Term
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Definition
| measure blood acid-base balance |
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Term
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Definition
| (partial pressure of oxygen) |
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Term
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Definition
| (% of hemoglobin saturated with O2/oxygen saturation) |
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Term
| PaCO2 (partial pressure of CO2) |
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Definition
PaCO2
• Normal range is 35-45 (low = alkalotic, high = acidotic)
• Carbon dioxide (CO2) is the respiratory component in acid-base balance |
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Term
|
Definition
HCO3
• Normal range is 22-26 (low = acidotic, high = alkalotic)
• Bicarbonate (HCO3) is the renal component in the acid-base balance
• |
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Term
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Definition
• If kidneys are impaired, the lungs can blow off excess acid in the form of CO2
• If the respiratory system is impaired, the kidneys can compensate for excess acid by secreting H+ and regenerating HCO3. Takes up to 72 hours.
• CO2 and HCO3 work through carbonic acid to balance pH
• Compensation for pH imbalance comes from the opposite system
• Compensation attempts to bring pH back to normal
• When PaCO2 & HCO3 move in opposite directions, compensation is present |
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Term
| Identifying the primary cause of acid/base imbalance |
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Definition
• If pH is abnormal, the component that moves in the same direction with it is the cause
• If pH is normal/near normal, the more deviant component is likely the cause |
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Term
| Respiratory acidosis uncompensated: |
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Definition
Respiratory acidosis uncompensated:
pH (low)
PaCO2 (elevated)
HCO3 normal |
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Term
| Respiratory acidosis partially compensated: |
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Definition
Respiratory acidosis partially compensated:
pH acid (low)
PaCO2 acid (elevated)
HCO3 base (elevated) |
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Term
| Respiratory acidosis totally compensated: |
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Definition
Respiratory acidosis totally compensated:
pH normal
PaCO2 acid (elevated)
HCO3 base (elevated) |
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Term
| Respiratory alkalosis uncompensated: |
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Definition
Respiratory alkalosis uncompensated:
pH base (elevated)
PaCO2 (low)
HCO3 normal |
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Term
| Respiratory alkalosis partially compensated: |
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Definition
Respiratory alkalosis partially compensated:
pH base (elevated)
PaCO2 (low)
HCO3 (low) |
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Term
| Respiratory alkalosis totally compensated: |
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Definition
Respiratory alkalosis totally compensated:
pH normal
PaCO2 (low)
HCO3 (low) |
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Term
| Metabolic acidosis uncompensated: |
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Definition
Metabolic acidosis uncompensated:
pH (low)
PaCO2 normal
HCO3 (low) |
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Term
| Metabolic acidosis partially compensated: |
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Definition
Metabolic acidosis partially compensated:
pH (low)
PaCO2 (low)
HCO3 (low) |
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Term
| Metabolic acidosis totally compensated: |
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Definition
Metabolic acidosis totally compensated:
pH normal
PaCO2 (low)
HCO3 (low) |
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Term
| Metabolic alkalosis uncompensated: |
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Definition
Metabolic alkalosis uncompensated:
pH base (elevated)
PaCO2 normal
HCO3 (elevated) |
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Term
| Metabolic alkalosis partially compensated: |
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Definition
Metabolic alkalosis partially compensated:
pH base (elevated)
PaCO2 (elevated)
HCO3 (elevated) |
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Term
| Metabolic alkalosis totally compensated: |
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Definition
Metabolic alkalosis totally compensated:
pH normal
PaCO2 (elevated)
HCO3 (elevated) |
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Term
|
Definition
pH and one other value (either PaCO2 or HCO3) are abnormal. Abnormal pH determines whether acidosis or alkalosis. Abnormal PaCO2 or HCO3 determines whether respiratory or metabolic.
PaCO2 abnormal = respiratory; HCO3 abnormal = metabolic. |
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Term
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Definition
| all values are abnormal. Two values “agree” (pH and either PaCO2 or HCO3 are BOTH acid or BOTH base), and the remaining value (either PaCO2 or HCO3) is the OPPOSITE of the pH. The value (PaCO2 or HCO3) that “agrees” with the pH is correct (determines whether respiratory or metabolic). |
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Term
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Definition
| pH is normal, both PaCO2 and HCO3 are abnormal. One will be acidotic, the other base. The value that most closely matches the pH identifies the true (underlying) state. If the fully compensated pH is between 7.35-7.40, then the normal pH is closer to the acid end and the acidotic value (either PaCO2 or HCO3) is correct. If the pH is between 7.40-7.45, then the normal pH is closer to the alkalotic end and the base value (either PaCO2 or HCO3) is correct. |
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Term
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Definition
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Acid
|
Normal
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Base (Alkaline)
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pH
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PaCO2
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HCO3
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Term
ABG tic tac toe
Respiratory acidosis uncompensated |
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Definition
|
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Acid
|
Normal
|
Base
|
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pH
|
X¯
|
|
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PaCO2
|
X
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HCO3
|
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X
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Term
ABG tic tac toe
Respiratory acidosis partially compensated |
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Definition
|
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Acid
|
Normal
|
Base
|
|
pH
|
X¯
|
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PaCO2
|
X
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HCO3
|
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X
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Term
ABG tic tac toe
Respiratory acidosis totally compensated |
|
Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
|
X
|
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PaCO2
|
X
|
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HCO3
|
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X
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Term
ABG tic tac toe
Respiratory alkalosis uncompensated |
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Definition
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Acid
|
Normal
|
Base
|
|
pH
|
|
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X
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PaCO2
|
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X¯
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HCO3
|
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X
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Term
ABG tic tac toe
Respiratory alkalosis partially compensated |
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Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
|
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X
|
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PaCO2
|
|
|
X¯
|
|
HCO3
|
X¯
|
|
|
|
|
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Term
ABG tic tac toe
Respiratory alkalosis totally compensated |
|
Definition
|
|
Term
ABG tic tac toe
Metabolic acidosis uncompensated |
|
Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
X¯
|
|
|
|
PaCO2
|
|
X
|
|
|
HCO3
|
X¯
|
|
|
|
|
|
Term
ABG tic tac toe
Metabolic acidosis partially compensated |
|
Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
X¯
|
|
|
|
PaCO2
|
|
|
X¯
|
|
HCO3
|
X¯
|
|
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|
Term
ABG tic tac toe
Metabolic acidosis totally compensated |
|
Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
|
X
|
|
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PaCO2
|
|
|
X¯
|
|
HCO3
|
X¯
|
|
|
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|
|
Term
ABG tic tac toe
Metabolic alkalosis uncompensated |
|
Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
|
|
X
|
|
PaCO2
|
|
X
|
|
|
HCO3
|
|
|
X
|
|
|
|
Term
ABG tic tac toe
Metabolic alkalosis partially compensated |
|
Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
|
|
X
|
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PaCO2
|
X
|
|
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HCO3
|
|
|
X
|
|
|
|
Term
ABG tic tac toe
Metabolic alkalosis totally compensated |
|
Definition
|
|
Acid
|
Normal
|
Base
|
|
pH
|
|
X
|
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PaCO2
|
X
|
|
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|
HCO3
|
|
|
X
|
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|
