acid base disorders Flashcards
acidaemia
low blood pH
alkalaemia
high blood pH
bicarbonate ions are mostly regulated by
the kidney and metabolism
CO2 is mostly regulated by
the lungs
how is pH of the blood detrrmined
why might acid build up in the blood
increased production or ingestion
body cant get rid of it
excess HCO3 loss
normal pH
7.35
compensatory response of metabolic acidosis
hyperventilation to eliminate CO2
so there are less hydrohen ions
anion gap
sodium - (chloride + bicarbonate)
normall 3-11
high anion gap metabolic acidosis
anion gap > 12
bicarbonate ions decrease due to bonding with extra H ions
hydrogen ions may be from increased organism acid production eg. lactic acid or diabetic ketoacidosis in uncontrolled diabetes
or chronic renal faailure (inability to excrete hydrogen ions)
accidental. ingestions of ethylene glycol (antifreeze)
substances that can lead to metabolic acidosis
propylene glycol
iron overdose
isoniazid overdose
promote lactic acid production
causes of metabolic acodisos
M methanol
U Uraemia
D DKA
P Propylene gycol
I Iron tablets and isoniazid
L Lactic acidosis
E ethylene glycol
S salicylates
normal gap metabolic acidosiss
decrease in bicarbonate is offset by build up of chloride so anion gap remains normal
most common cause of normal anion gap metabolic acidosis
diarrhoea
type 2 renal tubular acidosis
proximal convoluted tubule cant resorb bicarbonate
causes normal anion gap metabolic acidosis
addison disease
adrenal glands dont produce enough aldosterone
normally aldosterone would instruct the kidneys to absorb more sodium in the distal tubule which is linked to hydrogen ion secretion
more hydrogen remains in the blood in addisons disease
spironolactone
can lead to metabolic acidosis by blocking aldosterone receptorss
acetazolamide
lowers bicarbote resorbtion in the proximal tubule
leads to bicarbonate wasting
normal anion gap metabolic acidosis
saline infusion
standard 0.9 saline soltuion pH of 5.5
can cause normal anion gap metabolic acidosis
total parenteral nutrition
causes accumulation of H ions
causes of normal anion gap acidosis
H hyperalimentation
A addison disease
R renal tubular acidosis
D diarhhoea
A acetazolamide
S spironolactone
S saline infusion
winters formula
calculates the appropriate respiratory compensation for respiratory acidosis
(1.5 x HCO3 +8) +/-2
if the measured pCO2 is greater than winters formula calculation
metabolic acidosis and associated respiratory acidosis
if the measured pCO2 is less than winters formular calculation
metabolic acidosis and respiratory alkalosis
causes of respiratory acidosis
A airway obstruction
S sedative use
A acute lung disease
C chronic lung disease
O opiods
W weakeneing of respiratory muscles
metabolic alkalosis
loss of H ions or gain of HCO3 ions
compensatory response is immidiate hypoventilation which will retain CO2
loss of hydrogen ions happens by
GI tract - vomiting
kidneys - too much aldosterone (hyperaldosteronism)
causes of metabolic akalosis
L loop diuretics
A antacid use
V vomiting
A alosterone increase
UP
respiratory alkalosis
hyperventilation causes too much CO2 to be lost from the lungs
pH levels increase
kindeys decrease bicarbonate ion resorbtion to compensate
causes of respiratory alkalosis
P panic attacks
A anxiety attacks
S salicylates
T tumor
P pulomonary embolism
H hypoxaemia
compensatory responses
what is the compensation for respiratory acidosis
acute compensation: buffers in blood
chronic compensation: incrrease of resorbtion of HCO3 by proximal convoluted tubules
increase in excretion of H as H2PO4 and NH4 from the distal convoluted tubule and collecting duct
what is the compensation for respiratory alkalosis
acute compensation: buffers in blood
chronic compensation: decreased resorption of HCO3 by proximal convoluted tubule and decrease in renal extretion of H
what is the compensation of metabolic acidosis
stimulation of medullary chemoreceptors causes increase in respiraatory rate and todal volume
what is the compensation of metabolic alkalsosis
decreased stimulation of medullary chemoreceptors
decrease in respiratory rate and tidal volume
