W4 D1.5 - Acid Base Balance Flashcards
What are the functions of Bicarb H+ and how it is measured?
Acid base and their relationship to hydrogen
Differentiate volatile and non-volatile acids
Volatile - gas
* aerobic metabolism
* Ex. CO2 - to fix inbalance, ventilate
Non-volatile - liquid
* lactic acid - during anaerobic metabolism
* ketones - from fat breakdown
* sulphuric & phosphoric acid - from protein breakdowns
How are acids produced in the body?
What are buffers?
Buffers help maintain pH by neutralizing strong acids and bases to prevent major fluctuations
Explain how chemical buffers maintain pH
Carbonic acid-bicarbonate system
* most important, quick acting
* carbonic acid will neutralize bases
* bicarbonate willl neutralize acids
Phosphate system
* phosphate will either bind or release H+ ions to maintain pH
Blood/protein system
* most abundant buffer
* hides hydrogen in Hgb to lower impact
Explain how physiological buffers maintain pH balance
Lung - minutes to correct
* Medulla senses CO2/H increase
* increases RR to blow off CO2
* lowers pH to normal
Kidney - hours to correct
* only organ that can excrete H+ via urine
* bicarb and chloride exchange ?
* potassium is absorbed or excreted based on H+ ions
What are the normal ranges for pH, pCO2, HCO3, PaO2, SaO2?
pH: 7.35-7.45
pCO2: 45-35
HCO3: 22-28
PaO2:
SaO2: 92-100
Explain metabolic alkalosis and its causes
Accumulation of bases
* ingestion of antacids
* diuretics (loss of Cl)
* blood transfusions
Loss of non-volatile acids
* vomiting stomach contents
* NG suction
Treatment
* acetazolamide (diamox)
* decrease HCO3 production, not great
Explain metabolic acidosis and its causes
Accumulation of non-volatile acids
* lactic acid
* ketones
* renal failure
* ingestion of ASA
Loss of bases
* diarrhea
* vomiting - losing small bowel acidity
* ileostomy
Treatment
* sodium bicarbonate
* dialysis
Explain respiratory alkalosis and causes
Loss of volatile acids - excess loss of CO2
* alveolar hyperventilation
* hypoxemia
* over ventilation
Treatment
* underlying cause
* sedation
* correct RR and Vt
Explain respiratory acidosis and causes
Accumulation of volatile acid
* depression of resp centre
* airway obstruction
* resp. failure/exhaustion
* V/Q mismatch
Treatment
* airway, intubate, ventilate
* frequent assessment of sedation/analgesia
* ventilate with high RR to blow off CO2
What is mixed acidosis?
pH low (acidotic)
PaCO2 high (acidotic)
HCO3 low (acidotic)
both lungs and kidneys are damaged
Explain absent, partial, and full compensation
Absent
* the compensating organ is not adjusting to maintain
Partial
* organs are trying to compensate, pH is abnormal
* all values are out of range
Full
* normal pH with abnormal CO2 &/or HCO3
