Acid-Base Disorders Flashcards
Blood Gas Analysis (BGA):
- BGA important for assessment of problems related to = ?
Acid-Base Disorders
Blood Gas Analysis (BGA):
(a) BGA important for assessment of problems related to
- Acid-base balance
- Ventilation
- Oxygenation
- BGA: performed from blood obtained from anywhere in the circulatory system (artery, vein, capillary)
(b) Arterial blood gas (ABG): blood taken from a artery
- Used to monitor the conditions of patient in the critical care setting, and to help modify respiratory interventions.
- PT interventions may affect respiratory rate and blood gases
(c) For any of the following conditions:
- Lung disease
- Circulatory diseases
- Kidney disease
- Metabolic disease
(d) Typical report of ABG consist of:
- pH
- PaCO2
- PaO2
- SaO2
- HCO3-
Oxygenation:
- Normal = ?
- Mildly hypoxemic = ?
- Moderately hypoxemic = ?
- Severely hypoxemic = ?
Acid-Base Disorders
Oxygenation:
(a) Oxygenation status of a patient is assessed by determining the extent to which the observed PaO2 is above or below normal range.
- Normal - 97 mmHg or range is >80 mmHg
- PaO2 = 60 to 80 mm Hg - mildly hypoxemic
- PaO2 = 40 to 60 mm Hg - moderately hypoxemic
- PaO2 = 40 mm Hg - severely hypoxemic
Adequacy of Alveolar Ventilation:
- Normal = ?
- Hyperventilation = ?
- Hypoventilation = ?
- Ventilatory failure = ?
Acid-Base Disorders
Adequacy of Alveolar Ventilation:
(a) PaCO2 directly reflects adequacy of alveolar ventilation
- Normal Value 35-45 mmHg (40mmHg)
- PaCO2 <40 mm Hg = Hyperventilation
- PaCO2 >40 mm Hg = Hypoventilation
- PaCO2 >50 mm Hg = Ventilatory failure
(b) To determine the nature and severity of the illness with accuracy, the relationship of arterial pH and arterial CO2 tension is assessed
Acid-base Balance:
Hydrogen ions are high, pH is = ?
Acid-Base Disorders
Acid-base Balance:
(a) pH describes the balance between blood acids and blood bases.
- Insight into respiratory and metabolic disorders (pH, CO2 and HCO3-)
(b) Hydrogen ion concentration is inverse of pH
- pH is low, hydrogen ions are high
Arterial Blood Gas Analysis - Normal Values:
- pH = ?
- PCO2 = ?
- PO2 = ?
- HCO3- = ?
Acid-Base Disorders
Arterial Blood Gas Analysis - Normal Values:
Buffer Systems:
- Three buffer systems are = ?
Acid-Base Disorders
Buffer Systems:
(a) Mixture of acids and bases to resist pH change.
- Regulate acid base balance by trading stronger acids and bases for weaker varieties
(b) These buffer systems include:
- Plasma buffer system: Reacts within seconds in response to hydrogen ion concentration.
- Respiratory buffer system: Reacts within minutes to excrete CO2 through change in respiratory rate
- Renal buffer system: Reacts within hours/ days through the production, absorption, excretion of acids, bases and ions.
Acid-Base Terminology:
- Normal human blood pH = ?
- Metabolic acidosis = ?
- Respiratory acidosis = ?
Acid-Base Disorders
Acid-Base Terminology:
(a) Normal human blood pH = 7.4
- pH – 7.35-7.45 acceptable range
(b) pH <7.4 is acidic, defined as acidemia
- Process causing academia is called as acidosis
- Low HCO3- leads to metabolic acidosis
- High PaCO2 – leads to respiratory acidosis;
- (alveolar hypoventilation, hypercapnia)
(c) pH >7.4 is alkaline, defined as alkalemia
- Process causing alkalemia is called as alkalosis
- High HCO3- leads to metabolic alkalosis
- Low PaCO2 respiratory alkalosis;
- (alveolar hyperventilation, hypocapnia).
Acid-Base Terminology:
- Normal human blood pH = ?
- Metabolic alkalosis = ?
- Respiratory alkalosis = ?
Acid-Base Disorders
Acid-Base Terminology:
(a) Normal human blood pH = 7.4
- pH – 7.35-7.45 acceptable range
(b) pH <7.4 is acidic, defined as acidemia
- Process causing academia is called as acidosis
- Low HCO3- leads to metabolic acidosis
- High PaCO2 – leads to respiratory acidosis;
- (alveolar hypoventilation, hypercapnia)
(c) pH >7.4 is alkaline, defined as alkalemia
- Process causing alkalemia is called as alkalosis
- High HCO3- leads to metabolic alkalosis
- Low PaCO2 respiratory alkalosis;
- (alveolar hyperventilation, hypocapnia).
Acid-Base Interpretation:
- pH range = ?
- Low pH = ?
Acid-Base Disorders
Acid-Base Interpretation:
- pH range = 7.35-7.45
- Low pH = acidosis
Acid-Base Interpretation:
- pH range = ?
- High pH = ?
Acid-Base Disorders
Acid-Base Interpretation:
- pH range = 7.35-7.45
- High pH = alkalosis
Acid-Base Interpretation:
- PaCO2 range = ?
- Low PaCO2 = ?
Acid-Base Disorders
Acid-Base Interpretation:
- PaCO2 range = 35-45
- Low PaCO2 = Respiratory
Acid-Base Interpretation:
- HCO3 range = ?
- High HCO3 = ?
Acid-Base Disorders
Acid-Base Interpretation:
- HCO3 range = 22-26
- High HCO3 = Metabolic
Compensations:
- Respiratory compensations for ? disorders.
- Metabolic compensations for ? disorders
Acid-Base Disorders
Compensations:
(a) Each primary acid-base disorder can elicit a compensatory response.
(b) Respiratory compensations for primary metabolic disorders.
- If decreased HCO3 (metabolic acidosis)
- Decrease PaCO2 (a compensatory respiratory alkalosis); Hyperventilation
(c) Metabolic compensations for primary respiratory disorders.
(d) Kidneys compensate for primary respiratory disorders
Renal compensation requires 12-24 hours.
Compensation Terms - Respiratory compensations:
- Uncompensated = ?
- Partially compensated = ?
- Compensated = ?
Acid-Base Disorders
Compensation Terms - Respiratory compensations:
(a) Respiratory compensations for primary metabolic disorders.
- Uncompensated: if pH is outside the range and PCO2 is within the normal range.
- Partially compensated: pH and PCO2 are outside the normal range.
- Compensated: pH is within the normal range and PCO2 is outside the normal range
Compensation Terms - Metabolic compensations:
- Uncompensated = ?
- Partially compensated = ?
- Compensated = ?
Acid-Base Disorders
Compensation Terms - Metabolic compensations:
(a) Metabolic compensations for primary respiratory disorders.
- Uncompensated: If pH is outside the range and HCO3 is within the normal range.
- Partially compensated: pH and HCO3 are outside the normal range.
- Compensated: pH is within the normal range and HCO3 is outside the normal range.
Acid Base Disorders:
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Acid-Base Disorders
Acid Base Disorders:
(a) Respiratory Alkalosis:
(b) Respiratory Acidosis:
(c) Metabolic Alkalosis:
(d) Metabolic Acidosis:
