4.4 PULMONARY EMBOLISM

Question 1

Anatomy

Answer 1

(1) Pulmonary artery: after blood leaves through the pulmonary valve it travels into the main pulmonary artery and then it branches into the left and right main pulmonary artery then to three segments to supply lobes of the lung and then continues to branch further until it becomes pulmonary capillaries
(2) The right ventricle is small with only a thin muscular wall, so it is not built to pump against high pressures
(3) If a pulmonary embolism is large enough and lodges in the main pulmonary artery or at the branch point of the left and right main
pulmonary artery then the puts enormous pressure back up to the RV and the RV goes into failure and then the patient becomes hypotensive then cardiac arrests

Question 2

Pathophysiology

Answer 2

(1) Pulmonary embolism is a clot that travels (usually from the LE veins) and lodges into a pulmonary artery.
(2) The embolus will continue to travel out into the pulmonary artery tre until it becomes lodged in a vessel of the emboli’s diameter
(3) PE is a common and potentially fatal complication of DVT formation
(4) 50-70% of patients with PE will have lower extremity DVT when
evaluated
(5) 3rd leading cause of death in hospitalized patients
(6) Risk factors for PE are the same as DVT: stasis, hypercoagulability, or injury to vessel wall
(7) Physiological effects of PE include:
(a) Obstruction of the vascular bed increasing dead space (wasted ventilation) and hypoxemia
(b) Decreased CO
(c) Massive PE may cause RV failure
(d) Surfactant depletion leading to atelectasis

Question 3

Symptoms/Physical Findings

Answer 3

(1) Can be very difficult to make a clinical diagnosis
(2) Chest pain, tachypnea, and tachycardia
(3) Hypoxemia
(4) SOB
(5) Signs of DVT (unilateral leg swelling,
pain, redness) and the above
symptoms you must consider it to be PE until proven otherwise and
treated as such

Question 4

Differential Diagnosis

Answer 4

(1) AMI
(2) Pneumonia
(3) OSA
(4) Pulmonary HTN
(5) Anxiety
(6) Infection
(7) Pericarditis
(8) Pericardial effusion/Tamponade
(9) COPD
(10) Asthma

Question 5

Labs/Studies/EKG

Answer 5

(1) CXR: will be normal
(2) EKG: is abnormal in 70% of patients, however the most common abnormality is Sinus Tachycardia or non-specific ST and T wave changes
(3) Helical CT pulmonary angiography is the imaging study of choice
(4) Ultrasonography of extremities to look for DVT

Question 6

Treatment

Answer 6

(1) Goal of treatment is prevention of further PE propagation or further clot
burden due to DVT
(2) Aggressive anticoagulation with either Heparin or Lovenox (same dosing as DVT)

Question 7

Initial Care

Answer 7

(1) ABCs, IV, O2 if saturation < 94%
(2) Anticoagulate
(3) MEDEVAC

Question 8

Complications

Answer 8

(1) Pulmonary HTN
(2) RV failure
(3) Cardiac Arrest
(4) Death