Acid-Base Balance

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Acid:

- controls respitory rate

volatile: unstable acid in the body

nonvolatile: stable

Base:

- most important base is bicarbonate

Buffer systems:

the respiratory system buffers by blowing off CO2 (adjusting breathing to control CO2 levels)

the renal system buffers by excreting hydrogen ions and producing bicarbonate

- breathing adjusts CO2 levels to bring pH back to normal

Acidosis:

respiratory - too much acid/altered acid excretion

ex. obstructed airflow

low pH

high CO2

normal HCO3

high H+

metabolic - too much acid

ex. alcohol abuse, diarrhea, acid ingestion, low carb intake

low pH

normal CO2

low HCO3

high H+

Alkalosis:

respiratory - too little acid

ex. hyperventilation

high pH

low CO2

normal HCO3

low H+

metabolic - too little acid (bicarbonate gain)

ex. ingesting baking soda, hypokalemia, excessive IV sodium bicarbonate

high pH

normal CO2

high HCO3

low H+

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Compensation:

- lungs and kidneys are besties and help each other out until failure

- full compensation: pH returns to normal

- partial compensation: pH is still abnormal

- respiratory system kicks in within minutes for compensation

- renal system takes several days to compensate

Sodium Bicarbonate IV:

- buffer to raise pH

indications: metabolic acidosis, dehydration/shock

contraindications: hypocalcemia! hypernatremia, impaired renal

- short term use only!

Hyperventilation:

- blowing off CO2 increases blood pH

- reccommended during metabolic acidosis to increase blood pH