PULMONARY EMBOLISM

Question 1

What is a pulmonary embolism?

Answer 1

A blood clot occurring in the lungs as a consequence of thrombus formation within a deep vein of the body

Question 2

What are the effects of an embolism on the heart?

Answer 2

Increased pulmonary vascular pressure
= increase back flow to right side of the heart

= increase right ventricular pressure (dilation)

= right sided heart failure

= decreased BP, stroke volume and Cardiac Output

Question 3

What are the effects of embolism on the lungs?

Answer 3

It causes inflammation
= release of cytokines leading to bronchoconstriction

=decreases oxygen coming in leading to hyperventilation and hypocapnea

There will also be a v/q mismatch (hypoxemia)
= respiratory alkalosis

Question 4

What are the symptoms of PE?

Answer 4

Acute Breathlessness
Acute Pleuritic Chest Pain
Haemoptysis (cough up blood) 
Syncope 
Hypoxia
Low grade Fever

Question 5

What is the sign of PE?

Answer 5

Pyrexia 
Cyanosis
Tachypnoea 
Tachypnoea
Hypotension
Raised JVP
Pleural Effusion
Sign of DVT

Question 6

What is the Risk Factors of PE?

Answer 6

Leg Fracture
Pregnancy/Post-partum 
Combined contraceptive pill
Previous PE
Malignancy
Recent surgery (last 3months)
Thrombophilia

Question 7

What is the gold standard test for PE? What abnormalities would be present?

Answer 7

CTPA

Visualisation of thrombus in pulmonary artery
Sign of right ventricular enlargement (ventricular diameter >0.9)

Question 8

What would a PE ECG show?

Answer 8

Usually normal

ABNORMALITIES:
short r-r intervals (sinus tachycardia)

Inverted T wave in lead V1-4 (right ventricular strain)

Deep S wave in Lead I

Deep Q and T waves in Lead III

Question 9

How would respiratory alkalosis show on ABG for PE?

Answer 9

High pH and low pCO2

Question 10

What type of respiratory failure is seen in PE?

Answer 10

Type 1
Low pCO2 and pO2

This is due to v/q mismatch

Question 11

What is the cut off for PE being unlikely in the Well’s Score?

Answer 11

Less than 1 risk factors

Question 12

What are the general treatment of PE?

Answer 12

Respiratory Support (94-98% Oxygen sats)

IV fluid (if systolic BP <90mmHg)

Vasoactive agent (for hypotension)

Opioid for pain (Morphine)

Question 13

Which vasoactive agents are used? What do they do?

Answer 13

Norepinephrine or Epinephrine

Increase Cardiac Output
Trigger Vasoconstriction
Increase Blood Sugar

Question 14

Why should Opioids be closely monitored?

Answer 14

They lead to vasodilation which increases hypotension

Question 15

Which DOAC can you use for PE? And how do they work?

Answer 15

Rivaroxaban
Apixaban
Dabigatran

They inhibit clotting Factors - preventing formation of blood clot

Question 16

What other blood thinning drugs are used in PE?

Answer 16

Vitamin K Antagonist (Warfarin)

LMWH (Heparin, Enoxaparin, Dalteparin)

Question 17

Why is Warfarin given with Heparin?

Answer 17

Warfarin takes 5days to be effective

Question 18

When should Warfarin be stopped and why?

Answer 18

Once INR is between 2-3

A higher than normal INR prevents formation of clotting factors

Question 19

How long should LMWH be used for?

Answer 19

5-7days and then switch to DOAC

Question 20

How long should anticoagulants be taken for?

Answer 20

3months

Lifelong of high risk patient

Question 21

What treatment is used for emergencies in PE?

Answer 21

Thrombolytic therapy

Thrombolyses or embolectomy or Catheter-directed thrombolysis (using a thrombolytic agent - alteplase)