Week 8a: acid base balance Flashcards
normal pH
7.35-7.45
normal PaO2
80-100mmHg
normal PaCO2
35-45
HCO3
21-25mmol/L
Normal base excess
-2 - +2
high anion gap =
acidosis
base excess more than +2 =
metabolic alkalosis
base excess less than -2 =
metabolic acidosis
normal anion gap
8-16mmol/L
signs and symptoms of metabolic acidosis
- increased respiratory rate and depth
- acidic urine
- weakness, fatigue, nausea and vomiting
- later signs: decreased LOC, decreased CO, coma and death
for treatment of metabolic acidosis, why is sodium bicarbonate not always indicated?
it can cause hyperosmolarity and hypoxia
what is the primary disturbance in metabolic acidosis?
decrease in bicarbonate, DKA, sepsis, severe diarrhea, renal failure, shock
respiratory compensation in metabolic acidosis?
hyperventilation to decreased PCO2
renal compensation in metabolic acidosis?
if no renal disease, then increased H+ excretion and increased HCO3 reabsorption
what is the primary disturbance in metabolic alkalosis?
decrease in bicarbonate
respiratory compensation in metabolic alkalosis?
hypoventilation to increase PCO2
renal compensation in metabolic alkalosis?
if no renal disease, decrease in H+ excretion and decrease in HCO3 reabsorption
what are the causes of metabolic alkalosis?
alkaline ingestion, gastric suction, hypokalemia, loss of body fluids (diuretics), high lactate (ringers lactate)
signs and symptoms of metabolic alkalosis?
decreased respirations, hypotension, alkaline urine, confusion, convulsions, arrhythmias, tetany
what is one of the main treatments for metabolic alkalosis?
sodium chloride (mild) or ammonium chloride (severe)
what is the primary disturbance in respiratory acidosis ?
increase in PCO2
is there respiratory compensation in respiratory acidosis?
no
renal compensation in respiratory acidosis
increased H+ excretion and increased HCO3 reabsorption
causes of respiratory acidosis?
lung disease (COPD, pulmonary edema), hypoventilation in hospitalized ventilated patients, bradypnea (drug overdose), sepsis, trauma (burns and head injury)
signs and symptoms of respiratory acidosis?
changes in LOC, headache (due to vasodilation), confusion/paranoia/hallucinations (due to hypoxia), flushed skin (vasodilation)
primary disturbance in respiratory alkalosis?
decrease in PCO2
is there respiratory compensation in respiratory alkalosis?
no
renal compensation in respiratory alkalosis
decreased H+ excretion and decreased HCO3 reabsorption
causes of respiratory alkalosis?
hyperventilation due to increased mechanical ventilation, panic/anxiety, fever, encephalitis, compensation due to hypoxia and drug toxicity (ASA)
a urine output of _____ may indicate hypovolemia
0.5mg/kg/h
what are some signs of hypervolemia?
hypertension, bounding pulse, pulmonary crackles, dyspnea, SOB, peripheral edema, JVD and extra heart sounds such as S3
which IV solution is the fluid of choice for resuscitation efforts?
normal saline
which IV solution is used to replace fluid loss from hemorrhage, severe vomiting or diarrhea, heavy drainage from GI suctioning, fistulas or wounds?
normal saline
which IV solution is the fluid of choice for resuscitation of burn and trauma patients?
ringers lactate
Which IV solution is used to treat acute blood loss or hypovolemia due to 3rd space fluid shift; GI loss and fistula drainage, electrolyte loss and metabolic acidosis ?
ringers lactate
which IV solution is both isotonic and hypotonic?
D5W
which IV solution provides free water for the kidneys, aiding in renal excretion of solutes and may be used to treat hypernatremia
D5W
which type of solutions are typically used to treat conditions causing intracellular dehydration such as DKA and hyperosmolar hyperglycaemic states
hypotonic
what type of solutions may worsen existing hypovolemia and hypotension causing cardiovascular collapse?
hypotonic
which type of solutions may be used to correct critical electrolyte abnormalities?
hypertonic
which type of solutions may cause fluid volume overload and pulmonary edema
hypertonic
which type of solutions should be avoided in patients with cardiac or renal conditions who are dehydrated and in patients with DKA?
hypertonic
