is located in the brain
- E – Emboli that may block the pulmonary artery
- S – Spasms of bronchial tube mostly for asthma patients
- S – Sac elasticity of the alveolar sac is damaged
Signs and Symptoms of Respiratory Acidosis
- Respiration of fewer than 12 breaths per minute or a visible sign of bradypnea
- A low blood pressure
- Confusion, headaches, drowsiness, or any major neurological changes
Nursing Interventions for Patients With Respiratory Acidosis
- Deep breathing or breathing exercises and coughing
- For asthma patients, respiratory treatment is needed
- For pneumonia, suction
- When CO2 rises to 50 mmHg, and the respiration is distressed, endotracheal intubation is necessary
- Antibiotics for infection
- Monitor potassium level
- Administer oxygen
Knowing the pathophysiology of respiratory acidosis will help in making sure that proper care is given to the patient. It is also important for nurses to be able to correctly interpret ABG results—to determine if an acidosis or alkalosis is respiratory or metabolic in nature. Here’s the popular Tic-Tac-Toe Method in interpreting ABG results.
