Acid Base Balance Flashcards
Normal range of adult arterial blood is
7.35-7.45
pH less than 7.35
Acidosis
pH greater than 7.45
Alkalosis
What are buffers?
Pairs of chemicals that work together to maintain normal pH
Major buffer in ECF
Bicarbonate (HCO3)
Bicarbonate buffers
Metabolic acid
Ratio of bicarbonate acid to carbonic acid
20:1
What are the body’s two acid excretion systems?
Lungs and Kidneys
The lungs regulate
CO2 (excrete carbonic acid)
The kidneys regulate
Bicarbonate (HCO3)
What is PaCO2
The level of CO2 in the blood
Increase in PaCo2 triggers
Deeper and faster respirations
Decrease in PaCo2 triggers
Slow shallow respirations
Kidneys compensate for
Respiratory acid base imablances
Lungs compensate for
Metabolic acid base imbalances
Acidosis is a condition in which
Blood is too acidic
Alkalosis is a condition in which
Blood is too basic
What is metabolic acidosis
When there is a decrease in bicarbonate. The kidneys are unable to excrete metabolic acids. pH falls.
S/S of metabolic acidosis
HA light headedness Confusion/drowsiness Abdominal pain Increased respirations pH less than 7.35
Causes of metabolic acidosis
Diarrhea
Uremia
Ketoacidosis (diabetes, starvation, alcoholism)
What are the three D’s of metabolic acidosis
Diabetic ketoacidosis
Diarrhea
Dialysis
What is metabolic alkalosis
Increase of a base (HCO3) or decrease of metabolic acids
Causes of metabolic alkalosis
Vomiting Gastric suction Massive blood transfusion Excess aldosterone Ingestion of HCO3 (antacids)
S/S of metabolic alkalosis
Light headedness Numbness and tingling of fingers Confusion Dizziness Decreased respirations
What is respiratory acidosis
Rises from alveolar hypoventilation. Lungs are unable to excrete enough CO2, PaCo2 rises and causes an excess of carbonic acid
How do the kidneys compensate for respiratory acidosis
They increase excretion of metabolic acids in urine, which increases blood bicarbonate. This often takes 24hrs to show clinical effect and 3-5 days to reach a steady state.
Decreased CSF pH and intracellular pH of brain cells cause
Decreased level of consciousness
S/S of respiratory acidosis
HA Lightheadedness Confusion/lethargy Warm and flushed skin Increased repirations/pulse/BP
Causes of respiratory acidosis
Inadequate ventilation Pulmonary edema Aspiration Sleep apnea Pneumonia Respiratory failure
What is respiratory alkalosis
Rises from alveolar hyperventilation. The lungs excrete too much carbonic acid. PaCo2 decreases, pH rises.
If the pH rises enough in respiratory alkalosis central nervous system
Depression occurs
S/S of respiratory alkalosis
lightheadedness
Inability to concentrate
Tingling sensations
Excitement
Causes of respiratory alkalosis
Hyperventilation Anxiety Hypoxemia Acute pain Inappropriate ventilator settings
Normal value for anion gap
5-11mEq/L
Normal value for PaCo2
35-45
Normal value for HCO3
22-26
Normal value for PaO2
80-100
Normal value for O2 sat
97% or >
If CO2 follows pH
Respiratory problem
If HCO3 follows pH
Metabolic
CO2 below 35 is
alkalotic
CO2 greater than 45
acidic
When bicarbonate is normal
Uncompensated
