Acid-Base Balance
Values for normal HCO3 levels
22-26
Values for normal CO2 levels
45-35
Values for normal blood pH
7.35 to 7.45
What are the causes of acute respiratory acidosis?
Acute respiratory condition (pneumonia, asthma attack, pulm. edema), sedative overdose, airway obstruction, and chest trauma.
What components make up the chemical buffers? (4)
Bicarb, phosphate buffer system, protein buffer system, and the Hgb/Oxyhemoglobin buffer system
What are the causes of chronic respiratory acidosis?
COPD, cystic fibrosis, MS, stroke
What are the causes of metabolic alkalosis?
Loss of fluid through vomiting or gastric suction, Potassium-Wasting diuretics, and overuse of antacids and steroids
Interpret: pH- 7.36 CO2- 35 mmHg HCO3- 20 mEq/L
Metabolic acidosis
Interpret: pH- 7.28 CO2- 56 mmHg HCO3- 25 mEq/L
Respiratory acidosis
What are the causes of metabolic acidosis?
DKA, Diarrhea, Hyperkalemia, Shock, Sepsis, Renal Failure, Aspirin OD
Interpret: pH- 7.48 CO2- 33 mmHg HCO3- 24 mEq/L
Respiratory alkalosis
The arterial blood gases of a client with chronic obstructive pulmonary disease (COPD) deteriorate, and respiratory failure is impending. For which clinical indicator should the nurse assess first?
confusion
The nurse plans interventions for a client with smoke inhalation based on a negative chest x-ray and arterial blood gases that show a Po2 of 85 mm Hg, a PCO2 of 45 mm Hg, and a pH of 7.35. Which interventions should the nurse anticipate will be prescribed? Select all that apply
coughing, deep breathing, humidified O2
What three things maintain Acid-Base balance?
Chemical buffers, the lungs, and the kidneys
When assessing a client's arterial blood gases the nurse identifies that the client is in *compensated* respiratory acidosis when the pH value is 7.34 and the
HCO3 is over 26
What are the clinical manifestations of metabolic acidosis?
Headache, confusion, drowsiness, a decreased BP, an increase in respirations, and cardiac dysrhythmia.
What are the causes of respiratory alkalosis?
Hyperventilation from an anxiety attack, initial stages of a pulmonary embolism, hypoxia, fever, high altitudes, and pregnancy.
What are the clinical manifestations of respiratory alkalosis?
Inability to concentrate, lightheadedness, numbness and tingling.
Interpret: pH- 7.5 CO2- 35 mmHg HCO3- 27 mEq/L
Metabolic alkalosis
What are the clinical manifestations of acute respiratory acidosis?
Increased pulse, BP, and respirations, change in mental status
A client who sustained a closed head injury is being monitored for increased intracranial pressure. Arterial blood gases are obtained and the results include a Pco2 of 33 mm Hg. It is most important for the nurse to
Inform doctor of results and monitor for signs of increasing ICP
Scenario: Patient presents with headache and confusion, decreased BP and increased respirations. They have had diarrhea for several days and are a Type 1 diabetic.
Metabolic Acidosis
Scenario: Patient presents with muscle weakness and cramps after having persistent vomiting for several days. They have a rapid HR and a very low respiration rate.
Metabolic alkalosis
What are the clinical manifestations of chronic respiratory acidosis?
a feeling of fullness in the head; increased ICP
The laboratory data for a client with prolonged vomiting reveal arterial blood gases of pH 7.51, Pco2 of 50 mm Hg, HCO3of 58 mEq/L, and a serum potassium level of 3.8 mEq/L. The nurse concludes that the findings support what diagnosis?
Metabolic alkalosis
Explain the pathophysiology of metabolic acidosis.
Patient is either losing bicarb through diarrhea/diuretics, or accumulating too much fixed acid from DKA or aspirin OD.
Explain the pathophysiology of respiratory alkalosis.
Patient is hyper ventilating, blowing off CO2 which causes Hgb in blood to bind tighter to oxygen, decreasing perfusion in vital organs.
Explain the pathophysiology of respiratory acidosis.
Patient is hypoventilating and not getting rid of CO2 fast enough. Hgb is throwing off oxygen which increased perfusion to vital organs.
Explain the pathophysiology of metabolic alkalosis.
Patient loses acidic stomach content which makes blood more alkaline or they are taking too many antacids. The more alkaline the blood, the more bicarb that accumulates.
Scenario: Patient presents with an increase in pulse rate, BP and respiration rate after an apparent asthma attack.
Respiratory acidosis (acute)
Scenario: Patient presents with the complaint of feeling "fullness in the head". They suffer from emphysema and have stroke in their health history.
Respiratory acidosis (chronic)
Scenario: A pregnant patient presents with lightheadedness and numbness/tingling in her extremities. She is also having trouble concentrating.
Respiratory alkalosis
What are the clinical manifestations of metabolic alkalosis?
Respiratory depression, fast HR, muscle weakness and cramps, change in CNS, and cardiac dysrhythmia.
The nurse is caring for a client whose arterial blood gases (ABGs) values are: Po2 89 mm Hg, Pco2 35 mm Hg, and pH of 7.37. These findings indicate that the client is experiencing
acid-base balance
A client who experienced smoke inhalation has a negative chest x-ray and arterial blood gases that demonstrate PaO2 of 70 mm Hg, PaCO2 of 45 mm Hg, and pH of 7.35. What intervention should the nurse anticipate will be prescribed by the health care provider?
breathing exercises
After a gastrectomy, a client has a nasogastric tube to low continuous suction. The client begins to hyperventilate. The nurse anticipates that this breathing pattern will alter the client's arterial blood gases by:
decreasing to Co2 level
A client who has acquired human immunodeficiency syndrome (HIV) develops bacterial pneumonia. On admission to the emergency department, the client's PaO2 is 80 mm Hg. When the arterial blood gases are drawn again, the level is determined to be 65 mm Hg. What should the nurse do first?
increase the O2 flow rate
A 5-year-old child is admitted to the pediatric intensive care unit with a diagnosis of acute asthma. A blood sample is obtained to measure the child's arterial blood gases. What finding does the nurse expect?
increased CO2 level
A specimen for arterial blood gases is obtained from a severely dehydrated 3-month-old infant with a history of diarrhea. The pH is 7.30, Pco2 is 35 mm Hg, and HCO3- is 17 mEq/L. What complication does the nurse conclude has developed
metabolic acidosis
