Flashcards in Biochemistry Deck (67):
Where is most of [H+] in our body excreted?
Is urine acidic or alkaline?
Is buffering of H+ a temporary measure?
Give the bicarbonate equation.
[H+] + HCO3 = H2CO3 = CO2 + H2O
What is carbonic acid (H2CO3) removed as?
What is the equation which underpins all acid-base stuff?
[H+] (alpha sign) (pCO2/[HCO3])
What is the solution for too much H+ or too much CO2?
When you've got too much H+, what occurs as compensation?
Lungs blow off CO2
When you've got too much CO2, what occurs as compensation?
The kidneys get rid of [H+]
What is acidaemia?
What is alkalaemia?
What does acidosis tend to cause?
What does alkalosis tend to cause?
What is the respiratory component?
What is the metabolic component?
What is an increase in [H+], due to increase pCO2?
What is a decrease in [H+], due to decreased pCO2?
What is increased [H+], due to decreased HCO3?
What is decreased [H+], due to increased HCO3?
What is the respiratory compensation for metabolic acidosis?
Blow off CO2
What is the metabolic compensation for respiratory acidosis?
Excrete more H+
What is the compensatory response for increased pCO2 (respiratory acidosis)?
What is the compensatory response for decreased pCO2 (Respiratory alkalosis)?
What is the compensatory response for decreased HCO3 (metabolic acidosis)?
What is the compensatory response for increased HCO3 (metabolic alkalosis)?
What are the 4 arterial blood gases?
Give three causes of respiratory acidosis?
Give three causes for respiratory alkalosis?
Raised intracranial pressure
Give three causes of metabolic acidosis?
Imparied [H+] excretion
Increased [H+] production or ingestion
Loss of HCO3
Give three causes of metabolic alkalosis?
Loss of [H+] in vomit
What is the normal range of pH?
7.35 - 7.45
What must PaO2 always be interpreted against?
The inspired O2
What is PaO2?
the partial pressure of oxygen in arterial blood
What is the normal range breathing air of PaO2?
9.3 - 13.3 kPa
What is the normal range for PaCO2?
4.7 - 6 kPa
The body tries to compensate for a metabolic alkalosis by raising PaCO2, what does the body do physically?
The body will try to compensate for a metabolic acidosis by lowering PaCO2, what does the body do physically?
What is the normal range of base excess?
-2 to +2 mmol/l
What is base escess?
The measure of how much base has to be removed or added to the system to correct the pH in standard conditions. It is a measure of metabolic acidosis or alkalosis.
What does a negative BE indicate?
What does a positive BE indicate?
What does the kidney do to compensate for respiratory acidosis?
Creates a metabolic alkalosis by retaining bicarbonate
What does the kidney do to compensate for respiratory alkalosis?
Creates a metabolic acidosis by excreting bicarbonate
What does hypercapnic mean?
What is polydipsia?
If the patient has metabolic acidosis, and the pCO2 is normal, what does this indicate?
No respiratory compensation
What is hypoxia?
Lack of oxygen
What is hypoxaemia?
Low oxygen levels within the blood (pO2 and SaO2 combined)
Give four causes of tissue hypoxia
1. Anaemic hypoxia
2. Perfusional hypoxia
3. Toxic hypoxia
4. Hypoxaemic hypoxia
What causes anaemic hypoxia?
Lack of Hb
What causes perfusional hypoxia?
What causes toxic hypoxia?
Failure of release of O2 at tissue level
What causes hypoxaemic hypoxia?
Low pO2 and SaO2 - respiratory insufficiency
Name 4 buffers
Can overcompensation occur?
Name three causes of respiratory acidosis with metabolic compensation
Chronic type 2 respiratory failure: COPD, DF, kyphoscoliosis
Name 3 causes of metabolic alkalosis with respiratory compensation?
Milk alkali syndrome
Give 5 causes of metabolic acidosis with respiratory compensation?
What are general causes of respiratory alkalosis with metabolic compensation?
Chronic hyper-ventilatory states
What are 9 causes of high anion gap? (AMUDPILES)
A - alcohol (alcohol dissociates to become a weak acid)
M - methanol (causes blindness)
U - uraemia (failure to reabsorb HCO3 and excrete H+
D - DKA (ketones are dehydrogenated alcohols, and dissociate to acid)
P - paraquat (very nasty poison, universally lethal
I - infection (commonest, localised tissue hypoxia leads to...)
L - lactic acid (product of anaerobic respiration, and tissue necrosis)
E - erythlene gylcol (antifreeze)
S - salicylates (aspirin causes respiratory alkalosis, then metabolic acidosis
What can these 5 things occur as a result of? Addisons disease, high output fistulas, RTA I, II, IV, Acetazolamide therapy, diarrhoea?
Normal anion gap
Who were pink puffers traditionally though to be?
What to pink puffers react to hypoxaemia by doing?
Who were blue bloaters traditionally though to be?
Chronic bronchitis patients
What do blue bloaters not do?
React to hypoxia or hyperventilate