++
KEY POINTS
Pulmonary embolism (PE) is common and potentially lethal, yet readily treatable.
Prophylaxis and accurate diagnosis are essential to improving outcome.
There is no perfect diagnostic test for PE; accurate diagnosis requires both an informed clinical pretest probability and a stepwise application of helical CT angiography and/or lower extremity duplex ultrasonography.
A careful risk assessment may identify patients ideal for outpatient therapy. Conversely, patients with hypotension or right ventricular (RV) strain are at significantly higher risk for death from PE, and warrant ICU admission.
While low-molecular-weight heparin (LMWH) is approved and recommended as the initial therapy for PE, critically ill patients often have reason for shorter acting unfractionated heparin.
Thrombolytic therapy is lifesaving in patients with high-risk PE and circulatory instability. The benefits are less clear in patients with RV dysfunction without shock as there is less hemodynamic decompensation but increased risk of bleeding.
Catheter-based therapies may have a role in unstable patients with high bleeding risk and contraindications to systemic thrombolytic therapy; however, evidence is currently insufficient to recommend in patients with RV dysfunction without shock.
Air and fat embolism usually present as acute respiratory distress syndrome (ARDS), and are managed with mechanical ventilation, oxygen, and positive end-expiratory pressure (PEEP).
++
This chapter covers diseases causing embolism to the pulmonary circulation, including pulmonary thromboembolism, as well as the less common conditions of venous air embolism and fat embolism. Thromboembolism is predominantly an acute circulatory insult, with important but less dramatic consequences for gas exchange. In contrast, both air and fat embolism usually present as acute hypoxemic respiratory failure (AHRF). All three forms of embolism may cause acute right heart failure, more fully discussed in Chap. 37.
+++
PULMONARY THROMBOEMBOLISM: EPIDEMIOLOGY IN THE ICU
++
PE is a dramatic and life-threatening complication of underlying deep venous thrombosis (DVT). Therefore, much of the management of pulmonary embolism (PE) is grounded in the prophylaxis, diagnosis, and treatment of DVT. While extensive prospective data regarding the diagnosis and treatment of PE are available, the vast majority of patients in such trials have not been critically ill, and thus the treatment for ICU patients with thromboembolic disease relies on extrapolation, and may lack the strength of evidence now available for most patients with PE or DVT. Nonetheless, important distinctions exist between the critically ill and noncritically ill patient populations when considering PE diagnosis and treatment.
++
In the United States, venous thromboembolism (VTE) is common: as many as 2 million people are diagnosed with DVT annually and 500,000 to 600,000 are diagnosed with PE.1 Currently, PE is estimated to be responsible for over 100,000 deaths annually in the United States and VTE remains the third most common cause of cardiovascular mortality in the United States.2 Historically, acute PE was believed to be frequently underdiagnosed, and a common cause of unexplained sudden death, as it ...