PE

Question 1

RED FLAGS

Question 2

DIFFERNTIALS

Answer 2

• AMI
• Pneumonia
• Pericarditis
• Pleurisy
• Pneumothorax

Question 3

RISK FACTORS

Answer 3

• Hx. of DVT or PE
• Prolonged immobilisation
• Recent surgery/trauma
• Oral contraceptives
• Long-haul flights

Question 4

CAUSES

Answer 4

Thrombus from DVT, emboli’s from fat, air, amniotic fluid.

Question 5

DEFINITION

Answer 5

Obstruction of the pulmonary arteries from an embolus, most likely lower extremity DVT.

Virchow’s triad:
1. Endothelial damage – trauma, atherosclerosis, surgery, inflammation
2. Venous stasis – pooling  coagulability, immobility, obesity, venous obstruction
3. Hypercoagulability – clotting disorder, chemotherapy/cancer, pregnancy (particularly after C section), oral contraception.

Question 6

PATHOPHYSIOLOGY

Answer 6

Thrombus breaks off/dislodges  travels into venous blood flow (smallest vessels)  vascular occlusion, local ischaemia  redistribution of blood flow  increased pulmonary circulation pressure (pulmonary hypertension)  hydrostatic pressure out competes oncotic pressure in the blood vessels + ischaemia of the lung tissue  inflammation  increase pulmonary capillary permeability  fluid moves down its pressure gradient into the lungs
Pressure backlogs into R heart  increase HR and contractility that with time will eventually fail as heart is under perfused, + foramen ovale opens and O2 blood mixes with low O2 blood  hypoxaemia
Blood pools in systemic circuit  raised JVP, peripheral oedema, RVF
VQ mismatch- less blood for gas exchange  systemic hypoxaemia.

Question 7

TREATMENT

Answer 7

DRAB: oxygenation. C: 250-500ml IV fluids. DE.
Basic cares: position of comfort, minimising movement (thrombus to travel). Normothermia.
Analgesia: paracetamol. Fentanyl- antianxiety, heart problems.
Management - O2, analgesia, 12-lead ECG, Fluids administered judiciously (250-500ml) as it can put more pressure on an already over stretched R heart, clot may dislodge.
- Anticipate further deterioration (shock  resus, adrenaline)
- CCP: adrenaline

Question 8

ROLE OF PARAMEDIC

Answer 8

Attempt to rule out differential Dx. e.g. as ASC, maximise blood oxygenation.

Question 9

PHARMACOLOGY

Answer 9

Paracetamol mechanism– similar to NSAID:
- Analgesic properties: inhibits COX which blocks the production of prostaglandins. Prostaglandins act on neurons to cause pain response
- Antipyretic properties – directly act on temperature regulation in the hypothalamus

Question 10

DEFINITIVE CARE

Answer 10

Hospital:
- Blood tests: clot-dissolving substance D dimer. High levels suggest increased likelihood of clots. Blood tests measure the amount of O2 & CO2 in blood. A clot in the lungs can lower the level of O2 in the blood. Inherited clotting disorder.
- Chest X-ray: rule out conditions that mimic PE.
- Ultrasound: to check for DVTs.
- CT pulmonary angiography: detect abnormalities such as PE
- Ventilation-perfusion scan (V/Q scan): to avoid radiation exposure or contrast due to a medical condition. Tracer maps perfusion & compares it with ventilation & can be used to determine whether clots are causing symptoms of pulmonary hypertension.
- Pulmonary angiogram: provides a clear picture of the blood flow in lung arteries

Medications:
- Anticoagulants- prevent existing clots from enlarging & new clots from forming while your body works to break up the clots. Heparin + warfarin. Anticoagulant side effects: bleeding.
- Clot dissolvers (thrombolytics). Can cause sudden & severe bleeding, usually reserved for life-threatening situations.

Surgical / other procedures:
- Clot removal.
- Vein filter.