Week 9 Flashcards
Causes for abnormalities:
- Increased translucency (too black)
- Opacification (too white)
- Solid white
Increase translucency: Air, loss of tissue density
Opacification: Fluid, increased tissue e.g. lymphadenopathy
Solid white: Hardware e.g. Pacemaker, Endotracheal tube (ETT), NG tube, chest drain
What is consolidation?
Replacement of normal air space gas with fluid or solid material
Causes of consolidation?
Pus due to infection Blood due to pulmonary haemorrhage Fluid due to pulmonary oedema Cells due to lung cancer Protein due to alveolar proteinosis
What is atelectasis?
Aka: Collapse, pneumothorax
Definition: Reduction in inflation of all or part of the lung
Suspect atelectasis if on x-ray you see… (6)
- Volume loss
- Displacement of trachea
- Displacement of diaphragm
- Displacement of lung fissures
- Compensatory over inflation of non-collapsed lung
- Crowding of vessels and bronvhi
Causes of deviated trachea?
- Pneumonectomy/ lobectomy
- Lobar collapse
- Tension pneumothorax
- Pleural effusion
Pulmonary oedema signs found on XCR
A: Alveolar oedema (Bat's wing) B: Kerley B lines C: Cardiomegaly D: Upper lobe diversion E: Pleural effusions
For a pleural effusion:
- Describe the abnormality shown in the chest xray?
- What clinical signs might you find on examination?
- How would you manage the acute problem?
- Suggest 2 further investigations you might request?
CXR abnormality: Area of whiteness expanding over mid and lower zones
Clinical signs: Increased RR, low sats, dull to percussion, decreased vocal resonance
Acute management: O2 delivery, drain fluid
Further 2 investigations: CT scan send fluid to lab for investigation to identify fluid
What lobes and fissures are present in the right lung?
Fissures: Horizontal and oblique
Lobes: Superior, middle and inferior
What lobes and fissures are present in the left lung?
Fissures: Oblique
Lobes: Upper and lower
Stucture in left lung that is the equivalent to the right middle lobe?
The lingula
Course of the:
- Oblique fissure?
- Horizontal fissure?
Oblique: From 3rd thoracic vertebrae to 6th costochondral junction
Horizontal: From 4th right CC to meet the oblique fissure as it follows course of 6th rib
Structures and arrangement of the right and left lung hilum?
o Bronchus (most posterior, identified by the small plates of hyaline cartilage)
o Pulmonary artery (Anterosuperior to bronchus)
o Pulmonary veins (superior vein is most anterior structure in hilum, inferior vein is most inferior structure)
o Lymph nodes
o Branches of bronchial arteries and pulmonary nerve plexus
What is pKa?
Defined as the pH at which 50% is ionised and 50% is unionised in the reaction
What direction of reaction is favoured if the normal pH is higher than the pKa?
Favoured to the high so there would be more products vs reactants
The _____ levels of bicarbonate can be changed by breathing
Absolute
What components of the following respiratory equation contribute to respiratory and metabolic acid-base disturbances?
Respiratory: CO2, H20
Metabolic: HCO3-, H+
i.e.
Rise in PCO2 -> Respiratory acidosis
Rise in HCO3- -> Metabolic alkalosis
What are the 4 causes for acid-base disturbances?
- Increase CO2
- Decrease CO2
- Increase non-volatile acid / decrease base
- Increased base / decreased non-volatile acid
What 2 organs offer compensation for acid-base disturbances?
Lungs via alters ventilation (quick)
Kidneys via altered excretion of bicarbonate (2-3 days)
Respiratory acidosis: How does it arise? Acid-base disturbance? Compensation? Cause?
How does it arise:
-Results from an increase in PCO2 in hypoventilation (so less CO2 being blown away)
Acid-base disturbance:
- Increase in PCO2
- Increase in H+, lowering of pH
- plasma HCO3- levels increase to compensate for H+ concentration
Compensation: Renal. Increase HCO3- reabsorption and production to raise pH
Causes:
- COPD
- Blocked airway
- Lung collapse
- Injury to chest wall
- Drugs reducing respiratory drive e.g. morphine
Respiratory alkalosis: How does it arise? Acid-base disturbance? Compensation? Cause?
How does it arise:
Results from a decrease in PCO2 generally caused by alveolar hyperventilation (more CO2 being blown away).
Acid-base disturbance:
Causes a decrease in H+ thus a rise in pH
Compensation: Renal. Reduced reabsorption and production of HCO3-. Lowers pH back to normal as H+ increases
Causes:
- Increase ventilation from hypoxic drive in pneumonia, diffuse interstitial lung diseases, high altitude, mechanical ventilation
- Hyperventilation in brainstem damage, infection driving fever
Metabolic acidosis:
Acid-base disturbance?
Compensation?
Cause?
Acid-base disturbance:
- Result of excess of H+ in the body, reducing equation to left so reduces HCO3 levels
- PCO2 normal as respiration normal
Compensation: Respiratory
- Low pH detected by peripheral chemoreceptors
- Increases ventilation which lowers PCO2
- Shifts bicarbonate equation further to left, lowering H+ further
- pH increases to normal
- Cannot fully correct the pH so excess H+ needs to be removed or HCO3- restored
Causes:
- Loss of HCO3
- Exogenous acid overloading, endogenous acid production
- Failure to secrete H+ e.g. renal failure
Effect of high ventilation on PCO2
Increased ventilation –> lowers PCO2 as CO2 is being blown off
Metabolic alkalosis:
Acid-base disturbance?
Compensation?
Cause?
Acid-base disturbance:
- Increase in HCO3- concentration or fall in H+
- Removing H+ increased HCO3- levels are equation driven to the right
- Raises pH
Compensation: Respiratory
- Increase in pH detected by peripheral chemoreceptors
- Decreases ventilation which raises PCO2
- Equation driven further to right
- pH lowers to normal
- Ventilation cannot reduce enough to correct imbalance. Hence renal response is to secrete less H+
Causes:
- Vomiting (loss of HCl from stomach)
- Ingestion of alkali substances
- Potassium depletion (e.g. diuretics)