Acid-base: Metabolic Acidosis Flashcards
Describe what metabolic acidosis is
- characterized by low pH
- low bicarbonate
- may be caused by: excess of acid in the body or a loss of bicarbonate from the body
- respiratory system attempts to return pH to normal
What are the four basic mechanisms that may cause metabolic acidosis?
- accumulation of metabolic acids
- excess loss of bicarbonate
- increase in chloride levels
- fluid imbalance (impaired renal elimination, high anion gap acidosis)
What can cause an excess of metabolic acids?
- excess acid production
- impaired renal elimination of metabolic acids
- toxic substances may break down into acid products or stimulate metabolic acid production
- increase H+ concentration of body fluids
- Buffering by bicarbonate causes high anion gap acidosis
What can cause an excessive loss of bicarbonate?
- intestinal suction
- severe diarrhea
- Ileostomy drainage
- fistulas
How does metabolic acidosis affect the body?
- Depresses cell membrane excitability
- Increases free calcium in extracellular fluid
- depresses myocardial contractility= decreased Cardiac output
- If kidney function is normal= acid excretion and ammonia production increases
How does metabolic acidosis affect electrolyte balances?
- potassium is retained (hyperkalemia)
- calcium gets released from plasma proteins
- magnesium levels may fall
What can cause metabolic acidosis?
Metabolic acidosis usually develops during the course of another disease (tissue hypoxia from shock or cardiac arrest, T1DM, acute or chronic renal failure, diarrhea, intestinal suction, abdominal fistulas, ingestion of acidic substances, or one that can be metabolized to acid)
What are the risk factors for metabolic acidosis?
- DKA
- renal failure
- severe sepsis
- Salicylate intoxication
- Severe diarrhea
- Eating disorders involving laxative abuse, severe diet restriction
What are the clinical manifestations of metabolic acidosis?
- general manifestations: weakness, fatigue, headache, malaise
- GI manifestations
- neurologic manifestation
- cardiac manifestations
- Integumentary manifestations
- skeletal manifestations
- kussmaul respirations
What pharmacologic agent is typically used for metabolic acidosis?
alkalinizing solution
When is an alkalinizing solution used?
- if the pH is <7.1
- Given IV for severe acute acidosis
- oral route for chronic acidosis
- sodium bicarbonate is the most common type
- lactate, citrate, acetate solutions were also used
Why are infants and children more likely to develop metabolic acidosis?
- diarrhea
2. congenital or acquired renal tubular acidosis= large loss of bicarbonate with or without potassium depletion
What are some interventions to monitor the potential for excess fluid volume?
- monitor and maintain fluid replacement as ordered
- monitor serum sodium levels and osmolality
- monitor heart and lung sounds
- Monitor central venous pressure
- Monitor respiratory status
- Assess for edema
- Assess urine output hourly
- Maintain accurate intake and output record
- obtain daily weights, using consistent conditions
- administer prescribed diuretics
What are some interventions to reduce the risk for injury?
- monitor for neurologic function
- institute safety precautions
- orient to time, place, and circumstances as needed
- Keep familiar objects nearby, and allow significant others to stay with patient
How can a nurse help a patient plan for discharge?
- focus on the underlying cause of imbalance
- interventions and teaching to prevent further episodes of acidosis (DM, starvation, alcoholism, renal failure, diarrhea, ileostomy drainage
