Page 127 - Critical Care Notes

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Pathophysiology
Usually the result of DVT in the legs. Also femoral, popiteal, and iliac veins.
Other types: air, fat especially due to long bone fractures, amniotic fluid,
tumors, bone marrow, septic thrombi, vegetation on heart valves.
Risk factors include:
■ Venous stasis
■ Surgery (gynecological, abdominal, thoracic, orthopedic)
■ Pregnancy
■ Estrogen therapy (BCP, HRT)
■ Obesity
■ Advanced age
■ Carcinomas
■ Immobilization
■ Trauma
■ Heart failure
■ Stroke
■ Sepsis
Thrombus obstructs the pulmonary artery or branch → ↓ blood flow to lungs
· ·
→ impaired/absent gas exchange → V/Q mismatch (dead space ventilation)
→ platelets accumulate around thrombus → release of endotoxins → constrict
regional blood vessels + bronchioles →↑ pulmonary vascular resistance →
↑ pulmonary arterial pressure →↓ RV work to maintain pulmonary blood flow
→ RVF →↓ cardiac output →↓ systemic blood pressure → shock. A pulmonary
embolism may occur with or without pulmonary infarction; small, large or
multiple thrombi may exist.
Clinical Presentation
Symptoms, which depend on size of the thrombus and areas of the occlusion and
may vary from progressive dyspnea to hemodynamic collapse, may include:
■ SOB, dyspnea, tachypnea, crackles, wheezing, cyanosis
■ Hypoxemia with PaO 2 <80 mm Hg and SaO 2 <95%
■ Chest pain (sudden, pleuritic, sharp), angina pectoris, MI
■ Cardiac arrhythmias, especially new onset of atrial fibrillation, palpitations
or tachycardia, hypotension, S 3 or S 4 gallop, cardiac murmur
■ Acute cor pulmonale
■ Fever (>37.8°C), diaphoresis, chills
Clinical signs and symptoms of thrombophlebitis include:
■ Lower extremity edema
■ Leg cramps
■ Nausea and vomiting
■ Abdominal of flank pain
■ Hemoptysis, productive cough
■ Mental confusion, decreased level of consciousness, delirium in elderly patients
RESP