Acid Base Imbalances Flashcards
normal blood pH
7.35-7.45
normal PCO2
35-45 mm Hg
normal PO2
90-100 mm Hg
normal HCO3-
22-26 mEq/L
normal SaO2
95-100%
What are the 3 major buffer systems?
phosphate, protein, and carbonic acid-bicarbonate buffering
phosphate buffer system
- occurs in strictly ICF
- regulates intracellular pH
protein buffer system
- occurs inside and cell and bloodstream
- albumin maintains acidity in and around cell
- need healthy RBCs
carbonic acid-bicarbonate buffering
- occurs only in bloodstream
- how much acid is in blood vs how much bicarb
too much bicarb =
kidneys not working well and bicarb goes up
too much CO2 =
the body tries to get rid of it (compensation)
too little CO2 =
body tries to hold onto it
respiratory compensation
- lungs compensate by adjusting ventilation to alter CO2 levels
- ventilation, CO2 and pH are related
if pH is too acidic (acidosis) what will happen during compensation
ventilation will increase
if pH is too basic (alkalosis) what will happen during compensation
ventilation will decrease
renal compensation
adjust amount of HCO3- (bicarb) and H+ excreted and retained
if pH is too acidic what will happen during renal compensation
- retain bicarb
- excrete H+
if pH is too basic what will happen during renal compensation
- excrete bicarb
- retain H+
respiratory acidosis
- pH less than 7.35
- PCO2 greater than 45 mm Hg
- hypoventilation
- often due to pulmonary or airway obstruction
how does respiratory acidosis present
- anxiety
- restlessness
- headache
- lethargy
- fatigue
- SOB
- rapid breathing
- cough
- advanced respiratory acidosis may lead to confusion, possible coma
compensation for respiratory acidosis
kidney reabsorb bicarb and excrete H+
treatment for respiratory acidosis
- improve ventilation
- administer oxygen
respiratory alkalosis
- pH greater than 7.45
- PCO2 less than 35 mmHg
- hyperventilation
- often due to anxiety
- hypocalcemia nd hypokalemia may develop
how does respiratory alkalosis present
- tingling of extremities
- tetany
- dizziness
- if patient is hypoxic, cyanosis may be present
compensation for respiratory alkalosis
kidney reabsorb H+, excrete bicarb
treatment for respiratory alkalosis
- slow respiration
- breathing into paper bag
metabolic acidosis
- pH less than 7.35
- normal to low CO2
- HCO3- less than 22mEq/L
- hyperkalemia and hypercalcemia may develop
causes of metabolic acidosis
- excess acid: ex. diabetic ketoacidosis
- bicarb loss: ex. GI disorders
how does metabolic acidosis present
- increased respirations
- tachycardia
- hypotension
- confusion
compensation for metabolic acidosis
- lungs: increase ventilation
- Kidneys: excrete H+, reabsorb HCO3-
treatment for metabolic acidosis
correct underlying cause
metabolic alkalosis
- pH greater than 7.45
- normal or high CO2
- HCO3- greater than 26 mEq/L
- hypocalcemia and hypokalemia may develop
causes of metabolic alkalosis
- excessive loss of acids, unrelated to CO2
- kidneys and GI tract loss
- increase in bicarb levels
how does metabolic alkalosis present
- confusion
- dizziness
- weakness
compensation for metabolic alkalosis
- lungs: decrease ventilation to increase CO2
- kidneys: excrete HCO3- and retain H+
treatment for metabolic alkalosis
electrolyte and fluid replacement
how does acidosis affect pH and potassium
H+ shifts into cells and K+ shifts out of cells leading to hyperkalemia
how does alkalosis affect pH and potassium
K+ ions shift into the cells from plasma leading to hypokalemia
how does hyperkalemia affect pH and potassium
H+ shifts out of cells leading to acidosis
how does hypokalemia affect pH and potassium
H+ shifts into cells leading to alkalosis
how does acidosis affect pH and calcium
- increased free Ca++ (fewer binding sites on albumin for Ca++ due to H+ binding
- hypercalcemia
