ABGs

Question 1

Function of ABG

Answer 1

Evaluate the ability of lungs to move oxygen into the blood and remove carbon dioxide from the blood

Question 2

Where is ABG usually drawn?

Answer 2

Radial artery

Question 3

Why perform ABGs?

Answer 3

Assess oxygenation capacity of lungs
Assess respiratory adequacy
Assess acid-base balance

Question 4

Normal PaO2 range

Answer 4

80-100mmHg

Question 5

Normal PaCO2 range

Answer 5

35-45 mmHg

Question 6

Normal pH range

Answer 6

7.35-7.45

Question 7

Normal HCO3 range

Answer 7

24-28 meg/L

Question 8

Normal SO2 range

Answer 8

95-100%

Question 9

Normal Base Excess range

Answer 9

-2 to +2 mmol/L

Question 10

Base excess definition

Answer 10

Base excess=how much acid or base is necessary to get pH back to normal. (-) means pt is in an acidotic condition. (+) means pt is in a alkalotic condition

Question 11

Steps in ABG analysis

Answer 11

Is the pH normal?
Is the PaCO2 normal?
Is the HCO3 normal?
Do the PaCO2 and HCO3 match the pH?
Are the PaO2 and SO2 normal?

Question 12

How do we know if the primary disturbance is due to a respiratory cause?

Answer 12

Abnl pH and PaCO2

Question 13

How do we know if the primary disturbance is due to a metabolic cause?

Answer 13

Abnl pH, HCO3, and B.E.

Question 14

Primary ABG Disturbances

Answer 14

Respiratory Acidosis
Respiratory Alkalosis
Metabolic Acidosis
Metabolic Alkalosis

Question 15

Compensatory mechanisms for respiratory acidosis

Answer 15

Kidneys excrete H+ and reabsorb HCO3

Question 16

Compensatory mechanisms for respiratory alkalosis

Answer 16

Kidneys increase excretion HCO3 and decrease excretion H+

Question 17

Compensatory mechanisms for metabolic acidosis

Answer 17

Respiratory rate increases initially; kidneys then begin to excrete excess H+ and absorb HCO3.

Question 18

Compensatory mechanisms for metabolic alkalosis

Answer 18

Respiratory rate decreases initially; kidneys then begin to excrete HCO3 and retain H+.

Question 19

parameters for uncompensated Respiratory acidosis

Answer 19

1. pH < 7.35
2. PaCO2 > 45 mmHG
3. HCO3 normal

Question 20

parameters for compensated Respiratory acidosis

Answer 20

1. pH normal
2. PaCO2 >45 mmHg
3. HCO3 >28 meq/l

Question 21

parameters for uncompensated Respiratory alkalosis

Answer 21

1. pH > 7.45
2. PaCO2 <35 mmHG
3. HCO3 normal

Question 22

Parameters for compensated respiratory alkalosis

Answer 22

1. pH normal

2. PaCO2 < 24 meq/l

Question 23

Parameters for uncompensated metabolic acidosis

Answer 23

1. pH < 7.35
2. PaCO2 normal
3. HCO3 < 24 meq/l
4. B.E. less than -2

Question 24

Parameters for compensated metabolic acidosis

Answer 24

1. pH normal
2. PaCO2 < 24 meq/l
3. B.E. greater than +2

Question 25

Parameters for uncompensated metabolic acidosis

Answer 25

1. pH > 7.45 2. PaCO2 normal 3. HCO3 > 28 meq/l 4. B.E. greater than +2

Question 26

Parameters for compensated metabolic acidosis

Answer 26

1. pH normal 2. PaCO2 >45 mmHg 3. HCO3 > 28 meq/l 4. B.E. less than -2

Question 27

Diseases that cause Respiratory acidosis

Answer 27

Lung Diseases Airway Obstruction Respiratory Center Depression Neuromuscular Problems

Question 28

Sxs Respiratory acidosis

Answer 28

Dyspnea Rapid shallow respirations Diaphoresis Warm flushed skin

Question 29

Lab tests for Respiratory acidosis

Answer 29

1. ABG analysis 2. CXR 3. Electrolyte levels K+ > 5 meq/l when in resp. acidosis which may lead to arrhythmias 4. Other Blood Tests 5. Drug screen

Question 30

Treatment for Respiratory acidosis

Answer 30

``` Maintain airway Bronchodilators Supplemental oxygen Treat hyperkalemia Abx for infection Tracheal suctioning Monitor cardiac rhythm Observe for neurologic changes ```

Question 31

Diseases that cause respiratory alkalosis

Answer 31

``` Hyperventilation Acute hypoxia due to high altitude Severe anemia Pulmonary embolus Drugs: Nicotine, salicylates ```

Question 32

Sxs of respiratory alkalosis

Answer 32

``` Tachycardia Syncope Dyspnea Tachypnea Diaphoresis Anxiety Confusion Parathesias ```

Question 33

Lab Tests for respiratory alkalosis

Answer 33

ABG analysis EKG analysis Electrolytes: Hypokalemia Drug Screen: ASA

Question 34

Tx for resp. alkalosis

Answer 34

``` Treat underlying cause Supplemental oxygen Give sedative if anxiety is the cause Breathe in paper bag Monitor vital signs Observe for neurologic changes ```

Question 35

Diseases that cause metabolic acidosis

Answer 35

1. Ketone overproduction: Diabetes, alcoholism, hyperthyroidism 2. Lactic acidosis: shock, CHF, seizures, liver disease 3. Kidney Disorders 4. Drugs: ASA, Methanol

Question 36

Sxs of metabolic acidosis

Answer 36

``` Diarrhea, vomiting Muscle weakness Hypotension Warm dry flushed skin Lethargy Anorexia Confusion Kussmal’s respirations ```

Question 37

Lab tests for metabolic acidosis

Answer 37

1. ABG 2. EKG: Tall T waves Wide QRS Prolonged PR 3. Electrolytes: Hyperkalemia 4. Glucose and Ketones

Question 38

Tx of Metabolic acidosis

Answer 38

``` Mechanical ventilation if necessary Monitor K+ Administer rapid acting insulin Dialysis for renal failure Antidiarrheal med Watch neurologic status ```

Question 39

Diseases that cause metabolic alkalosis

Answer 39

Diuretics Excessive acid loss from GI tract: Vomiting, NG suctioning Drugs: antacids, diuretics

Question 40

Sxs of metabolic alkalosis

Answer 40

``` Hypotension Cyanosis N/V/Anorexia Weakness Parathesias Confusion ```

Question 41

Lab Tests for metabolic alkalosis

Answer 41

ABG EKG: low T waves Electrolytes: hypokalemia, hypocalcemia

Question 42

Tx for metabolic alkalosis

Answer 42

``` D/C diuretics and/or NG suctioning Antiemetic to treat N/V Supplemental oxygen Seizure precautions Monitor for muscle weakness, tetany ```

Question 43

``` Identify the ABG state: pH 7.55 PaCO2 37 mmHg PaO2 99 mmHg SO2 98% HCO3 31 meq/l ```

Answer 43

Metabolic Alkalosis

Question 44

``` Identify the ABG state: pH 7.36 PaCO2 32 mmHg PaO2 44 mmHg SO2 78% HCO3 17 meq/l ```

Answer 44

Compensated Metabolic Acidosis

Question 45

``` Identify the ABG state: pH 7.23 PaCO2 50 mmHg PaO2 84 mmHg SO2 80% HCO3 26 meq/l ```

Answer 45

Respiratory Acidosis