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.
*increases sodium reabsorption = raised blood sodium levels
*promotes potassium secretion = 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
- Bounding pulse, hypertension, weight gain, pitting oedema
What can cause respiratory acidosis?
This is hypoventilation (can’t breathe out CO2)
Causes:
* COPD with CO2 trapping
* Meds that cause sedation and decreased RR
* Brain injury
* lung diseases
* Rib fractures
* paralysis of anything respiratory
Signs/Symptoms:
* Headache
* Blurred vision
* Twitch/tremor
* Convulsion/Coma
What can cause respiratory alkalosis?
This is hyperventilation (too much breathing out)
Causes:
* Hypoxia
* Pain
* Anxiety
* Responding to high metabolic rates (fever, sepsis)
* Excessive mechanical ventilation
Signs/Symptoms:
* Dizzy
* Tingling
* Confusion
* Convulsion/Coma
What can cause metabolic acidosis?
In the body/kidney system - potentially kidneys can’t rid body of acid
Causes:
* Diabetic Ketoacidosis (DKA) - BSL over 15 check ketones
* Renal Failure
* Lactic acid production
* Severe diarrhoea - lose bicarbonate
Signs/Symptoms:
* Kussmaul respirations - fast, deep breathing
* Nausea/vomiting
* Arrhythmia/hypotension
NB: Often occur with hypokalaemia (similar symptoms)
What can cause metabolic alkalosis?
In the body/kidney system
Causes:
* Severe vomiting – loss of HCI from stomach
* loop diuretics – make the kidneys
get rid of acid
* “Hyper”aldosteronism – causes kidneys to reabsorb Na+ but lose
both H+ and K+
Signs/Symptoms:
* Hyperactive reflexes
* Cramps/Tetany
* Atrial Tachy
* Convulsions
NB: causes hypocalcemia (low calcuim) = same symptoms
What are some causes of Hypernatermia (sodium above 145mmol/L)?
Losing more water than sodium:
* Dehydration/decreased thirst
* 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 (ICF to ECF)
- Moves potassium ions (K+) into cells (ECF to ICF)
- Maintains cell volume and resting membrance potential
- essential for nerve impulse transmission and muscle contraction
What is 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 from kidneys
- Renin converts angiotensinogen to angiotensin I
- ACE converts angiotensin I to angiotensin II
- Effects A: Vasoconstriction to increase BP
- Effects B: Aldosterone keeps sodium and water (salt sucks) & excretes potassium.
