CVR - X-Ray and ABG's Flashcards
What are the types of X-ray views you can have?
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
What is the ABCDE approach with X-rays?
Airways Bones Cardiac Diaphragm Everything - exposure - lung fields - soft tissue - lines/airways
On an X-ray, what do you look at for the airways?
Can the trachea be seen, and is it central?
On an X-ray, what do you look at for the bones and soft tissues?
- Clavicular level
- Rib markings (fractures)
- Identify the scapula borders
- Vertebral and spinous processes
- Breast shadows
- Surgical emphysema under the skin
On an X-ray, what do you look at for the cardiac section?
Heart:
- Position
- extended slightly to midline - Size
- in right ventricular hypertrophy, the heart is enlarged
- a rounded heart mat indicate pericardial effusion - Heart borders
- Lt lower lobe = left hemidiaphragm
- Rt lower lobe = right hemidiaphragm
- Lt upper lobe = aortic arch
- Rt upper lobe = right upper mediastinum
On an X-ray, what do you look at for the diaphragm section?
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
On an X-ray, what do you look at for the ‘everything else’ section?
- Snowstorm appearance indicates acute respiratory distress syndrome
- Unilateral white out caused by lung collapse or large pleural effusion
- Chest drains, tracheostomy, ECG leads
What are arterial blood gases (ABGs)?
Blood test that measures the acidity (pH) and the levels of O2 and CO2 from an artery
Give the ABG normal values for:
- pH
- PaO2
- PaCO2
- HCO3-
- Base excess (BE)
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
With regards to H+ when is there a respiratory and metabolic mechanism?
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
When would the following occur:
- Respiratory acidosis
- Respiratory alkalosis
- Metabolic acidosis
- Metabolic alkalosis
- Respiratory acidosis = increase in PaCO2
- Respiratory alkalosis = decrease in PaCO2
- Metabolic acidosis = decrease HCO3- or BE
- Metabolic alkalosis = increase HCO3- or BE
Define respiratory failure
Failure of the respiratory system to provide adequate gaseous exchange for metabolic requirements
What are type I and type II respiratory failure?
Type I RF (hypoxaemic) = failure of oxygenation
Type II RF (hypercapnic) = failure of ventilation
What are the target O2 saturations?
Normal = 94-98%
TYPE II RF or COPD = 88-92%