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Types of acid/base imbalances
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acidosis and alkalosis – both
metabolic & respiratory
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definition of metabolic imbalance
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change in amount of fixed acids or in
bicarbonate levels
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examples of fixed acids
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lactic acid, hydrochloric acid,
ketoacids
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the volatile acid in the body is
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carbonic acid
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carbonic acid is created through:
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the hydrolysis of carbon dioxide, aka
CO2 and water
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carbonic acid dissociates into:
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hydrogen and bicarbonate ions
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carbonic acid's concentration can be
altered via
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respiration
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for every 20 carbonic acid molecules
formed, the body saves:
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20 bicarbonate ions and 1 hydrogen ion;
kidney excretes the rest
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fixed acids are termed fixed because:
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they cannot be eliminated by changing
respiration
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in metabolic acidosis, what happens:
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pH decreases. Either acid increases or
bicarbonate decreases.
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In metabolic alkalosis, what happens:
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pH increases. Either acid decreases or
bicarbonate increases.
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What does PaCO2 stand for?
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Partial concentration/pressure of CO2
in arterial blood
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in respiratory imbalance:
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change in PacCO2
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cause of respiratory acidosis:
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accumulation of carbonic acid due to
too much CO2
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In respiratory acidosis, what happens:
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CO2 undergoes hydration; hydrogen is
released from carbonic acid; pH decreases
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any condition causing _____ will cause
respiratory acidosis
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hypoventilation
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as CO2 is retained, it will undergo
______ to form ______.
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hydration; carbonic acid.
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As carbonic acid is dissociated,
________ are released.
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Hydrogen ions
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causes of respiratory acidosis – 4
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obstructive lung disease, neuromuscular
weakness, damage to cervical spinal cord, depression of respiratory
center due to drugs/damage
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respiratory center of the brain:
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medulla & pons
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manifestations of respiratory acidosis
- 8
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headache, decreased consciousness,
disorientation, coma, ventricular arrhythmia, decreased cardiac
output, pulmonary hypertension, reduced blood flow to organs
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nervous system manifestations of resp
acidosis occur because:
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blood vessels dilate in response
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ventricular arrhythmia occurs with resp
acidosis because:
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electrical conduction and contractility
are affected
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pulmonary hypertension with resp
acidosis occurs because:
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as ventilation decreases, capillary
restriction increases
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cause of respiratory alkalosis:
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loss of carbonic acid during
hyperventilation causes excretion of CO2 and drop in pH
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in respiratory alkalosis, what happens:
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free hydrogen will be tied up with
water; pH increases
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causes of respiratory
alkalosis/hyperventilation - 5
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anxiety, hypoxia, CNS disorders,
pregnancy, fever
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respiratory and metabolic alkalosis
causes
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hypokalemia & hypocalcemia and vice
versa
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manifestations of respiratory alkalosis
- 9
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anxiety, dizziness, confusion, loss of
consciousness, coma, numbness/tingling, tetany, Chvostek’s and
Trousseau’s signs (from hypocalcemia)
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hypocalcemia occurs in alkalosis
because:
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calcium takes the place of hydrogen
ions
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for a respiratory problem, compensation
and correction must:
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employ a metabolic solution
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compensation for respiratory acidosis
|
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combine excess acid with available body
buffers; excretion of hydrogen & retention & production of bicarbonate via kidney
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compensation for respiratory alkalosis
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combine excess base with available body
buffers; hydrogen secretion will be stopped & bicarbonate ion
will be excreted by the kidney
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general etiology of metabolic acidosis
|
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loss of bicarbonate ion or accumulation
of non-volatile acid
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specific causes of metabolic acidosis -
7
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renal failure, diabetic ketoacidosis,
decompensated shock (lactic acid), diarrhea, bilious vomiting,
poisoning, starvation
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renal failure causes acidosis because:
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normal secretion of hydrogen and
reabsorption of bicarbonate ion doesn't happen
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poisons that cause acidosis: 4
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antifreeze, aspirin, methanol, iron
salts
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manifestations of metabolic acidosis
|
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deep/rapid respiration, acetone breath,
decreased LOC, disorientation, coma, ventricular arrhythmia
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ventricular arrhythmia occurs with
metabolic acidosis because:
|
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electrical conduction and contractility
are affected
|
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for metabolic imbalance, compensation
and correction must always
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employ a respiratory solution
|
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compensation for metabolic acidosis
|
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combine excess acid with available body
buffers, increased respiratory rate and depth to decrease PaCO2
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as CO2 is excreted via exhalation,
|
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carbonic acid concentration is
decreased and Hydrogen ions are tied to water
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correction for metabolic acidosis
|
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repair cause of imbalance, hydrogen
excretion and bicarbonate reabsorption
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etiology of metabolic alkalosis
|
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excess bicarbonate or loss of
non-volatile acid
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specific causes of metabolic alkalosis
- 4
|
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gastric vomiting, nasogastric
suctioning, diuretics that cause hydrogen excretion, ingestion of
alkaloids
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manifestations of metabolic alkalosis
|
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apathy, confusion, dizziness,
parasthesias, shallow breathing, muscle spasm
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manifestations of metabolic alkalosis
are similar to those of:
|
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hypokalemia
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compensations for metabolic alkalosis
|
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pair excess bicarbonate with available
buffers, decrease rate of respiration to increase CO2
|
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as CO2 accumulates, it will undergo:
|
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hydration to produce carbonic acid,
which will then dissociate and release hydrogen ions
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two important urine buffers are:
|
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phosphate & ammonia-ammonium
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