ABG’s & Imaging

Question 1

What do ABG’s tell us?

Answer 1

Assessment of problems related to:
-acid base balance (pH)
-alveolar ventilation
-oxygenation

Contain:
-arterial pH, PCO2, PO2, O2 sat, HCO3- concentration, base excess

Question 2

ABG Norm Values

Answer 2

pH: 7.4 (7.35-7.45)
PCO2: 40 (35-45)
PO2: 97 (>80)
HCO3-: 24 (22-28)
BE: 0 (+/- 2)
O2 Sat: 97% (>95%)

Question 3

What directly reflects adequacy of alveolar ventilation?

Answer 3

PaCO2

Question 4

Hypoventilation

Answer 4

PaCO2 > 40mmHg

Question 5

Hyperventilation

Answer 5

PaCO2 <40mmHg

Question 6

Ventilatory Failure

Question 7

How do we determine nature and severity of alveolar ventilation?

Answer 7

Relationship of arterial pH and arterial CO2 tension
-extent of acidemia and rapidity of change of pH

Question 8

Acid base balance

Answer 8

Assessment of blood pH (nature and magnitude of respiratory/metabolic disorders)

Lungs/kidneys regulate pH in bloodstream

Kidney regulates HCO3- as buffer for acids in blood

Question 9

Acidosis

Answer 9

pH < 7.4
-low HCO3-
-high PaCO2

Question 10

Metabolic acidosis

Answer 10

HCO3- <24

Question 11

Hypercapnia/Respiratory Acidosis

Answer 11

PaCO2 > 40

Question 12

Alkalosis

Answer 12

pH > 7.4
-high HCO3-
-low PaCO2

Question 13

Metabolic alkalosis

Answer 13

HCO3- >24

Question 14

Hypocapnia/Respiratory Alkalosis

Answer 14

PaCO2 < 40

Question 15

Hypoxemia

Answer 15

PaO2 < 80

Question 16

Causes of Respiratory Acidosis

Answer 16

Hypoventilation:
-over sedation
-head trauma
-NM disorders
-cardiac arrest
-chest trauma
-COPD (can’t get air out)
-pneumonia

Question 17

S/S of Respiratory Acidosis

Answer 17

Tachycardia
Confusion
Drowsiness
Dizziness
Minimal COPD (if chronic)

Question 18

Metabolic Alkalosis Causes

Answer 18

1. Loss of acid from GI tract or kidney
   -vomiting, laxatives
2. increased HCO3- reabsorption

Question 19

S/S of Metabolic Alkalosis

Answer 19

Tetany
Hypertonic muscles
Numbness
Asymptomatic

Question 20

Metabolic Acidosis Causes

Answer 20

1. Increased production of acids
   -ketoacidosis, lactic acidosis
2. Decreased excretion by kidneys (kidney failure)
3. Loss of alkali (diarrhea)

Question 21

S/S of Metabolic Acidosis

Answer 21

DOE
Deep, rapid breathing
Disorientation
Fatigue
Weakness

Question 22

Respiratory Alkalosis Causes

Answer 22

1. Hyperventilation
   -anxiety, fear, pain, excessive mechanical ventilation
2. Hypoxemia
3. CHF
4. PE

Question 23

S/S of Respiratory Alkalosis

Answer 23

Numbness and tingling of lips/extremities
Dizziness
Sinus arrhythmias

Question 24

Relationship b/w PaO2 and O2 Saturation

Answer 24

PaO2 40 -> 70% O2 sat
PaO2 50 -> 80% O2 sat
paO2 60 -> 90% O2 sat

Question 25

Mild Hypoxemia

Answer 25

PaO2 60-80mmHg

Question 26

Moderate Hypoxemia

Answer 26

PaO2 40-60mmHg

Question 27

Severe Hypoxemia

Answer 27

PaO2 < 40mmHg

Question 28

Chest radiographs

Answer 28

Predominant diagnostic test to determine an atomic abnormalities and pathological processes w/in the chest

Question 29

Checking for film quality

Answer 29

At least 9 posterior ribs on R side of chest Branching of small pulmonary vessels to edges of the lungs and rib outlines behind their heart shadow Check for rotation: trachea midline and medial clavicles equidistant from midline

Question 30

General scan

Answer 30

Spine alignment, sternum, clavicle/rib fxs R/L diaphragms (R higher than left) Hear (should be <50% of width of chest wall) Great vessels (aorta should be wider than t spine) Trachea Main bronchi Lungs

Question 31

Darker areas on chest x ray

Answer 31

Radiolucent Pneumothorax Bullae Air bronchograms

Question 32

Lighter areas on chest x ray

Answer 32

Opacities Infiltrates (blood, pus, water) Nodules or mass

Question 33

Chest imaging CT

Answer 33

More sensitive Localizes diseas Detect pneumothorax or effusions

Question 34

Chest MRI

Answer 34

Indicated for evaluation of chest wall processes Indicated in individuals with an abnormal chest radiograph that shows nodule or mass

Question 35

Chest bronchogram

Answer 35

Studies anatomy and gross pathological changes in the bronchial wall and lumen

Question 36

Ventilation/perfusion ratio

Answer 36

Average value = 0.80 Ordered when pulmonary embolus is suspected

Question 37

Compensated

Answer 37

pH is normal PaCO2 and HCO3- are both out of normal range (high or low) -> body is trying to compensated

Question 38

Decompensated

Answer 38

pH is off If one (PaCO2 or HCO3-) is normal and the other is out of normal range -> acute or body cannot compensate

Question 39

Chest X-ray (A)

Answer 39

Assessment for exam data/image quality, excess rotation, full lung expansion, correct exposure Air where it shouldn’t be Airways aren’t bent or deviated (underlying mass)

Question 40

Chest X Ray (B)

Answer 40

Bones (12 ribs and clavicles) Body wall (soft tissue o/s chest for swelling/masses)

Question 41

Chest X Ray (C)

Answer 41

Cardiac silhouette and size

Question 42

Chest Xray (D)

Answer 42

Diaphragms (symmetric or not) -not too flat but fairly symmetric

Question 43

Chest Xray (E)

Answer 43

Equipment (lines, tubes, wires involved) Effusion (pleural)

Question 44

Chest Xray (F)

Answer 44

Fields (lung) -should be symmetric -no haziness, white dots, blotches) -frontal/lateral views determine lobe/lung abnormal

Question 45

Chest Xray (G)

Answer 45

great vessels (deviation) -congenital abnormality or disease