Investigations in Respiratory disease part 1 Flashcards
What is “D-Dimer” and how is it produced?
Produced when a blood clot is starting to break down and is formed through fibrin degradation products.
What causes a raised D-Dimer?
- Venous blood clots/stroke/AF
- Pregnancy (pre-eclampsia)
- Severe liver disease
- Malignancy
- Cardiac disease
- Renal disease
- Trauma
- Infection
- Recent surgery
How is a d-dimer test used?
- Exclude VTE (DVT or PE
- Diagnose and monitor DIC
What is DIC? (Disseminated intravascular coagulation)
Rare condition that causes numerous blood clots within the body, using up the fibrin and therefore leading to high risk of excessive bleeding
Alongside D-dimer, what else is requested when monitoring DIC?
1) Prothrombin Time
2) APTT
3) Fibrinogen
4) Platelet count
What components are part of the wells score?
1) Clinical features of DVT - 3 points
2) Other diagnosis less likely than PE - 3 points
3) HR > 100 BPM - 1.5 points
4) Immobilisation or surgery within 4 weeks - 1.5 points
5) Previous DVT/PE - 1.5
6) Haemoptysis - 1 point
7) Malignancy - 1 point
What components are part of the PERC score?
HAD CLOTS
H - Hormone
A - Age (>50)
D - DVT/PE history
C - Coughing blood L - Leg swelling O - O2 <92% T - Tachycardia S - Surgery/trauma <28 days
What are the five components are tested in a blood gas and what do they test for?
1) pH - check the H+ ions in the blood and whether there is a balance between the acid-base state
2) p02 - the amount of oxygen dissolved in the blood
3) pCO2 - the amount of CO2 dissolved in the blood
4) O2 saturation - How much oxygen is bound to haemoglobin in the RBC
5) HCO3- - directly related to the pH level, excreted and reabsorbed by the kidneys
What is the indication for collecting a blood gas?
- Difficulty breathing/SOB
- Hyperventilation
- Hypoxia
- Hypocapnia (tingling sensation, abnormal heart beat)
- Trauma to head/neck that may impact breathing
- Prolonged anaesthesia during surgery
What values would you see for Respiratory Acidosis and what causes it? ROME
Low pH & high CO2
- Pneumonia
- COPD
- Over sedation of drugs
What values would you see for Respiratory alkalosis and what causes it?
High pH & low CO2
- Hyperventilation
What values would you see for metabolic acidosis and what causes it?
Low pH & low HCO3- (blood is too acidic due to metabolic/kidney disorder)
- Diabetes
- Medication
- Kidney failure
What values would you see for metabolic alkalosis and what causes it?
High pH & high HCO3-
- Hypokalaemia
- Chronic vomiting
- dehydration
- sodium bicarbonate overdose
What is type 1 respiratory failure and what can cause it?
Damage to lung tissues makes it harder to take in enough oxygen, however some of the lungs still work properly to expel CO2
: low oxygen + low/normal CO2
Causes:
1) COPD
2) Asthma
3) Pneumonia
4) Pneumothorax
5) PE
What is type 2 respiratory failure and what causes it?
Alveolar ventilation insufficiency due to reduced ventilatory effort affecting the lungs as a whole, making it harder for CO2 to be expelled
:Normal O2 + High CO2
Causes:
1) COPD
2) CNS depression
3) Obesity
