ABGs BB
ABG Analysis
Normal values:
pH – 7.35 – 7.45
PaO2 – 80 to 100 mm Hg
O2 Saturation – 95% - 100%
PaCO2 – 35 – 45 mm Hg
HCO3 – 22 – 26 mEq / L
1
ABG Analysis
pH – body must maintain a delicate balance of
acids and bases to maintain homeostasis
pH indicates the concentration of hydrogen ions in the blood
Respiratory and metabolic processes work to keep hydrogen ion (H+) levels stable
Normal pH of arterial blood is 7.35 – 7.45 (slightly alkaline or basic)
pH of less than 7.35 indicates acidosis (high H+)
pH of more than 7.45 indicates alkalosis (low H+)
2
ABG Analysis
pH is affected by carbon dioxide on respiratory
side
CO2 will combine with water in blood to form
carbonic acid (CO2 + H2O = H2CO3)
CO2 is considered an acid
pH is affected by bicarbonate on metabolic (renal)
side
HCO3 binds with free H+ to reduce its concentration
(HCO3 + H+ = H2CO3)
HCO3 is an alkaline substance or base
3
ABG Analysis
Respiratory alkalosis – blowing off CO2
pH up / CO2 down
Always caused by hyperventilation
Fear
Anxiety
Pain
Fever
Drugs
High altitudes
Pregnancy
4
ABG Analysis
Respiratory acidosis – retaining CO2
pH down / CO2 up
Always caused by hypoventilation
Neurological problems
Respiratory disease states
Pulmonary edema
Airway obstruction
Chest trauma
Drugs (anesthesia, overdose)
5
ABG Analysis
Metabolic alkalosis – too much bicarbonate
pH up / HCO3 up
Loss of gastric acid (vomiting)
Overuse of antacids
Potassium wasting diuretics
6
ABG Analysis
Metabolic acidosis – too little bicarbonate
pH down / HCO3 down
Diarrhea
Renal failure
Shock
ASA overdose
Diabetic ketoacidosis
Sepsis
7
ABG Analysis
Acid
pH
< 7.35
Normal
7.35 – 7.45
Alkaline
> 7.45
PaCO2
>45
35 – 45
<35
HCO3
< 22
22 - 26
>26
Acid
Normal
Alkaline
8
ABG Analysis
Compare patient’s ABG results to acid-base
parameters
Write “pH”, “PaCO2”, and “HCO3” under the appropriate column head
Column with pH tells you
Normal values:
pH – 7.35 – 7.45
PaO2 – 80 to 100 mm Hg
O2 Saturation – 95% - 100%
PaCO2 – 35 – 45 mm Hg
HCO3 – 22 – 26 mEq / L
1
ABG Analysis
pH – body must maintain a delicate balance of
acids and bases to maintain homeostasis
pH indicates the concentration of hydrogen ions in the blood
Respiratory and metabolic processes work to keep hydrogen ion (H+) levels stable
Normal pH of arterial blood is 7.35 – 7.45 (slightly alkaline or basic)
pH of less than 7.35 indicates acidosis (high H+)
pH of more than 7.45 indicates alkalosis (low H+)
2
ABG Analysis
pH is affected by carbon dioxide on respiratory
side
CO2 will combine with water in blood to form
carbonic acid (CO2 + H2O = H2CO3)
CO2 is considered an acid
pH is affected by bicarbonate on metabolic (renal)
side
HCO3 binds with free H+ to reduce its concentration
(HCO3 + H+ = H2CO3)
HCO3 is an alkaline substance or base
3
ABG Analysis
Respiratory alkalosis – blowing off CO2
pH up / CO2 down
Always caused by hyperventilation
Fear
Anxiety
Pain
Fever
Drugs
High altitudes
Pregnancy
4
ABG Analysis
Respiratory acidosis – retaining CO2
pH down / CO2 up
Always caused by hypoventilation
Neurological problems
Respiratory disease states
Pulmonary edema
Airway obstruction
Chest trauma
Drugs (anesthesia, overdose)
5
ABG Analysis
Metabolic alkalosis – too much bicarbonate
pH up / HCO3 up
Loss of gastric acid (vomiting)
Overuse of antacids
Potassium wasting diuretics
6
ABG Analysis
Metabolic acidosis – too little bicarbonate
pH down / HCO3 down
Diarrhea
Renal failure
Shock
ASA overdose
Diabetic ketoacidosis
Sepsis
7
ABG Analysis
Acid
pH
< 7.35
Normal
7.35 – 7.45
Alkaline
> 7.45
PaCO2
>45
35 – 45
<35
HCO3
< 22
22 - 26
>26
Acid
Normal
Alkaline
8
ABG Analysis
Compare patient’s ABG results to acid-base
parameters
Write “pH”, “PaCO2”, and “HCO3” under the appropriate column head
Column with pH tells you