When we breathe, we blow out CO2. You breathe slower, you retain CO2.
But our CO2 levels are also determined by how deep we breathe. You breathe at a normal rate, but your breaths are shallow, you retain CO2.
Example: A client with pneumonia may be breathing at 20 breaths/minute. But due to the pneumonia, he or she cannot breathe deep enough and blood gas reads as follows: pH 7.32 pCo2 54 HCO3- 23
pH is low and pCO2 is high Respiratory acidosis without compensation.
Compensation occurs when the body has retained CO2 over time and the kidneys have had time to normalized pH.
Example: A client with Chronic Obstructive Pulmonary Disease has a pH 7.4 pCO2 54 HCO3- 28
Notice that the pCO2 is elevated. This client is in respiratory acidosis; however, the pH is normal because over time the kidneys have compensated by getting rid of H+ acid, making the blood more alkalotic. Notice that the bicarb level is elevated.
Pco2 > 40 mm Hg
Hypoventilation
Retaining CO2
Drug Overdose
Any CNS depression
Pulmonary embolism
Pneumonia
Emphysema/COPD
Asthma
Hypoventilation w/
hypoxia
Confusion
↓ resp. rate
Dyspnea
May need to intubate
Monitor Blood Gases
Tx Cause
Eg, if drug overdose
give reversal agent
pH is normalized by the kidneys. Bicarb is increased to normalized pH.
Example Blood Gas
pH 7.40
Pco2 56
Po2 80
HCO3‾ 26
Notice that Pco2 is elevated (respiratory acidosis); however, pH is normal. Overtime, kidneys help compensate by getting rid of a excess acid H+. But this takes time. Happens in chronic retaining of CO2 such as in COPD, but in acute respiratory acidosis, client may go into respiratory arrest before any compensation can occur.
Guillian Barre clients hypoventilate due to muscle paralysis that leads to hypoventilation
No! This client has respiratory alkalosis. He or she is breathing fast. Choose the one where pH is low and pCO2 is high. pCO2 retention due to hypoventilation
Yes! Clients with guillian barre hypoventilate. They cannot take a deep breath due to muscle weakness. pH will be low and pCO2 will be high.
Notice that respiratory rate is almost normal, but respirations are shallow. What is the most likely blood gas for this client?
Yes! Due to the large secretions the clients is not breathing deep enought to blow off normal amount of CO2. The client is retaining CO2. He is in respiratory acidosis.
No! The respiratory rate is not fast enough to blow off that much CO2. A client with this pH and CO2 is either breathing fast or taking deep breaths.
