Acid Base Balance and ABG Interpretation Flashcards
what is the normal pH of the body?
7.35-7.45
what are the chemical buffers in our blood?
carbonic acid = PaCO2
bicarbonate = HCO3
what do our lungs do when there is too much CO2?
hyperventilation to exhale excess CO2
what do our lungs do when there is not enough CO2?
hypoventilation to avoid exhaling CO2
what controls the carbonic acid/respiratory buffer system?
medulla controls respiratory drive to get rid of or conserve CO2
what controls the metabolic buffer system?
kidneys excretes or reabsorbs hydrogen ions to produce appropriate amount of HCO3
what do the kidneys do when the blood is too acidic?
reabsorb H+ and form bicarbonate to increase pH (make it less acidic)
what do the kidneys do when the blood is too alkaline?
excrete bicarbonate to decrease pH (make it more acidic)
what value indicates acidosis?
pH <7.35
what value indicates alkalosis?
pH >7.45
what can cause respiratory alkalosis?
hyperventilation
signs and symptoms of respiratory alkalosis
seizures
deep rapid breathing, hyperventilation
tachycardia
low or normal BP
hypokalemia
numbness and tingling of extremities
lethargy, confusion, light headedness
N/V
treating respiratory alkalosis
treat underlying cause of hyperventilation
EKG
electrolyte imbalances (hypokalemia)
anxiolytics and sedatives
rebreathe CO2 - paper bag
what can cause metabolic alkalosis?
loss of gastric juices
potassium wasting diuretics cause loss of H+
overuse of antacids
signs and symptoms of metabolic alkalosis
restlessness and lethargy
tachycardia
compensatory hypoventilation
confusioon
N/V/D
tremors and cramps
tingling fingers and toes
hypokalemia
treating metabolic alkalosis
EKG
IV fluids
treat electrolyte imbalances
potassium supplementation
what can cause respiratory acidosis?
things that decrease ventilation:
drug overdose
airway obstruction
chest trauma
neuromuscular disease
pulmonary edema
signs and symptoms of respiratory acidosis
hypoventilation and hypoxia
rapid shallow respirations
decreased BP
headache
dysrhythmias and weakness r/t hyperkalemia
drowsy, dizzy, disoriented
treating respiratory acidosis
pulmonary toileting
vital signs
EKG
semi-fowlers
bronchodilators
treat electrolyte imbalances - hyperkalemia
supplemental O2 - caution with COPD
mechanical ventilation in ICU if needed
what can cause metabolic acidosis?
DKA
sepsis
shock
renal failure
severe diarrhea
signs and symptoms of metabolic acidosis
headache
low BP
hylerkalemia
muscle twitching
warm, flushed skin
N/V
changes in LOC
kussmaul respirations
treating metabolic acidosis
EKG
IV fluids if caused by diarrhea
treat electrolyte imbalances - hyperkalemia
dialysis
IV bicarb, insulin if caused by DKA
what electrolyte imbalance is associated with acidosis?
hyperkalemia
what electrolyte imbalance is associated with alkalosis?
hypokalemia
what treatment methods are used for all acid base imbalances?
Vital signs
EKG
treat electrolyte imbalances
monitor ABGs
what is normal PaCO2?
35-45
can use pH (7.35-7.45) to remember this value
what is normal HCO3?
22-26
what is normal PaO2 (partial pressure of oxygen dissolved in blood)
80-100
what is normal SaO2 (oxygen bound to hemoglobin)
> 94%
how are PaO2 and SaO2 related?
partial pressure of oxygen drives binding to hemoglobin
need good PaO2 to achieve good SaO2
what is the ROME mnemonic?
Respiratory = Opposite pH and CO2
increased pH and decreased CO2 = respiratory alkalosis
decreased pH and increased CO2 = respiratory acidosis
Metabolic = Equal pH and HCO3
increased pH and increased HCO3 = metabolic alkalosis
decreased pH and decreased HCO3 = metabolic acidosis
how to differentiate compensated vs uncompensated acid base imbalances
compensated - CO2 and HCO3 are both outside of reference range
uncompensated - one value is outside of reference range and one is WNL
partial compensation if both are outside of reference range but pH is still not WNL
full compensation if both are outside of reference range and pH is WNL
