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18 Cards in this Set
- Front
- Back
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Purpose of Blood Gas Analysis
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1. Determine acid-base balance
2. Assess adequacy of alveolar ventilation 3. Assess oxygenation status |
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Measurement obtained and purpose:
pH |
1. Determine the acidity (acidosis) or alkalinity (alkalosis) of the blood
2. Assess the concentration of hydrogen ions (the acid-base balance) in the blood |
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Measurement obtained and purpose:
PaCO2 |
1. Evaluate the adequacy of alveolar ventilation
2. Determine how well the lungs are able to remove carbon dioxide 3. Assess the respiratory component of acid-base balance |
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Measurement obtained and purpose:
HCO3 |
1. Indicates the level of base in the blood
2. Assess the metabolic component of acid-base balance |
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Measurement obtained and purpose:
BE |
1. Determines if there is an excess of base, expressed as a positive number (+)
2. Determines if there is a deficit of base expressed as a negative number (-) |
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Measurement obtained and purpose:
PaO2 |
1. Evaluate the adequacy of oxygenation
2. Reflects the amount of oxygen dissolved in the blood |
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Normal arterial values
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pH 7.35 - 7.45
PaCO2 35-45 mmHg HCO3 22 - 26 mEq/L BE +or- 2 mEq/L PaO2 80 - 100 mmHg SaO2 97% (>90%) |
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Arterial blood vs. venous blood
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Arterial reflects the status of the whole body
Venous reflects the status of the organ/muscle from where it is obtained |
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pH definition
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negative logarithm of the hydrogen ion concentration (H+) = 0.000 000 1 = 7
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Acid
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Substances capable of donating a hydrogen ion in a chemical reaction
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Base
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Substances capable of accepting a hydrogen ion in a chemical reaction
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H+ and pH
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The greater the concentration of H+ the lower the pH = inverse relationship
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pH homeostasis
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The body does what it can to achieve a balance between the KIDNEYS and the LUNGS for the purpose of trying to normalize the pH through: Acid, Base, Buffers
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Regulation of pH
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1. Kidneys regulate the level of base HCO3
2. Lungs regulate the level of acid H2CO3 (PCO2) |
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pH = Base/Acid
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Base = HCO3 (bicarbonate) - kidneys (metabolic)
Acid = H2CO3 (carbonic acid) - Lungs (respiratory) |
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Fixed Acids #1
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1. Produced as a result of normal body metabolism
2. Cannot be converted into gases 3. Kidneys are responsible for maintaining normal fixed acid homeostasis 4. Several conditions can result in an abnormal increase in fixed acids (i.e., diabetes, hypoxia) |
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Fixed Acids #2
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- Sulfuric Acid
- Phosphoric Acid - Ketoacids - Lactic Acid |
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pH ranges
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in arterial blood = 7.40
normal range = 7.35 - 7.45 Acidosis = pH < 7.35 Alkalosis = pH > 7.45 |
