Acid-base Balance3 Flashcards
Acid-base Imbalance
mention two classifications of acid-base disturbances
- Metabolic acidosis/alkalosis
- Respiratory acidosis/alkalosis
What is metabolic acidosis readily detected by a decrease in what?
By a decrease in plasma bicarbonate levels.
What causes decrease in plasma bicarbonate
- production of organic acids that exceeds the rate of elimination
- Reduced excretion of acids (H+) as occurs in renal failure
- Excessive loss of bicarbonate due to increased renal excretion
What primarily causes metabolic acidosis?
- Production of organic acids (such as in ketoacidosis) that exceeds the rate of elimination.
- Reduced excretion of acids (H⁺), which occurs in conditions like renal failure and some renal tubular acidosis (RTAs).
- Excessive loss of bicarbonate, either due to increased renal excretion or excessive loss from the duodenum.
What does ketoacidosis refer to?
Ketoacidosis refers to the production of organic acids (such as ketone bodies) that exceeds the rate at which they are eliminated.
How does reduced excretion of acids lead to metabolic acidosis?
Reduced excretion of acids (H⁺) in conditions like renal failure and RTAs results in an accumulation of acid that consumes bicarbonate, leading to metabolic acidosis.
What can cause an excessive loss of bicarbonate
- Increased renal excretion
2.Excessive loss from the duodenum (part of the small intestine).
What physiological response is stimulated by the resulting drop in pH due to metabolic acidosis?
Stimulates respiratory compensation via hyperventilation. This process lowers the partial pressure of carbon dioxide (PCO₂) and raises the pH.
How can metabolic acidosis be categorized?
- Increased anion gap acidosis (organic acidosis)
- Normal anion gap acidosis (inorganic acidosis)
What are some causes of increased anion gap metabolic acidosis?
- Methanol poisoning
- Uremia of renal failure
- Ketoacidosis
- Paraldehyde toxicity
- Lactic acidosis
- Salicylate intoxication
what causes normal anion gap metabolic acidosis
It is caused by the loss of bicarbonate rich fluid from the kidney or GIT
what happens when bicarbonate is lost
More cl- ions are absorbed with Na + or k+
normal acid gap acidosis can be divided into 2. namely?
- Hypokalemic normokalemic
- Hyperkalemic acidoses
What causes normal anion gap metabolic acidosis
Normal anion gap metabolic acidosis is caused by the loss of bicarbonate-rich fluid from the kidney or the gastrointestinal tract.
How can normal anion gap acidosis be divided
Normal anion gap acidosis can be divided into hypokalemic, normokalemic, and hyperkalemic acidoses.
What happens as bicarbonate is lost
As bicarbonate is lost, more chloride ions (Cl⁻) are reabsorbed along with sodium (Na⁺) or potassium (K⁺) ions
What is the average Anion gap value in healthy individuals?
In healthy individuals, the average Anion gap value is 12 mmol/L.
when does metabolic alkalosis occur (3)
- when excess base is added into the system
- When base elimination is decreased
- When acid rich fluids are lost
What occurs during metabolic alkalosis
Metabolic alkalosis occurs when there is an excess base added to the system, base elimination is decreased, or acid-rich fluids are lost.
What can lead to a primary bicarbonate excess?
Conditions such as excess base addition, decreased base elimination, or loss of acid-rich fluids can lead to a primary bicarbonate excess.
What will a patient do in response to metabolic alkalosis?
In response to metabolic alkalosis, the patient will hyperventilate to raise PCO2 (partial pressure of carbon dioxide), thereby lowering the pH toward normal.
What is Respiratory acidosis?
Respiratory acidosis is a condition that results from an increase in carbon dioxide (CO2) through the lungs, leading to an elevated level of CO2 in the blood.
How does Respiratory acidosis occur?
It occurs due to lung conditions that cause an accumulation of carbon dioxide. These conditions can be either acute or chronic
How can conditions leading to Respiratory acidosis be classified?
- acute
- chronic.
What are some ways that these conditions affect the body?
These conditions can depress the respiratory center, affect the respiratory apparatus, or cause mechanical obstruction of the airway.
what are the factors that directly depress the respiratory centre
- Drugs e.g narcotics ad barbiturates
- Infections of the CNS e.g encephalitis and meningitis
- Comatose states such as cerebralvascular accident due to intracranial hemorrhage and primary central hypoventilation
Conditions that Affect the Respiratory Apparatus (“Factors that Impact the Respiratory System)
- Chronic obstructive pulmonary disease (most common cause), Severe pulmonary fibrosis
- Disease of the upper airways such as laryngospasm or tumor, Pulmonary infection (severe)
- Pneumothorax, Adult respiratory distress syndrome, Chest wall disease and chest wall deformity
- Neurologic disorders affecting the muscles of respiration
What are the two conditions listed under pulmonary disorders that involve the lungs’ air sacs
Pneumonia and Interstitial lung disease
What condition is characterized by a PCO2 level less than 50 mm Hg?
Large right-to-left atrial shunt.
Which disorder is associated with the body’s response to correct an imbalance in blood pH?
Respiratory compensation after correction of metabolic acidosis
Mention 5 non-pulmonary stimulation of respiratory center
- Anxiety, hysteria, Febrile state
- Gram-negative septicemia
- Metabolic encephalopathy (e.g., due to liver disease)
- Central nervous system infection such as meningitis,
Encephalitis, Cerebrovascular accident
5.Intracranial surgery, Hypoxia - Drugs and agents such as salicylates, catecholamines, and
- Progesterone, Hyperthyroidism
Pregnancy, mainly third trimester (↑ progesterone?)
