**17. Massive pulmonary embolism**

The management of massive PE requires a multifaceted approach to resolve pulmonary vascular obstruction, reverse hemodynamic instability, and support respiratory insufficiency (Tapson 2008). Supportive measures often require volume resuscitation, vasopressors, supplemental oxygen, and occasionally mechanical ventilation (Tapson 2012). Current American College of Chest Physicians (ACCP) (Kearon 2012) and American Heart Association (AHA) (Jaff 2011) guidelines support the use of thrombolytic therapy in patients with acute massive PE and no contraindications. A 2004 meta-analysis revealed that thrombolysis significantly reduced recurrent PE and mortality (9.4% versus 19.0%; OR 0.45, 95% CI 0.22 to 0.92; number needed to treat=10) in patients with hemodynamically unstable PE (Wan 2004). There are limited clinical trial data to provide guidance on the best management of massive PE. A small prospective randomized clinical trial evaluating 8 patients with massive PE showed that streptokinase plus heparin improved hemodynamics within the first hour after treatment and survival at 2 years compared with heparin alone (Jerjes-Sanchez 1995). The heparin treated group had 100% mortality 1-3 hours after initial presentation. Autopsy studies in the heparin treated group revealed massive pulmonary emboli with RV infarction and no coronary artery obstruction (Jerjes-Sanchez 1995). Additional studies are required to determine the optimal management of patients with massive PE.
