CVR - X-Ray and ABG's

Question 1

What are the types of X-ray views you can have?

Answer 1

AP = anteroposterior
- a beam passes through the chest from front to back. portable CXRs performed at bedside
PA = posteroanterior
- a beam passes through the chest from back to front. the patient must stand whilst CXR is taken

Question 2

What is the ABCDE approach with X-rays?

Answer 2

Airways
Bones
Cardiac
Diaphragm
Everything
 - exposure
 - lung fields
 - soft tissue
 - lines/airways

Question 3

On an X-ray, what do you look at for the airways?

Answer 3

Can the trachea be seen, and is it central?

Question 4

On an X-ray, what do you look at for the bones and soft tissues?

Answer 4

• Clavicular level
• Rib markings (fractures)
• Identify the scapula borders
• Vertebral and spinous processes
• Breast shadows
• Surgical emphysema under the skin

Question 5

On an X-ray, what do you look at for the cardiac section?

Answer 5

Heart:

1. Position
   - extended slightly to midline
2. Size
   - in right ventricular hypertrophy, the heart is enlarged
   - a rounded heart mat indicate pericardial effusion
3. Heart borders
   - Lt lower lobe = left hemidiaphragm
   - Rt lower lobe = right hemidiaphragm
   - Lt upper lobe = aortic arch
   - Rt upper lobe = right upper mediastinum

Question 6

On an X-ray, what do you look at for the diaphragm section?

Answer 6

The diaphragm should be level with 6th rib anteriorely
Should be domed shaped and smooth
Flattened diaphragm is caused by hyperinflation
Tenting is caused by excess gas in the stomach, paralysed hemi-diaphragm

Question 7

On an X-ray, what do you look at for the ‘everything else’ section?

Answer 7

• Snowstorm appearance indicates acute respiratory distress syndrome
• Unilateral white out caused by lung collapse or large pleural effusion
• Chest drains, tracheostomy, ECG leads

Question 8

What are arterial blood gases (ABGs)?

Answer 8

Blood test that measures the acidity (pH) and the levels of O2 and CO2 from an artery

Question 9

Give the ABG normal values for:

• pH
• PaO2
• PaCO2
• HCO3-
• Base excess (BE)

Answer 9

pH = 7.35-7.45
 PaO2 = 10.7-13.3 kPa
PaCO2 = 4.7-6.0 kPa
HCO3- = 22-26 mmol/l
BE = -2 to +2

Question 10

With regards to H+ when is there a respiratory and metabolic mechanism?

Answer 10

Respiratory mechanism:
- if CO2 production is altered, breathing is adjusted to exhale more or less CO2
- increase CO2 = increase H+ = decrease pH = increased depth & rate of breathing
Metabolic mechanism:
- kidneys are responsible for excreting metabolic acids
- they secrete H+ ions in the urine and reabsorb HCO3- from the urine = reduce H+ in the blood

Question 11

When would the following occur:

1. Respiratory acidosis
2. Respiratory alkalosis
3. Metabolic acidosis
4. Metabolic alkalosis

Answer 11

1. Respiratory acidosis = increase in PaCO2
2. Respiratory alkalosis = decrease in PaCO2
3. Metabolic acidosis = decrease HCO3- or BE
4. Metabolic alkalosis = increase HCO3- or BE

Question 12

Define respiratory failure

Answer 12

Failure of the respiratory system to provide adequate gaseous exchange for metabolic requirements

Question 13

What are type I and type II respiratory failure?

Answer 13

Type I RF (hypoxaemic) = failure of oxygenation

Type II RF (hypercapnic) = failure of ventilation

Question 14

What are the target O2 saturations?

Answer 14

Normal = 94-98%

TYPE II RF or COPD = 88-92%