Interpretation of test results Flashcards
What are the normal ranges for an ABG?
pH = 7.35-7.45 PaO2 >10kPa PaCo2 4-6kPa Bicarbonate 22-26mmol/L BE -2 to +2
What are some causes of metabolic acidosis?
MUDPILES Methanol Ureaemia - kidney disease Diabetic ketoacidosis Propylene glycol Infection, inborn error of metabolism Lactate (sepsis) Ethanol Salicylates e.g. aspirin hence why people with aspirin OD hyperventilate
Why does respiratory alkalosis usually occur?
When people are hyperventilating and blowing off more of there CO2. This can be due to anxiety, it can be metabolic, due to drugs
What is T1RF and T2RF?
Type 1 is when they are hypoxic
Type 2 is when they are also retaining oxygen
Who has T2RF and how will this show on ABG?
RESPIRATORY ACIDOSIS
Usually in people with chronic lung disease who are chronically retaining O2 (aim for sats 88-92% so as not to suppress their respiratory drive)
Can also occur in people who’s respiratory drive has been suppressed (opioid overdose and CNS trauma or problem) can also occur in people who have been in T1RF for a log time and are starting to tire. WORRYING.
What is the base excess and how does it become deranged?
This shows how much base BUFFER there is to compensate for an acidosis or alkalosis. Show’s how much difference there is between this buffer and the expected value.
So if there is a large negative base excess this suggests large base deficit and therefore suggests acidosis etc.
What system can you use to interpret a CXR?
RIPE ABCDE Rotation Inspiratory effort (should be able to see 5-6 anterior ribs) Projection Exposure Airway Breathing Cardiac border Diaphragm Everything Else
What is involved in airway assessment on CXR?
Is trachea central (spinous processes down midline), if it is deviated where is the defect (pushing or pulling)
Look for the carina and main bronchi
Look at the medistinum
- Is it widened (lymphadenopathy, mass, retrosternal mass, is there air there (emphysema)
Finally look at the hilar
- Hilar lymphadenopathy might be caused by infection or sarcoidosis
- There can be malignancy in the hilum
What is involved in breathing assessment on CXR?
Look around all LUNG FIELDS - do lung markings extend to the edges of thorax
Look for masses or consolidation
Look for evidence of pulmonary oedema (CHF)
Look for the pleura - shouldn’t be able to see but will be able to in fibrosis
What does cardiac assessment on a CXR involve?
Look for HEART SIZE (cardiomegaly = >50% chest cavity on PA film)
Trace the heart borders - are they clear
Look at the heart shape - does it look normal
What are some reasons you might not be able to see the heart borders on CXR?
Sometimes consolidation in certain lobes can blunt the corners of the heart
- LOSS OF L HEART BORDER - consolidation in lingual lobe
- LOSS OF R HEART BORDER - consolidation in Right middle lobe
What should be involved in the diaphragm assessment in the CXR?
Trace the borders of the diaphragm
Look for the costophrenic angles - if you can’t see them sharply this might suggest effusions
Look to see if the diaphragm is flattened - this might suggest hyperinflation of the lungs which occurs in COPD
Check for gas bubbles under the lung (normal bubble on L - gastric bubble, but bubble on R is always pathological = pneumoperitoneum)
What should you look for on the ‘everything else’ section of CXR?
BONES - check all the bones you can see for any obvious fractures or abnormalities
Look for soft tissues - large haematomas might be seen
Visualise any lines, drains or devices in the chest
Where do the ECG leads go?
Red - Right wrist Yellow - Left wrist Green - Left ankle Black - Right ankle V1 - 2nd IC space R sternal edge V2 - 2nd IC space L sternal edge V3 - between V2 and V4 V4 - 5th IC space mid clav line V5 - between V4 and V6 V6 - 5th IC space Mid axillary line
What might be some causes of an irregularly irregular heart beat?
AF or other supra ventricular tachycardias
Ectopics - multiple
