Page 1266 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 93: Oncologic Emergencies 873

intensive care unit (ICU). Currently, cancer patients in the ICU are more Treatment of PE should be based on risk stratification (Fig. 93-2). 10,11
frequently admitted for respiratory and cardiac failure, life-threatening Many modalities of treatment exist for PE, and anticoagulation with
sepsis, metabolic complications, and hemorrhagic and thrombotic dis- unfractionated heparin, low-molecular-weight heparin, or fondaparinux
orders. Similar to the classic oncologic emergencies, these syndromes remains the standard initial therapy. A recent study showed that riva-
often result from the cancer itself and/or from treatment of the cancer. roxaban, a new oral factor Xa inhibitor, was as effective as standard
This chapter will discuss the epidemiology, pathophysiology, clinical anticoagulation for patients with symptomatic PE; however, since few
presentation, diagnosis, and management of the common and classic patients in this study were admitted to the ICU, the utility of this agent
oncologic emergencies that ICU clinicians will encounter in their practice. in this setting remains to be determined. Other treatment modalities
12
These include respiratory, neurologic, metabolic, thoracic, and cardiac such as thrombolysis, surgical embolectomy, and catheter devices for
emergencies. clot removal are used occasionally as rescue therapy, and their exact
indications continue to be under evaluation.
Thrombolytic agents have been used since the late 1960s for the treat-
RESPIRATORY EMERGENCIES ment of PE. The American College of Chest Physicians recommends
■ PULMONARY EMBOLISM the use of thrombolytics for all patients with PE accompanied by hemo-
11
Pulmonary embolism (PE) leads to 300,000 deaths a year and is the dynamic instability. Early use of thrombolytics decreases pulmonary
artery pressures and leads to rapid recovery of ventricular function.
3,13,14
second most common cause of death in cancer patients. Increased In a meta-analysis comparing systemic anticoagulation with heparin
1-3
activation of the coagulation system, administration of thrombo- versus thrombolytics in hemodynamically unstable patients, patients
genic chemotherapy regimens, and placement of intravascular venous treated with thrombolytics had lower recurrence of thromboembolic
catheters place oncological patients at higher risk for thromboembolic events and decreased mortality. Thus, in the presence of hemodynamic
15
disease. Early recognition and treatment of PE is essential due to its compromise, thrombolytics are the first-line treatment if there is no con-
3
high mortality when left untreated. traindication to their use. 10,11,13 On the contrary, the role of thrombolytics
Patients with PE should be admitted to the ICU when there is signifi- in patients with submassive PE (hemodynamically stable patients with
cant respiratory compromise, presence of hemodynamic instability, right- early signs of RV dysfunction and elevated pulmonary artery pressures) is
sided heart failure, or high risk of cardiovascular collapse. Right-sided not clear. One study showed that patients with submassive PE who were
heart failure in the setting of massive PE is associated with a mortal- treated with thrombolytics and anticoagulation had a less complicated
ity rate ranging from 25% to 58%. The acute elevation in pulmonary hospital course and no higher risk of bleeding, when compared to those
1,4
artery pressures after massive PE causes severe strain to the right ven- treated with heparin and placebo. However, there was no difference in
16
tricle (RV), myocardial dysfunction, and ventricular failure. Moreover, overall mortality between the two groups. Because of these findings,
5
16
increased right-sided pressures cause the septum to shift into the left consensus guidelines have a grade 2B recommendation for thrombolytic
ventricle (LV), decreasing end-diastolic volume, worsening cardiac use in submassive PE. A prospective, multicenter, randomized double-
11
output, and resulting in cardiogenic shock. 1,5 blind RCT, called the Pulmonary Embolism THrOmbolysis (PEITHO)
In the ICU setting, early diagnosis and treatment of PE are essential. trial noted reduced hemodynamic decompensation, albeit at a price of
Computed tomography angiography is the most commonly used test for increased major hemorrhage and stroke. When considering thrombolysis,
diagnosis and can also be used for risk stratification of PE. Studies sug- and even anticoagulation, it is important to discuss with the patient and
gest that an RV/LV ratio greater than 1 is suggestive of RV dysfunction their surrogate decision makers the risks of these treatments. Although
and can be associated with increased mortality. Echocardiography bleeding complications are rare, they may carry substantial morbidity and
6
should also be a part of routine evaluation of ICU patients who even mortality in some patients.
are admitted with PE. Patients with echocardiographic signs of RV The use of catheter-directed thrombectomy (with or without local
strain (Fig. 93-1) have in-hospital mortality rate of 10% to 53% even thrombolytics) has increased significantly in specialized centers, despite the
without clinical signs of right-sided heart failure. 4,7,8 The elevation of absence of well-designed trials demonstrating improvements in outcomes.
cardiac markers such as troponins, B-type natriuretic peptide (BNP),
and pro-BNP has also been associated with increased mortality in
patients with PE. 9,10
Pulmonary
embolism

Hemodynamically Hemodynamically
unstable stable

Contraindications for Yes Echocardiogram (+)
thrombolytics Troponin and BNP elevation
CT RV/LV >1
No Yes No

Embolectomy
Thrombolytics Anticoagulation
(surgical vs catheter)
a A positive echocardiogram refers to any signs of right ventricular (RV)
enlargement, septal bowing, or RV dysfunction.
FIGURE 93-1. Echocardiogram showing RV enlargement and septal bowing in a case of
severe pulmonary embolism. FIGURE 93-2. Risk stratification and treatment of pulmonary embolism.

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