Acid Base & Electrolytes Flashcards
What is the optimum pH level for the body?
7.35-7.45
What hormone regulates both sodium (Na+) and potassium (K+) levels and what is the effect of this hormone on each of these electrolytes?
Aldosterone regulates sodium and potassium levels. It increases sodium reabsorption, raising blood sodium levels, and promotes potassium secretion, helping maintain normal blood levels of both electrolytes.
Which two body systems/structures are responsible for regulating acid-base balance?
- Respiratory (lungs)
- Renal (kidneys)
Name the 4 pH imbalances and their characteristics
- Metabolic acidosis - Excess hydrogen ions (H+) or loss of bicarbonate ions (HCO3-)
- Metabolic alkalosis - Excess bicarbonate ions (HCO3-) or loss of hydrogen ions (H+)
- Respiratory acidosis - Retention of CO2 - causes you to breathe slower and not get enough O2
- Repiratory alkalosis - excessive CO2 loss - breathing out too much
Signs and symptoms of Hypernatremia (high salt in blood)
- Increased thirst (polydipsia)
- Dry mucous membranes
- Fever
Also:
- CNS symptoms of cellular dysfunction, including: lethargy, irritability, muscle twitching/convulsions, seizures and possiblycoma
- Other: Bounding pulse, hypertension, weight gain, pitting oedema
What can cause respiratory acidosis?
- COPD with C02 trapping
- Meds that cause seadation and decreased RR
- Brain injury
- lung diseases
- Rib fractures
- paralysis of anything respiratory
What can cause respiratory alkalosis?
- Anxiety
- Responding to high metabolic rates (fever, sepsis)
- Some head injuries - Alkalosis lowers the pressure in the head, so the body may make itself alkalotic if pressure is building in the head.
- Excessive mechanical ventilation
What can cause metabolic acidosis?
- Diabetic Ketoacidosis (DKA) - BSL over 15 check ketones
- Renal Failure
- Lactic acid production
- Severe diarrhoea
What can cause metabolic alkalosis?
- Severe vomiting – loss of hydrochloric acid from the stomach
- Loop (frusemide) and thiazide diuretics – make the kidneys
get rid of acid - Hyperaldosteronism – causes kidneys to reabsorb Na+ but lose
both H+ and K+ - Overtreatment with bicarbonate as the hospital corrects
acidosis - causes hypocalcemia (low calcuim) = same symptoms
What are some causes of Hypernatermia (sodium above 145mmol/L)?
- Losing more water than sodium:
- Dehydration from fever or pneumonia due to an increased RR
- Decreased thirst in the elderly, so not drinking water
- Increased urination due to our body trying to flush out glucose with hyperglycaemia
- Diarrhoea
- Gaining more sodium than water:
- Hyperaldosteronism
- Diabetes insipidus (too little ADH)
- Being given 3% Saline or Bicarbonate IV fluids
- Kidney disease not filtering out sodium correctly
Outline the function of the sodium potassium pump
- Moves sodium ions (Na+) out of cells
- Moves potassium ions (K+) into cells
- Maintains cell volume and resting membrance potential
- essential for nerve impulse transmission and muscle contraction
Oultine the function of the RAAS
- Regulates blood pressure and fluid balance.
- Stimulates vasoconstriction and aldosterone release.
Outline the process of RAAS
Trigger: Low blood pressure or low sodium levels.
Renin Released: Kidneys release renin
Angiotensinogen to Angiotensin I: Renin converts angiotensinogen to angiotensin I
Angiotensin I to Angiotensin II: ACE converts angiotensin I to angiotensin II
Angiotensin II Effects: Vasoconstriction & releases aldosterone
Aldosterone Effects: Keeps sodium and water & flushes out potassium.
